1
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Tsujii Y, Atwell BJ, Lambers H, Wright IJ. Leaf phosphorus fractions vary with leaf economic traits among 35 Australian woody species. New Phytol 2024; 241:1985-1997. [PMID: 38189091 DOI: 10.1111/nph.19513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Accepted: 12/06/2023] [Indexed: 01/09/2024]
Abstract
Adaptations of plants to phosphorus (P) deficiency include reduced investment of leaf P in storage (orthophosphates in vacuoles), nucleic acids and membrane lipids. Yet, it is unclear how these adaptations are associated with plant ecological strategies. Five leaf P fractions (orthophosphate P, Pi ; metabolite P, PM ; nucleic acid P, PN ; lipid P, PL ; and residual P, PR ) were analysed alongside leaf economic traits among 35 Australian woody species from three habitats: one a high-P basalt-derived soil and two low-P sandstone-derived soils, one undisturbed and one disturbed by human activities with artificial P inputs. Species at the undisturbed low-P site generally exhibited lower concentrations of total leaf P ([Ptotal ]), primarily associated with lower concentrations of Pi , and PN . The relative allocation of P to each fraction varied little among sites, except that higher PL per [Ptotal ] (rPL ) was recorded at the undisturbed low-P site than at the high-P site. This higher rPL , reflecting relative allocation to membranes, was primarily associated with lower concentrations of leaf nitrogen at the undisturbed low-P site than at the high-P site. Associations between leaf P fractions and leaf nitrogen may provide a basis for understanding the variation in plant ecological strategies dependent on soil P availability.
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Affiliation(s)
- Yuki Tsujii
- Forestry and Forest Products Research Institute, Tsukuba, 305-8687, Japan
- Faculty of Science, Kyushu University, Fukuoka, 819-0395, Japan
- School of Natural Sciences, Macquarie University, Penrith, NSW, 2109, Australia
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW, 2751, Australia
| | - Brian J Atwell
- School of Natural Sciences, Macquarie University, Penrith, NSW, 2109, Australia
| | - Hans Lambers
- School of Biological Sciences, The University of Western Australia, Perth, WA, 6009, Australia
| | - Ian J Wright
- School of Natural Sciences, Macquarie University, Penrith, NSW, 2109, Australia
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW, 2751, Australia
- ARC Centre for Plant Success in Nature & Agriculture, Western Sydney University, Richmond, NSW, 2753, Australia
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2
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Masoomi-Aladizgeh F, Jabbari L, Khayam Nekouei R, Aalami A, Atwell BJ, Haynes PA. A universal protocol for high-quality DNA and RNA isolation from diverse plant species. PLoS One 2023; 18:e0295852. [PMID: 38096235 PMCID: PMC10721051 DOI: 10.1371/journal.pone.0295852] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Accepted: 11/30/2023] [Indexed: 12/17/2023] Open
Abstract
Next-generation sequencing demands high-quality nucleic acid, yet isolating DNA and RNA is often challenging, particularly from plant tissues. Despite advances in developing various kits and reagents, these products are tailored to isolation of nucleic acid from model plant tissues. Here we introduce a universal lysis buffer to separate nucleic acid from various plant species, including recalcitrant plants, to facilitate molecular analyses, such as quantitative PCR (qPCR), transcriptomics, and whole-genome sequencing (WGS). The protocol is a modification of the original CTAB methods, which leads to nucleic acid isolation from many plant species, including monocots and eudicots. The lysis buffer consists of hexadecyltrimethylammonium bromide (CTAB), sodium chloride (NaCl), Tris base, ethylenediaminetetraacetic acid (EDTA) and β-mercaptoethanol (βME). The modified CTAB method enables the isolation of nucleic acid from small amounts of plant tissues (e.g., 15-100 mg) in a timely manner, which is well-suited for a large number of samples and also when adequate sample collection is a limiting factor. The protocol isolates not only DNA from various plant species but also RNA. This makes it highly effective for molecular analyses compared to previously described CTAB methods optimised for DNA isolation. The appropriate concentration of the components enables high-quality DNA and RNA isolation from plant tissues simultaneously. Additionally, this protocol is compatible with commercially available columns. For DNA and RNA to be qualified for next-generation sequencing platforms, the protocol is supplemented with columns to purify either DNA or RNA from the same tissue to meet high standards for sequencing analyses. This protocol provides an ideal approach to overcome potential obstacles in isolating high-quality DNA or RNA from a wide range of plant species for downstream molecular analysis.
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Affiliation(s)
| | - Leila Jabbari
- Department of Tissue Culture and Gene Transformation, Agricultural Biotechnology Research Institute of Iran (ABRII), AREEO, Karaj, Iran
| | - Reza Khayam Nekouei
- Department of Agronomy and Plant Breeding, Faculty of Agricultural Sciences, University of Guilan, Rasht, Iran
| | - Ali Aalami
- Department of Agronomy and Plant Breeding, Faculty of Agricultural Sciences, University of Guilan, Rasht, Iran
| | - Brian J. Atwell
- School of Natural Sciences, Macquarie University, Sydney, NSW, Australia
| | - Paul A. Haynes
- School of Natural Sciences, Macquarie University, Sydney, NSW, Australia
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3
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Habibpourmehraban F, Wu Y, Masoomi-Aladizgeh F, Amirkhani A, Atwell BJ, Haynes PA. Pre-Treatment of Rice Plants with ABA Makes Them More Tolerant to Multiple Abiotic Stress. Int J Mol Sci 2023; 24:ijms24119628. [PMID: 37298579 DOI: 10.3390/ijms24119628] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 05/26/2023] [Accepted: 05/29/2023] [Indexed: 06/12/2023] Open
Abstract
Multiple abiotic stress is known as a type of environmental unfavourable condition maximizing the yield and growth gap of crops compared with the optimal condition in both natural and cultivated environments. Rice is the world's most important staple food, and its production is limited the most by environmental unfavourable conditions. In this study, we investigated the pre-treatment of abscisic acid (ABA) on the tolerance of the IAC1131 rice genotype to multiple abiotic stress after a 4-day exposure to combined drought, salt and extreme temperature treatments. A total of 3285 proteins were identified and quantified across the four treatment groups, consisting of control and stressed plants with and without pre-treatment with ABA, with 1633 of those proteins found to be differentially abundant between groups. Compared with the control condition, pre-treatment with the ABA hormone significantly mitigated the leaf damage against combined abiotic stress at the proteome level. Furthermore, the application of exogenous ABA did not affect the proteome profile of the control plants remarkably, while the results were different in stress-exposed plants by a greater number of proteins changed in abundance, especially those which were increased. Taken together, these results suggest that exogenous ABA has a potential priming effect for enhancing the rice seedlings' tolerance against combined abiotic stress, mainly by affecting stress-responsive mechanisms dependent on ABA signalling pathways in plants.
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Affiliation(s)
- Fatemeh Habibpourmehraban
- School of Natural Sciences, Macquarie University, North Ryde, NSW 2109, Australia
- Biomolecular Discovery Research Centre, Macquarie University, North Ryde, NSW 2109, Australia
| | - Yunqi Wu
- School of Natural Sciences, Macquarie University, North Ryde, NSW 2109, Australia
- Australian Proteome Analysis Facility (APAF), Macquarie University, North Ryde, NSW 2109, Australia
| | - Farhad Masoomi-Aladizgeh
- School of Natural Sciences, Macquarie University, North Ryde, NSW 2109, Australia
- Biomolecular Discovery Research Centre, Macquarie University, North Ryde, NSW 2109, Australia
| | - Ardeshir Amirkhani
- School of Natural Sciences, Macquarie University, North Ryde, NSW 2109, Australia
- Australian Proteome Analysis Facility (APAF), Macquarie University, North Ryde, NSW 2109, Australia
| | - Brian J Atwell
- School of Natural Sciences, Macquarie University, North Ryde, NSW 2109, Australia
- Biomolecular Discovery Research Centre, Macquarie University, North Ryde, NSW 2109, Australia
| | - Paul A Haynes
- School of Natural Sciences, Macquarie University, North Ryde, NSW 2109, Australia
- Biomolecular Discovery Research Centre, Macquarie University, North Ryde, NSW 2109, Australia
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4
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Abdirad S, Wu Y, Ghorbanzadeh Z, Tazangi SE, Amirkhani A, Fitzhenry MJ, Kazemi M, Ghaffari MR, Koobaz P, Zeinalabedini M, Habibpourmehraban F, Masoomi-Aladizgeh F, Atwell BJ, Mirzaei M, Salekdeh GH, Haynes PA. Proteomic analysis of the meristematic root zone in contrasting genotypes reveals new insights in drought tolerance in rice. Proteomics 2022; 22:e2200100. [PMID: 35920597 DOI: 10.1002/pmic.202200100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 07/18/2022] [Accepted: 07/21/2022] [Indexed: 12/29/2022]
Abstract
Drought is responsible for major losses in rice production. Root tips contain meristematic and elongation zones that play major roles in determination of root traits and adaptive strategies to drought. In this study we analysed two contrasting genotypes of rice: IR64, a lowland, drought-susceptible, and shallow-rooting genotype; and Azucena, an upland, drought-tolerant, and deep-rooting genotype. Samples were collected of root tips of plants grown under control and water deficit stress conditions. Quantitative proteomics analysis resulted in the identification of 7294 proteins from the root tips of IR64 and 6307 proteins from Azucena. Data are available via ProteomeXchange with identifier PXD033343. Using a Partial Least Square Discriminant Analysis on 4170 differentially abundant proteins, 1138 statistically significant proteins across genotypes and conditions were detected. Twenty two enriched biological processes showing contrasting patterns between two genotypes in response to stress were detected through gene ontology enrichment analysis. This included identification of novel proteins involved in root elongation with specific expression patterns in Azucena, including four Expansins and seven Class III Peroxidases. We also detected an antioxidant network and a metallo-sulfur cluster assembly machinery in Azucena, with roles in reactive oxygen species and iron homeostasis, and positive effects on root cell cycle, growth and elongation.
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Affiliation(s)
- Somayeh Abdirad
- Department of Systems Biology, Agricultural Biotechnology Research Institute of Iran (ABRII), Agricultural Research Education and Extension Organization (AREEO), Karaj, Iran
| | - Yunqi Wu
- Australian Proteome Analysis Facility, Macquarie University, North Ryde, New South Wales, Australia
| | - Zahra Ghorbanzadeh
- Department of Systems Biology, Agricultural Biotechnology Research Institute of Iran (ABRII), Agricultural Research Education and Extension Organization (AREEO), Karaj, Iran
| | - Sara Esmaeili Tazangi
- Department of Systems Biology, Agricultural Biotechnology Research Institute of Iran (ABRII), Agricultural Research Education and Extension Organization (AREEO), Karaj, Iran
| | - Ardeshir Amirkhani
- Australian Proteome Analysis Facility, Macquarie University, North Ryde, New South Wales, Australia
| | - Matthew J Fitzhenry
- Australian Proteome Analysis Facility, Macquarie University, North Ryde, New South Wales, Australia
| | - Mehrbano Kazemi
- Department of Systems Biology, Agricultural Biotechnology Research Institute of Iran (ABRII), Agricultural Research Education and Extension Organization (AREEO), Karaj, Iran
| | - Mohammad Reza Ghaffari
- Department of Systems Biology, Agricultural Biotechnology Research Institute of Iran (ABRII), Agricultural Research Education and Extension Organization (AREEO), Karaj, Iran
| | - Parisa Koobaz
- Department of Molecular Physiology, Agricultural Biotechnology Research Institute of Iran (ABRII), Agricultural Research Education and Extension Organization (AREEO), Karaj, Iran
| | - Mehrshad Zeinalabedini
- Department of Systems Biology, Agricultural Biotechnology Research Institute of Iran (ABRII), Agricultural Research Education and Extension Organization (AREEO), Karaj, Iran
| | | | | | - Brian J Atwell
- School of Natural Sciences, Macquarie University, North Ryde, New South Wales, Australia
| | - Mehdi Mirzaei
- Australian Proteome Analysis Facility, Macquarie University, North Ryde, New South Wales, Australia.,School of Natural Sciences, Macquarie University, North Ryde, New South Wales, Australia
| | - Ghasem Hosseini Salekdeh
- Department of Systems Biology, Agricultural Biotechnology Research Institute of Iran (ABRII), Agricultural Research Education and Extension Organization (AREEO), Karaj, Iran.,School of Natural Sciences, Macquarie University, North Ryde, New South Wales, Australia
| | - Paul A Haynes
- School of Natural Sciences, Macquarie University, North Ryde, New South Wales, Australia
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5
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Phillips AL, Scafaro AP, Atwell BJ. Photosynthetic traits of Australian wild rice (Oryza australiensis) confer tolerance to extreme daytime temperatures. Plant Mol Biol 2022; 110:347-363. [PMID: 34997897 PMCID: PMC9646608 DOI: 10.1007/s11103-021-01210-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Accepted: 10/27/2021] [Indexed: 05/08/2023]
Abstract
A wild relative of rice from the Australian savannah was compared with cultivated rice, revealing thermotolerance in growth and photosynthetic processes and a more robust carbon economy in extreme heat. Above ~ 32 °C, impaired photosynthesis compromises the productivity of rice. We compared leaf tissues from heat-tolerant wild rice (Oryza australiensis) with temperate-adapted O. sativa after sustained exposure to heat, as well as diurnal heat shock. Leaf elongation and shoot biomass in O. australiensis were unimpaired at 45 °C, and soluble sugar concentrations trebled during 10 h of a 45 °C shock treatment. By contrast, 45 °C slowed growth strongly in O. sativa. Chloroplastic CO2 concentrations eliminated CO2 supply to chloroplasts as the basis of differential heat tolerance. This directed our attention to carboxylation and the abundance of the heat-sensitive chaperone Rubisco activase (Rca) in each species. Surprisingly, O. australiensis leaves at 45 °C had 50% less Rca per unit Rubisco, even though CO2 assimilation was faster than at 30 °C. By contrast, Rca per unit Rubisco doubled in O. sativa at 45 °C while CO2 assimilation was slower, reflecting its inferior Rca thermostability. Plants grown at 45 °C were simultaneously exposed to 700 ppm CO2 to enhance the CO2 supply to Rubisco. Growth at 45 °C responded to CO2 enrichment in O. australiensis but not O. sativa, reflecting more robust carboxylation capacity and thermal tolerance in the wild rice relative.
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Affiliation(s)
- Aaron L Phillips
- Waite Research Institute and School of Agriculture, Food, and Wine, University of Adelaide, Adelaide, SA, Australia
- Department of Biological Sciences, Macquarie University, Sydney, NSW, Australia
- ARC Centre of Excellence in Plant Energy Biology, School of Agriculture, Food, and Wine, The University of Adelaide, Adelaide, SA, Australia
| | - Andrew P Scafaro
- ARC Centre of Excellence in Plant Energy Biology, Research School of Biology, The Australian National University, Canberra, ACT, Australia
| | - Brian J Atwell
- Department of Biological Sciences, Macquarie University, Sydney, NSW, Australia.
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6
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Masoomi‐Aladizgeh F, Kamath KS, Haynes PA, Atwell BJ. Genome survey sequencing of wild cotton (Gossypium robinsonii) reveals insights into proteomic responses of pollen to extreme heat. Plant Cell Environ 2022; 45:1242-1256. [PMID: 35092006 PMCID: PMC9415111 DOI: 10.1111/pce.14268] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 01/04/2022] [Indexed: 06/14/2023]
Abstract
Heat stress specifically affects fertility by impairing pollen viability but cotton wild relatives successfully reproduce in hot savannas where they evolved. An Australian arid-zone cotton (Gossypium robinsonii) was exposed to heat events during pollen development then mature pollen was subjected to deep proteomic analysis using 57 023 predicted genes from a genomic database we assembled for the same species. Three stages of pollen development, including tetrads (TEs), uninucleate microspores (UNs) and binucleate microspores (BNs) were exposed to 36°C or 40°C for 5 days and the resulting mature pollen was collected at anthesis (p-TE, p-UN and p-BN, respectively). Using the sequential windowed acquisition of all theoretical mass spectra proteomic analysis, 2704 proteins were identified and quantified across all pollen samples analysed. Proteins predominantly decreased in abundance at all stages in response to heat, particularly after exposure of TEs to 40°C. Functional enrichment analyses demonstrated that extreme heat increased the abundance of proteins that contributed to increased messenger RNA splicing via spliceosome, initiation of cytoplasmic translation and protein refolding in p-TE40. However, other functional categories that contributed to intercellular transport were inhibited in p-TE40, linked potentially to Rab proteins. We ascribe the resilience of reproductive processes in G. robinsonii at temperatures up to 40°C, relative to commercial cotton, to a targeted reduction in protein transport.
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Affiliation(s)
| | | | - Paul A. Haynes
- School of Natural SciencesMacquarie UniversityNorth RydeNew South WalesAustralia
| | - Brian J. Atwell
- School of Natural SciencesMacquarie UniversityNorth RydeNew South WalesAustralia
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7
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Masoomi-Aladizgeh F, McKay MJ, Asar Y, Haynes PA, Atwell BJ. Patterns of gene expression in pollen of cotton (Gossypium hirsutum) indicate downregulation as a feature of thermotolerance. Plant J 2022; 109:965-979. [PMID: 34837283 DOI: 10.1111/tpj.15608] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Revised: 11/22/2021] [Accepted: 11/23/2021] [Indexed: 06/13/2023]
Abstract
Reproductive performance in plants is impaired as maximum temperatures consistently approach 40°C. However, the timing of heatwaves critically affects their impact. We studied the molecular responses during pollen maturation in cotton to investigate the vulnerability to high temperature. Tetrads (TEs), uninucleate and binucleate microspores, and mature pollen were subjected to SWATH-MS and RNA-seq analyses after exposure to 38/28°C (day/night) for 5 days. The results indicated that molecular signatures were downregulated progressively in response to heat during pollen development. This was even more evident in leaves, where three-quarters of differentially changed proteins decreased in abundance during heat. Functional analysis showed that translation of genes increased in TEs after exposure to heat; however, the reverse pattern was observed in mature pollen and leaves. For example, proteins involved in transport were highly abundant in TEs whereas in later stages of pollen formation and leaves, heat suppressed synthesis of proteins involved in cell-to-cell communication. Moreover, a large number of heat shock proteins were identified in heat-affected TEs, but these proteins were less abundant in mature pollen and leaves. We speculate that the sensitivity of TE cells to heat is related to high rates of translation targeted to pathways that might not be essential for thermotolerance. Molecular signatures during stages of pollen development after heatwaves could provide markers for future genetic improvement.
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Affiliation(s)
| | - Matthew J McKay
- Australian Proteome Analysis Facility, Department of Molecular Sciences, Macquarie University, NSW, Australia
| | - Yasmin Asar
- School of Life and Environmental Sciences, University of Sydney, NSW, Australia
| | - Paul A Haynes
- Department of Molecular Sciences, Macquarie University, NSW, Australia
| | - Brian J Atwell
- Department of Biological Sciences, Macquarie University, NSW, Australia
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8
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Lei Z, Liu F, Wright IJ, Carriquí M, Niinemets Ü, Han J, Jia M, Atwell BJ, Cai X, Zhang W, Zhou Z, Zhang Y. Comparisons of photosynthetic and anatomical traits between wild and domesticated cotton. J Exp Bot 2022; 73:873-885. [PMID: 34153103 DOI: 10.1093/jxb/erab293] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Accepted: 06/19/2021] [Indexed: 06/13/2023]
Abstract
Mesophyll conductance (gm) is a crucial leaf trait contributing to the photosynthetic rate (AN). Plant domestication typically leads to an enhancement of AN that is often associated with profound anatomical modifications, but it is unclear which of these structural alterations influence gm. We analyzed the implication of domestication on leaf anatomy and its effect on gm in 26 wild and 31 domesticated cotton genotypes (Gossypium sp.) grown under field conditions. We found that domesticated genotypes had higher AN but similar gm to wild genotypes. Consistent with this, domestication did not translate into significant differences in the fraction of mesophyll occupied by intercellular air spaces (fias) or mesophyll and chloroplast surface area exposed to intercellular air space (Sm/S and Sc/S, respectively). However, leaves of domesticated genotypes were significantly thicker, with larger but fewer mesophyll cells with thinner cell walls. Moreover, domesticated genotypes had higher cell wall conductance (gcw) but smaller cytoplasmic conductance (gcyt) than wild genotypes. It appears that domestication in cotton has not generally led to significant improvement in gm, in part because their thinner mesophyll cell walls (increasing gcw) compensate for their lower gcyt, itself due to larger distance between plasmalemma and chloroplast envelopes.
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Affiliation(s)
- Zhangying Lei
- The Key Laboratory of Oasis Eco-agriculture, Xinjiang Production and Construction Group, Shihezi University, Shihezi, 832003, PR China
- Department of Biological Sciences, Macquarie University, North Ryde, NSW 2109, Australia
| | - Fang Liu
- State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, 455000, PR China
| | - Ian J Wright
- Department of Biological Sciences, Macquarie University, North Ryde, NSW 2109, Australia
| | - Marc Carriquí
- School of Natural Sciences, University of Tasmania, Bag 55, 7001 Hobart, Tasmania, Australia
| | - Ülo Niinemets
- Chair of Crop Science and Plant Biology, Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi 1, 51006 Tartu, Estonia
| | - Jimei Han
- School of Integrative Plant Science, Soil and Crop Science Section, Cornell University, Ithaca, NY 14850, USA
| | - Mengmeng Jia
- The Key Laboratory of Oasis Eco-agriculture, Xinjiang Production and Construction Group, Shihezi University, Shihezi, 832003, PR China
| | - Brian J Atwell
- Department of Biological Sciences, Macquarie University, North Ryde, NSW 2109, Australia
| | - Xiaoyan Cai
- State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, 455000, PR China
| | - Wangfeng Zhang
- The Key Laboratory of Oasis Eco-agriculture, Xinjiang Production and Construction Group, Shihezi University, Shihezi, 832003, PR China
| | - Zhongli Zhou
- State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, 455000, PR China
| | - Yali Zhang
- The Key Laboratory of Oasis Eco-agriculture, Xinjiang Production and Construction Group, Shihezi University, Shihezi, 832003, PR China
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9
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Rahman S, Copeland L, Atwell BJ, Roberts TH. Impact of elevated atmospheric CO2 on aleurone cells and starch granule morphology in domesticated and wild rices. J Cereal Sci 2022. [DOI: 10.1016/j.jcs.2021.103389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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10
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Hamzelou S, Melino VJ, Plett DC, Kamath KS, Nawrocki A, Larsen MR, Atwell BJ, Haynes PA. The phosphoproteome of rice leaves responds to water and nitrogen supply. Mol Omics 2021; 17:706-718. [PMID: 34291261 DOI: 10.1039/d1mo00137j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The scarcity of freshwater is an increasing concern in flood-irrigated rice, whilst excessive use of nitrogen fertilizers is costly and contributes to environmental pollution. To co-ordinate growth adaptation under prolonged exposure to limited water or excess nitrogen supply, plants employ complex systems for signalling and regulation of metabolic processes. There is limited information on the involvement of one of the most important post-translational modifications (PTMs), protein phosphorylation, in plant adaptation to long-term changes in resource supply. Oryza sativa cv. Nipponbare was grown under two regimes of nitrogen from the time of germination to final harvest. Twenty-five days after germination, water was withheld from half the pots in each nitrogen treatment and low water supply continued for an additional 26 days, while the remaining pots were well watered. Leaves from all four groups of plants were harvested after 51 days in order to test whether phosphorylation of leaf proteins responded to prior abiotic stress events. The dominant impact of these resources is exerted in leaves, where PTMs have been predicted to occur. Proteins were extracted and phosphopeptides were analysed by nanoLC-MS/MS analysis, coupled with label-free quantitation. Water and nitrogen regimes triggered extensive changes in phosphorylation of proteins involved in membrane transport, such as the aquaporin OsPIP2-6, a water channel protein. Our study reveals phosphorylation of several peptides belonging to proteins involved in RNA-processing and carbohydrate metabolism, suggesting that phosphorylation events regulate the signalling cascades that are required to optimize plant response to resource supply.
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Affiliation(s)
- Sara Hamzelou
- Department of Molecular Sciences, Macquarie University, North Ryde, NSW 2109, Australia.
| | - Vanessa J Melino
- King Abdullah University for Science and Technology, 2955-6990, Kingdom of Saudi Arabia
| | - Darren C Plett
- The Plant Accelerator, Australian Plant Phenomics Facility, The University of Adelaide, PMB 1, Glen Osmond, SA 5064, Australia
| | - Karthik Shantharam Kamath
- Department of Molecular Sciences, Macquarie University, North Ryde, NSW 2109, Australia. and Australian Proteome Analysis Facility, Macquarie University, North Ryde, NSW 2109, Australia
| | - Arkadiusz Nawrocki
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, DK 5230 Odense M, Denmark
| | - Martin R Larsen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, DK 5230 Odense M, Denmark
| | - Brian J Atwell
- Department of Biological Sciences, Macquarie University, North Ryde, NSW 2109, Australia
| | - Paul A Haynes
- Department of Molecular Sciences, Macquarie University, North Ryde, NSW 2109, Australia.
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11
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Rahman S, Copeland L, Atwell BJ, Roberts TH. Elevated CO2 differentially affects the properties of grain from wild and domesticated rice. J Cereal Sci 2021. [DOI: 10.1016/j.jcs.2021.103227] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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12
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Masoomi-Aladizgeh F, Najeeb U, Hamzelou S, Pascovici D, Amirkhani A, Tan DKY, Mirzaei M, Haynes PA, Atwell BJ. Pollen development in cotton (Gossypium hirsutum) is highly sensitive to heat exposure during the tetrad stage. Plant Cell Environ 2021; 44:2150-2166. [PMID: 33047317 DOI: 10.1111/pce.13908] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 09/29/2020] [Accepted: 09/30/2020] [Indexed: 05/22/2023]
Abstract
The development of gametes in plants is acutely susceptible to heatwaves as brief as a few days, adversely affecting pollen maturation and reproductive success. Pollen in cotton (Gossypium hirsutum) was differentially affected when tetrad and binucleate stages were exposed to heat, revealing new insights into the interaction between heat and pollen development. Squares were tagged and exposed to 36/25°C (day/night, moderate heat) or 40/30°C (day/night, extreme heat) for 5 days. Mature pollen grains and leaves were collected for physiological and proteomic responses. While photosynthetic competence was not compromised even at 40°C, leaf tissues became leakier. In contrast, pollen grains were markedly smaller after the tetrad stage was exposed to 40°C and boll production was reduced by 65%. Sugar levels in pollen grains were elevated after exposure to heat, eliminating carbohydrate deficits as a likely cause of poor reproductive capacity. Proteomic analysis of pure pollen samples revealed a particularly high abundance of 70-kDa heat shock (Hsp70s) and cytoskeletal proteins. While short-term bursts of heat had a minor impact on leaves, male gametophyte development was profoundly damaged. Cotton acclimates to maxima of 36°C at both the vegetative and reproductive stages but 5-days exposure to 40°C significantly impairs reproductive development.
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Affiliation(s)
| | - Ullah Najeeb
- Queensland Alliance for Agriculture & Food Innovation, The University of Queensland, Toowoomba, Australia
| | - Sara Hamzelou
- Department of Molecular Sciences, Macquarie University, North Ryde, New South Wales, Australia
| | - Dana Pascovici
- Australian Proteome Analysis Facility, Macquarie University, North Ryde, New South Wales, Australia
| | - Ardeshir Amirkhani
- Australian Proteome Analysis Facility, Macquarie University, North Ryde, New South Wales, Australia
| | - Daniel K Y Tan
- Faculty of Science, School of Life and Environmental Sciences, The University of Sydney, Plant Breeding Institute, Sydney Institute of Agriculture, Sydney, New South Wales, Australia
| | - Mehdi Mirzaei
- Australian Proteome Analysis Facility, Macquarie University, North Ryde, New South Wales, Australia
| | - Paul A Haynes
- Department of Molecular Sciences, Macquarie University, North Ryde, New South Wales, Australia
| | - Brian J Atwell
- Department of Biological Sciences, Macquarie University, North Ryde, New South Wales, Australia
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13
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Jiang M, Kelly JWG, Atwell BJ, Tissue DT, Medlyn BE. Drought by CO 2 interactions in trees: a test of the water savings mechanism. New Phytol 2021; 230:1421-1434. [PMID: 33496969 DOI: 10.1111/nph.17233] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Accepted: 01/21/2021] [Indexed: 06/12/2023]
Abstract
Elevated atmospheric CO2 (eCa ) may benefit plants during drought by reducing stomatal conductance (gs ) but any 'water savings effect' could be neutralized by concurrent stimulation of leaf area. We investigated whether eCa enhanced water savings, thereby ameliorating the impact of drought on carbon and water relations in trees. We report leaf-level gas exchange and whole-plant and soil water relations during a short-term dry-down in two Eucalyptus species with contrasting drought tolerance. Plants had previously been established for 9 to 11 months in steady-state conditions of ambient atmospheric CO2 (aCa ) and eCa , with half of each treatment group exposed to sustained drought for 5 to 7 months. The lower stomatal conductance under eCa did not lead to soil moisture savings during the dry-down due to the counteractive effect of increased whole-plant leaf area. Nonetheless, eCa -grown plants maintained higher photosynthetic rates and leaf water potentials, making them less stressed during the dry-down, despite being larger. These effects were more pronounced in the xeric species than the mesic species, and in previously water-stressed plants. Our findings indicate that eCa may enhance plant performance during drought despite a lack of soil water savings, especially in species with more conservative growth and water-use strategies.
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Affiliation(s)
- Mingkai Jiang
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW, 2751, Australia
| | - Jeff W G Kelly
- Department of Biological Sciences, Macquarie University, North Ryde, NSW, 2109, Australia
| | - Brian J Atwell
- Department of Biological Sciences, Macquarie University, North Ryde, NSW, 2109, Australia
| | - David T Tissue
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW, 2751, Australia
| | - Belinda E Medlyn
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW, 2751, Australia
- Department of Biological Sciences, Macquarie University, North Ryde, NSW, 2109, Australia
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14
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Rahman S, Khoddami A, Copeland L, Atwell BJ, Roberts TH. Optimal Silver Nitrate Concentration to Inhibit α‐Amylase Activity During Pasting of Rice Flour. STARCH-STARKE 2020. [DOI: 10.1002/star.202000150] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Sayedur Rahman
- Plant Breeding Institute Sydney Institute of Agriculture School of Life and Environmental Sciences University of Sydney Sydney NSW 2006 Australia
| | - Ali Khoddami
- Plant Breeding Institute Sydney Institute of Agriculture School of Life and Environmental Sciences University of Sydney Sydney NSW 2006 Australia
| | - Les Copeland
- Plant Breeding Institute Sydney Institute of Agriculture School of Life and Environmental Sciences University of Sydney Sydney NSW 2006 Australia
| | - Brian J. Atwell
- Department of Biological Sciences Faculty of Science and Engineering Macquarie University North Ryde NSW 2109 Australia
| | - Thomas H. Roberts
- Plant Breeding Institute Sydney Institute of Agriculture School of Life and Environmental Sciences University of Sydney Sydney NSW 2006 Australia
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15
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Hamzelou S, Kamath KS, Masoomi-Aladizgeh F, Johnsen MM, Atwell BJ, Haynes PA. Wild and Cultivated Species of Rice Have Distinctive Proteomic Responses to Drought. Int J Mol Sci 2020; 21:ijms21175980. [PMID: 32825202 PMCID: PMC7504292 DOI: 10.3390/ijms21175980] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 08/13/2020] [Accepted: 08/13/2020] [Indexed: 12/25/2022] Open
Abstract
Drought often compromises yield in non-irrigated crops such as rainfed rice, imperiling the communities that depend upon it as a primary food source. In this study, two cultivated species (Oryza sativa cv. Nipponbare and Oryza glaberrima cv. CG14) and an endemic, perennial Australian wild species (Oryza australiensis) were grown in soil at 40% field capacity for 7 d (drought). The hypothesis was that the natural tolerance of O. australiensis to erratic water supply would be reflected in a unique proteomic profile. Leaves from droughted plants and well-watered controls were harvested for label-free quantitative shotgun proteomics. Physiological and gene ontology analysis confirmed that O. australiensis responded uniquely to drought, with superior leaf water status and enhanced levels of photosynthetic proteins. Distinctive patterns of protein accumulation in drought were observed across the O. australiensis proteome. Photosynthetic and stress-response proteins were more abundant in drought-affected O. glaberrima than O. sativa, and were further enriched in O. australiensis. In contrast, the level of accumulation of photosynthetic proteins decreased when O. sativa underwent drought, while a narrower range of stress-responsive proteins showed increased levels of accumulation. Distinctive proteomic profiles and the accumulated levels of individual proteins with specific functions in response to drought in O. australiensis indicate the importance of this species as a source of stress tolerance genes.
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Affiliation(s)
- Sara Hamzelou
- Department of Molecular Sciences, Macquarie University, North Ryde, NSW 2109, Australia; (S.H.); (K.S.K.); (M.M.J.)
| | - Karthik Shantharam Kamath
- Department of Molecular Sciences, Macquarie University, North Ryde, NSW 2109, Australia; (S.H.); (K.S.K.); (M.M.J.)
- Australian Proteome Analysis Facility, Macquarie University, North Ryde, NSW 2109, Australia
| | - Farhad Masoomi-Aladizgeh
- Department of Biological Sciences, Macquarie University, North Ryde, NSW 2109, Australia; (F.M.-A.); (B.J.A.)
| | - Matthew M. Johnsen
- Department of Molecular Sciences, Macquarie University, North Ryde, NSW 2109, Australia; (S.H.); (K.S.K.); (M.M.J.)
| | - Brian J. Atwell
- Department of Biological Sciences, Macquarie University, North Ryde, NSW 2109, Australia; (F.M.-A.); (B.J.A.)
| | - Paul A. Haynes
- Department of Molecular Sciences, Macquarie University, North Ryde, NSW 2109, Australia; (S.H.); (K.S.K.); (M.M.J.)
- Correspondence:
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16
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Yichie Y, Hasan MT, Tobias PA, Pascovici D, Goold HD, Van Sluyter SC, Roberts TH, Atwell BJ. Salt-Treated Roots of Oryza australiensis Seedlings are Enriched with Proteins Involved in Energetics and Transport. Proteomics 2019; 19:e1900175. [PMID: 31475433 DOI: 10.1002/pmic.201900175] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Revised: 08/05/2019] [Indexed: 11/08/2022]
Abstract
Salinity is a major constraint on rice productivity worldwide. However, mechanisms of salt tolerance in wild rice relatives are unknown. Root microsomal proteins are extracted from two Oryza australiensis accessions contrasting in salt tolerance. Whole roots of 2-week-old seedlings are treated with 80 mM NaCl for 30 days to induce salt stress. Proteins are quantified by tandem mass tags (TMT) and triple-stage Mass Spectrometry. More than 200 differentially expressed proteins between the salt-treated and control samples in the two accessions (p-value <0.05) are found. Gene Ontology (GO) analysis shows that proteins categorized as "metabolic process," "transport," and "transmembrane transporter" are highly responsive to salt treatment. In particular, mitochondrial ATPases and SNARE proteins are more abundant in roots of the salt-tolerant accession and responded strongly when roots are exposed to salinity. mRNA quantification validated the elevated protein abundances of a monosaccharide transporter and an antiporter observed in the salt-tolerant genotype. The importance of the upregulated monosaccharide transporter and a VAMP-like protein by measuring salinity responses of two yeast knockout mutants for genes homologous to those encoding these proteins in rice are confirmed. Potential new mechanisms of salt tolerance in rice, with implications for breeding of elite cultivars are also discussed.
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Affiliation(s)
- Yoav Yichie
- Sydney Institute of Agriculture, University of Sydney, Sydney, Australia
| | - Mafruha T Hasan
- Sydney Institute of Agriculture, University of Sydney, Sydney, Australia
| | - Peri A Tobias
- Sydney Institute of Agriculture, University of Sydney, Sydney, Australia
| | - Dana Pascovici
- Australian Proteome Analysis Facility, Department of Molecular Sciences, Macquarie University, Sydney, Australia
| | - Hugh D Goold
- NSW Department of Primary Industries, Macquarie University, Sydney, Australia.,Department of Molecular Sciences, Macquarie University, Sydney, Australia
| | | | - Thomas H Roberts
- Sydney Institute of Agriculture, University of Sydney, Sydney, Australia
| | - Brian J Atwell
- Department of Biological Sciences, Macquarie University, Sydney, Australia
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17
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Wu Y, Mirzaei M, Pascovici D, Haynes PA, Atwell BJ. Front Cover: Proteomes of Leaf‐Growing Zones in Rice Genotypes with Contrasting Drought Tolerance. Proteomics 2019. [DOI: 10.1002/pmic.201970071] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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18
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Wu Y, Mirzaei M, Pascovici D, Haynes PA, Atwell BJ. Proteomes of Leaf-Growing Zones in Rice Genotypes with Contrasting Drought Tolerance. Proteomics 2019; 19:e1800310. [PMID: 30891909 DOI: 10.1002/pmic.201800310] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2018] [Revised: 02/25/2019] [Indexed: 11/10/2022]
Abstract
Plants require a distinctive cohort of enzymes to coordinate cell division and expansion. Proteomic analysis now enables interrogation of immature leaf bases where these processes occur. Hence, proteins in tissues sampled from leaves of a drought-tolerant rice (IAC1131) are investigated to provide insights into the effect of soil drying on gene expression relative to the drought-sensitive genotype Nipponbare. Shoot growth zones are dissected to estimate the proportion of dividing cells and extract protein for subsequent tandem mass tags quantitative proteomic analysis. Gene ontology annotations of differentially expressed proteins provide insights into responses of Nipponbare and IAC1131 to drought. Soil drying does not affect the percentage of mitotic cells in IAC1131. More than 800 proteins across most functional categories increase in drought (and decrease on rewatering) in IAC1131, including proteins involved in "organizing the meristem" and "new cell formation". On the other hand, the percentage of dividing cells in Nipponbare is severely impaired during drought and fewer than 200 proteins respond in abundance when growing zones undergo a drying cycle. Remarkably, the proteomes of the growing zones of each genotype respond in a highly distinctive manner, reflecting their contrasting drought tolerance even at the earliest stages of leaf development.
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Affiliation(s)
- Yunqi Wu
- Department of Molecular Sciences, Macquarie University, North Ryde, NSW, 2109, Australia
| | - Mehdi Mirzaei
- Australian Proteome Analysis Facility, Macquarie University, North Ryde, NSW, 2109, Australia
| | - Dana Pascovici
- Australian Proteome Analysis Facility, Macquarie University, North Ryde, NSW, 2109, Australia
| | - Paul A Haynes
- Department of Molecular Sciences, Macquarie University, North Ryde, NSW, 2109, Australia
| | - Brian J Atwell
- Department of Biological Sciences, Macquarie University, North Ryde, NSW, 2109, Australia
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19
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Wu Y, Mirzaei M, Atwell BJ, Haynes PA. Label-free and isobaric tandem mass tag (TMT) multiplexed quantitative proteomic data of two contrasting rice cultivars exposed to drought stress and recovery. Data Brief 2019; 22:697-702. [PMID: 30656201 PMCID: PMC6329202 DOI: 10.1016/j.dib.2018.12.041] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Revised: 11/28/2018] [Accepted: 12/12/2018] [Indexed: 12/03/2022] Open
Abstract
Two rice cultivars, IAC1131 (drought tolerant) and Nipponbare (drought sensitive), with contrasting genetic backgrounds and levels of tolerance to drought, were analysed using both label-free and tandem mass tags (TMTs) quantitative proteomics approaches, aiming to elucidate the mechanisms of drought tolerance. Four-week-old seedlings of both cultivars were grown in large soil volumes in the glasshouse under controlled conditions and then exposed to moderate and extreme drought for 7 days, followed by 3 days of re-watering period. Mature leaves were harvested from plants of each treatment for protein extraction and subsequent complementary shotgun proteomic analyses. The data from this study are related to the research article “Quantitative proteomic analysis of two different rice varieties reveals that drought tolerance is correlated with reduced abundance of photosynthetic machinery and increased abundance of ClpD1 protease” (Wu et al., 2016) [1].
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Affiliation(s)
- Yunqi Wu
- Department of Molecular Sciences, Macquarie University, North Ryde, NSW 2109, Australia
| | - Mehdi Mirzaei
- Department of Molecular Sciences, Macquarie University, North Ryde, NSW 2109, Australia
| | - Brian J Atwell
- Department of Biological Sciences, Macquarie University, North Ryde, NSW 2109, Australia
| | - Paul A Haynes
- Department of Molecular Sciences, Macquarie University, North Ryde, NSW 2109, Australia
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20
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Yichie Y, Brien C, Berger B, Roberts TH, Atwell BJ. Salinity tolerance in Australian wild Oryza species varies widely and matches that observed in O. sativa. Rice (N Y) 2018; 11:66. [PMID: 30578452 PMCID: PMC6303227 DOI: 10.1186/s12284-018-0257-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Accepted: 12/03/2018] [Indexed: 05/02/2023]
Abstract
BACKGROUND Soil salinity is widespread in rice-producing areas globally, restricting both vegetative growth and grain yield. Attempts to improve the salt tolerance of Asian rice, Oryza sativa-the most salt sensitive of the major cereal crops-have met with limited success, due to the complexity of the trait and finite variation in salt responses among O. sativa lines. Naturally occurring variation among the more than 20 wild species of the Oryza genus has great potential to provide breeders with novel genes to improve resistance to salt. Here, through two distinct screening experiments, we investigated variation in salinity tolerance among accessions of two wild rice species endemic to Australia, O. meridionalis and O. australiensis, with O. sativa cultivars Pokkali and IR29 providing salt-tolerant and sensitive controls, respectively. RESULTS Rice plants were grown on soil supplemented with field-relevant concentrations of NaCl (0, 40, 80, and 100 mM) for 30 d, a period sufficient to reveal differences in growth and physiological traits. Two complementary screening approaches were used: destructive phenotyping and high-throughput image-based phenotyping. All genotypes displayed clear responses to salt treatment. In the first experiment, both salt-tolerant Pokkali and an O. australiensis accession (Oa-VR) showed the least reduction in biomass accumulation, SES score and chlorophyll content in response to salinity. Average shoot Na+/K+ values of these plants were the lowest among the genotypes tested. In the second experiment, plant responses to different levels of salt stress were quantified over time based on projected shoot area calculated from visible red-green-blue (RGB) and fluorescence images. Pokkali grew significantly faster than the other genotypes. Pokkali and Oa-VR plants displayed the same absolute growth rate under 80 and 100 mM, while Oa-D grew significantly slower with the same treatments. Oa-VR showed substantially less inhibition of growth in response to salinity when compared with Oa-D. Senescence was seen in Oa-D after 30 d treatment with 40 mM NaCl, while the putatively salt-tolerant Oa-VR had only minor leaf damage, even at higher salt treatments, with less than a 40% increase in relative senescence at 100 mM NaCl compared to 120% for Oa-VR. CONCLUSION The combination of our two screening experiments uncovered striking levels of salt tolerance diversity among the Australian wild rice accessions tested and enabled analysis of their growth responses to a range of salt levels. Our results validate image-based phenotyping as a valuable tool for quantitative measurement of plant responses to abiotic stresses. They also highlight the potential of exotic germplasm to provide new genetic variation for salinity tolerance in rice.
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Affiliation(s)
- Yoav Yichie
- Sydney Institute of Agriculture, University of Sydney, Sydney, Australia
| | - Chris Brien
- School of Agriculture Food and Wine, University of Adelaide, Adelaide, Australia
- Australian Plant Phenomics Facility, The Plant Accelerator, Waite Research Institute, University of Adelaide, Adelaide, Australia
| | - Bettina Berger
- School of Agriculture Food and Wine, University of Adelaide, Adelaide, Australia
- Australian Plant Phenomics Facility, The Plant Accelerator, Waite Research Institute, University of Adelaide, Adelaide, Australia
| | - Thomas H. Roberts
- Sydney Institute of Agriculture, University of Sydney, Sydney, Australia
| | - Brian J. Atwell
- Department of Biological Sciences, Macquarie University, Sydney, Australia
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21
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Najeeb U, Tan DKY, Bange MP, Atwell BJ. Protecting cotton crops under elevated CO 2 from waterlogging by managing ethylene. Funct Plant Biol 2018; 45:340-349. [PMID: 32290957 DOI: 10.1071/fp17184] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Accepted: 09/13/2017] [Indexed: 05/29/2023]
Abstract
Soil waterlogging and subsequent ethylene release from cotton (Gossypium hirsutum L.) tissues has been linked with abscission of developing cotton fruits. This glasshouse study investigates the effect of a 9-day waterlogging event and CO2 enrichment (eCO2, 700 parts per million (ppm)) on a fully linted cultivar 'Empire' and a lintless cotton mutant (5B). We hypothesised that cotton performance in extreme environments such as waterlogging can be improved through mitigating ethylene action. Plants were grown at 28:20°C day:night temperature, 50-70% relative humidity and a 14:10 light:dark photoperiod under natural light and were exposed to waterlogging and eCO2 at early reproductive growth. Ethylene synthesis was inhibited by spraying aminoethoxyvinylglycine (830ppm) 1 day before waterlogging. Waterlogging significantly increased ethylene release from both cotton genotypes, although fruit production was significantly inhibited only in Empire. Aminoethoxyvinylglycine consistently reduced waterlogging-induced abscission of fruits, mainly in Empire. Limited damage to fruits in 5B, despite increased ethylene production during waterlogging, suggested that fruit abscission in 5B was inhibited by disrupting ethylene metabolism genetically. Elevated CO2 promoted fruit production in both genotypes and was more effective in 5B than in Empire plants. Hence 5B produced more fruits than Empire, providing additional sinks (existing and new fruit) that enhanced the response to CO2 enrichment.
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Affiliation(s)
- Ullah Najeeb
- The University of Sydney, Sydney Institute of Agriculture, School of Life and Environmental Sciences, Faculty of Science, Sydney, NSW 2015, Australia
| | - Daniel K Y Tan
- The University of Sydney, Sydney Institute of Agriculture, School of Life and Environmental Sciences, Faculty of Science, Sydney, NSW 2015, Australia
| | - Michael P Bange
- The University of Sydney, Sydney Institute of Agriculture, School of Life and Environmental Sciences, Faculty of Science, Sydney, NSW 2015, Australia
| | - Brian J Atwell
- Department of Biological Sciences, Faculty of Science and Engineering, Macquarie University, Sydney, NSW 2109, Australia
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22
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Scafaro AP, Atwell BJ, Muylaert S, Reusel BV, Ruiz GA, Rie JV, Gallé A. A Thermotolerant Variant of Rubisco Activase From a Wild Relative Improves Growth and Seed Yield in Rice Under Heat Stress. Front Plant Sci 2018; 9:1663. [PMID: 30524456 PMCID: PMC6256286 DOI: 10.3389/fpls.2018.01663] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Accepted: 10/26/2018] [Indexed: 05/03/2023]
Abstract
Genes encoding thermostable variants of the photosynthesis heat-labile protein Rubisco activase (Rca) from a wild relative Oryza australiensis were overexpressed in domesticated rice (Oryza sativa). Proteomics was used to quantify the abundance of O. australiensis Rca (Rca-Oa) in the resulting plants. Plants were grown to maturity in growth rooms and from early tillering until immediately prior to anthesis, they were exposed to daytime maximum temperatures of 28, 40, and 45°C and constant night temperatures of 22°C. Non-destructive measurements of leaf elongation and photosynthesis were used to compare the null segregant with a transfected line in which 19% of its total Rca content was the recombinant O. australiensis Rca (T-Oa-19). Height, fresh mass, panicle number, seed set, and seed number were measured at final harvest. Traits at maturity after heat stress at 45°C correlated strongly with recombinant protein abundance. Seed number was far the most responsive trait to an increase in Rca-Oa abundance, improving by up to 150%. Leaf elongation rates (LER) and tiller number were significantly greater in the transformed plants in the first two weeks of exposure to 45°C but tiller numbers later became equal in the two genotypes. Gas exchange measurements showed that T-Oa-19 had faster light induction of photosynthesis but not significantly higher CO2 assimilation rates, indicating that the carbon gain that resulted in large yield improvement after growth at 45°C was not strongly correlated with an instantaneous measurement of steady-state photosynthesis. When plants were grown at 40°C daytime maximum, there was no improvement in the final biomass, panicle or seed number when compared with 28°C, indicating that the threshold for heat damage and beneficial effects of the thermostable Rca recombinant protein was between 40 and 45°C, which corresponded to leaf temperatures in the range 38-42°C. The results suggest that the thermotolerant form of Rca from O. australiensis was sufficient to enhance carbohydrate accumulation and storage by rice over the life of the plant, dramatically improving yields after exposure to heat throughout the vegetative phase.
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Affiliation(s)
- Andrew P. Scafaro
- Bayer CropScience SA-NV, Innovation Center Ghent, Ghent, Belgium
- *Correspondence: Andrew P. Scafaro,
| | - Brian J. Atwell
- Department of Biological Sciences, Macquarie University, Sydney, NSW, Australia
| | - Steven Muylaert
- Bayer CropScience SA-NV, Innovation Center Ghent, Ghent, Belgium
| | | | | | - Jeroen Van Rie
- Bayer CropScience SA-NV, Innovation Center Ghent, Ghent, Belgium
| | - Alexander Gallé
- Bayer CropScience SA-NV, Innovation Center Ghent, Ghent, Belgium
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23
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Najeeb U, Sarwar M, Atwell BJ, Bange MP, Tan DKY. Endogenous Ethylene Concentration Is Not a Major Determinant of Fruit Abscission in Heat-Stressed Cotton ( Gossypium hirsutum L.). Front Plant Sci 2017; 8:1615. [PMID: 28983303 PMCID: PMC5613130 DOI: 10.3389/fpls.2017.01615] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2017] [Accepted: 09/04/2017] [Indexed: 05/22/2023]
Abstract
We investigated the role of ethylene in the response of cotton to high temperature using cotton genotypes with genetically interrupted ethylene metabolism. In the first experiment, Sicot 71BRF and 5B (a lintless variant with compromised ethylene metabolism) were exposed to 45°C, either by instantaneous heat shock or by ramping temperatures by 3°C daily for 1 week. One day prior to the start of heat treatment, half the plants were sprayed with 0.8 mM of the ethylene synthesis inhibitor, aminoethoxyvinylglycine (AVG). In a subsequent experiment, Sicot 71BRF and a putatively heat-tolerant line, CIM 448, were exposed to 36 or 45°C for 1 week, and half the plants were sprayed with 20 μM of the ethylene precursor, 1-aminocyclopropane-1-carboxylic acid, (ACC). High temperature exposure of plants in both experiments was performed at the peak reproductive phase (65-68 days after sowing). Elevated temperature (heat shock or ramping to 45°C) significantly reduced production and retention of fruits in all cotton lines used in this study. At the termination of heat treatment, cotton plants exposed to 45°C had at least 50% fewer fruits than plants under optimum temperature in all three genotypes, while plants at 36°C remained unaffected. Heat-stressed plants continued producing new squares (fruiting buds) after termination of heat stress but these squares did not turn into cotton bolls due to pollen infertility. In vitro inhibition of pollen germination by high temperatures supported this observation. Leaf photosynthesis (Pn) of heat-stressed plants (45°C) measured at the end of heat treatments remained significantly inhibited, despite an increased leaf stomatal conductance (gs), suggesting that high temperature impairs Pn independently of stomatal behavior. Metabolic injury was supported by high relative cellular injury and low photosystem II yield of the heat-stressed plants, indicating that high temperature impaired photosynthetic electron transport. Both heat shock and ramping of heat significantly reduced ethylene release from cotton leaf tissues measured at the end of heat treatment but modulating ethylene production via AVG or ACC application had no significant effect on fruit production or retention in heat-stressed cotton plants. Instead, high temperature accelerated fruit abortion by impairing pollen development and/or restricting leaf photosynthesis.
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Affiliation(s)
- Ullah Najeeb
- Faculty of Science, Plant Breeding Institute, Sydney Institute of Agriculture, School of Life and Environmental Sciences, University of SydneySydney, NSW, Australia
| | - Muhammad Sarwar
- Agronomic Research Institute, Ayub Agricultural Research InstituteFaisalabad, Pakistan
| | - Brian J. Atwell
- Faculty of Science, Plant Breeding Institute, Sydney Institute of Agriculture, School of Life and Environmental Sciences, University of SydneySydney, NSW, Australia
- Department of Biological Sciences, Faculty of Science and Engineering, Macquarie UniversitySydney NSW, Australia
| | - Michael P. Bange
- Faculty of Science, Plant Breeding Institute, Sydney Institute of Agriculture, School of Life and Environmental Sciences, University of SydneySydney, NSW, Australia
- Commonwealth Scientific and Industrial Research Organisation Agriculture and Food, Australian Cotton Research InstituteNarrabri, NSW, Australia
| | - Daniel K. Y. Tan
- Faculty of Science, Plant Breeding Institute, Sydney Institute of Agriculture, School of Life and Environmental Sciences, University of SydneySydney, NSW, Australia
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Sasidharan R, Bailey-Serres J, Ashikari M, Atwell BJ, Colmer TD, Fagerstedt K, Fukao T, Geigenberger P, Hebelstrup KH, Hill RD, Holdsworth MJ, Ismail AM, Licausi F, Mustroph A, Nakazono M, Pedersen O, Perata P, Sauter M, Shih MC, Sorrell BK, Striker GG, van Dongen JT, Whelan J, Xiao S, Visser EJW, Voesenek LACJ. Community recommendations on terminology and procedures used in flooding and low oxygen stress research. New Phytol 2017; 214:1403-1407. [PMID: 28277605 DOI: 10.1111/nph.14519] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Affiliation(s)
- Rashmi Sasidharan
- Institute of Environmental Biology, Utrecht University, Padualaan 8, Utrecht, 3584CH, the Netherlands
| | - Julia Bailey-Serres
- Institute of Environmental Biology, Utrecht University, Padualaan 8, Utrecht, 3584CH, the Netherlands
- Center for Plant Cell Biology, Department of Botany and Plant Science, University of California, Riverside, CA, 92521-0124, USA
| | - Motoyuki Ashikari
- Bioscience and Biotechnology Center, Nagoya University, Chikusa, Nagoya, Aichi, 464-8601, Japan
| | - Brian J Atwell
- Department of Biological Sciences, Faculty of Science and Engineering, Macquarie University, Sydney, NSW, 2109, Australia
| | - Timothy D Colmer
- UWA School of Agriculture and Environment, The University of Western Australia, 35 Stirling Highway, Crawley, WA, 6009, Australia
| | - Kurt Fagerstedt
- Department of Biosciences, Viikki Plant Science Center, Helsinki University, PO Box 65, Helsinki, FI-00014, Finland
| | - Takeshi Fukao
- Department of Crop and Soil Environmental Sciences, Translational Plant Science Program, Fralin Life Science Institute, Virginia Tech, Blacksburg, VA, 24061, USA
| | - Peter Geigenberger
- Department of Biol 1, Ludwig Maximilian University of Munich, Grosshaderner Str 2-4, Martinsried, Planegg, Munich, D-82152, Germany
| | - Kim H Hebelstrup
- Department of Molecular Biology and Genetics, Aarhus University, Flakkebjerg, Slagelse, 4200, Denmark
| | - Robert D Hill
- Department of Plant Science, University of Manitoba, Winnipeg, MB, R3T 2N2, Canada
| | - Michael J Holdsworth
- Plant and Crop Sciences Division, School of Biosciences, University of Nottingham, Nottingham, LE12 5RD, UK
| | - Abdelbagi M Ismail
- International Rice Research Institute, Los Banõs, Laguna, 4031, Philippines
| | - Francesco Licausi
- PlantLab, Institute of Life Sciences, Scuola Superiore Sant'Anna, Via Mariscoglio 34, Pisa, 56124, Italy
| | - Angelika Mustroph
- Plant Physiology, University Bayreuth, Universitaetsstr. 30, Bayreuth, 95440, Germany
| | - Mikio Nakazono
- Graduate School of Bioagricultural Sciences, Nagoya University, Chikusa, Nagoya, 464-8601, Japan
| | - Ole Pedersen
- Freshwater Biological Laboratory, Department of Biology, University of Copenhagen, Universitetsparken 4, 3rd floor, Copenhagen, 2100, Denmark
| | - Pierdomenico Perata
- PlantLab, Institute of Life Sciences, Scuola Superiore Sant'Anna, Via Mariscoglio 34, Pisa, 56124, Italy
| | - Margret Sauter
- Plant Developmental Biology and Plant Physiology, Kiel University, Kiel, 24118, Germany
| | - Ming-Che Shih
- Agricultural Biotechnology Research Center, Academia Sinica, 115, Taipei, Taiwan
| | - Brian K Sorrell
- Department of Bioscience, Aarhus University, Aarhus, 8000, Denmark
| | - Gustavo G Striker
- IFEVA, Facultad de Agronomía, Universidad de Buenos Aires, CONICET, Av. San Martin 4453, Buenos Aires, Argentina
| | | | - James Whelan
- Department of Animal, Plant and Soil Science, School of Life Science, Australian Research Council Center of Excellence in Plant Energy Biology, La Trobe University, Bundoora, VIC, 3086, Australia
| | - Shi Xiao
- State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, China
| | - Eric J W Visser
- Department of Experimental Plant Ecology, Institute for Water and Wetland Research, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, the Netherlands
| | - Laurentius A C J Voesenek
- Institute of Environmental Biology, Utrecht University, Padualaan 8, Utrecht, 3584CH, the Netherlands
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25
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Srikanta Dani KG, Marino G, Taiti C, Mancuso S, Atwell BJ, Loreto F, Centritto M. De novo post-illumination monoterpene burst in Quercus ilex (holm oak). Planta 2017; 245:459-465. [PMID: 27990573 DOI: 10.1007/s00425-016-2636-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2016] [Accepted: 12/04/2016] [Indexed: 06/06/2023]
Abstract
Explicit proof for de novo origin of a rare post-illumination monoterpene burst and its consistency under low O 2 , shows interaction of photorespiration, photosynthesis, and isoprenoid biosynthesis during light-dark transitions. Quercus ilex L (holm oak) constitutively emits foliar monoterpenes in an isoprene-like fashion via the methyl erythritol phosphate (MEP) pathway located in chloroplasts. Isoprene-emitting plants are known to exhibit post-illumination isoprene burst, a transient emission of isoprene in darkness. An analogous post-illumination monoterpene burst (PiMB) had remained elusive and is reported here for the first time in Q. ilex. Using 13CO2 labelling, we show that PiMB is made from freshly fixed carbon. PiMB is rare at ambient (20%) O2, absent at high (50%) O2, and becomes consistent in leaves exposed to low (2%) O2. PiMB is stronger and occurs earlier at higher temperatures. We also show that primary and secondary post-illumination CO 2 bursts (PiCO2B) are sensitive to O2 in Q. ilex. The primary photorespiratory PiCO2B is absent under both ambient and low O2, but is induced under high (>50%) O2, while the secondary PiCO2B (of unknown origin) is absent under ambient, but present at low and high O2. We propose that post-illumination recycling of photorespired CO2 competes with the MEP pathway for photosynthetic carbon and energy, making PiMB rare under ambient O2 and absent at high O2. PiMB becomes consistent when photorespiration is suppressed in Q. ilex.
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Affiliation(s)
- K G Srikanta Dani
- Institute of Ecosystem Studies, National Research Council of Italy, via Madonna del Piano 10, 50019, Sesto Fiorentino (FI), Italy.
- Department of Biological Sciences, Macquarie University, North Ryde, Sydney, NSW 2109, Australia.
- School of Biology, Indian Institute of Science Education and Research, Thiruvananthapuram, Kerala, 695016, India.
| | - Giovanni Marino
- Trees and Timber Institute, National Research Council of Italy, via Madonna del Piano 10, 50019, Sesto Fiorentino (FI), Italy
| | - Cosimo Taiti
- Department of Environmental Science and Agricultural Production, University of Florence, Viale delle Idee 30, 50019, Sesto Fiorentino (FI), Italy
| | - Stefano Mancuso
- Department of Environmental Science and Agricultural Production, University of Florence, Viale delle Idee 30, 50019, Sesto Fiorentino (FI), Italy
| | - Brian J Atwell
- Department of Biological Sciences, Macquarie University, North Ryde, Sydney, NSW 2109, Australia
| | - Francesco Loreto
- Department of Biology, Agriculture and Food Sciences, National Research Council of Italy, Piazzale Aldo Moro 7, 00185, Rome, Italy
| | - Mauro Centritto
- Trees and Timber Institute, National Research Council of Italy, via Madonna del Piano 10, 50019, Sesto Fiorentino (FI), Italy
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26
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Scafaro AP, Gallé A, Van Rie J, Carmo-Silva E, Salvucci ME, Atwell BJ. Heat tolerance in a wild Oryza species is attributed to maintenance of Rubisco activation by a thermally stable Rubisco activase ortholog. New Phytol 2016; 211:899-911. [PMID: 27145723 DOI: 10.1111/nph.13963] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Accepted: 03/03/2016] [Indexed: 05/10/2023]
Abstract
The mechanistic basis of tolerance to heat stress was investigated in Oryza sativa and two wild rice species, Oryza meridionalis and Oryza australiensis. The wild relatives are endemic to the hot, arid Australian savannah. Leaf elongation rates and gas exchange were measured during short periods of supra-optimal heat, revealing species differences. The Rubisco activase (RCA) gene from each species was sequenced. Using expressed recombinant RCA and leaf-extracted RCA, the kinetic properties of the two isoforms were studied under high temperatures. Leaf elongation was undiminished at 45°C in O. australiensis. The net photosynthetic rate was almost 50% slower in O. sativa at 45°C than at 28°C, while in O. australiensis it was unaffected. Oryza meridionalis exhibited intermediate heat tolerance. Based on previous reports that RCA is heat-labile, the Rubisco activation state was measured. It correlated positively with leaf elongation rates across all three species and four periods of exposure to 45°C. Sequence analysis revealed numerous polymorphisms in the RCA amino acid sequence from O. australiensis. The O. australiensis RCA enzyme was thermally stable up to 42°C, contrasting with RCA from O. sativa, which was inhibited at 36°C. We attribute heat tolerance in the wild species to thermal stability of RCA, enabling Rubisco to remain active.
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Affiliation(s)
- Andrew P Scafaro
- Department of Biological Sciences, Faculty of Science and Engineering, Macquarie University, Sydney, NSW, 2109, Australia
- ARC Centre of Excellence in Plant Energy Biology, Research School of Biology, The Australian National University, Canberra, ACT, 0200, Australia
| | - Alexander Gallé
- Bayer CropScience NV, Innovation Center - Trait Research, Technologiepark 38, Zwijnaarde (Gent), 9052, Belgium
| | - Jeroen Van Rie
- Bayer CropScience NV, Innovation Center - Trait Research, Technologiepark 38, Zwijnaarde (Gent), 9052, Belgium
| | | | - Michael E Salvucci
- US Department of Agriculture, Agricultural Research Service, Arid-Land Agricultural Research Center, Maricopa, AZ, 85138, USA
| | - Brian J Atwell
- Department of Biological Sciences, Faculty of Science and Engineering, Macquarie University, Sydney, NSW, 2109, Australia
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27
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Kelly JWG, Duursma RA, Atwell BJ, Tissue DT, Medlyn BE. Drought × CO2 interactions in trees: a test of the low-intercellular CO2 concentration (Ci ) mechanism. New Phytol 2016; 209:1600-12. [PMID: 26526873 DOI: 10.1111/nph.13715] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Accepted: 09/16/2015] [Indexed: 05/06/2023]
Abstract
Models of tree responses to climate typically project that elevated atmospheric CO2 concentration (eCa ) will reduce drought impacts on forests. We tested one of the mechanisms underlying this interaction, the 'low Ci effect', in which stomatal closure in drought conditions reduces the intercellular CO2 concentration (Ci ), resulting in a larger relative enhancement of photosynthesis with eCa , and, consequently, a larger relative biomass response. We grew two Eucalyptus species of contrasting drought tolerance at ambient and elevated Ca for 6-9 months in large pots maintained at 50% (drought) and 100% field capacity. Droughted plants did not have significantly lower Ci than well-watered plants, which we attributed to long-term changes in leaf area. Hence, there should not have been an interaction between eCa and water availability on biomass, and we did not detect one. The xeric species did have higher Ci than the mesic species, indicating lower water-use efficiency, but both species exhibited similar responses of photosynthesis and biomass to eCa , owing to compensatory differences in the photosynthetic response to Ci . Our results demonstrate that long-term acclimation to drought, and coordination among species traits may be important for predicting plant responses to eCa under low water availability.
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Affiliation(s)
- Jeff W G Kelly
- Department of Biological Sciences, Macquarie University, North Ryde, NSW, 2109, Australia
- School of Forest Science and Management, Department of Renewable Resources, University of Alberta, 4-29 Earth Sciences Building, Edmonton, AB, T6G 2E3, Canada
| | - Remko A Duursma
- Hawkesbury Institute for the Environment, Western Sydney University, Hawkesbury Campus, Locked Bag 1797, Penrith, NSW, 2751, Australia
| | - Brian J Atwell
- Department of Biological Sciences, Macquarie University, North Ryde, NSW, 2109, Australia
| | - David T Tissue
- Hawkesbury Institute for the Environment, Western Sydney University, Hawkesbury Campus, Locked Bag 1797, Penrith, NSW, 2751, Australia
| | - Belinda E Medlyn
- Department of Biological Sciences, Macquarie University, North Ryde, NSW, 2109, Australia
- Hawkesbury Institute for the Environment, Western Sydney University, Hawkesbury Campus, Locked Bag 1797, Penrith, NSW, 2751, Australia
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28
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Najeeb U, Bange MP, Tan DKY, Atwell BJ. Consequences of waterlogging in cotton and opportunities for mitigation of yield losses. AoB Plants 2015; 7:plv080. [PMID: 26194168 PMCID: PMC4565423 DOI: 10.1093/aobpla/plv080] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2014] [Accepted: 06/27/2015] [Indexed: 05/22/2023]
Abstract
Climatic variability, typified by erratic heavy-rainfall events, causes waterlogging in intensively irrigated crops and is exacerbated under warm temperature regimes on soils with poor internal drainage. Irrigated cotton is often grown in precisely these conditions, exposing it to waterlogging-induced yield losses after substantial summer rainfall. This calls for a deeper understanding of mechanisms of waterlogging tolerance and its relevance to cotton. Hence this review suggests possible causes of waterlogging-induced yield loss in cotton and approaches to improvement of waterlogging tolerance, drawing upon the slight body of published data in cotton and principles from other species. The yield penalty depends on soil type, phenological stage and cumulative period of root exposure to air-filled porosities below 10 %. Events in the soil include O2 deficiency in the root zone that changes the redox state of nutrients, making them unavailable (e.g. nitrogen) or potentially toxic for plants. Furthermore, root-derived hormones that are transported in the xylem have long been associated with oxygen deficits. These belowground effects (impaired root growth, nutrient uptake and transport, hormonal signalling) affect the shoots, interfering with canopy development, photosynthesis and radiation-use efficiency. Compared with the more waterlogging-tolerant cereals, cotton does not have identified adaptations to waterlogging in the root zone, forming no conspicuous root aerenchyma and having low fermentative activity. We speculate that these factors contribute substantially to the sensitivity of cotton to sustained periods of waterlogging. We discuss the impact of these belowground factors on shoot performance, photosynthesis and yield components. Management practices, i.e. soil aeration, scheduling irrigation and fertilizer application, can reduce waterlogging-induced damage. Limiting ethylene biosynthesis using anti-ethylene agents and down-regulating expression of genes controlling ethylene biosynthesis are strong candidates to minimize yield losses in waterlogged cotton crops. Other key pathways of anoxia tolerance are also cited as potential tools towards waterlogging-tolerant cotton genotypes.
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Affiliation(s)
- Ullah Najeeb
- Department of Plant and Food Sciences, Faculty of Agriculture and Environment, The University of Sydney, NSW 2015, Australia
| | - Michael P Bange
- Department of Plant and Food Sciences, Faculty of Agriculture and Environment, The University of Sydney, NSW 2015, Australia CSIRO Agriculture Flagship, Australian Cotton Research Institute, Narrabri, NSW 2390, Australia
| | - Daniel K Y Tan
- Department of Plant and Food Sciences, Faculty of Agriculture and Environment, The University of Sydney, NSW 2015, Australia
| | - Brian J Atwell
- Department of Plant and Food Sciences, Faculty of Agriculture and Environment, The University of Sydney, NSW 2015, Australia Department of Biological Sciences, Faculty of Science, Macquarie University, Sydney, NSW 2109, Australia
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29
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Atwell BJ, Greenway H, Colmer TD. Efficient use of energy in anoxia-tolerant plants with focus on germinating rice seedlings. New Phytol 2015; 206:36-56. [PMID: 25472708 DOI: 10.1111/nph.13173] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Accepted: 10/09/2014] [Indexed: 05/08/2023]
Abstract
Anoxia tolerance in plants is distinguished by direction of the sparse supply of energy to processes crucial to cell maintenance and sometimes to growth, as in rice seedlings. In anoxic rice coleoptiles energy is used to synthesise proteins, take up K(+) , synthesise cell walls and lipids, and in cell maintenance. Maintenance of electrochemical H(+) gradients across the tonoplast and plasma membrane is crucial for solute compartmentation and thus survival. These gradients sustain some H(+) -solute cotransport and regulate cytoplasmic pH. Pyrophosphate (PPi ), the alternative energy donor to ATP, allows direction of energy to the vacuolar H(+) -PPi ase, sustaining H(+) gradients across the tonoplast. When energy production is critically low, operation of a biochemical pHstat allows H(+) -solute cotransport across plasma membranes to continue for at least for 18 h. In active (e.g. growing) cells, PPi produced during substantial polymer synthesis allows conversion of PPi to ATP by PPi -phosphofructokinase (PFK). In quiescent cells with little polymer synthesis and associated PPi formation, the PPi required by the vacuolar H(+) -PPi ase and UDPG pyrophosphorylase involved in sucrose mobilisation via sucrose synthase might be produced by conversion of ATP to PPi through reversible glycolytic enzymes, presumably pyruvate orthophosphate dikinase. These hypotheses need testing with species characterised by contrasting anoxia tolerance.
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Affiliation(s)
- Brian J Atwell
- Department of Biological Sciences, Faculty of Science, Macquarie University, Sydney, 2109, NSW, Australia
| | - Hank Greenway
- School of Plant Biology and the UWA Institute of Agriculture, The University of Western Australia, 35 Stirling Highway, Crawley, 6009, WA, Australia
| | - Timothy D Colmer
- School of Plant Biology and the UWA Institute of Agriculture, The University of Western Australia, 35 Stirling Highway, Crawley, 6009, WA, Australia
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30
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Narsai R, Edwards JM, Roberts TH, Whelan J, Joss GH, Atwell BJ. Mechanisms of growth and patterns of gene expression in oxygen-deprived rice coleoptiles. Plant J 2015; 82:25-40. [PMID: 25650041 DOI: 10.1111/tpj.12786] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2014] [Revised: 01/21/2015] [Accepted: 01/22/2015] [Indexed: 05/04/2023]
Abstract
Coleoptiles of rice (Oryza sativa) seedlings grown under water commonly elongate by up to 1 mm h(-1) to reach the atmosphere. We initially analysed this highly specialized phenomenon by measuring epidermal cell lengths along the coleoptile axis to determine elongation rates. This revealed a cohort of cells in the basal zone that elongated rapidly following emergence from the embryo, reaching 200 μm within 12 h. After filming coleoptiles in vivo for a day, kinematic analysis was applied. Eight time-sliced 'segments' were defined by their emergence from the embryo at four-hourly intervals, revealing a mathematically simple growth model. Each segment entering the coleoptile from the embryo elongated at a constant velocity, resulting in accelerating growth for the entire organ. Consistent with the epidermal cell lengths, relative rates of elongation (mm mm(-1) h(-1)) were tenfold greater in the small, newly emerged basal segments than the older distal tip segments. This steep axial gradient defined two contrasting growth zones (bases versus tips) in which we measured ATP production and protein, RNA and DNA content, and analysed the global transcriptome under steady-state normoxia, hypoxia (3% O2) and anoxia. Determination of the transcriptome revealed tip-specific induction of genes encoding TCP [Teosinte Branched1 (Tb1) of maize, Cycloidea (Cyc), and Proliferating Cell Factor (Pcf)] transcription factors, RNA helicases, ribosomal proteins and proteins involved in protein folding, whilst expression of F-box domain-containing proteins in the ubiquitin E3-SCF complex (Skp, Cullin, F-box containing complex) was induced specifically in bases under low oxygen conditions. We ascribed the sustained elongation under hypoxia to hypoxia-specific responses such as controlled suppression of photosystem components and induction of RNA binding/splicing functions, indicating preferential allocation of energy to cell extension.
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Affiliation(s)
- Reena Narsai
- Department of Botany, School of Life Science, La Trobe University, Melbourne, Victoria, 3086, Australia
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31
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Dani KGS, Jamie IM, Prentice IC, Atwell BJ. Species-specific photorespiratory rate, drought tolerance and isoprene emission rate in plants. Plant Signal Behav 2015; 10:e990830. [PMID: 25734586 PMCID: PMC4622504 DOI: 10.4161/15592324.2014.990830] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Revised: 11/06/2014] [Accepted: 11/10/2014] [Indexed: 05/23/2023]
Abstract
The effect of drought on plant isoprene emission varies tremendously across species and environments. It was recently shown that an increased ratio of photosynthetic electron transport rate (ETR) to net carbon assimilation rate (NAR) consistently supported increased emission under drought. In this commentary, we highlight some of the physiological aspects of drought tolerance that are central to the observed variability. We briefly discuss some of the issues that must be addressed in order to refine our understanding of plant isoprene emission response to drought and increasing global temperature.
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Affiliation(s)
- K G Srikanta Dani
- Department of Biological Sciences; Macquarie University; North Ryde, Sydney, NSW, Australia
- Department of Chemistry and Biomolecular Sciences; Macquarie University; North Ryde, Sydney, NSW, Australia
- Institute of Ecosystem Studies; The National Research Council; Sesto Fiorentino, Italy
| | - Ian M Jamie
- Department of Chemistry and Biomolecular Sciences; Macquarie University; North Ryde, Sydney, NSW, Australia
| | - I Colin Prentice
- Department of Biological Sciences; Macquarie University; North Ryde, Sydney, NSW, Australia
- Grantham Institute for Climate Change, and Division of Biology; Imperial College London; Ascot, UK
| | - Brian J Atwell
- Department of Biological Sciences; Macquarie University; North Ryde, Sydney, NSW, Australia
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32
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Dani KGS, Jamie IM, Prentice IC, Atwell BJ. Evolution of isoprene emission capacity in plants. Trends Plant Sci 2014; 19:439-46. [PMID: 24582468 DOI: 10.1016/j.tplants.2014.01.009] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2013] [Revised: 01/06/2014] [Accepted: 01/15/2014] [Indexed: 05/21/2023]
Abstract
Light-dependent de novo volatile isoprene emission by terrestrial plants (approximately 2% of carbon fixed during photosynthesis) contributes as much as 0.5 PgC/year to the global carbon cycle. Although most plant taxa exhibit either constitutive or inducible monoterpene emissions, the evolution of isoprene emission capacity in multiple lineages has remained unexplained. Based on the predominant occurrence of isoprene emission capacity in long-lived, fast-growing woody plants; the relationship between 'metabolic scope' of tree genera and their species richness; and the proposed role of high growth rates and long generation times in accelerating molecular evolution, we hypothesise that long-lived plant genera with inherently high speciation rates have repeatedly acquired and lost the capacity to emit isoprene in their evolutionary history.
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Affiliation(s)
- K G Srikanta Dani
- Department of Biological Sciences, Macquarie University, North Ryde, Sydney, NSW 2109, Australia; Department of Chemistry and Biomolecular Sciences, Macquarie University, North Ryde, Sydney, NSW 2109, Australia
| | - Ian M Jamie
- Department of Chemistry and Biomolecular Sciences, Macquarie University, North Ryde, Sydney, NSW 2109, Australia
| | - I Colin Prentice
- Department of Biological Sciences, Macquarie University, North Ryde, Sydney, NSW 2109, Australia; Grantham Institute for Climate Change, and Division of Biology, Imperial College London, Silwood Park, Ascot SL5 7PY, UK
| | - Brian J Atwell
- Department of Biological Sciences, Macquarie University, North Ryde, Sydney, NSW 2109, Australia.
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33
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Atwell BJ, Wang H, Scafaro AP. Could abiotic stress tolerance in wild relatives of rice be used to improve Oryza sativa? Plant Sci 2014; 215-216:48-58. [PMID: 24388514 DOI: 10.1016/j.plantsci.2013.10.007] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2013] [Revised: 09/28/2013] [Accepted: 10/11/2013] [Indexed: 05/02/2023]
Abstract
Oryza sativa and Oryza glaberrima have been selected to acquire and partition resources efficiently as part of the process of domestication. However, genetic diversity in cultivated rice is limited compared to wild Oryza species, in spite of 120,000 genotypes being held in gene banks. By contrast, there is untapped diversity in the more than 20 wild species of Oryza, some having been collected from just a few coastal locations (e.g. Oryza schlechteri), while others are widely distributed (e.g. Oryza nivara and Oryza rufipogon). The extent of DNA sequence diversity and phenotypic variation is still being established in wild Oryza, with genetic barriers suggesting a vast range of morphologies and function even within species, such as has been demonstrated for Oryza meridionalis. With increasing climate variability and attempts to make more marginal land arable, abiotic and biotic stresses will be managed over the coming decades by tapping into the genetic diversity of wild relatives of O. sativa. To help create a more targeted approach to sourcing wild rice germplasm for abiotic stress tolerance, we have created a climate distribution map by plotting the natural occurrence of all Oryza species against corresponding temperature and moisture data. We then discuss interspecific variation in phenotype and its significance for rice, followed by a discussion of ways to integrate germplasm from wild relatives into domesticated rice.
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Affiliation(s)
- Brian J Atwell
- Department of Biological Sciences, Faculty of Science, Macquarie University, New South Wales 2109, Australia.
| | - Han Wang
- Department of Biological Sciences, Faculty of Science, Macquarie University, New South Wales 2109, Australia
| | - Andrew P Scafaro
- Department of Biological Sciences, Faculty of Science, Macquarie University, New South Wales 2109, Australia
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34
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Mirzaei M, Soltani N, Sarhadi E, George IS, Neilson KA, Pascovici D, Shahbazian S, Haynes PA, Atwell BJ, Salekdeh GH. Manipulating Root Water Supply Elicits Major Shifts in the Shoot Proteome. J Proteome Res 2013; 13:517-26. [DOI: 10.1021/pr400696u] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Mehdi Mirzaei
- Australian
School of Advanced Medicine, Faculty of Human Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Neda Soltani
- Agricultural Biotechnology Research Institute of Iran, Karaj, Tehran, Iran
| | - Elham Sarhadi
- Agricultural Biotechnology Research Institute of Iran, Karaj, Tehran, Iran
| | - Iniga S. George
- Department
of Chemistry and Biomolecular Sciences, Macquarie University, North Ryde, New South Wales, Australia
| | - Karlie A. Neilson
- Australian
Proteome Analysis Facility (APAF), Department of Chemistry and Biomolecular
Sciences, Macquarie University, Sydney, Australia
| | - Dana Pascovici
- Australian
Proteome Analysis Facility (APAF), Department of Chemistry and Biomolecular
Sciences, Macquarie University, Sydney, Australia
| | - Shila Shahbazian
- Department
of Chemistry and Biomolecular Sciences, Macquarie University, North Ryde, New South Wales, Australia
| | - Paul A. Haynes
- Department
of Chemistry and Biomolecular Sciences, Macquarie University, North Ryde, New South Wales, Australia
| | - Brian J. Atwell
- Department
of Biological Sciences, Macquarie University, North Ryde, New South Wales, Australia
| | - Ghasem Hosseini Salekdeh
- Agricultural Biotechnology Research Institute of Iran, Karaj, Tehran, Iran
- Department
of Molecular Systems Biology at Cell Science Research Center, Royan
Institute for Stem Cell Biology and Technology, ACECR, Tehran, Iran
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35
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Neilson KA, Scafaro AP, Chick JM, George IS, Van Sluyter SC, Gygi SP, Atwell BJ, Haynes PA. The influence of signals from chilled roots on the proteome of shoot tissues in rice seedlings. Proteomics 2013; 13:1922-33. [DOI: 10.1002/pmic.201200475] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2012] [Revised: 12/06/2012] [Accepted: 02/07/2013] [Indexed: 02/02/2023]
Affiliation(s)
- Karlie A. Neilson
- Department of Chemistry and Biomolecular Sciences; Macquarie University; New South Wales; Australia
| | - Andrew P. Scafaro
- Department of Biological Sciences, Macquarie University; New South Wales Australia
| | - Joel M. Chick
- Department of Cell Biology, Harvard Medical School; MA USA
| | - Iniga S. George
- Department of Chemistry and Biomolecular Sciences; Macquarie University; New South Wales; Australia
| | - Steven C. Van Sluyter
- Department of Chemistry and Biomolecular Sciences; Macquarie University; New South Wales; Australia
| | - Steven P. Gygi
- Department of Cell Biology, Harvard Medical School; MA USA
| | - Brian J. Atwell
- Department of Biological Sciences, Macquarie University; New South Wales Australia
| | - Paul A. Haynes
- Department of Chemistry and Biomolecular Sciences; Macquarie University; New South Wales; Australia
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Harrison SP, Morfopoulos C, Dani KGS, Prentice IC, Arneth A, Atwell BJ, Barkley MP, Leishman MR, Loreto F, Medlyn BE, Niinemets Ü, Possell M, Peñuelas J, Wright IJ. Volatile isoprenoid emissions from plastid to planet. New Phytol 2013; 197:49-57. [PMID: 23145556 DOI: 10.1111/nph.12021] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2012] [Accepted: 09/22/2012] [Indexed: 05/22/2023]
Abstract
Approximately 1-2% of net primary production by land plants is re-emitted to the atmosphere as isoprene and monoterpenes. These emissions play major roles in atmospheric chemistry and air pollution-climate interactions. Phenomenological models have been developed to predict their emission rates, but limited understanding of the function and regulation of these emissions has led to large uncertainties in model projections of air quality and greenhouse gas concentrations. We synthesize recent advances in diverse fields, from cell physiology to atmospheric remote sensing, and use this information to propose a simple conceptual model of volatile isoprenoid emission based on regulation of metabolism in the chloroplast. This may provide a robust foundation for scaling up emissions from the cellular to the global scale.
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Affiliation(s)
- Sandy P Harrison
- Department of Biological Sciences, Macquarie University, North Ryde, NSW 2109, Australia.
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Francis SE, Ersoy RA, Ahn JW, Atwell BJ, Roberts TH. Serpins in rice: protein sequence analysis, phylogeny and gene expression during development. BMC Genomics 2012; 13:449. [PMID: 22947050 PMCID: PMC3534287 DOI: 10.1186/1471-2164-13-449] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2012] [Accepted: 03/19/2012] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Most members of the serpin family of proteins are potent, irreversible inhibitors of specific serine or cysteine proteinases. Inhibitory serpins are distinguished from members of other families of proteinase inhibitors by their metastable structure and unique suicide-substrate mechanism. Animal serpins exert control over a remarkable diversity of physiological processes including blood coagulation, fibrinolysis, innate immunity and aspects of development. Relatively little is known about the complement of serpin genes in plant genomes and the biological functions of plant serpins. RESULTS A structurally refined amino-acid sequence alignment of the 14 full-length serpins encoded in the genome of the japonica rice Oryza sativa cv. Nipponbare (a monocot) showed a diversity of reactive-centre sequences (which largely determine inhibitory specificity) and a low degree of identity with those of serpins in Arabidopsis (a eudicot). A new convenient and functionally informative nomenclature for plant serpins in which the reactive-centre sequence is incorporated into the serpin name was developed and applied to the rice serpins. A phylogenetic analysis of the rice serpins provided evidence for two main clades and a number of relatively recent gene duplications. Transcriptional analysis showed vastly different levels of basal expression among eight selected rice serpin genes in callus tissue, during seedling development, among vegetative tissues of mature plants and throughout seed development. The gene OsSRP-LRS (Os03g41419), encoding a putative orthologue of Arabidopsis AtSerpin1 (At1g47710), was expressed ubiquitously and at high levels. The second most highly expressed serpin gene was OsSRP-PLP (Os11g11500), encoding a non-inhibitory serpin with a surprisingly well-conserved reactive-centre loop (RCL) sequence among putative orthologues in other grass species. CONCLUSIONS The diversity of reactive-centre sequences among the putatively inhibitory serpins of rice point to a range of target proteases with different proteolytic specificities. Large differences in basal expression levels of the eight selected rice serpin genes during development further suggest a range of functions in regulation and in plant defence for the corresponding proteins.
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Affiliation(s)
- Sheila E Francis
- Department of Chemistry and Biomolecular Sciences, Macquarie University, North Ryde, NSW, 2109, Australia
| | - Renan A Ersoy
- Department of Chemistry and Biomolecular Sciences, Macquarie University, North Ryde, NSW, 2109, Australia
| | - Joon-Woo Ahn
- Department of Chemistry and Biomolecular Sciences, Macquarie University, North Ryde, NSW, 2109, Australia
- Green Bio Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), 111 Gwahangno, Yuseong-gu, Daejeon, 305-806, Korea
| | - Brian J Atwell
- Department of Biological Sciences, Macquarie University, North Ryde, NSW, 2109, Australia
| | - Thomas H Roberts
- Department of Chemistry and Biomolecular Sciences, Macquarie University, North Ryde, NSW, 2109, Australia
- Department of Plant and Food Sciences, Faculty of Agriculture and Environment, University of Sydney, Sydney, NSW, 2006, Australia
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Scafaro AP, Yamori W, Carmo-Silva AE, Salvucci ME, von Caemmerer S, Atwell BJ. Rubisco activity is associated with photosynthetic thermotolerance in a wild rice (Oryza meridionalis). Physiol Plant 2012; 146:99-109. [PMID: 22324885 DOI: 10.1111/j.1399-3054.2012.01597.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Oryza meridionalis is a wild species of rice, endemic to tropical Australia. It shares a significant genome homology with the common domesticated rice Oryza sativa. Exploiting the fact that the two species are highly related but O. meridionalis has superior heat tolerance, experiments were undertaken to identify the impact of temperature on key events in photosynthesis. At an ambient CO(2) partial pressure of 38 Pa and irradiance of 1500 µmol quanta m(-2) s(-1), the temperature optimum of photosynthesis was 33.7 ± 0.8°C for O. meridionalis, significantly higher than the 30.6 ± 0.7°C temperature optimum of O. sativa. To understand the basis for this difference, we measured gas exchange and rubisco activation state between 20 and 42°C and modeled the response to determine the rate-limiting steps of photosynthesis. The temperature response of light respiration (R(light)) and the CO(2) compensation point in the absence of respiration (Γ(*)) were determined and found to be similar for the two species. C3 photosynthesis modeling showed that despite the difference in susceptibility to high temperature, both species had a similar temperature-dependent limitation to photosynthesis. Both rice species were limited by ribulose-1,5-bisphosphate (RuBP) regeneration at temperatures of 25 and 30°C but became RuBP carboxylation limited at 35 and 40°C. The activation state of rubisco in O. meridionalis was more stable at higher temperatures, explaining its greater heat tolerance compared with O. sativa.
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Affiliation(s)
- Andrew P Scafaro
- Department of Biological Sciences, Macquarie University, Sydney, New South Wales 2109, Australia
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39
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Mirzaei M, Pascovici D, Atwell BJ, Haynes PA. Differential regulation of aquaporins, small GTPases and V-ATPases proteins in rice leaves subjected to drought stress and recovery. Proteomics 2012; 12:864-77. [PMID: 22539437 DOI: 10.1002/pmic.201100389] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Mechanisms of drought tolerance are complex, interacting, and polygenic. This paper describes patterns of gene expression at precise physiological stages of drought in 35-day-old seedlings of Oryza sativa cv. Nipponbare. Drought was imposed gradually for up to 15 days, causing abscisic acid levels to rise and growth to cease, and plants were then re-watered. Proteins were identified from leaf samples after moderate drought, extreme drought, and 3 and 6 days of re-watering. Label-free quantitative shotgun proteomics resulted in identification of 1548 non-redundant proteins. More proteins were down-regulated in early stages of drought but more were up-regulated as severe drought developed. After re-watering, there was notable down regulation, suggesting that stress-related proteins were being degraded. Proteins involved in signalling and transport became dominant as severe drought took hold but decreased again on re-watering. Most of the nine aquaporins identified were responsive to drought, with six decreasing rapidly in abundance as plants were re-watered. Nine G-proteins appeared in large amounts during severe drought and dramatically degraded once plants were re-watered. We speculate that water transport and drought signalling are critical elements of the overall response to drought in rice and might be the key to biotechnological approaches to drought tolerance.
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Affiliation(s)
- Mehdi Mirzaei
- Department of Chemistry and Biomolecular Sciences, Macquarie University, North Ryde, NSW, Australia
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40
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Edwards JM, Roberts TH, Atwell BJ. Quantifying ATP turnover in anoxic coleoptiles of rice (Oryza sativa) demonstrates preferential allocation of energy to protein synthesis. J Exp Bot 2012; 63:4389-402. [PMID: 22585748 PMCID: PMC3421981 DOI: 10.1093/jxb/ers114] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2011] [Revised: 03/22/2012] [Accepted: 03/23/2012] [Indexed: 05/20/2023]
Abstract
Oxygen deprivation limits the energy available for cellular processes and yet no comprehensive ATP budget has been reported for any plant species under O(2) deprivation, including Oryza sativa. Using 3-d-old coleoptiles of a cultivar of O. sativa tolerant to flooding at germination, (i) rates of ATP regeneration in coleoptiles grown under normoxia (aerated solution), hypoxia (3% O(2)), and anoxia (N(2)) and (ii) rates of synthesis of proteins, lipids, nucleic acids, and cell walls, as well as K(+) transport, were determined. Based on published bioenergetics data, the cost of synthesizing each class of polymer and the proportion of available ATP allocated to each process were then compared. Protein synthesis consumed the largest proportion of ATP synthesized under all three oxygen regimes, with the proportion of ATP allocated to protein synthesis in anoxia (52%) more than double that in normoxic coleoptiles (19%). Energy allocation to cell wall synthesis was undiminished in hypoxia, consistent with preferential elongation typical of submerged coleoptiles. Lipid synthesis was also conserved strongly in O(2) deficits, suggesting that membrane integrity was maintained under anoxia, thus allowing K(+) to be retained within coleoptile cells. Rates of protein synthesis in coleoptiles from rice cultivars with contrasting tolerance to oxygen deficits (including mutants deficient in fermentative enzymes) confirmed that synthesis and turnover of proteins always accounted for most of the ATP consumed under anoxia. It is concluded that successful establishment of rice seedlings under water is largely due to the capacity of coleoptiles to allocate energy to vital processes, particularly protein synthesis.
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Affiliation(s)
- Joshua M. Edwards
- Department of Biological Sciences, Macquarie University, North Ryde, NSW 2109, Australia
| | - Thomas H. Roberts
- Department of Plant and Food Sciences, Faculty of Agriculture and Environment, University of Sydney, NSW 2006, Australia
| | - Brian J. Atwell
- Department of Biological Sciences, Macquarie University, North Ryde, NSW 2109, Australia
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41
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Duursma RA, Falster DS, Valladares F, Sterck FJ, Pearcy RW, Lusk CH, Sendall KM, Nordenstahl M, Houter NC, Atwell BJ, Kelly N, Kelly JWG, Liberloo M, Tissue DT, Medlyn BE, Ellsworth DS. Light interception efficiency explained by two simple variables: a test using a diversity of small- to medium-sized woody plants. New Phytol 2012; 193:397-408. [PMID: 22066945 DOI: 10.1111/j.1469-8137.2011.03943.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
• Plant light interception efficiency is a crucial determinant of carbon uptake by individual plants and by vegetation. Our aim was to identify whole-plant variables that summarize complex crown architecture, which can be used to predict light interception efficiency. • We gathered the largest database of digitized plants to date (1831 plants of 124 species), and estimated a measure of light interception efficiency with a detailed three-dimensional model. Light interception efficiency was defined as the ratio of the hemispherically averaged displayed to total leaf area. A simple model was developed that uses only two variables, crown density (the ratio of leaf area to total crown surface area) and leaf dispersion (a measure of the degree of aggregation of leaves). • The model explained 85% of variation in the observed light interception efficiency across the digitized plants. Both whole-plant variables varied across species, with differences in leaf dispersion related to leaf size. Within species, light interception efficiency decreased with total leaf number. This was a result of changes in leaf dispersion, while crown density remained constant. • These results provide the basis for a more general understanding of the role of plant architecture in determining the efficiency of light harvesting.
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Affiliation(s)
- R A Duursma
- Hawkesbury Institute for the Environment, University of Western Sydney, Penrith, NSW, Australia.
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42
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Mirzaei M, Soltani N, Sarhadi E, Pascovici D, Keighley T, Salekdeh GH, Haynes PA, Atwell BJ. Shotgun Proteomic Analysis of Long-distance Drought Signaling in Rice Roots. J Proteome Res 2011; 11:348-58. [DOI: 10.1021/pr2008779] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Mehdi Mirzaei
- Department of Chemistry and Biomolecular Sciences, Macquarie University, North Ryde, NSW, Australia
| | - Neda Soltani
- Department of Systems Biology, Agricultural Biotechnology Research Institute of Iran, Karaj, Iran
| | - Elham Sarhadi
- Department of Systems Biology, Agricultural Biotechnology Research Institute of Iran, Karaj, Iran
| | - Dana Pascovici
- Australian Proteome Analysis Facility, Macquarie University, North Ryde, NSW, Australia
| | - Tim Keighley
- Australian Proteome Analysis Facility, Macquarie University, North Ryde, NSW, Australia
| | - Ghasem Hosseini Salekdeh
- Department of Systems Biology, Agricultural Biotechnology Research Institute of Iran, Karaj, Iran
| | - Paul A. Haynes
- Department of Chemistry and Biomolecular Sciences, Macquarie University, North Ryde, NSW, Australia
| | - Brian J. Atwell
- Department of Biological Sciences, Macquarie University, North Ryde, NSW, Australia
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43
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Scafaro AP, Von Caemmerer S, Evans JR, Atwell BJ. Temperature response of mesophyll conductance in cultivated and wild Oryza species with contrasting mesophyll cell wall thickness. Plant Cell Environ 2011; 34:1999-2008. [PMID: 21752031 DOI: 10.1111/j.1365-3040.2011.02398.x] [Citation(s) in RCA: 104] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
A critical component of photosynthetic capacity is the conductance of CO(2) from intercellular airspaces to the sites of CO(2) fixation in the stroma of chloroplasts, termed mesophyll conductance (g(m)). Leaf anatomy has been identified as an important determinant of g(m). There are few studies of the temperature response of g(m) and none has examined the implications of leaf anatomy. Hence, we compared a cultivar of Oryza sativa with two wild Oryza relatives endemic to the hot northern savannah of Australia, namely Oryza meridionalis and Oryza australiensis. All three species had similar leaf anatomical properties, except that the wild relatives had significantly thicker mesophyll cell walls than O. sativa. Thicker mesophyll cell walls in the wild rice species are likely to have contributed to the reduction in g(m) , which was associated with a greater drawdown of CO(2) into chloroplasts (C(i) -C(c) ) compared with O. sativa. Mesophyll conductance increased at higher temperatures, whereas the rate of CO(2) assimilation was relatively stable between 20 and 40 °C. Consequently, C(i) -C(c) decreased for all three species as temperature increased.
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Affiliation(s)
- Andrew P Scafaro
- Department of Biological Sciences, Macquarie University, Sydney, New South Wales 2109, Australia
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44
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Gammulla CG, Pascovici D, Atwell BJ, Haynes PA. Differential proteomic response of rice (Oryza sativa) leaves exposed to high- and low-temperature stress. Proteomics 2011; 11:2839-50. [PMID: 21695689 DOI: 10.1002/pmic.201100068] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2011] [Revised: 04/05/2011] [Accepted: 04/26/2011] [Indexed: 11/07/2022]
Abstract
Global mean surface temperature has been predicted to increase by 1.8-4°C within this century, accompanied by an increase in the magnitude and frequency of extreme temperature events. Developing rice cultivars better adapted to non-optimal temperatures is essential to increase rice yield in the future and, hence, understanding the molecular response of rice to temperature stress is necessary. In this study, we investigated the proteomic responses of leaves of 24-day-old rice seedlings to sudden temperature changes. Rice seedlings grown at 28/20°C (day/night) were subjected to 3-day exposure to 12/5°C or 20/12°C (day/night) for low-temperature stress, and 36/28°C or 44/36°C (day/night) for high-temperature stress, followed by quantitative label-free shotgun proteomic analysis on biological triplicates of each treatment. Out of over 1100 proteins identified in one or more temperature treatments, more than 400 were found to be responsive to temperature stress. Of these, 43, 126 and 47 proteins were exclusively found at 12/5, 20/12 and 44/36°C (day/night), respectively. Our results showed that a greater change occurs in the rice leaf proteome at 20/12°C (day/night) in comparison to other non-optimal temperature regimes. In addition, our study identified more than 20 novel stress-response proteins.
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Affiliation(s)
- C Gayani Gammulla
- Department of Chemistry and Biomolecular Sciences, Macquarie University, North Ryde, NSW 2109, Australia
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45
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Gammulla CG, Pascovici D, Atwell BJ, Haynes PA. Differential metabolic response of cultured rice (Oryza sativa) cells exposed to high- and low-temperature stress. Proteomics 2010; 10:3001-19. [PMID: 20645384 DOI: 10.1002/pmic.201000054] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Global mean temperatures are expected to rise by 2-4.5 degrees C by 2100, accompanied by an increase in frequency and amplitude of extreme temperature events. Greater climatic extremes and an expanded range of cultivation will expose rice to increasing stress in the future. Understanding gene expression in disparate thermal regimes is important for the engineering of cultivars with tolerance to nonoptimal temperatures. Our study investigated the proteomic responses of rice cell suspension cultures to sudden temperature changes. Cell cultures grown at 28 degrees C were subjected to 3-day exposure to 12 or 20 degrees C for low-temperature stress, and 36 or 44 degrees C for high-temperature stress. Quantitative label-free shotgun proteomic analysis was performed on biological triplicates of each treatment. Over 1900 proteins were expressed in one or more temperature treatments, and, of these, more than 850 were found to be responsive to either of the temperature extremes. These temperature-responsive proteins included more than 300 proteins which were uniquely expressed at either 12 or 44 degrees C. Our study also identified 40 novel stress-response proteins and observed that switching between the classical and the alternative pathways of sucrose metabolism occurs in response to extremes of temperature.
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46
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Jerkovic A, Kriegel AM, Bradner JR, Atwell BJ, Roberts TH, Willows RD. Strategic distribution of protective proteins within bran layers of wheat protects the nutrient-rich endosperm. Plant Physiol 2010; 152:1459-70. [PMID: 20061449 PMCID: PMC2832279 DOI: 10.1104/pp.109.149864] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2009] [Accepted: 01/05/2010] [Indexed: 05/13/2023]
Abstract
Bran from bread wheat (Triticum aestivum 'Babbler') grain is composed of many outer layers of dead maternal tissues that overlie living aleurone cells. The dead cell layers function as a barrier resistant to degradation, whereas the aleurone layer is involved in mobilizing organic substrates in the endosperm during germination. We microdissected three defined bran fractions, outer layers (epidermis and hypodermis), intermediate fraction (cross cells, tube cells, testa, and nucellar tissue), and inner layer (aleurone cells), and used proteomics to identify their individual protein complements. All proteins of the outer layers were enzymes, whose function is to provide direct protection against pathogens or improve tissue strength. The more complex proteome of the intermediate layers suggests a greater diversity of function, including the inhibition of enzymes secreted by pathogens. The inner layer contains proteins involved in metabolism, as would be expected from live aleurone cells, but this layer also includes defense enzymes and inhibitors as well as 7S globulin (specific to this layer). Using immunofluorescence microscopy, oxalate oxidase was localized predominantly to the outer layers, xylanase inhibitor protein I to the xylan-rich nucellar layer of the intermediate fraction and pathogenesis-related protein 4 mainly to the aleurone. Activities of the water-extractable enzymes oxalate oxidase, peroxidase, and polyphenol oxidase were highest in the outer layers, whereas chitinase activity was found only in assays of whole grains. We conclude that the differential protein complements of each bran layer in wheat provide distinct lines of defense in protecting the embryo and nutrient-rich endosperm.
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Affiliation(s)
| | | | | | | | | | - Robert D. Willows
- Department of Chemistry and Biomolecular Sciences (A.J., A.M.K., J.R.B., T.H.R., R.D.W.) and Department of Biological Sciences (B.J.A.), Macquarie University, Sydney, New South Wales 2109, Australia; and Grain Foods Cooperative Research Centre Ltd., North Ryde, New South Wales 2113, Australia (A.J., A.M.K., J.R.B., B.J.A., T.H.R., R.D.W.)
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Abstract
Oryza meridionalis Ng. is a wild relative of Oryza sativa L. found throughout northern Australia where temperatures regularly exceed 35 degrees C in the monsoon growing season. Heat tolerance in O. meridionalis was established by comparing leaf elongation and photosynthetic rates at 45 degrees C with plants maintained at 27 degrees C. By comparison with O. sativa ssp. japonica cv. Amaroo, O. meridionalis was heat tolerant. Elongation rates of the third leaf of O. meridionalis declined by 47% over 24 h at 45 degrees C compared with a 91% decrease for O. sativa. Net photosynthesis was significantly higher in O. sativa at 27 degrees C whereas the two species had the same assimilation rates at 45 degrees C. The leaf proteome and expression levels of individual heat-responsive genes provided insight into the heat response of O. meridionalis. After 24 h of heat exposure, many enzymes involved in the Calvin Cycle were more abundant, while mRNA of their genes generally decreased. Ferredoxin-NADP(H) oxidoreductase, a key enzyme in photosynthetic electron transport had both reduced abundance and gene expression, suggesting light reactions were highly susceptible to heat stress. Rubisco activase was strongly up-regulated after 24 h of heat, with the large isoform having the largest relative increase in protein abundance and a significant increase in gene expression. The protective proteins Cpn60, Hsp90, and Hsp70 all increased in both protein abundance and gene expression. A thiamine biosynthesis protein (THI1), previously shown to act protectively against stress, increased in abundance during heat, even as thiamine levels fell in O. meridionalis.
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Affiliation(s)
- Andrew P. Scafaro
- Department of Biological Sciences, Macquarie University, NSW 2109, Australia
| | - Paul A. Haynes
- Department of Chemistry and Biomolecular Sciences, Macquarie University, NSW 2109, Australia
| | - Brian J. Atwell
- Department of Biological Sciences, Macquarie University, NSW 2109, Australia
- To whom correspondence should be addressed: E-mail:
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48
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Liu Q, Zhang Q, Burton RA, Shirley NJ, Atwell BJ. Expression of vacuolar H+-pyrophosphatase (OVP3) is under control of an anoxia-inducible promoter in rice. Plant Mol Biol 2010; 72:47-60. [PMID: 19763843 DOI: 10.1007/s11103-009-9549-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2008] [Accepted: 09/07/2009] [Indexed: 05/08/2023]
Abstract
Vacuolar H(+)-pyrophosphatase (V-PPase) expression increases in a number of abiotic stresses and is thought to play a role in adaptation to abiotic stresses. This paper reports on the regulation of six V-PPase genes in rice (Oryza sativa L.) coleoptiles under anoxia, using flood tolerant and intolerant cultivars to test our hypothesis. Quantitative PCR analysis showed that one vacuolar H(+)-pyrophosphatase (OVP3) was induced by anoxia, particularly in flood-tolerant rice. Regulation of OVP3 expression under anoxia was investigated by analysing putative OVP promoters. The putative OVP3 promoter contained more previously identified anoxia-inducible motifs than the putative promoters of the other five OVP genes. GUS activity in transgenic rice plants containing the OVP3 promoter region linked to the GUS reporter gene was induced only by anoxia. Salt and cold treatments had little effect on OVP3 promoter-driven GUS expression when compared to the anoxic treatment.
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Affiliation(s)
- Qinxiang Liu
- Department of Biological Sciences, Macquarie University, Sydney, NSW, 2109, Australia
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49
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Ahn JW, Atwell BJ, Roberts TH. Serpin genes AtSRP2 and AtSRP3 are required for normal growth sensitivity to a DNA alkylating agent in Arabidopsis. BMC Plant Biol 2009; 9:52. [PMID: 19426562 PMCID: PMC2689219 DOI: 10.1186/1471-2229-9-52] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2008] [Accepted: 05/11/2009] [Indexed: 05/23/2023]
Abstract
BACKGROUND The complex responses of plants to DNA damage are incompletely understood and the role of members of the serpin protein family has not been investigated. Serpins are functionally diverse but structurally conserved proteins found in all three domains of life. In animals, most serpins have regulatory functions through potent, irreversible inhibition of specific serine or cysteine proteinases via a unique suicide-substrate mechanism. Plant serpins are also potent proteinase inhibitors, but their physiological roles are largely unknown. RESULTS Six Arabidopsis genes encoding full-length serpins were differentially expressed in developing seedlings and mature tissues. Basal levels of AtSRP2 (At2g14540) and AtSRP3 (At1g64030) transcripts were highest in reproductive tissues. AtSRP2 was induced 5-fold and AtSRP3 100-fold after exposure of seedlings to low concentrations of methyl methanesulfonate (MMS), a model alkylating reagent that causes DNA damage. Homozygous T-DNA insertion mutants atsrp2 and atsrp3 exhibited no differential growth when mutant and wild-type plants were left untreated or exposed to gamma-radiation or ultraviolet light. In contrast, atsrp2 and atsrp3 plants exhibited greater root length, leaf number and overall size than wild-type plants when exposed to MMS. Neither of the two serpins was required for meiosis. GFP-AtSRP2 was localized to the nucleus, whereas GFP-AtSRP3 was cytosolic, suggesting that they target different proteinases. Induction of cell cycle- and DNA damage-related genes AtBRCA1, AtBARD1, AtRAD51, AtCYCB1;1 and AtCYCD1;1, but not AtATM, was reduced relative to wild-type in atsrp2 and atsrp3 mutants exposed to MMS. CONCLUSION Expression of specific serpin genes (AtSRP2 and AtSRP3 in Arabidopsis) is required for normal responses of plants following exposure to alkylating genotoxins such as MMS.
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Affiliation(s)
- Joon-Woo Ahn
- Department of Chemistry and Biomolecular Sciences, Macquarie University, North Ryde NSW 2109, Australia
| | - Brian J Atwell
- Department of Biological Sciences, Macquarie University, North Ryde NSW 2109, Australia
| | - Thomas H Roberts
- Department of Chemistry and Biomolecular Sciences, Macquarie University, North Ryde NSW 2109, Australia
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50
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Atwell BJ, Henery ML, Ball MC. Does soil nitrogen influence growth, water transport and survival of snow gum (Eucalyptus pauciflora Sieber ex Sprengel.) under CO enrichment? Plant Cell Environ 2009; 32:553-566. [PMID: 19210643 DOI: 10.1111/j.1365-3040.2009.01949.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Eucalyptus pauciflora Sieber ex Sprengel. (snow gum) was grown under ambient (370 microL L(-1)) and elevated (700 microL L(-1)) atmospheric [CO2] in open-top chambers (OTCs) in the field and temperature-controlled glasshouses. Nitrogen applications to the soil ranged from 0.1 to 2.75 g N per plant. Trees in the field at high N levels grew rapidly during summer, particularly in CO2-enriched atmosphere, but suffered high mortality during summer heatwaves. Generally, wider and more numerous secondary xylem vessels at the root-shoot junction in CO2-enriched trees conferred fourfold higher below-ground hydraulic conductance. Enhanced hydraulic capacity was typical of plants at elevated [CO2] (in which root and shoot growth was accelerated), but did not result from high N supply. However, because high rates of N application consistently made trees prone to dehydration during heatwaves, glasshouse studies were required to identify the effect of N nutrition on root development and hydraulics. While the effects of elevated [CO2] were again predominantly on hydraulic conductivity, N nutrition acted specifically by constraining deep root penetration into soil. Specifically, 15-40% shallower root systems supported marginally larger shoot canopies. Independent changes to hydraulics and root penetration have implications for survival of fertilized trees under elevated atmospheric [CO2], particularly during water stress.
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Affiliation(s)
- Brian J Atwell
- Department of Biological Sciences, Macquarie University, Sydney, NSW 2109, Australia.
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