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DELAY OF GERMINATION 1, the Master Regulator of Seed Dormancy, Integrates the Regulatory Network of Phytohormones at the Transcriptional Level to Control Seed Dormancy. Curr Issues Mol Biol 2022; 44:6205-6217. [PMID: 36547084 PMCID: PMC9777134 DOI: 10.3390/cimb44120423] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 11/30/2022] [Accepted: 12/05/2022] [Indexed: 12/13/2022] Open
Abstract
Seed dormancy, an important adaptive trait that governs germination timing, is endogenously controlled by phytohormones and genetic factors. DELAY OF GERMINATION 1 (DOG1) is the vital genetic regulator of dormancy, significantly affecting the expression of numerous ABA and GA metabolic genes. However, whether DOG1 could influence the expression of other phytohormone-related genes is still unknown. Here, we comprehensively investigated all well-documented hormone-related genes which might be affected in dog1-2 dry or imbibed seeds by using whole-transcriptome sequencing (RNA-seq). We found that DOG1 could systematically control the expression of phytohormone-related genes. An evident decrease was observed in the endogenous signal intensity of abscisic acid (ABA) and indole-3-acetic acid (IAA), while a dramatic increase appeared in that of gibberellins (GA), brassinosteroids (BR), and cytokinin (CK) in the dog1-2 background, which may contribute considerably to its dormancy-deficient phenotype. Collectively, our data highlight the role of DOG1 in balancing the expression of phytohormone-related genes and provide inspirational evidence that DOG1 may integrate the phytohormones network to control seed dormancy.
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Rog I, Chaturvedi AK, Tiwari V, Danon A. Low light-regulated intramolecular disulfide fine-tunes the role of PTOX in Arabidopsis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2022; 109:585-597. [PMID: 34767654 DOI: 10.1111/tpj.15579] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 11/01/2021] [Accepted: 11/08/2021] [Indexed: 06/13/2023]
Abstract
Disulfide-based regulation links the activity of numerous chloroplast proteins with photosynthesis-derived redox signals. The plastid terminal oxidase (PTOX) is a thylakoid-bound plastoquinol oxidase that has been implicated in multiple roles in the light and in the dark, which could require different levels of PTOX activity. Here we show that Arabidopsis PTOX contains a conserved C-terminus domain (CTD) with cysteines that evolved progressively following the colonization of the land by plants. Furthermore, the CTD contains a regulatory disulfide that is in the oxidized state in the dark and is rapidly reduced, within 5 min, in low light intensity (1-5 µE m-2 sec-1 ). The reduced PTOX form in the light was reoxidized within 15 min after transition to the dark. Mutation of the cysteines in the CTD prevented the formation of the oxidized form. This resulted in higher levels of reduced plastoquinone when measured at transition to the onset of low light. This is consistent with the reduced state of PTOX exhibiting diminished PTOX oxidase activity under conditions of limiting PQH2 substrate. Our findings suggest that AtPTOX-CTD evolved to provide light-dependent regulation of PTOX activity for the adaptation of plants to terrestrial conditions.
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Affiliation(s)
- Ido Rog
- Department of Plant & Environmental Sciences, Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Amit Kumar Chaturvedi
- Department of Plant & Environmental Sciences, Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Vivekanand Tiwari
- Department of Plant & Environmental Sciences, Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Avihai Danon
- Department of Plant & Environmental Sciences, Weizmann Institute of Science, Rehovot, 76100, Israel
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Cha JY, Lee DY, Ali I, Jeong SY, Shin B, Ji H, Kim JS, Kim MG, Kim WY. Arabidopsis GIGANTEA negatively regulates chloroplast biogenesis and resistance to herbicide butafenacil. PLANT CELL REPORTS 2019; 38:793-801. [PMID: 30968200 DOI: 10.1007/s00299-019-02409-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Accepted: 03/28/2019] [Indexed: 06/09/2023]
Abstract
Arabidopsis GI negatively regulates chloroplast biogenesis and resistance to the herbicide butafenacil by enhanced activity and transcriptional levels of antioxidant enzymes Chloroplast biogenesis is blocked by retrograde signaling triggered by diverse internal and external cues, including sugar, reactive oxygen species (ROS), phytohormones, and abiotic stress. Efficient chloroplast biogenesis is essential for crop productivity due to its effect on photosynthetic efficiency, and is associated with agronomic traits such as insect/disease resistance, herbicide resistance, and abiotic stress tolerance. Here, we show that the circadian clock-controlled gene GIGANTEA (GI) regulates chloroplast biogenesis in Arabidopsis thaliana. The gi-2 mutant showed reduced sensitivity to the chloroplast biogenesis inhibitor lincomycin, maintaining high levels of photosynthetic proteins. By contrast, wild-type and GI-overexpressing plants were sensitive to lincomycin, with variegated leaves and reduced photosynthetic protein levels. GI is degraded by lincomycin, suggesting that GI is genetically linked to chloroplast biogenesis. The GI mutant alleles gi-1 and gi-2 were resistant to the herbicide butafenacil, which inhibits protoporphyrinogen IX oxidase activity and triggers ROS-mediated cell death via the accumulation of chlorophyll precursors. Butafenacil-mediated accumulation of superoxide anions and H2O2 was not detected in gi-1 or gi-2, as revealed by histochemical staining. The activities of the antioxidant enzymes superoxide dismutase, peroxidase, and catalase were 1.2-1.4-fold higher in both gi mutants compared to the wild type. Finally, the expression levels of antioxidant enzyme genes were 1.5-2-fold higher in the mutants than in the wild type. These results suggest that GI negatively regulates chloroplast biogenesis and resistance to the herbicide butafenacil, providing evidence for a genetic link between GI and chloroplast biogenesis, which could facilitate the development of herbicide-resistant crops.
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Affiliation(s)
- Joon-Yung Cha
- Division of Applied Life Science (BK21Plus), Plant Molecular Biology and Biotechnology Research Center (PMBBRC), Institute of Agricultural and Life Science (IALS), Gyeongsang National University, Jinju, 52828, Republic of Korea
| | - Da-Yeon Lee
- Division of Applied Life Science (BK21Plus), Plant Molecular Biology and Biotechnology Research Center (PMBBRC), Institute of Agricultural and Life Science (IALS), Gyeongsang National University, Jinju, 52828, Republic of Korea
| | - Imdad Ali
- Division of Applied Life Science (BK21Plus), Plant Molecular Biology and Biotechnology Research Center (PMBBRC), Institute of Agricultural and Life Science (IALS), Gyeongsang National University, Jinju, 52828, Republic of Korea
| | - Song Yi Jeong
- Division of Applied Life Science (BK21Plus), Plant Molecular Biology and Biotechnology Research Center (PMBBRC), Institute of Agricultural and Life Science (IALS), Gyeongsang National University, Jinju, 52828, Republic of Korea
| | - Bobae Shin
- Department of Agricultural Chemistry and Food Science and Technology, Gyeongsang National University, Jinju, 52828, Republic of Korea
| | - Hyunjung Ji
- Department of Agricultural Chemistry and Food Science and Technology, Gyeongsang National University, Jinju, 52828, Republic of Korea
| | - Jung Sun Kim
- Department of Agricultural Biotechnology, National Institute of Agricultural Sciences, Rural Development Administration, Jeonju, 54874, Republic of Korea
| | - Min-Gab Kim
- College of Pharmacy and Research Institute of Pharmaceutical Science, PMBBRC, Gyeongsang National University, Jinju, 52828, Republic of Korea
| | - Woe-Yeon Kim
- Division of Applied Life Science (BK21Plus), Plant Molecular Biology and Biotechnology Research Center (PMBBRC), Institute of Agricultural and Life Science (IALS), Gyeongsang National University, Jinju, 52828, Republic of Korea.
- Department of Agricultural Chemistry and Food Science and Technology, Gyeongsang National University, Jinju, 52828, Republic of Korea.
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Singh M, Mas P. A Functional Connection between the Circadian Clock and Hormonal Timing in Arabidopsis. Genes (Basel) 2018; 9:E567. [PMID: 30477118 PMCID: PMC6315462 DOI: 10.3390/genes9120567] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 11/20/2018] [Accepted: 11/20/2018] [Indexed: 02/04/2023] Open
Abstract
The rotation of the Earth entails changes in environmental conditions that pervasively influence an organism's physiology and metabolism. An internal cellular mechanism known as the circadian clock acts as an internal timekeeper that is able to perceive the changes in environmental cues to generate 24-h rhythms in synchronization with daily and seasonal fluctuations. In plants, the circadian clock function is particularly important and regulates nearly every aspect of plant growth and development as well as proper responses to stresses. The circadian clock does not function in isolation but rather interconnects with an intricate network of different pathways, including those of phytohormones. Here, we describe the interplay of the circadian clock with a subset of hormones in Arabidopsis. The molecular components directly connecting the circadian and hormone pathways are described, highlighting the biological significance of such connections in the control of growth, development, fitness, and survival. We focus on the overlapping as well as contrasting circadian and hormonal functions that together provide a glimpse on how the Arabidopsis circadian system regulates hormone function in response to endogenous and exogenous cues. Examples of feedback regulation from hormone signaling to the clock are also discussed.
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Affiliation(s)
- Manjul Singh
- Center for Research in Agricultural Genomics (CRAG), Consortium CSIC-IRTA-UAB-UB, Campus UAB, Bellaterra, 08193 Barcelona, Spain.
| | - Paloma Mas
- Center for Research in Agricultural Genomics (CRAG), Consortium CSIC-IRTA-UAB-UB, Campus UAB, Bellaterra, 08193 Barcelona, Spain.
- Consejo Superior de Investigaciones Científicas, 08028 Barcelona, Spain.
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Li JX, Hou XJ, Zhu J, Zhou JJ, Huang HB, Yue JQ, Gao JY, Du YX, Hu CX, Hu CG, Zhang JZ. Identification of Genes Associated with Lemon Floral Transition and Flower Development during Floral Inductive Water Deficits: A Hypothetical Model. FRONTIERS IN PLANT SCIENCE 2017; 8:1013. [PMID: 28659956 PMCID: PMC5468436 DOI: 10.3389/fpls.2017.01013] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2017] [Accepted: 05/26/2017] [Indexed: 05/11/2023]
Abstract
UNLABELLED Water deficit is a key factor to induce flowering in many woody plants, but reports on the molecular mechanisms of floral induction and flowering by water deficit are scarce. Here, we analyzed the morphology, cytology, and different hormone levels of lemon buds during floral inductive water deficits. Higher levels of ABA were observed, and the initiation of floral bud differentiation was examined by paraffin sections analysis. A total of 1638 differentially expressed genes (DEGs) were identified by RNA sequencing. DEGs were related to flowering, hormone biosynthesis, or metabolism. The expression of some DEGs was associated with floral induction by real-time PCR analysis. However, some DEGs may not have anything to do with flowering induction/flower development; they may be involved in general stress/drought response. Four genes from the phosphatidylethanolamine-binding protein family were further investigated. Ectopic expression of these genes in Arabidopsis changed the flowering time of transgenic plants. Furthermore, the 5' flanking region of these genes was also isolated and sequence analysis revealed the presence of several putative cis-regulatory elements, including basic elements and hormone regulation elements. The spatial and temporal expression patterns of these promoters were investigated under water deficit treatment. Based on these findings, we propose a model for citrus flowering under water deficit conditions, which will enable us to further understand the molecular mechanism of water deficit-regulated flowering in citrus. HIGHLIGHT Based on gene activity during floral inductive water deficits identified by RNA sequencing and genes associated with lemon floral transition, a model for citrus flowering under water deficit conditions is proposed.
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Affiliation(s)
- Jin-Xue Li
- College of Resources and Environment, Huazhong Agricultural UniversityWuhan, China
- Institute of Tropical and Subtropical Cash Crops, Yunnan Academy of Agricultural SciencesKunming, China
| | - Xiao-Jin Hou
- Key Laboratory of Horticultural Plant Biology (Ministry of Education), College of Horticulture and Forestry Science, Huazhong Agricultural UniversityWuhan, China
| | - Jiao Zhu
- Key Laboratory of Horticultural Plant Biology (Ministry of Education), College of Horticulture and Forestry Science, Huazhong Agricultural UniversityWuhan, China
| | - Jing-Jing Zhou
- College of Horticulture and Forestry Science, Huazhong Agricultural UniversityWuhan, China
- *Correspondence: Jing-Jing Zhou, Jin-Zhi Zhang,
| | - Hua-Bin Huang
- Institute of Tropical and Subtropical Cash Crops, Yunnan Academy of Agricultural SciencesKunming, China
| | - Jian-Qiang Yue
- Institute of Tropical and Subtropical Cash Crops, Yunnan Academy of Agricultural SciencesKunming, China
| | - Jun-Yan Gao
- Institute of Tropical and Subtropical Cash Crops, Yunnan Academy of Agricultural SciencesKunming, China
| | - Yu-Xia Du
- Institute of Tropical and Subtropical Cash Crops, Yunnan Academy of Agricultural SciencesKunming, China
| | - Cheng-Xiao Hu
- Key Laboratory of Horticultural Plant Biology (Ministry of Education), College of Horticulture and Forestry Science, Huazhong Agricultural UniversityWuhan, China
| | - Chun-Gen Hu
- Key Laboratory of Horticultural Plant Biology (Ministry of Education), College of Horticulture and Forestry Science, Huazhong Agricultural UniversityWuhan, China
| | - Jin-Zhi Zhang
- Key Laboratory of Horticultural Plant Biology (Ministry of Education), College of Horticulture and Forestry Science, Huazhong Agricultural UniversityWuhan, China
- *Correspondence: Jing-Jing Zhou, Jin-Zhi Zhang,
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Kambakam S, Bhattacharjee U, Petrich J, Rodermel S. PTOX Mediates Novel Pathways of Electron Transport in Etioplasts of Arabidopsis. MOLECULAR PLANT 2016; 9:1240-1259. [PMID: 27353362 DOI: 10.1016/j.molp.2016.06.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2015] [Revised: 06/05/2016] [Accepted: 06/16/2016] [Indexed: 05/21/2023]
Abstract
The immutans (im) variegation mutant of Arabidopsis defines the gene for PTOX (plastid terminal oxidase), a versatile plastoquinol oxidase in chloroplast membranes. In this report we used im to gain insight into the function of PTOX in etioplasts of dark-grown seedlings. We discovered that PTOX helps control the redox state of the plastoquinone (PQ) pool in these organelles, and that it plays an essential role in etioplast metabolism by participating in the desaturation reactions of carotenogenesis and in one or more redox pathways mediated by PGR5 (PROTON GRADIENT REGULATION 5) and NDH (NAD(P)H dehydrogenase), both of which are central players in cyclic electron transport. We propose that these elements couple PTOX with electron flow from NAD(P)H to oxygen, and by analogy to chlororespiration (in chloroplasts) and chromorespiration (in chromoplasts), we suggest that they define a respiratory process in etioplasts that we have termed "etiorespiration". We further show that the redox state of the PQ pool in etioplasts might control chlorophyll biosynthesis, perhaps by participating in mechanisms of retrograde (plastid-to-nucleus) signaling that coordinate biosynthetic and photoprotective activities required to poise the etioplast for light development. We conclude that PTOX is an important component of metabolism and redox sensing in etioplasts.
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Affiliation(s)
- Sekhar Kambakam
- Department of Genetics, Development and Cell Biology, Iowa State University, 445 Bessey Hall, Ames, IA 50011, USA
| | | | - Jacob Petrich
- Department of Chemistry, Iowa State University, Ames, IA 50011, USA
| | - Steve Rodermel
- Department of Genetics, Development and Cell Biology, Iowa State University, 445 Bessey Hall, Ames, IA 50011, USA.
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Impaired Chloroplast Biogenesis in Immutans, an Arabidopsis Variegation Mutant, Modifies Developmental Programming, Cell Wall Composition and Resistance to Pseudomonas syringae. PLoS One 2016; 11:e0150983. [PMID: 27050746 PMCID: PMC4822847 DOI: 10.1371/journal.pone.0150983] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Accepted: 02/21/2016] [Indexed: 12/20/2022] Open
Abstract
The immutans (im) variegation mutation of Arabidopsis has green- and white- sectored leaves due to action of a nuclear recessive gene. IM codes for PTOX, a plastoquinol oxidase in plastid membranes. Previous studies have revealed that the green and white sectors develop into sources (green tissues) and sinks (white tissues) early in leaf development. In this report we focus on white sectors, and show that their transformation into effective sinks involves a sharp reduction in plastid number and size. Despite these reductions, cells in the white sectors have near-normal amounts of plastid RNA and protein, and surprisingly, a marked amplification of chloroplast DNA. The maintenance of protein synthesis capacity in the white sectors might poise plastids for their development into other plastid types. The green and white im sectors have different cell wall compositions: whereas cell walls in the green sectors resemble those in wild type, cell walls in the white sectors have reduced lignin and cellulose microfibrils, as well as alterations in galactomannans and the decoration of xyloglucan. These changes promote susceptibility to the pathogen Pseudomonas syringae. Enhanced susceptibility can also be explained by repressed expression of some, but not all, defense genes. We suggest that differences in morphology, physiology and biochemistry between the green and white sectors is caused by a reprogramming of leaf development that is coordinated, in part, by mechanisms of retrograde (plastid-to-nucleus) signaling, perhaps mediated by ROS. We conclude that variegation mutants offer a novel system to study leaf developmental programming, cell wall metabolism and host-pathogen interactions.
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Abadie C, Lamothe-Sibold M, Gilard F, Tcherkez G. Isotopic evidence for nitrogen exchange between autotrophic and heterotrophic tissues in variegated leaves. FUNCTIONAL PLANT BIOLOGY : FPB 2016; 43:298-306. [PMID: 32480462 DOI: 10.1071/fp15187] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Accepted: 11/12/2015] [Indexed: 05/15/2023]
Abstract
Many plant species or cultivars form variegated leaves in which blades are made of green and white sectors. On the one hand, there is little photosynthetic CO2 assimilation in white tissue simply because of the lack of functional chloroplasts and thus, leaf white tissue is heterotrophic and fed by photosynthates exported by leaf green tissue. On the other hand, it has been previously shown that the white tissue is enriched in nitrogenous compounds such as amino acids and polyamines, which can, in turn, be remobilised upon nitrogen deficiency. However, the origin of organic nitrogen in leaf white tissue, including the possible requirement for N-reduction in leaf green tissue before export to white tissue, has not been examined. Here, we took advantage of isotopic methods to investigate the source of nitrogen in the white tissue. A survey of natural isotope abundance (δ15N) and elemental composition (%N) in various variegated species shows no visible difference between white and green tissues, suggesting a common N source. However, there is a tendency for N-rich white tissue to be naturally 15N-enriched whereas in the model species Pelargonium×hortorum, white sectors are naturally 15N-depleted, indicating that changes in metabolic composition and/or N-partitioning may occur. Isotopic labelling with 15N-nitrate on illuminated leaf discs clearly shows that the white tissue assimilates little nitrogen and thus relies on nitrate reduction and metabolism in the green tissue. The N-sink represented by the white tissue is considerable, accounting for nearly 50% of total assimilated nitrate.
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Affiliation(s)
- Cyril Abadie
- Research School of Biology, ANU College of Medicine, Biology and Environment, Australian National University, Canberra, ACT 2601, Australia
| | - Marlène Lamothe-Sibold
- Université Paris-Sud, Institute of Plant Sciences Paris-Saclay IPS2 (Bâtiment 630), UMR CNRS-INRA 9213, Université Paris-Saclay, 91405 Orsay, France
| | - Françoise Gilard
- Université Paris-Sud, Institute of Plant Sciences Paris-Saclay IPS2 (Bâtiment 630), UMR CNRS-INRA 9213, Université Paris-Saclay, 91405 Orsay, France
| | - Guillaume Tcherkez
- Research School of Biology, ANU College of Medicine, Biology and Environment, Australian National University, Canberra, ACT 2601, Australia
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Park H, Kim WY, Pardo J, Yun DJ. Molecular Interactions Between Flowering Time and Abiotic Stress Pathways. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2016; 327:371-412. [DOI: 10.1016/bs.ircmb.2016.07.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Investigating the Association between Flowering Time and Defense in the Arabidopsis thaliana-Fusarium oxysporum Interaction. PLoS One 2015; 10:e0127699. [PMID: 26034991 PMCID: PMC4452756 DOI: 10.1371/journal.pone.0127699] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Accepted: 04/17/2015] [Indexed: 12/21/2022] Open
Abstract
Plants respond to pathogens either by investing more resources into immunity which is costly to development, or by accelerating reproductive processes such as flowering time to ensure reproduction occurs before the plant succumbs to disease. In this study we explored the link between flowering time and pathogen defense using the interaction between Arabidopsis thaliana and the root infecting fungal pathogen Fusarium oxysporum. We report that F. oxysporum infection accelerates flowering time and regulates transcription of a number of floral integrator genes, including FLOWERING LOCUS C (FLC), FLOWERING LOCUS T (FT) and GIGANTEA (GI). Furthermore, we observed a positive correlation between late flowering and resistance to F. oxysporum in A. thaliana natural ecotypes. Late-flowering gi and autonomous pathway mutants also exhibited enhanced resistance to F. oxysporum, supporting the association between flowering time and defense. However, epistasis analysis showed that accelerating flowering time by deletion of FLC in fve-3 or fpa-7 mutants did not alter disease resistance, suggesting that the effect of autonomous pathway on disease resistance occurs independently from flowering time. Indeed, RNA-seq analyses suggest that fve-3 mediated resistance to F. oxysporum is most likely a result of altered defense-associated gene transcription. Together, our results indicate that the association between flowering time and pathogen defense is complex and can involve both pleiotropic and direct effects.
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Kooyers NJ. The evolution of drought escape and avoidance in natural herbaceous populations. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2015; 234:155-62. [PMID: 25804818 DOI: 10.1016/j.plantsci.2015.02.012] [Citation(s) in RCA: 170] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Revised: 02/04/2015] [Accepted: 02/19/2015] [Indexed: 05/03/2023]
Abstract
While the functional genetics and physiological mechanisms controlling drought resistance in crop plants have been intensely studied, less research has examined the genetic basis of adaptation to drought stress in natural populations. Drought resistance adaptations in nature reflect natural rather than human-mediated selection and may identify novel mechanisms for stress tolerance. Adaptations conferring drought resistance have historically been divided into alternative strategies including drought escape (rapid development to complete a life cycle before drought) and drought avoidance (reducing water loss to prevent dehydration). Recent studies in genetic model systems such as Arabidopsis, Mimulus, and Panicum have begun to elucidate the genes, expression profiles, and physiological changes responsible for ecologically important variation in drought resistance. Similar to most crop plants, variation in drought escape and avoidance is complex, underlain by many QTL of small effect, and pervasive gene by environment interactions. Recently identified major-effect alleles point to a significant role for genetic constraints in limiting the concurrent evolution of both drought escape and avoidance strategies, although these constraints are not universally found. This progress suggests that understanding the mechanistic basic and fitness consequences of gene by environment interactions will be critical for crop improvement and forecasting population persistence in unpredictable environments.
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Affiliation(s)
- Nicholas J Kooyers
- Department of Biology, University of Virginia, Charlottesville, VA 22904, USA.
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