1
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Wexler Y, Schroeder JI, Shkolnik D. Hydrotropism mechanisms and their interplay with gravitropism. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2024; 118:1732-1746. [PMID: 38394056 DOI: 10.1111/tpj.16683] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Revised: 01/29/2024] [Accepted: 02/02/2024] [Indexed: 02/25/2024]
Abstract
Plants partly optimize their water recruitment from the growth medium by directing root growth toward a moisture source, a phenomenon termed hydrotropism. The default mechanism of downward growth, termed gravitropism, often functions to counteract hydrotropism when the water-potential gradient deviates from the gravity vector. This review addresses the identity of the root sites in which hydrotropism-regulating factors function to attenuate gravitropism and the interplay between these various factors. In this context, the function of hormones, including auxin, abscisic acid, and cytokinins, as well as secondary messengers, calcium ions, and reactive oxygen species in the conflict between these two opposing tropisms is discussed. We have assembled the available data on the effects of various chemicals and genetic backgrounds on both gravitropism and hydrotropism, to provide an up-to-date perspective on the interactions that dictate the orientation of root tip growth. We specify the relevant open questions for future research. Broadening our understanding of root mechanisms of water recruitment holds great potential for providing advanced approaches and technologies that can improve crop plant performance under less-than-optimal conditions, in light of predicted frequent and prolonged drought periods due to global climate change.
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Affiliation(s)
- Yonatan Wexler
- Faculty of Life Sciences, School of Plant Sciences and Food Security, Tel Aviv University, Tel Aviv, 69978, Israel
| | - Julian I Schroeder
- Cell and Developmental Biology Department, School of Biological Sciences, University of California San Diego, La Jolla, California, 92093-0116, USA
| | - Doron Shkolnik
- Faculty of Agriculture, Food and Environment, Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, The Hebrew University of Jerusalem, Rehovot, 7610001, Israel
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2
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Kohler AR, Scheil A, Hill JL, Allen JR, Al-Haddad JM, Goeckeritz CZ, Strader LC, Telewski FW, Hollender CA. Defying gravity: WEEP promotes negative gravitropism in peach trees by establishing asymmetric auxin gradients. PLANT PHYSIOLOGY 2024; 195:1229-1255. [PMID: 38366651 PMCID: PMC11142379 DOI: 10.1093/plphys/kiae085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Revised: 01/09/2024] [Accepted: 01/14/2024] [Indexed: 02/18/2024]
Abstract
Trees with weeping shoot architectures are valued for their beauty and are a resource for understanding how plants regulate posture control. The peach (Prunus persica) weeping phenotype, which has elliptical downward arching branches, is caused by a homozygous mutation in the WEEP gene. Little is known about the function of WEEP despite its high conservation throughout Plantae. Here, we present the results of anatomical, biochemical, biomechanical, physiological, and molecular experiments that provide insight into WEEP function. Our data suggest that weeping peach trees do not have defects in branch structure. Rather, transcriptomes from the adaxial (upper) and abaxial (lower) sides of standard and weeping branch shoot tips revealed flipped expression patterns for genes associated with early auxin response, tissue patterning, cell elongation, and tension wood development. This suggests that WEEP promotes polar auxin transport toward the lower side during shoot gravitropic response, leading to cell elongation and tension wood development. In addition, weeping peach trees exhibited steeper root systems and faster lateral root gravitropic response. This suggests that WEEP moderates root gravitropism and is essential to establishing the set-point angle of lateral roots from the gravity vector. Additionally, size exclusion chromatography indicated that WEEP proteins self-oligomerize, like other proteins with sterile alpha motif domains. Collectively, our results from weeping peach provide insight into polar auxin transport mechanisms associated with gravitropism and lateral shoot and root orientation.
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Affiliation(s)
- Andrea R Kohler
- Department of Horticulture, Michigan State University, East Lansing, MI 48824, USA
| | - Andrew Scheil
- Department of Horticulture, Michigan State University, East Lansing, MI 48824, USA
| | - Joseph L Hill
- Department of Horticulture, Michigan State University, East Lansing, MI 48824, USA
| | - Jeffrey R Allen
- Department of Biology, Duke University, Durham, NC 27708, USA
| | - Jameel M Al-Haddad
- Department of Plant Biology, Michigan State University, East Lansing, MI 48824, USA
| | - Charity Z Goeckeritz
- Department of Horticulture, Michigan State University, East Lansing, MI 48824, USA
| | - Lucia C Strader
- Department of Biology, Duke University, Durham, NC 27708, USA
| | - Frank W Telewski
- Department of Plant Biology, Michigan State University, East Lansing, MI 48824, USA
| | - Courtney A Hollender
- Department of Horticulture, Michigan State University, East Lansing, MI 48824, USA
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3
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Waite JM, Dardick C. IGT/LAZY genes are differentially influenced by light and required for light-induced change to organ angle. BMC Biol 2024; 22:8. [PMID: 38233837 PMCID: PMC10795295 DOI: 10.1186/s12915-024-01813-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Accepted: 01/02/2024] [Indexed: 01/19/2024] Open
Abstract
BACKGROUND Plants adjust their growth orientations primarily in response to light and gravity signals. Considering that the gravity vector is fixed and the angle of light incidence is constantly changing, plants must somehow integrate these signals to establish organ orientation, commonly referred to as gravitropic set-point angle (GSA). The IGT gene family contains known regulators of GSA, including the gene clades LAZY, DEEPER ROOTING (DRO), and TILLER ANGLE CONTROL (TAC). RESULTS Here, we investigated the influence of light on different aspects of GSA phenotypes in LAZY and DRO mutants, as well as the influence of known light signaling pathways on IGT gene expression. Phenotypic analysis revealed that LAZY and DRO genes are collectively required for changes in the angle of shoot branch tip and root growth in response to light. Single lazy1 mutant branch tips turn upward in the absence of light and in low light, similar to wild-type, and mimic triple and quadruple IGT mutants in constant light and high-light conditions, while triple and quadruple IGT/LAZY mutants show little to no response to changing light regimes. Further, the expression of IGT/LAZY genes is differentially influenced by daylength, circadian clock, and light signaling. CONCLUSIONS Collectively, the data show that differential expression of LAZY and DRO genes are required to enable plants to alter organ angles in response to light-mediated signals.
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Affiliation(s)
- Jessica Marie Waite
- United States Department of Agriculture (USDA) Appalachian Fruit Research Station, 2217 Wiltshire Road, Kearneysville, WV, USA.
- Present Address: USDA Tree Fruit Research Laboratory, 1104 N Western Avenue, Wenatchee, WA, USA.
| | - Christopher Dardick
- United States Department of Agriculture (USDA) Appalachian Fruit Research Station, 2217 Wiltshire Road, Kearneysville, WV, USA
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4
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Waite JM, Hollender CA, Eilers JR, Burchard E, Dardick C. Peach LAZY1 and DRO1 protein-protein interactions and co-expression with PRAF/RLD family support conserved gravity-related protein interactions across plants. MICROPUBLICATION BIOLOGY 2024; 2024:10.17912/micropub.biology.000995. [PMID: 38287925 PMCID: PMC10823791 DOI: 10.17912/micropub.biology.000995] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Figures] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Revised: 12/12/2023] [Accepted: 01/09/2024] [Indexed: 01/31/2024]
Abstract
IGT/LAZY proteins play a central role in determining gravitropic set point angle and orientation of lateral organs across plant species. Recent work in model systems has demonstrated that interactions between IGT/LAZY proteins and BREVIS RADIX (BRX)-domain containing proteins, such as PH, RCC1, AND FYVE/RCC1-LIKE DOMAIN (PRAF/RLD), and BREVIS RADIX LIKE (BRXL) family members, are mechanistically important for setting gravitropic set point angle. Here, we identified peach PRAF/RLD proteins as interactors of the peach IGT/LAZY proteins PpeLAZY1 and DEEPER ROOTING 1 (PpeDRO1) from a yeast-two-hybrid screen. We also show that the BRX domains of these interacting proteins have high sequence similarity with PRAF/RLD and BRX family proteins from rice and Arabidopsis. Further, PpeLAZY1 and the peach PRAF/RLD interactors are all expressed at relatively high levels in leaf, meristem, and shoot tip tissues. Together, this evidence supports the importance and conservation of IGT/LAZY-BRX-domain interactions, which underlie setting gravitropic set point angle across angiosperms.
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Affiliation(s)
| | | | - Jon R. Eilers
- USDA ARS Tree Fruit Research Laboratory, Wenatchee, WA
| | - Erik Burchard
- USDA ARS Appalachian Fruit Research Station, Kearneysville, WV
| | - Chris Dardick
- USDA ARS Appalachian Fruit Research Station, Kearneysville, WV
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5
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Totsline N, Kniel KE, Sabagyanam C, Bais HP. Simulated microgravity facilitates stomatal ingression by Salmonella in lettuce and suppresses a biocontrol agent. Sci Rep 2024; 14:898. [PMID: 38195662 PMCID: PMC10776768 DOI: 10.1038/s41598-024-51573-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Accepted: 01/07/2024] [Indexed: 01/11/2024] Open
Abstract
As human spaceflight increases in duration, cultivation of crops in spaceflight is crucial to protecting human health under microgravity and elevated oxidative stress. Foodborne pathogens (e.g., Salmonella enterica) carried by leafy green vegetables are a significant cause of human disease. Our previous work showed that Salmonella enterica serovar Typhimurium suppresses defensive closure of foliar stomata in lettuce (Lactuca sativa L.) to ingress interior tissues of leaves. While there are no reported occurrences of foodborne disease in spaceflight to date, known foodborne pathogens persist aboard the International Space Station and space-grown lettuce has been colonized by a diverse microbiome including bacterial genera known to contain human pathogens. Interactions between leafy green vegetables and human bacterial pathogens under microgravity conditions present in spaceflight are unknown. Additionally, stomatal dynamics under microgravity conditions need further elucidation. Here, we employ a slow-rotating 2-D clinostat to simulate microgravity upon in-vitro lettuce plants following a foliar inoculation with S. enterica Typhimurium and use confocal microscopy to measure stomatal width in fixed leaf tissue. Our results reveal significant differences in average stomatal aperture width between an unrotated vertical control, plants rotated at 2 revolutions per minute (2 RPM), and 4 RPM, with and without the presence of S. typhimurium. Interestingly, we found stomatal aperture width in the presence of S. typhimurium to be increased under rotation as compared to unrotated inoculated plants. Using confocal Z-stacking, we observed greater average depth of stomatal ingression by S. typhimurium in lettuce under rotation at 4 RPM compared to unrotated and inoculated plants, along with greater in planta populations of S. typhimurium in lettuce rotated at 4 RPM using serial dilution plating of homogenized surface sterilized leaves. Given these findings, we tested the ability of the plant growth-promoting rhizobacteria (PGPR) Bacillus subtilis strain UD1022 to transiently restrict stomatal apertures of lettuce both alone and co-inoculated with S. typhimurium under rotated and unrotated conditions as a means of potentially reducing stomatal ingression by S. typhimurium under simulated microgravity. Surprisingly, rotation at 4 RPM strongly inhibited the ability of UD1022 alone to restrict stomatal apertures and attenuated its efficacy as a biocontrol following co-inoculation with S. typhimurium. Our results highlight potential spaceflight food safety issues unique to production of crops in microgravity conditions and suggest microgravity may dramatically reduce the ability of PGPRs to restrict stomatal apertures.
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Affiliation(s)
- Noah Totsline
- Department of Plant and Soil Sciences, University of Delaware, Newark, DE, 19713, USA.
- Delaware Biotechnology Institute, University of Delaware, 311 AP Biopharma, 590 Avenue 1743, Newark, DE, 19713, USA.
| | - Kalmia E Kniel
- Department of Animal and Food Sciences, University of Delaware, Newark, DE, 19713, USA
| | - Chandran Sabagyanam
- Delaware Biotechnology Institute, University of Delaware, 311 AP Biopharma, 590 Avenue 1743, Newark, DE, 19713, USA
| | - Harsh P Bais
- Department of Plant and Soil Sciences, University of Delaware, Newark, DE, 19713, USA.
- Delaware Biotechnology Institute, University of Delaware, 311 AP Biopharma, 590 Avenue 1743, Newark, DE, 19713, USA.
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6
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Farkas S, Kleine-Vehn J. Gravitropism: The LAZY way of intracellular hitchhiking. Curr Biol 2023; 33:R1224-R1226. [PMID: 38052169 DOI: 10.1016/j.cub.2023.10.032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/07/2023]
Abstract
Plant gravitropism has fascinated scientists for centuries. A new study provides a major mechanistic update of the so-called starch/statolith hypothesis, revealing how gravity perception is converted into a physiological response.
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Affiliation(s)
- Sophie Farkas
- Institute of Biology II, Chair of Molecular Plant Physiology (MoPP), University of Freiburg, 79104 Freiburg, Germany.
| | - Jürgen Kleine-Vehn
- Institute of Biology II, Chair of Molecular Plant Physiology (MoPP), University of Freiburg, 79104 Freiburg, Germany; Center for Integrative Biological Signalling Studies (CIBSS), University of Freiburg, 79104 Freiburg, Germany.
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7
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Chu W, Zhu X, Jiang T, Wang S, Ni W. Genome-wide identification of peanut IGT family genes and their potential roles in the development of plant architecture. Sci Rep 2023; 13:20400. [PMID: 37990054 PMCID: PMC10663514 DOI: 10.1038/s41598-023-47722-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Accepted: 11/17/2023] [Indexed: 11/23/2023] Open
Abstract
IGT family genes play essential roles in shaping plant architecture. However, limited amount of information is available about IGT family genes in peanuts (Arachis hypogaea). In the current study, 13 AhIGT genes were identified and classified into three groups based on their phylogenetic relationship. Gene structure, conserved domain analyses indicated all AhIGTs were observed to share a similar exon-intron distribution pattern. AhIGTs within the same subfamily maintained a consistent motif composition. Chromosomal localization and synteny analyses showed that AhIGTs were unevenly localized on 9 chromosomes and that segmental duplication and purifying selection may have played important roles in the evolution of AhIGT genes. The analysis of conserved motifs, GO annotation, and transcript profile suggested that AhLAZY1-3 may play roles in gravity sensing and shaping peanut plant architecture. Transcript profile analysis suggested that AhTAC1 could potentially be involved gynophore ('peg') penetration into the soil. The cis-element analysis revealed that the light-responsive elements accounted for most of all cis-acting elements. Furthermore, qRT-PCR analysis showed that the expression of several AhIGT genes, like AhTAC1-2/4, was light-dependent, indicating that these genes may regulate plant architecture in response to light signals. This study may facilitate functional studies of the IGT genes in peanut.
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Affiliation(s)
- Wen Chu
- Crops Research Institute, Anhui Academy of Agricultural Sciences, Hefei, 230031, China
| | - Xiaofeng Zhu
- Crops Research Institute, Anhui Academy of Agricultural Sciences, Hefei, 230031, China
| | - Tao Jiang
- Crops Research Institute, Anhui Academy of Agricultural Sciences, Hefei, 230031, China
| | - Song Wang
- Crops Research Institute, Anhui Academy of Agricultural Sciences, Hefei, 230031, China
| | - Wanli Ni
- Crops Research Institute, Anhui Academy of Agricultural Sciences, Hefei, 230031, China.
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8
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Kuya N, Nishijima R, Kitomi Y, Kawakatsu T, Uga Y. Transcriptome profiles of rice roots under simulated microgravity conditions and following gravistimulation. FRONTIERS IN PLANT SCIENCE 2023; 14:1193042. [PMID: 37360733 PMCID: PMC10288856 DOI: 10.3389/fpls.2023.1193042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Accepted: 05/24/2023] [Indexed: 06/28/2023]
Abstract
Root system architecture affects the efficient uptake of water and nutrients in plants. The root growth angle, which is a critical component in determining root system architecture, is affected by root gravitropism; however, the mechanism of root gravitropism in rice remains largely unknown. In this study, we conducted a time-course transcriptome analysis of rice roots under conditions of simulated microgravity using a three-dimensional clinostat and following gravistimulation to detect candidate genes associated with the gravitropic response. We found that HEAT SHOCK PROTEIN (HSP) genes, which are involved in the regulation of auxin transport, were preferentially up-regulated during simulated microgravity conditions and rapidly down-regulated by gravistimulation. We also found that the transcription factor HEAT STRESS TRANSCRIPTION FACTOR A2s (HSFA2s) and HSFB2s, showed the similar expression patterns with the HSPs. A co-expression network analysis and an in silico motif search within the upstream regions of the co-expressed genes revealed possible transcriptional control of HSPs by HSFs. Because HSFA2s are transcriptional activators, whereas HSFB2s are transcriptional repressors, the results suggest that the gene regulatory networks governed by HSFs modulate the gravitropic response through transcriptional control of HSPs in rice roots.
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Affiliation(s)
- Noriyuki Kuya
- Institute of Crop Science, National Agriculture and Food Research Organization, Tsukuba, Japan
| | - Ryo Nishijima
- Institute of Agrobiological Sciences, National Agriculture and Food Research Organization, Tsukuba, Japan
| | - Yuka Kitomi
- Institute of Crop Science, National Agriculture and Food Research Organization, Tsukuba, Japan
| | - Taiji Kawakatsu
- Institute of Agrobiological Sciences, National Agriculture and Food Research Organization, Tsukuba, Japan
| | - Yusaku Uga
- Institute of Crop Science, National Agriculture and Food Research Organization, Tsukuba, Japan
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9
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Basu U, Parida SK. Restructuring plant types for developing tailor-made crops. PLANT BIOTECHNOLOGY JOURNAL 2023; 21:1106-1122. [PMID: 34260135 DOI: 10.1111/pbi.13666] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 07/08/2021] [Accepted: 07/12/2021] [Indexed: 05/27/2023]
Abstract
Plants have adapted to different environmental niches by fine-tuning the developmental factors working together to regulate traits. Variations in the developmental factors result in a wide range of quantitative variations in these traits that helped plants survive better. The major developmental pathways affecting plant architecture are also under the control of such pathways. Most notable are the CLAVATA-WUSCHEL pathway regulating shoot apical meristem fate, GID1-DELLA module influencing plant height and tillering, LAZY1-TAC1 module controlling branch/tiller angle and the TFL1-FT determining the floral fate in plants. Allelic variants of these key regulators selected during domestication shaped the crops the way we know them today. There is immense yield potential in the 'ideal plant architecture' of a crop. With the available genome-editing techniques, possibilities are not restricted to naturally occurring variations. Using a transient reprogramming system, one can screen the effect of several developmental gene expressions in novel ecosystems to identify the best targets. We can use the plant's fine-tuning mechanism for customizing crops to specific environments. The process of crop domestication can be accelerated with a proper understanding of these developmental pathways. It is time to step forward towards the next-generation molecular breeding for restructuring plant types in crops ensuring yield stability.
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Affiliation(s)
- Udita Basu
- Genomics-Assisted Breeding and Crop Improvement Laboratory, National Institute of Plant Genome Research (NIPGR), New Delhi, India
| | - Swarup K Parida
- Genomics-Assisted Breeding and Crop Improvement Laboratory, National Institute of Plant Genome Research (NIPGR), New Delhi, India
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10
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Kohler AR, Scheil A, Hill JL, Allen JR, Al-Haddad JM, Goeckeritz CZ, Strader LC, Telewski FW, Hollender CA. Defying Gravity: WEEP promotes negative gravitropism in Prunus persica (peach) shoots and roots by establishing asymmetric auxin gradients. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.26.542472. [PMID: 37292987 PMCID: PMC10245973 DOI: 10.1101/2023.05.26.542472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Trees with weeping shoot architectures are valued for their beauty and serve as tremendous resources for understanding how plants regulate posture control. The Prunus persica (peach) weeping phenotype, which has elliptical downward arching branches, is caused by a homozygous mutation in the WEEP gene. Until now, little was known about the function of WEEP protein despite its high conservation throughout Plantae. Here, we present the results of anatomical, biochemical, biomechanical, physiological, and molecular experiments that provide insight into WEEP function. Our data suggest that weeping peach does not have defects in branch structure. Rather, transcriptomes from the adaxial (upper) and abaxial (lower) sides of standard and weeping branch shoot tips revealed flipped expression patterns for genes associated with early auxin response, tissue patterning, cell elongation, and tension wood development. This suggests that WEEP promotes polar auxin transport toward the lower side during shoot gravitropic response, leading to cell elongation and tension wood development. In addition, weeping peach trees exhibited steeper root systems and faster root gravitropic response, just as barley and wheat with mutations in their WEEP homolog EGT2. This suggests that the role of WEEP in regulating lateral organ angles and orientations during gravitropism may be conserved. Additionally, size-exclusion chromatography indicated that WEEP proteins self-oligomerize, like other SAM-domain proteins. This oligomerization may be required for WEEP to function in formation of protein complexes during auxin transport. Collectively, our results from weeping peach provide new insight into polar auxin transport mechanisms associated with gravitropism and lateral shoot and root orientation.
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Affiliation(s)
- Andrea R. Kohler
- Department of Horticulture, Michigan State University, East Lansing, MI 48824
| | - Andrew Scheil
- Department of Horticulture, Michigan State University, East Lansing, MI 48824
| | - Joseph L. Hill
- Department of Horticulture, Michigan State University, East Lansing, MI 48824
| | | | - Jameel M. Al-Haddad
- Department of Plant Biology, Michigan State University, East Lansing, MI 48824
| | | | | | - Frank W. Telewski
- Department of Plant Biology, Michigan State University, East Lansing, MI 48824
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11
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Barker R, Kruse CPS, Johnson C, Saravia-Butler A, Fogle H, Chang HS, Trane RM, Kinscherf N, Villacampa A, Manzano A, Herranz R, Davin LB, Lewis NG, Perera I, Wolverton C, Gupta P, Jaiswal P, Reinsch SS, Wyatt S, Gilroy S. Meta-analysis of the space flight and microgravity response of the Arabidopsis plant transcriptome. NPJ Microgravity 2023; 9:21. [PMID: 36941263 PMCID: PMC10027818 DOI: 10.1038/s41526-023-00247-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Accepted: 01/10/2023] [Indexed: 03/23/2023] Open
Abstract
Spaceflight presents a multifaceted environment for plants, combining the effects on growth of many stressors and factors including altered gravity, the influence of experiment hardware, and increased radiation exposure. To help understand the plant response to this complex suite of factors this study compared transcriptomic analysis of 15 Arabidopsis thaliana spaceflight experiments deposited in the National Aeronautics and Space Administration's GeneLab data repository. These data were reanalyzed for genes showing significant differential expression in spaceflight versus ground controls using a single common computational pipeline for either the microarray or the RNA-seq datasets. Such a standardized approach to analysis should greatly increase the robustness of comparisons made between datasets. This analysis was coupled with extensive cross-referencing to a curated matrix of metadata associated with these experiments. Our study reveals that factors such as analysis type (i.e., microarray versus RNA-seq) or environmental and hardware conditions have important confounding effects on comparisons seeking to define plant reactions to spaceflight. The metadata matrix allows selection of studies with high similarity scores, i.e., that share multiple elements of experimental design, such as plant age or flight hardware. Comparisons between these studies then helps reduce the complexity in drawing conclusions arising from comparisons made between experiments with very different designs.
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Affiliation(s)
- Richard Barker
- Department of Botany, University of Wisconsin, Madison, WI, 53706, USA
| | - Colin P S Kruse
- Los Alamos National Laboratory, Bioscience Division, Los Alamos, NM, 87545, USA
| | | | - Amanda Saravia-Butler
- Space Biosciences Division, NASA Ames Research Center, Moffett Field, CA, 94035, USA
- Logyx, LLC, Mountain View, CA, 94043, USA
| | - Homer Fogle
- Space Biosciences Division, NASA Ames Research Center, Moffett Field, CA, 94035, USA
- Bionetics, Yorktown, VA, 23693, USA
| | - Hyun-Seok Chang
- Department of Botany, University of Wisconsin, Madison, WI, 53706, USA
| | - Ralph Møller Trane
- Department of Statistics, University of Wisconsin, Madison, WI, 53706, USA
| | - Noah Kinscherf
- Department of Botany, University of Wisconsin, Madison, WI, 53706, USA
| | - Alicia Villacampa
- Centro de Investigaciones Biológicas Margarita Salas (CSIC), 28040, Madrid, Spain
| | - Aránzazu Manzano
- Centro de Investigaciones Biológicas Margarita Salas (CSIC), 28040, Madrid, Spain
| | - Raúl Herranz
- Centro de Investigaciones Biológicas Margarita Salas (CSIC), 28040, Madrid, Spain
| | - Laurence B Davin
- Institute of Biological Chemistry, Washington State University, Pullman, WA, 99164-741, USA
| | - Norman G Lewis
- Institute of Biological Chemistry, Washington State University, Pullman, WA, 99164-741, USA
| | - Imara Perera
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC, 27695, USA
| | - Chris Wolverton
- Department of Botany and Microbiology, Ohio Wesleyan University, Delaware, OH, 43015, USA
| | - Parul Gupta
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, 97331, USA
| | - Pankaj Jaiswal
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, 97331, USA
| | - Sigrid S Reinsch
- Space Biosciences Division, NASA Ames Research Center, Moffett Field, CA, 94035, USA
| | - Sarah Wyatt
- Department of Environmental and Plant Biology, Ohio University, Athens, OH, 45701, USA
| | - Simon Gilroy
- Department of Botany, University of Wisconsin, Madison, WI, 53706, USA.
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12
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Su SH, Moen A, Groskopf RM, Baldwin KL, Vesperman B, Masson PH. Low-Speed Clinorotation of Brachypodium distachyon and Arabidopsis thaliana Seedlings Triggers Root Tip Curvatures That Are Reminiscent of Gravitropism. Int J Mol Sci 2023; 24:ijms24021540. [PMID: 36675054 PMCID: PMC9861679 DOI: 10.3390/ijms24021540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Revised: 11/28/2022] [Accepted: 01/09/2023] [Indexed: 01/15/2023] Open
Abstract
Clinostats are instruments that continuously rotate biological specimens along an axis, thereby averaging their orientation relative to gravity over time. Our previous experiments indicated that low-speed clinorotation may itself trigger directional root tip curvature. In this project, we have investigated the root curvature response to low-speed clinorotation using Arabidopsis thaliana and Brachypodium distachyon seedlings as models. We show that low-speed clinorotation triggers root tip curvature in which direction is dictated by gravitropism during the first half-turn of clinorotation. We also show that the angle of root tip curvature is modulated by the speed of clinorotation. Arabidopsis mutations affecting gravity susception (pgm) or gravity signal transduction (arg1, toc132) are shown to affect the root tip curvature response to low-speed clinorotation. Furthermore, low-speed vertical clinorotation triggers relocalization of the PIN3 auxin efflux facilitator to the lateral membrane of Arabidopsis root cap statocytes, and creates a lateral gradient of auxin across the root tip. Together, these observations support a role for gravitropism in modulating root curvature responses to clinorotation. Interestingly, distinct Brachypodium distachyon accessions display different abilities to develop root tip curvature responses to low-speed vertical clinorotation, suggesting the possibility of using genome-wide association studies to further investigate this process.
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Affiliation(s)
- Shih-Heng Su
- Laboratory of Genetics, University of Wisconsin-Madison, 425 Henry Mall, Madison, WI 53706, USA
- Correspondence: (S.-H.S.); (P.H.M.)
| | - Alexander Moen
- Laboratory of Genetics, University of Wisconsin-Madison, 425 Henry Mall, Madison, WI 53706, USA
| | - Rien M. Groskopf
- Laboratory of Genetics, University of Wisconsin-Madison, 425 Henry Mall, Madison, WI 53706, USA
| | | | - Brian Vesperman
- Kate Baldwin LLC, Analytical Design, Cross Plains, WI 53528, USA
| | - Patrick H. Masson
- Laboratory of Genetics, University of Wisconsin-Madison, 425 Henry Mall, Madison, WI 53706, USA
- Correspondence: (S.-H.S.); (P.H.M.)
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13
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Che X, Splitt BL, Eckholm MT, Miller ND, Spalding EP. BRXL4-LAZY1 interaction at the plasma membrane controls Arabidopsis branch angle and gravitropism. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2023; 113:211-224. [PMID: 36478485 PMCID: PMC10107345 DOI: 10.1111/tpj.16055] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Revised: 11/28/2022] [Accepted: 12/03/2022] [Indexed: 06/17/2023]
Abstract
Gravitropism guides growth to shape plant architecture above and below ground. Mutations in LAZY1 impair stem gravitropism and cause less upright inflorescence branches (wider angles). The LAZY1 protein resides at the plasma membrane and in the nucleus. The plasma membrane pool is necessary and sufficient for setting branch angles. To investigate the molecular mechanism of LAZY1 function, we screened for LAZY1-interacting proteins in yeast. We identified BRXL4, a shoot-specific protein related to BREVIS RADIX. The BRXL4-LAZY1 interaction occurred at the plasma membrane in plant cells, and not detectably in the nucleus. Mutations in the C-terminus of LAZY1, but not other conserved regions, prevented the interaction. Opposite to lazy1, brxl4 mutants displayed faster gravitropism and more upright branches. Overexpressing BRXL4 produced strong lazy1 phenotypes. The apparent negative regulation of LAZY1 function is consistent with BRXL4 reducing LAZY1 expression or the amount of LAZY1 at the plasma membrane. Measurements indicated that both are true. LAZY1 mRNA was three-fold more abundant in brxl4 mutants and almost undetectable in BRXL4 overexpressors. Plasma membrane LAZY1 was higher and nuclear LAZY1 lower in brxl4 mutants compared with the wild type. To explain these results, we suggest that BRXL4 reduces the amount of LAZY1 at the plasma membrane where it functions in gravity signaling and promotes LAZY1 accumulation in the nucleus where it reduces LAZY1 expression, possibly by suppressing its own transcription. This explanation of how BRXL4 negatively regulates LAZY1 suggests ways to modify shoot system architecture for practical purposes.
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Affiliation(s)
- Ximing Che
- Department of BotanyUniversity of Wisconsin‐MadisonMadisonWI53706USA
| | - Bessie L. Splitt
- Department of BotanyUniversity of Wisconsin‐MadisonMadisonWI53706USA
| | - Magnus T. Eckholm
- Department of BotanyUniversity of Wisconsin‐MadisonMadisonWI53706USA
| | - Nathan D. Miller
- Department of BotanyUniversity of Wisconsin‐MadisonMadisonWI53706USA
| | - Edgar P. Spalding
- Department of BotanyUniversity of Wisconsin‐MadisonMadisonWI53706USA
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14
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Kirschner GK. It takes more than being LAZY: regulation of shoot branching angle by BRXL4. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2023; 113:209-210. [PMID: 36651818 DOI: 10.1111/tpj.16076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
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15
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Kawamoto N, Morita MT. Gravity sensing and responses in the coordination of the shoot gravitropic setpoint angle. THE NEW PHYTOLOGIST 2022; 236:1637-1654. [PMID: 36089891 PMCID: PMC9828789 DOI: 10.1111/nph.18474] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Accepted: 08/13/2022] [Indexed: 06/15/2023]
Abstract
Gravity is one of the fundamental environmental cues that affect plant development. Indeed, the plant architecture in the shoots and roots is modulated by gravity. Stems grow vertically upward, whereas lateral organs, such as the lateral branches in shoots, tend to grow at a specific angle according to a gravity vector known as the gravitropic setpoint angle (GSA). During this process, gravity is sensed in specialised gravity-sensing cells named statocytes, which convert gravity information into biochemical signals, leading to asymmetric auxin distribution and driving asymmetric cell division/expansion in the organs to achieve gravitropism. As a hypothetical offset mechanism against gravitropism to determine the GSA, the anti-gravitropic offset (AGO) has been proposed. According to this concept, the GSA is a balance of two antagonistic growth components, that is gravitropism and the AGO. Although the nature of the AGO has not been clarified, studies have suggested that gravitropism and the AGO share a common gravity-sensing mechanism in statocytes. This review discusses the molecular mechanisms underlying gravitropism as well as the hypothetical AGO in the control of the GSA.
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Affiliation(s)
- Nozomi Kawamoto
- Division of Plant Environmental ResponsesNational Institute for Basic BiologyMyodaijiOkazaki444‐8556Japan
| | - Miyo Terao Morita
- Division of Plant Environmental ResponsesNational Institute for Basic BiologyMyodaijiOkazaki444‐8556Japan
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16
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Baba AI, Mir MY, Riyazuddin R, Cséplő Á, Rigó G, Fehér A. Plants in Microgravity: Molecular and Technological Perspectives. Int J Mol Sci 2022; 23:ijms231810548. [PMID: 36142459 PMCID: PMC9505700 DOI: 10.3390/ijms231810548] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Revised: 08/31/2022] [Accepted: 09/08/2022] [Indexed: 01/19/2023] Open
Abstract
Plants are vital components of our ecosystem for a balanced life here on Earth, as a source of both food and oxygen for survival. Recent space exploration has extended the field of plant biology, allowing for future studies on life support farming on distant planets. This exploration will utilize life support technologies for long-term human space flights and settlements. Such longer space missions will depend on the supply of clean air, food, and proper waste management. The ubiquitous force of gravity is known to impact plant growth and development. Despite this, we still have limited knowledge about how plants can sense and adapt to microgravity in space. Thus, the ability of plants to survive in microgravity in space settings becomes an intriguing topic to be investigated in detail. The new knowledge could be applied to provide food for astronaut missions to space and could also teach us more about how plants can adapt to unique environments. Here, we briefly review and discuss the current knowledge about plant gravity-sensing mechanisms and the experimental possibilities to research microgravity-effects on plants either on the Earth or in orbit.
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Affiliation(s)
- Abu Imran Baba
- Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, SE-901 83 Umeå, Sweden
- Correspondence: or
| | - Mohd Yaqub Mir
- Doctoral School of Neuroscience, Semmelweis University, H-1083 Budapest, Hungary
- Theoretical Neuroscience and Complex Systems Group, Department of Computational Sciences, Wigner Research Centre for Physics, H-1121 Budapest, Hungary
| | - Riyazuddin Riyazuddin
- Department of Plant Biology, Faculty of Science and Informatics, University of Szeged, Közép fasor 52, H-6726 Szeged, Hungary
- Biological Research Centre (BRC), Institute of Plant Biology, Eötvös Loránd Research Network (ELKH), H-6726 Szeged, Hungary
| | - Ágnes Cséplő
- Biological Research Centre (BRC), Institute of Plant Biology, Eötvös Loránd Research Network (ELKH), H-6726 Szeged, Hungary
| | - Gábor Rigó
- Biological Research Centre (BRC), Institute of Plant Biology, Eötvös Loránd Research Network (ELKH), H-6726 Szeged, Hungary
| | - Attila Fehér
- Department of Plant Biology, Faculty of Science and Informatics, University of Szeged, Közép fasor 52, H-6726 Szeged, Hungary
- Biological Research Centre (BRC), Institute of Plant Biology, Eötvös Loránd Research Network (ELKH), H-6726 Szeged, Hungary
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17
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Blocking Rice Shoot Gravitropism by Altering One Amino Acid in LAZY1. Int J Mol Sci 2022; 23:ijms23169452. [PMID: 36012716 PMCID: PMC9409014 DOI: 10.3390/ijms23169452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 08/18/2022] [Accepted: 08/18/2022] [Indexed: 11/17/2022] Open
Abstract
Tiller angle is an important trait that determines plant architecture and yield in cereal crops. Tiller angle is partially controlled during gravistimulation by the dynamic re-allocation of LAZY1 (LA1) protein between the nucleus and plasma membrane, but the underlying mechanism remains unclear. In this study, we identified and characterized a new allele of LA1 based on analysis of a rice (Oryza sativa L.) spreading-tiller mutant la1G74V, which harbors a non-synonymous mutation in the predicted transmembrane (TM) domain-encoding region of this gene. The mutation causes complete loss of shoot gravitropism, leading to prostrate growth of plants. Our results showed that LA1 localizes not only to the nucleus and plasma membrane but also to the endoplasmic reticulum. Removal of the TM domain in LA1 showed spreading-tiller phenotype of plants similar to la1G74V but did not affect the plasma membrane localization; thus, making it distinct from its ortholog ZmLA1 in Zea mays. Therefore, we propose that the TM domain is indispensable for the biological function of LA1, but this domain does not determine the localization of the protein to the plasma membrane. Our study provides new insights into the LA1-mediated regulation of shoot gravitropism.
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18
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Li L, Gallei M, Friml J. Bending to auxin: fast acid growth for tropisms. TRENDS IN PLANT SCIENCE 2022; 27:440-449. [PMID: 34848141 DOI: 10.1016/j.tplants.2021.11.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 11/03/2021] [Accepted: 11/04/2021] [Indexed: 06/13/2023]
Abstract
The phytohormone auxin is the major growth regulator governing tropic responses including gravitropism. Auxin build-up at the lower side of stimulated shoots promotes cell expansion, whereas in roots it inhibits growth, leading to upward shoot bending and downward root bending, respectively. Yet it remains an enigma how the same signal can trigger such opposite cellular responses. In this review, we discuss several recent unexpected insights into the mechanisms underlying auxin regulation of growth, challenging several existing models. We focus on the divergent mechanisms of apoplastic pH regulation in shoots and roots revisiting the classical Acid Growth Theory and discuss coordinated involvement of multiple auxin signaling pathways. From this emerges a more comprehensive, updated picture how auxin regulates growth.
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Affiliation(s)
- Lanxin Li
- Institute of Science and Technology Austria, 3400 Klosterneuburg, Austria
| | - Michelle Gallei
- Institute of Science and Technology Austria, 3400 Klosterneuburg, Austria
| | - Jiří Friml
- Institute of Science and Technology Austria, 3400 Klosterneuburg, Austria.
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19
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Tiller Angle Control 1 Is Essential for the Dynamic Changes in Plant Architecture in Rice. Int J Mol Sci 2022; 23:ijms23094997. [PMID: 35563391 PMCID: PMC9105778 DOI: 10.3390/ijms23094997] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2022] [Revised: 04/26/2022] [Accepted: 04/27/2022] [Indexed: 02/05/2023] Open
Abstract
Plant architecture is dynamic as plants develop. Although many genes associated with specific plant architecture components have been identified in rice, genes related to underlying dynamic changes in plant architecture remain largely unknown. Here, we identified two highly similar recombinant inbred lines (RILs) with different plant architecture: RIL-Dynamic (D) and RIL-Compact (C). The dynamic plant architecture of RIL-D is characterized by ‘loosetiller angle (tillering stage)–compact (heading stage)–loosecurved stem (maturing stage)’ under natural long-day (NLD) conditions, and ‘loosetiller angle (tillering and heading stages)–loosetiller angle and curved stem (maturing stage)’ under natural short-day (NSD) conditions, while RIL-C exhibits a compact plant architecture both under NLD and NSD conditions throughout growth. The candidate locus was mapped to the chromosome 9 tail via the rice 8K chip assay and map-based cloning. Sequencing, complementary tests, and gene knockout tests demonstrated that Tiller Angle Control 1 (TAC1) is responsible for dynamic plant architecture in RIL-D. Moreover, TAC1 positively regulates loose plant architecture, and high TAC1 expression cannot influence the expression of tested tiller-angle-related genes. Our results reveal that TAC1 is necessary for the dynamic changes in plant architecture, which can guide improvements in plant architecture during the modern super rice breeding.
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20
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Aronne G, Muthert LWF, Izzo LG, Romano LE, Iovane M, Capozzi F, Manzano A, Ciska M, Herranz R, Medina FJ, Kiss JZ, van Loon JJWA. A novel device to study altered gravity and light interactions in seedling tropisms. LIFE SCIENCES IN SPACE RESEARCH 2022; 32:8-16. [PMID: 35065766 DOI: 10.1016/j.lssr.2021.09.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 09/27/2021] [Accepted: 09/29/2021] [Indexed: 06/14/2023]
Abstract
Long-duration space missions will need to rely on the use of plants in bio-regenerative life support systems (BLSSs) because these systems can produce fresh food and oxygen, reduce carbon dioxide levels, recycle metabolic waste, and purify water. In this scenario, the need for new experiments on the effects of altered gravity conditions on plant biological processes is increasing, and significant efforts should be devoted to new ideas aimed at increasing the scientific output and lowering the experimental costs. Here, we report the design of an easy-to-produce and inexpensive device conceived to analyze the effect of interaction between gravity and light on root tropisms. Each unit consisted of a polystyrene multi-slot rack with light-emitting diodes (LEDs), capable of holding Petri dishes and assembled with a particular filter-paper folding. The device was successfully used for the ROOTROPS (for root tropisms) experiment performed in the Large Diameter Centrifuge (LDC) and Random Positioning Machine (RPM) at ESA's European Space Research and Technology centre (ESTEC). During the experiments, four light treatments and six gravity conditions were factorially combined to study their effects on root orientation of Brassica oleracea seedlings. Light treatments (red, blue, and white) and a dark condition were tested under four hypergravity levels (20 g, 15 g, 10 g, 5 g), a 1 g control, and a simulated microgravity (RPM) condition. Results of validation tests showed that after 24 h, the assembled system remained unaltered, no slipping or displacement of seedlings occurred at any hypergravity treatment or on the RPM, and seedlings exhibited robust growth. Overall, the device was effective and reliable in achieving scientific goals, suggesting that it can be used for ground-based research on phototropism-gravitropism interactions. Moreover, the concepts developed can be further expanded for use in future spaceflight experiments with plants.
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Affiliation(s)
- Giovanna Aronne
- Department of Agricultural Sciences, University of Naples Federico II, Portici, Italy
| | | | - Luigi Gennaro Izzo
- Department of Agricultural Sciences, University of Naples Federico II, Portici, Italy.
| | - Leone Ermes Romano
- Department of Agricultural Sciences, University of Naples Federico II, Portici, Italy
| | - Maurizio Iovane
- Department of Agricultural Sciences, University of Naples Federico II, Portici, Italy
| | - Fiore Capozzi
- Department of Biology, University of Naples Federico II, Naples, Italy
| | - Aránzazu Manzano
- Centro de Investigaciones Biológicas Margarita Salas - CSIC, Madrid, Spain
| | - Malgorzata Ciska
- Centro de Investigaciones Biológicas Margarita Salas - CSIC, Madrid, Spain
| | - Raúl Herranz
- Centro de Investigaciones Biológicas Margarita Salas - CSIC, Madrid, Spain
| | - F Javier Medina
- Centro de Investigaciones Biológicas Margarita Salas - CSIC, Madrid, Spain
| | - John Z Kiss
- Department of Biology, University of North Carolina-Greensboro, Greensboro NC 27402, United States of America
| | - Jack J W A van Loon
- Department Oral & Maxillofacial Surgery/Pathology, Amsterdam Movement Sciences & Amsterdam Bone Center (ABC), Amsterdam University Medical Center Location VUmc & Academic Center for Dentistry Amsterdam (ACTA), Amsterdam, Netherlands; TEC-MMG-LISLab, European Space Agency (ESA) Technology Center (ESTEC), Noordwijk, Netherlands
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21
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Du M, Bou Daher F, Liu Y, Steward A, Tillmann M, Zhang X, Wong JH, Ren H, Cohen JD, Li C, Gray WM. Biphasic control of cell expansion by auxin coordinates etiolated seedling development. SCIENCE ADVANCES 2022; 8:eabj1570. [PMID: 35020423 PMCID: PMC8754305 DOI: 10.1126/sciadv.abj1570] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Seedling emergence is critical for food security. It requires rapid hypocotyl elongation and apical hook formation, both of which are mediated by regulated cell expansion. How these events are coordinated in etiolated seedlings is unclear. Here, we show that biphasic control of cell expansion by the phytohormone auxin underlies this process. Shortly after germination, high auxin levels restrain elongation. This provides a temporal window for apical hook formation, involving a gravity-induced auxin maximum on the eventual concave side of the hook. This auxin maximum induces PP2C.D1 expression, leading to asymmetrical H+-ATPase activity across the hypocotyl that contributes to the differential cell elongation underlying hook development. Subsequently, auxin concentrations decline acropetally and switch from restraining to promoting elongation, thereby driving hypocotyl elongation. Our findings demonstrate how differential auxin concentrations throughout the hypocotyl coordinate etiolated development, leading to successful soil emergence.
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Affiliation(s)
- Minmin Du
- Department of Plant and Microbial Biology, University of Minnesota, St. Paul, MN 55108, USA
| | - Firas Bou Daher
- Department of Plant and Microbial Biology, University of Minnesota, St. Paul, MN 55108, USA
| | - Yuanyuan Liu
- State Key Laboratory of Plant Genomics, National Centre for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Andrew Steward
- Department of Horticultural Science and Microbial and Plant Genomics Institute, University of Minnesota, St. Paul, MN 55108, USA
| | - Molly Tillmann
- Department of Horticultural Science and Microbial and Plant Genomics Institute, University of Minnesota, St. Paul, MN 55108, USA
| | - Xiaoyue Zhang
- State Key Laboratory of Plant Genomics, National Centre for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Jeh Haur Wong
- Department of Plant and Microbial Biology, University of Minnesota, St. Paul, MN 55108, USA
| | - Hong Ren
- Department of Plant and Microbial Biology, University of Minnesota, St. Paul, MN 55108, USA
| | - Jerry D. Cohen
- Department of Horticultural Science and Microbial and Plant Genomics Institute, University of Minnesota, St. Paul, MN 55108, USA
| | - Chuanyou Li
- State Key Laboratory of Plant Genomics, National Centre for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
- Corresponding author. (C.L.); (W.M.G.)
| | - William M. Gray
- Department of Plant and Microbial Biology, University of Minnesota, St. Paul, MN 55108, USA
- Corresponding author. (C.L.); (W.M.G.)
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22
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Barker R, Johns S, Trane R, Gilroy S. Analysis of Plant Root Gravitropism. Methods Mol Biol 2022; 2494:3-16. [PMID: 35467196 DOI: 10.1007/978-1-0716-2297-1_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Gravity is a powerful element in shaping plant development, with gravitropism, the oriented growth response of plant organs to the direction of gravity, leading to each plant's characteristic form both above and below ground. Despite being conceptually simple to follow, monitoring a plant's directional growth responses can become complex as variation arises from both internal developmental cues as well as effects of the environment. In this protocol, we discuss approaches to gravitropism assays, focusing on automated analyses of root responses. For Arabidopsis, we recommend a simple 90° rotation using seedlings that are 5-8 days old. If images are taken at regular intervals and the environmental metadata is recorded during both seedling development and gravitropic assay, these data can be used to reveal quantitative kinetic patterns at distinct stages of the assay. The use of software that analyzes root system parameters and stores this data in the RSML format opens up the possibility for a host of root parameters to be extracted to characterize growth of the primary root and a range of lateral root phenotypes.
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Affiliation(s)
- Richard Barker
- Department of Botany, University of Wisconsin, Madison, WI, USA
| | - Sarah Johns
- Department of Botany, University of Wisconsin, Madison, WI, USA
| | - Ralph Trane
- Department of Statistics, University of Wisconsin, Madison, WI, USA
| | - Simon Gilroy
- Department of Botany, University of Wisconsin, Madison, WI, USA.
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23
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Chin S, Blancaflor EB. Plant Gravitropism: From Mechanistic Insights into Plant Function on Earth to Plants Colonizing Other Worlds. Methods Mol Biol 2022; 2368:1-41. [PMID: 34647245 DOI: 10.1007/978-1-0716-1677-2_1] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Gravitropism, the growth of roots and shoots toward or away from the direction of gravity, has been studied for centuries. Such studies have not only led to a better understanding of the gravitropic process itself, but also paved new paths leading to deeper mechanistic insights into a wide range of research areas. These include hormone biology, cell signal transduction, regulation of gene expression, plant evolution, and plant interactions with a variety of environmental stimuli. In addition to contributions to basic knowledge about how plants function, there is accumulating evidence that gravitropism confers adaptive advantages to crops, particularly under marginal agricultural soils. Therefore, gravitropism is emerging as a breeding target for enhancing agricultural productivity. Moreover, research on gravitropism has spawned several studies on plant growth in microgravity that have enabled researchers to uncouple the effects of gravity from other tropisms. Although rapid progress on understanding gravitropism witnessed during the past decade continues to be driven by traditional molecular, physiological, and cell biological tools, these tools have been enriched by technological innovations in next-generation omics platforms and microgravity analog facilities. In this chapter, we review the field of gravitropism by highlighting recent landmark studies that have provided unique insights into this classic research topic while also discussing potential contributions to agriculture on Earth and beyond.
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Affiliation(s)
- Sabrina Chin
- Department of Botany, University of Wisconsin, Madison, WI, USA.
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24
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Furutani M, Morita MT. LAZY1-LIKE-mediated gravity signaling pathway in root gravitropic set-point angle control. PLANT PHYSIOLOGY 2021; 187:1087-1095. [PMID: 34734273 PMCID: PMC8566294 DOI: 10.1093/plphys/kiab219] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 03/10/2021] [Indexed: 06/13/2023]
Abstract
Gravity signaling components contribute to the control of root gravitropic set-point angle through protein polarization relay within columella.
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Affiliation(s)
- Masahiko Furutani
- College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China
- FAFU-UCR Joint Center and Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China
| | - Miyo Terao Morita
- Division of Plant Environmental Responses, National Institute for Basic Biology, Myodaiji, Okazaki 444-8556, Japan
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25
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Montesinos Á, Dardick C, Rubio-Cabetas MJ, Grimplet J. Polymorphisms and gene expression in the almond IGT family are not correlated to variability in growth habit in major commercial almond cultivars. PLoS One 2021; 16:e0252001. [PMID: 34644299 PMCID: PMC8513883 DOI: 10.1371/journal.pone.0252001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Accepted: 09/29/2021] [Indexed: 11/18/2022] Open
Abstract
Almond breeding programs aimed at selecting cultivars adapted to intensive orchards have recently focused on the optimization of tree architecture. This multifactorial trait is defined by numerous components controlled by processes such as hormonal responses, gravitropism and light perception. Gravitropism sensing is crucial to control the branch angle and therefore, the tree habit. A gene family, denominated IGT family after a shared conserved domain, has been described as involved in the regulation of branch angle in several species, including rice and Arabidopsis, and even in fruit trees like peach. Here we identified six members of this family in almond: LAZY1, LAZY2, TAC1, DRO1, DRO2, IGT-like. After analyzing their protein sequences in forty-one almond cultivars and wild species, little variability was found, pointing a high degree of conservation in this family. To our knowledge, this is the first effort to analyze the diversity of IGT family proteins in members of the same tree species. Gene expression was analyzed in fourteen cultivars of agronomical interest comprising diverse tree habit phenotypes. Only LAZY1, LAZY2 and TAC1 were expressed in almond shoot tips during the growing season. No relation could be established between the expression profile of these genes and the variability observed in the tree habit. However, some insight has been gained in how LAZY1 and LAZY2 are regulated, identifying the IPA1 almond homologues and other transcription factors involved in hormonal responses as regulators of their expression. Besides, we have found various polymorphisms that could not be discarded as involved in a potential polygenic origin of regulation of architectural phenotypes. Therefore, we have established that neither the expression nor the genetic polymorphism of IGT family genes are correlated to diversity of tree habit in currently commercialized almond cultivars, with other gene families contributing to the variability of these traits.
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Affiliation(s)
- Álvaro Montesinos
- Centro de Investigación y Tecnología Agroalimentaria de Aragón (CITA), Unidad de Hortofruticultura, Gobierno de Aragón, Avda. Montañana, Zaragoza, Spain
- Instituto Agroalimentario de Aragón–IA2 (CITA-Universidad de Zaragoza), Calle Miguel Servet, Zaragoza, Spain
| | - Chris Dardick
- Appalachian Fruit Research Station, United States Department of Agriculture—Agriculture Research Service, Kearneysville, WV, United States of America
| | - María José Rubio-Cabetas
- Centro de Investigación y Tecnología Agroalimentaria de Aragón (CITA), Unidad de Hortofruticultura, Gobierno de Aragón, Avda. Montañana, Zaragoza, Spain
- Instituto Agroalimentario de Aragón–IA2 (CITA-Universidad de Zaragoza), Calle Miguel Servet, Zaragoza, Spain
| | - Jérôme Grimplet
- Centro de Investigación y Tecnología Agroalimentaria de Aragón (CITA), Unidad de Hortofruticultura, Gobierno de Aragón, Avda. Montañana, Zaragoza, Spain
- Instituto Agroalimentario de Aragón–IA2 (CITA-Universidad de Zaragoza), Calle Miguel Servet, Zaragoza, Spain
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26
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Villacampa A, Sora L, Herranz R, Medina FJ, Ciska M. Analysis of Graviresponse and Biological Effects of Vertical and Horizontal Clinorotation in Arabidopsis thaliana Root Tip. PLANTS (BASEL, SWITZERLAND) 2021; 10:734. [PMID: 33918741 PMCID: PMC8070489 DOI: 10.3390/plants10040734] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Revised: 04/05/2021] [Accepted: 04/06/2021] [Indexed: 06/12/2023]
Abstract
Clinorotation was the first method designed to simulate microgravity on ground and it remains the most common and accessible simulation procedure. However, different experimental settings, namely angular velocity, sample orientation, and distance to the rotation center produce different responses in seedlings. Here, we compare A. thaliana root responses to the two most commonly used velocities, as examples of slow and fast clinorotation, and to vertical and horizontal clinorotation. We investigate their impact on the three stages of gravitropism: statolith sedimentation, asymmetrical auxin distribution, and differential elongation. We also investigate the statocyte ultrastructure by electron microscopy. Horizontal slow clinorotation induces changes in the statocyte ultrastructure related to a stress response and internalization of the PIN-FORMED 2 (PIN2) auxin transporter in the lower endodermis, probably due to enhanced mechano-stimulation. Additionally, fast clinorotation, as predicted, is only suitable within a very limited radius from the clinorotation center and triggers directional root growth according to the direction of the centrifugal force. Our study provides a full morphological picture of the stages of graviresponse in the root tip, and it is a valuable contribution to the field of microgravity simulation by clarifying the limitations of 2D-clinostats and proposing a proper use.
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Affiliation(s)
- Alicia Villacampa
- Centro de Investigaciones Biológicas Margarita Salas-CSIC, Ramiro de Maeztu 9, 28040 Madrid, Spain; (A.V.); (L.S.); (R.H.); (F.-J.M.)
| | - Ludovico Sora
- Centro de Investigaciones Biológicas Margarita Salas-CSIC, Ramiro de Maeztu 9, 28040 Madrid, Spain; (A.V.); (L.S.); (R.H.); (F.-J.M.)
- Department of Aerospace Science and Technology, Politecnico di Milano, Via La Masa 34, 20156 Milano, Italy
| | - Raúl Herranz
- Centro de Investigaciones Biológicas Margarita Salas-CSIC, Ramiro de Maeztu 9, 28040 Madrid, Spain; (A.V.); (L.S.); (R.H.); (F.-J.M.)
| | - Francisco-Javier Medina
- Centro de Investigaciones Biológicas Margarita Salas-CSIC, Ramiro de Maeztu 9, 28040 Madrid, Spain; (A.V.); (L.S.); (R.H.); (F.-J.M.)
| | - Malgorzata Ciska
- Centro de Investigaciones Biológicas Margarita Salas-CSIC, Ramiro de Maeztu 9, 28040 Madrid, Spain; (A.V.); (L.S.); (R.H.); (F.-J.M.)
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27
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Casal JJ, Estevez JM. Auxin-Environment Integration in Growth Responses to Forage for Resources. Cold Spring Harb Perspect Biol 2021; 13:a040030. [PMID: 33431585 PMCID: PMC8015692 DOI: 10.1101/cshperspect.a040030] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Plant fitness depends on the adequate morphological adjustment to the prevailing conditions of the environment. Therefore, plants sense environmental cues through their life cycle, including the presence of full darkness, light, or shade, the range of ambient temperatures, the direction of light and gravity vectors, and the presence of water and mineral nutrients (such as nitrate and phosphate) in the soil. The environmental information impinges on different aspects of the auxin system such as auxin synthesis, degradation, transport, perception, and downstream transcriptional regulation to modulate organ growth. Although a single environmental cue can affect several of these points, the relative impacts differ significantly among the various growth processes and cues. While stability in the generation of precise auxin gradients serves to guide the basic developmental pattern, dynamic changes in the auxin system fine-tune body shape to optimize the capture of environmental resources.
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Affiliation(s)
- Jorge J Casal
- Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura (IFEVA), Facultad de Agronomía, Buenos Aires 1417, Argentina
- Fundación Instituto Leloir and IIBBA-CONICET, Buenos Aires C1405BWE, Argentina
| | - José M Estevez
- Fundación Instituto Leloir and IIBBA-CONICET, Buenos Aires C1405BWE, Argentina
- Centro de Biotecnología Vegetal, Facultad de Ciencias de la Vida, Universidad Andres Bello and Millennium Institute for Integrative Biology (iBio), Santiago 8370146, Chile
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28
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Sun C, Zhang C, Wang X, Zhao X, Chen F, Zhang W, Hu M, Fu S, Yi B, Zhang J. Genome-Wide Identification and Characterization of the IGT Gene Family in Allotetraploid Rapeseed ( Brassica napus L.). DNA Cell Biol 2021; 40:441-456. [PMID: 33600242 DOI: 10.1089/dna.2020.6227] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
IGT family genes function critically to regulate lateral organ orientation in plants. However, little information is available about this family of genes in Brassica napus. In this study, 27 BnIGT genes were identified on 16 chromosomes and divided into seven clades, namely LAZY1∼LAZY6 and TAC1 (Tiller Angle Control 1), based on their phylogenetic relationships. Duplication analysis revealed that 91.1% of the gene pairs were derived from whole-genome duplication. Most BnIGT genes had a similar structural pattern with one or two very short exons followed by a long and a shorter exon. Common and specific motifs were identified among the seven clades, and motif 1, containing the family-specific GφL(A/T)IGT sequence, was observed in all clades except LAZY5. Three types of cis-elements pertinent to transcription factor binding, light responses, and hormone signaling were detected in the BnIGT promoters. Intriguingly, more than half of the BnIGT genes exhibited no or very low expression in various tissues, and the LAZY1 and TAC1 clade members showed distinct tissue expression preferences. Coexpression analysis revealed that the LAZY1 members had strong associations with cell wall biosynthesis genes. This analysis provides a deeper understanding of the BnIGT gene family and will facilitate further deduction of their role in regulating plant architecture in B. napus.
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Affiliation(s)
- Chengming Sun
- Key Laboratory of Cotton and Rapeseed, Ministry of Agriculture and Rural Affairs/Provincial Key Laboratory of Agrobiology/Institute of Industrial Crops, Jiangsu Academy of Agricultural Sciences, Nanjing, China.,National Key Laboratory of Crop Genetic Improvement/College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Chun Zhang
- Key Laboratory of Cotton and Rapeseed, Ministry of Agriculture and Rural Affairs/Provincial Key Laboratory of Agrobiology/Institute of Industrial Crops, Jiangsu Academy of Agricultural Sciences, Nanjing, China.,National Key Laboratory of Crop Genetics and Germplasm Innovation, Nanjing Agricultural University/Jiangsu Collaborative Innovation Center for Modern Crop Production, Nanjing, China
| | - Xiadong Wang
- Key Laboratory of Cotton and Rapeseed, Ministry of Agriculture and Rural Affairs/Provincial Key Laboratory of Agrobiology/Institute of Industrial Crops, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Xiaozhen Zhao
- Key Laboratory of Cotton and Rapeseed, Ministry of Agriculture and Rural Affairs/Provincial Key Laboratory of Agrobiology/Institute of Industrial Crops, Jiangsu Academy of Agricultural Sciences, Nanjing, China.,National Key Laboratory of Crop Genetics and Germplasm Innovation, Nanjing Agricultural University/Jiangsu Collaborative Innovation Center for Modern Crop Production, Nanjing, China
| | - Feng Chen
- Key Laboratory of Cotton and Rapeseed, Ministry of Agriculture and Rural Affairs/Provincial Key Laboratory of Agrobiology/Institute of Industrial Crops, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Wei Zhang
- Key Laboratory of Cotton and Rapeseed, Ministry of Agriculture and Rural Affairs/Provincial Key Laboratory of Agrobiology/Institute of Industrial Crops, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Maolong Hu
- Key Laboratory of Cotton and Rapeseed, Ministry of Agriculture and Rural Affairs/Provincial Key Laboratory of Agrobiology/Institute of Industrial Crops, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Sanxiong Fu
- Key Laboratory of Cotton and Rapeseed, Ministry of Agriculture and Rural Affairs/Provincial Key Laboratory of Agrobiology/Institute of Industrial Crops, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Bin Yi
- National Key Laboratory of Crop Genetic Improvement/College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Jiefu Zhang
- Key Laboratory of Cotton and Rapeseed, Ministry of Agriculture and Rural Affairs/Provincial Key Laboratory of Agrobiology/Institute of Industrial Crops, Jiangsu Academy of Agricultural Sciences, Nanjing, China.,National Key Laboratory of Crop Genetics and Germplasm Innovation, Nanjing Agricultural University/Jiangsu Collaborative Innovation Center for Modern Crop Production, Nanjing, China
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Waite JM, Dardick C. The roles of the IGT gene family in plant architecture: past, present, and future. CURRENT OPINION IN PLANT BIOLOGY 2021; 59:101983. [PMID: 33422965 DOI: 10.1016/j.pbi.2020.101983] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 11/13/2020] [Accepted: 12/02/2020] [Indexed: 05/03/2023]
Abstract
Genetic improvement of architectural traits offers tremendous opportunities to dramatically improve crop densities, productivity, and ultimately sustainability. Among these, the orientation, or gravitropic set point angle (GSA), of plant organs is critical to optimize crop profiles, light capture, and nutrient acquisition. Mutant GSA phenotypes have been studied in plants since the 1930's but only recently have the underlying genes been identified. Many of these genes have turned out to fall within the IGT (LAZY1/DRO1/TAC1) family, which initially was not previously recognized due to the lack of sequence conservation of homologous genes across species. Here we discuss recent progress on IGT family genes in various plant species over the past century, review possible functional mechanisms, and provide further analysis of their evolution in land plants and their past and future roles in crop domestication.
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Affiliation(s)
- Jessica Marie Waite
- USDA Tree Fruit Research Laboratory, 1104 N Western Avenue, Wenatchee, WA, USA
| | - Christopher Dardick
- United States Department of Agriculture (USDA) Appalachian Fruit Research Station, 2217 Wiltshire Road, Kearneysville, WV, USA.
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30
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Jiao Z, Du H, Chen S, Huang W, Ge L. LAZY Gene Family in Plant Gravitropism. FRONTIERS IN PLANT SCIENCE 2021; 11:606241. [PMID: 33613583 PMCID: PMC7893674 DOI: 10.3389/fpls.2020.606241] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Accepted: 12/01/2020] [Indexed: 05/26/2023]
Abstract
Adapting to the omnipresent gravitational field was a fundamental basis driving the flourishing of terrestrial plants on the Earth. Plants have evolved a remarkable capability that not only allows them to live and develop within the Earth's gravity field, but it also enables them to use the gravity vector to guide the growth of roots and shoots, in a process known as gravitropism. Triggered by gravistimulation, plant gravitropism is a highly complex, multistep process that requires many organelles and players to function in an intricate coordinated way. Although this process has been studied for several 100 years, much remains unclear, particularly the early events that trigger the relocation of the auxin efflux carrier PIN-FORMED (PIN) proteins, which presumably leads to the asymmetrical redistribution of auxin. In the past decade, the LAZY gene family has been identified as a crucial player that ensures the proper redistribution of auxin and a normal tropic response for both roots and shoots upon gravistimulation. LAZY proteins appear to be participating in the early steps of gravity signaling, as the mutation of LAZY genes consistently leads to altered auxin redistribution in multiple plant species. The identification and characterization of the LAZY gene family have significantly advanced our understanding of plant gravitropism, and opened new frontiers of investigation into the novel molecular details of the early events of gravitropism. Here we review current knowledge of the LAZY gene family and the mechanism modulated by LAZY proteins for controlling both roots and shoots gravitropism. We also discuss the evolutionary significance and conservation of the LAZY gene family in plants.
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Affiliation(s)
- Zhicheng Jiao
- College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou, China
- Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, South China Agricultural University, Guangzhou, China
| | - Huan Du
- College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou, China
- Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, South China Agricultural University, Guangzhou, China
| | - Shu Chen
- College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou, China
- Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, South China Agricultural University, Guangzhou, China
| | - Wei Huang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Sciences, South China Agricultural University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, China
| | - Liangfa Ge
- College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou, China
- Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, South China Agricultural University, Guangzhou, China
- The Guangdong Subcenter of the National Center for Soybean Improvement, College of Agriculture, South China Agricultural University, Guangzhou, China
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31
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Levernier N, Pouliquen O, Forterre Y. An Integrative Model of Plant Gravitropism Linking Statoliths Position and Auxin Transport. FRONTIERS IN PLANT SCIENCE 2021; 12:651928. [PMID: 33854523 PMCID: PMC8039511 DOI: 10.3389/fpls.2021.651928] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Accepted: 03/03/2021] [Indexed: 05/10/2023]
Abstract
Gravity is a major cue for the proper growth and development of plants. The response of plants to gravity implies starch-filled plastids, the statoliths, which sediments at the bottom of the gravisensing cells, the statocytes. Statoliths are assumed to modify the transport of the growth hormone, auxin, by acting on specific auxin transporters, PIN proteins. However, the complete gravitropic signaling pathway from the intracellular signal associated to statoliths to the plant bending is still not well-understood. In this article, we build on recent experimental results showing that statoliths do not act as gravitational force sensor, but as position sensor, to develop a bottom-up theory of plant gravitropism. The main hypothesis of the model is that the presence of statoliths modifies PIN trafficking close to the cell membrane. This basic assumption, coupled with auxin transport and growth in an idealized tissue made of a one-dimensional array of cells, recovers several major features of the gravitropic response of plants. First, the model provides a new interpretation for the response of a plant to a steady stimulus, the so-called sine-law of plant gravitropism. Second, it predicts the existence of a gravity-independent memory process as observed recently in experiments studying the response to transient stimulus. The model suggests that the timescale of this process is associated to PIN turnover, calling for new experimental studies.
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32
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Su SH, Keith MA, Masson PH. Gravity Signaling in Flowering Plant Roots. PLANTS (BASEL, SWITZERLAND) 2020; 9:E1290. [PMID: 33003550 PMCID: PMC7601833 DOI: 10.3390/plants9101290] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 09/24/2020] [Accepted: 09/27/2020] [Indexed: 12/28/2022]
Abstract
Roots typically grow downward into the soil where they anchor the plant and take up water and nutrients necessary for plant growth and development. While the primary roots usually grow vertically downward, laterals often follow a gravity set point angle that allows them to explore the surrounding environment. These responses can be modified by developmental and environmental cues. This review discusses the molecular mechanisms that govern root gravitropism in flowering plant roots. In this system, the primary site of gravity sensing within the root cap is physically separated from the site of curvature response at the elongation zone. Gravity sensing involves the sedimentation of starch-filled plastids (statoliths) within the columella cells of the root cap (the statocytes), which triggers a relocalization of plasma membrane-associated PIN auxin efflux facilitators to the lower side of the cell. This process is associated with the recruitment of RLD regulators of vesicular trafficking to the lower membrane by LAZY proteins. PIN relocalization leads to the formation of a lateral gradient of auxin across the root cap. Upon transmission to the elongation zone, this auxin gradient triggers a downward curvature. We review the molecular mechanisms that control this process in primary roots and discuss recent insights into the regulation of oblique growth in lateral roots and its impact on root-system architecture, soil exploration and plant adaptation to stressful environments.
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Affiliation(s)
| | | | - Patrick H. Masson
- Laboratory of Genetics, University of Wisconsin-Madison, 425G Henry Mall, Madison, WI 53706, USA; (S.-H.S.); (M.A.K.)
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Root angle modifications by the DRO1 homolog improve rice yields in saline paddy fields. Proc Natl Acad Sci U S A 2020; 117:21242-21250. [PMID: 32817523 PMCID: PMC7474696 DOI: 10.1073/pnas.2005911117] [Citation(s) in RCA: 93] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The root system architecture (RSA) of crops can affect their production, particularly in abiotic stress conditions, such as with drought, waterlogging, and salinity. Salinity is a growing problem worldwide that negatively impacts on crop productivity, and it is believed that yields could be improved if RSAs that enabled plants to avoid saline conditions were identified. Here, we have demonstrated, through the cloning and characterization of qSOR1 (quantitative trait locus for SOIL SURFACE ROOTING 1), that a shallower root growth angle (RGA) could enhance rice yields in saline paddies. qSOR1 is negatively regulated by auxin, predominantly expressed in root columella cells, and involved in the gravitropic responses of roots. qSOR1 was found to be a homolog of DRO1 (DEEPER ROOTING 1), which is known to control RGA. CRISPR-Cas9 assays revealed that other DRO1 homologs were also involved in RGA. Introgression lines with combinations of gain-of-function and loss-of-function alleles in qSOR1 and DRO1 demonstrated four different RSAs (ultra-shallow, shallow, intermediate, and deep rooting), suggesting that natural alleles of the DRO1 homologs could be utilized to control RSA variations in rice. In saline paddies, near-isogenic lines carrying the qSOR1 loss-of-function allele had soil-surface roots (SOR) that enabled rice to avoid the reducing stresses of saline soils, resulting in increased yields compared to the parental cultivars without SOR. Our findings suggest that DRO1 homologs are valuable targets for RSA breeding and could lead to improved rice production in environments characterized by abiotic stress.
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Ditengou FA, Teale WD, Palme K. Settling for Less: Do Statoliths Modulate Gravity Perception? PLANTS (BASEL, SWITZERLAND) 2020; 9:E121. [PMID: 31963631 PMCID: PMC7020169 DOI: 10.3390/plants9010121] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/07/2019] [Revised: 01/13/2020] [Accepted: 01/16/2020] [Indexed: 01/20/2023]
Abstract
Plants orientate their growth either towards (in roots) or away from (in shoots) the Earth's gravitational field. While we are now starting to understand the molecular architecture of these gravity response pathways, the gravity receptor remains elusive. This perspective looks at the biology of statoliths and suggests it is conceivable that their immediate environment may be tuned to modulate the strength of the gravity response. It then suggests how mutant screens could use this hypothesis to identify the gravity receptor.
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Affiliation(s)
- Franck Anicet Ditengou
- Institute of Biology II, Faculty of Biology, Albert-Ludwigs-University of Freiburg, Schänzlestrasse 1, 79104 Freiburg, Germany
| | - William David Teale
- Institute of Biology II, Faculty of Biology, Albert-Ludwigs-University of Freiburg, Schänzlestrasse 1, 79104 Freiburg, Germany
| | - Klaus Palme
- Institute of Biology II, Faculty of Biology, Albert-Ludwigs-University of Freiburg, Schänzlestrasse 1, 79104 Freiburg, Germany
- BIOSS Center for Biological Signaling Studies, Albert-Ludwigs-University of Freiburg, Schänzlestrasse 18, 79104 Freiburg, Germany
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Daizong Street 61, Tai’an 271018, China
- Sino-German Joint Research Center on Agricultural Biology, College of Life Sciences, Shandong Agricultural University, Daizong Street 61, Tai’an 271018, China
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