Signaling in Plant Gravitropism

Stanga, John P.; Neal, C. O. S.; Vaughn, Laura; Baldwin, Katherine; Jia, Gengxiang

doi:10.1007/978-3-540-89228-1_11

Cited by 4 publications

(1 citation statement)

References 124 publications

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“…The cytoskeleton is one of the most dynamic cellular components, which modulates its architecture by responding constantly to various environmental stimuli. In plants, cytoskeleton dynamics is critical for numerous cellular processes, such as cell division, morphogenesis, polarized cell expansion, root and pollen tube tip growth, cytoplasmic streaming/cyclosis (Menand et al, 2007;Pollard and Cooper, 2009), cell-to-cell communication through plasmodesmata (Higaki et al, 2008), perception of gravitropism (Kordyum et al, 2009;Stanga et al, 2009), regulation of cell shape (Smith and Oppenheimer, 2005), and in response to wounding, pathogen attack, hormone distribution and cold acclimation (Deng et al, 2010;Hussey et al, 2006;Staiger, 2000;Staiger and Blanchoin, 2006;Wasteneys and Galway, 2003).…”

Section: Introductionmentioning

confidence: 99%

An actin‐depolymerizing factor from the halophyte smooth cordgrass, Spartina alterniflora (SaADF2), is superior to its rice homolog (OsADF2) in conferring drought and salt tolerance when constitutively overexpressed in rice

Sengupta

Mangu

Sanchez

et al. 2018

Plant Biotechnology Journal

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Summary Actin‐depolymerizing factors ( ADF s) maintain the cellular actin network dynamics by regulating severing and disassembly of actin filaments in response to environmental cues. An ADF isolated from a monocot halophyte, Spartina alterniflora ( Sa ADF 2 ), imparted significantly higher level of drought and salinity tolerance when expressed in rice than its rice homologue Os ADF 2 . Sa ADF 2 differs from Os ADF 2 by a few amino acid residues, including a substitution in the regulatory phosphorylation site serine‐6, which accounted for its weak interaction with Os CDPK 6 (calcium‐dependent protein kinase), thus resulting in an increased efficacy of Sa ADF 2 and enhanced cellular actin dynamics. Sa ADF 2 overexpression preserved the actin filament organization better in rice protoplasts under desiccation stress. The predicted tertiary structure of Sa ADF 2 showed a longer F‐loop than Os ADF 2 that could have contributed to higher actin‐binding affinity and rapid F‐actin depolymerization in vitro by Sa ADF 2. Rice transgenics constitutively overexpressing Sa ADF 2 ( Sa ADF 2 ‐ OE ) showed better growth, relative water content, and photosynthetic and agronomic yield under drought conditions than wild‐type ( WT ) and Os ADF 2 overexpressers ( Os ADF 2‐ OE ). Sa ADF 2 ‐ OE preserved intact grana structure after prolonged drought stress, whereas WT and Os ADF 2 ‐ OE presented highly damaged and disorganized grana stacking. The possible role of ADF 2 in transactivation was hypothesized from the comparative transcriptome analyses, which showed significant differential expression of stress‐related genes including interacting partners of ADF 2 in overexpressers. Identification of a complex, differential interactome decorating or regulating stress‐modulated cytoskeleton driven by ADF isoforms will lead us to key pathways that could be potential target for genome engineering to improve abiotic stress tolerance in agricultural crops.

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Section: Introductionmentioning

confidence: 99%

An actin‐depolymerizing factor from the halophyte smooth cordgrass, Spartina alterniflora (SaADF2), is superior to its rice homolog (OsADF2) in conferring drought and salt tolerance when constitutively overexpressed in rice

Sengupta

Mangu

Sanchez

et al. 2018

Plant Biotechnology Journal

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Strigolactones regulate rice tiller angle by attenuating shoot gravitropism through inhibiting auxin biosynthesis

Sang

Chen

Liu

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

137

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Tiller angle, a key agronomic trait for achieving ideal plant architecture and increasing grain yield, is regulated mainly by shoot gravitropism. Strigolactones (SLs) are a group of newly identified plant hormones that are essential for shoot branching/ rice tillering and have further biological functions as yet undetermined. Through screening for suppressors of lazy1 (sols), a classic rice mutant exhibiting large tiller angle and defective shoot gravitropism, we identified multiple SOLS that are involved in the SL biosynthetic or signaling pathway. We show that SL biosynthetic or signaling mutants can rescue the spreading phenotype of lazy1 (la1) and that SLs can inhibit auxin biosynthesis and attenuate rice shoot gravitropism, mainly by decreasing the local indoleacetic acid content. Although both SLs and LA1 are negative regulators of polar auxin transport, SLs do not alter the lateral auxin transport of shoot base, unlike LA1, which is a positive regulator of lateral auxin transport in rice. Genetic evidence demonstrates that SLs and LA1 participate in regulating shoot gravitropism and tiller angle in distinct genetic pathways. In addition, the SL-mediated shoot gravitropism is conserved in Arabidopsis. Our results disclose a new role of SLs and shed light on a previously unidentified mechanism underlying shoot gravitropism. Our study indicates that SLs could be considered as an important tool to achieve ideal plant architecture in the future. P lant shoot gravitropism is a process in which plants perceive gravity stimuli and reorient the direction of growth during the plant growth and development. Gravitropism is a dynamic process, including the perception of gravity, transduction of the corresponding information into a biochemical signal, transmission of the biochemical signal to a response site, and organ curvature (1). Genetic studies have disclosed that shoot endodermal cells act as statocytes for shoot gravitropism (2). Amyloplast sedimentation transduces the gravitropic signal and leads to auxin redistribution, resulting in a higher auxin level on the lower side than on the upper side (1, 3). Although auxin redistribution upon gravistimulation plays an important role in shoot gravitropism, the mechanism by which auxin regulates shoot gravitropism is not yet understood.In rice the tiller angle, which is defined as the angle between the tiller and main culm, plays a key role in determining rice plant architecture and thus grain yield (4). Several genes controlling the tiller angle have been identified previously in rice, including LAZY1 (LA1), TILLER ANGLE CONTROL1 (TAC1), PROSTRATE GROWTH1 (PROG1), and LOOSE PLANT ARCHITECTURE1 (LPA1) (5-9). Among these genes, LA1 and LPA1 are reported to regulate tiller angle through shoot gravitropism. In the la1 mutant, the polar auxin transport (PAT) is enhanced, and the lateral auxin transport is decreased, resulting in a disturbance of auxin asymmetric distribution in the shoot base and therefore the tiller-spreading phenotype of rice plants (5).Strigolactones (S...

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Ammonium-induced loss of root gravitropism is related to auxin distribution and TRH1 function, and is uncoupled from the inhibition of root elongation in Arabidopsis

Zou

Gao

et al. 2012

Journal of Experimental Botany

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Signaling in Plant Gravitropism

Cited by 4 publications

References 124 publications

An actin‐depolymerizing factor from the halophyte smooth cordgrass, Spartina alterniflora (SaADF2), is superior to its rice homolog (OsADF2) in conferring drought and salt tolerance when constitutively overexpressed in rice

An actin‐depolymerizing factor from the halophyte smooth cordgrass, Spartina alterniflora (SaADF2), is superior to its rice homolog (OsADF2) in conferring drought and salt tolerance when constitutively overexpressed in rice

Strigolactones regulate rice tiller angle by attenuating shoot gravitropism through inhibiting auxin biosynthesis

Ammonium-induced loss of root gravitropism is related to auxin distribution and TRH1 function, and is uncoupled from the inhibition of root elongation in Arabidopsis

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