scholarly journals Suberin plasticity to developmental and exogenous cues is regulated by a set of MYB transcription factors

2021 ◽  
Vol 118 (39) ◽  
pp. e2101730118
Author(s):  
Vinay Shukla ◽  
Jian-Pu Han ◽  
Fabienne Cléard ◽  
Linnka Lefebvre-Legendre ◽  
Kay Gully ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Compensatory Mechanism ◽  
Biotic And Abiotic Stress ◽  
Environmental Signals ◽  
Myb Transcription Factors ◽  
Spatiotemporal Regulation ◽  
Exogenous Cues ◽  
Mineral Transport ◽  
Casparian Strips ◽  
Endodermal Cells

Suberin is a hydrophobic biopolymer that can be deposited at the periphery of cells, forming protective barriers against biotic and abiotic stress. In roots, suberin forms lamellae at the periphery of endodermal cells where it plays crucial roles in the control of water and mineral transport. Suberin formation is highly regulated by developmental and environmental cues. However, the mechanisms controlling its spatiotemporal regulation are poorly understood. Here, we show that endodermal suberin is regulated independently by developmental and exogenous signals to fine-tune suberin deposition in roots. We found a set of four MYB transcription factors (MYB41, MYB53, MYB92, and MYB93), each of which is individually regulated by these two signals and is sufficient to promote endodermal suberin. Mutation of these four transcription factors simultaneously through genome editing leads to a dramatic reduction in suberin formation in response to both developmental and environmental signals. Most suberin mutants analyzed at physiological levels are also affected in another endodermal barrier made of lignin (Casparian strips) through a compensatory mechanism. Through the functional analysis of these four MYBs, we generated plants allowing unbiased investigation of endodermal suberin function, without accounting for confounding effects due to Casparian strip defects, and were able to unravel specific roles of suberin in nutrient homeostasis.

scholarly journals Suberin plasticity to developmental and exogenous cues is regulated by a set of MYB transcription factors

2021 ◽  
Author(s):  
Vinay Shukla ◽  
Jian-Pu Han ◽  
Fabienne Cléard ◽  
Linnka Legendre-Lefebvre ◽  
Kay Gully ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Compensatory Mechanism ◽  
Biotic And Abiotic Stress ◽  
Environmental Signals ◽  
Myb Transcription Factors ◽  
Spatiotemporal Regulation ◽  
Exogenous Cues ◽  
Mineral Transport ◽  
Casparian Strips ◽  
Endodermal Cells

AbstractSuberin is a hydrophobic biopolymer that can be deposited at the periphery of cells, forming protective barriers against biotic and abiotic stress. In roots, suberin forms lamellae at the periphery of endodermal cells where it plays crucial roles in the control of water and mineral transport. Suberin formation is highly regulated by developmental and environmental cues. However, the mechanisms controlling its spatiotemporal regulation are poorly understood. Here, we show that endodermal suberin is regulated independently by developmental and exogenous signals to fine tune suberin deposition in roots. We found a set of four MYB transcription factors (MYB41, MYB53, MYB92 and MYB93), that are regulated by these two signals, and are sufficient to promote endodermal suberin. Mutation of these four transcription factors simultaneously through genome editing, lead to a dramatic reduction of suberin formation in response to both developmental and environmental signals. Most suberin mutants analyzed at physiological levels are also affected in another endodermal barrier made of lignin (Casparian strips), through a compensatory mechanism. Through the functional analysis of these four MYBs we generated plants allowing unbiased investigations of endodermal suberin function without accounting for confounding effects due to Casparian strip defects, and could unravel specific roles of suberin in nutrient homeostasis.

scholarly journals MYB Transcription Factors and Its Regulation in Secondary Cell Wall Formation and Lignin Biosynthesis during Xylem Development

2021 ◽  
Vol 22 (7) ◽  
pp. 3560
Author(s):  
Ruixue Xiao ◽  
Chong Zhang ◽  
Xiaorui Guo ◽  
Hui Li ◽  
Hai Lu
Keyword(s):  
Cell Wall ◽  
Transcription Factors ◽  
Secondary Wall ◽  
Secondary Cell Wall ◽  
Lignin Biosynthesis ◽  
Cell Wall Formation ◽  
Long Distance ◽  
Secondary Cell Wall Formation ◽  
Myb Transcription Factors ◽  
Wall Formation

The secondary wall is the main part of wood and is composed of cellulose, xylan, lignin, and small amounts of structural proteins and enzymes. Lignin molecules can interact directly or indirectly with cellulose, xylan and other polysaccharide molecules in the cell wall, increasing the mechanical strength and hydrophobicity of plant cells and tissues and facilitating the long-distance transportation of water in plants. MYBs (v-myb avian myeloblastosis viral oncogene homolog) belong to one of the largest superfamilies of transcription factors, the members of which regulate secondary cell-wall formation by promoting/inhibiting the biosynthesis of lignin, cellulose, and xylan. Among them, MYB46 and MYB83, which comprise the second layer of the main switch of secondary cell-wall biosynthesis, coordinate upstream and downstream secondary wall synthesis-related transcription factors. In addition, MYB transcription factors other than MYB46/83, as well as noncoding RNAs, hormones, and other factors, interact with one another to regulate the biosynthesis of the secondary wall. Here, we discuss the biosynthesis of secondary wall, classification and functions of MYB transcription factors and their regulation of lignin polymerization and secondary cell-wall formation during wood formation.

scholarly journals Two chemically distinct root lignin barriers control solute and water balance

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Guilhem Reyt ◽  
Priya Ramakrishna ◽  
Isai Salas-González ◽  
Satoshi Fujita ◽  
Ashley Love ◽  
...  
Keyword(s):  
Critical Role ◽  
Phenylpropanoid Pathway ◽  
Cellular Functions ◽  
Casparian Strip ◽  
Transcriptional Reprogramming ◽  
Exogenous Cues ◽  
Endodermal Cells ◽  
Complex Polymer ◽  
Nutrient Homeostasis ◽  
Lignin Deposition

AbstractLignin is a complex polymer deposited in the cell wall of specialised plant cells, where it provides essential cellular functions. Plants coordinate timing, location, abundance and composition of lignin deposition in response to endogenous and exogenous cues. In roots, a fine band of lignin, the Casparian strip encircles endodermal cells. This forms an extracellular barrier to solutes and water and plays a critical role in maintaining nutrient homeostasis. A signalling pathway senses the integrity of this diffusion barrier and can induce over-lignification to compensate for barrier defects. Here, we report that activation of this endodermal sensing mechanism triggers a transcriptional reprogramming strongly inducing the phenylpropanoid pathway and immune signaling. This leads to deposition of compensatory lignin that is chemically distinct from Casparian strip lignin. We also report that a complete loss of endodermal lignification drastically impacts mineral nutrients homeostasis and plant growth.

scholarly journals Expression of MYB transcription factor gene ZmMYB59 affects seed germination in Nicotiana tabacum and Oryza sativa

2020 ◽  
Author(s):  
Kaihui Zhai ◽  
Guangwu Zhao ◽  
Hongye Jiang ◽  
Caixia Sun ◽  
Jingyu Ren
Keyword(s):  
Transcription Factor ◽  
Transcription Factors ◽  
Seed Germination ◽  
Transgenic Tobacco ◽  
Germination Rate ◽  
Myb Transcription Factor ◽  
Transcription Factor Gene ◽  
Factor Gene ◽  
Myb Transcription Factors ◽  
Vigor Index

Abstract Background MYB transcription factors are involved in many biological processes, including metabolism, development and responses to biotic and abiotic stresses. In our previous work, a new MYB transcription factor gene, ZmMYB59 was induced by deep sowing and down-regulated during maize seed germination via Real-Time PCR. However, there are few reports on seed germination regulated by MYB proteins and the functions of ZmMYB59 remain unknown. Results In this study, to examine its functions, Agrobacterium -mediated transformation was exploited to generate ZmMYB59 transgenic tobacco and rice. In T 2 generation transgenic tobacco, germination rate, germination index, vigor index and hypocotyl length were significantly decreased by 25.0~50.9%, 34.5~54.4%, 57.5~88.3% and 21.9~31.2% compared to wild-type (WT) lines. In T 2 generation transgenic rice, germination rate, germination index, vigor index and mesocotyl length were notably reduced by 39.1~53.8%, 51.4~71.4%, 52.5~74.0% and 28.3~41.5%, respectively. On this basis, relative physiological indicators were determined. The activities of catalase, peroxidase, superoxide dismutase, ascorbate peroxidase and proline content of transgenic lines were significantly lower than those of WT, suggesting that ZmMYB59 reduced their antioxidant capacity. As well, ZmMYB59 expression extremely inhibited the synthesis of gibberellin A1 (GA 1 ) and cytokinin (CTK), and promoted the synthesis of abscisic acid (ABA) concurrently, which implied that seed germination was repressed by ZmMYB59 in hormone levels. Furthermore, cell length and cell number of hypocotyl/mesocotyl in transgenic plants were notably decreased. Conclusions Taken together, it proposed that ZmMYB59 plays a negative regulation during seed germination in tobacco and rice, which also contributes to illuminate the molecular mechanisms regulated by MYB transcription factors.

scholarly journals Molecular integration of casanova in the Nodal signalling pathway controlling endoderm formation

Development ◽  
2002 ◽  
Vol 129 (2) ◽  
pp. 275-286 ◽  
Author(s):  
Tazu O. Aoki ◽  
Nicolas B. David ◽  
Gabriella Minchiotti ◽  
Laure Saint-Etienne ◽  
Thomas Dickmeis ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Signalling Pathway ◽  
Partial Activation ◽  
Mesoderm Formation ◽  
Genes Encoding ◽  
Endodermal Differentiation ◽  
Endodermal Cells

Endoderm originates from a large endomesodermal field requiring Nodal signalling. The mechanisms that ensure segregation of endoderm from mesoderm are not fully understood. We first show that the timing and dose of Nodal activation are crucial for endoderm formation and the endoderm versus mesoderm fate choice, because sustained Nodal signalling is required to ensure endoderm formation but transient signalling is sufficient for mesoderm formation. In zebrafish, downstream of Nodal signals, three genes encoding transcription factors (faust, bonnie and clyde and the recently identified gene casanova) are required for endoderm formation and differentiation. However their positions within the pathway are not completely established. In the present work, we show that casanova is the earliest specification marker for endodermal cells and that its expression requires bonnie and clyde. Furthermore, we have analysed the molecular activities of casanova on endoderm formation and found that it can induce endodermal markers and repress mesodermal markers during gastrulation, as well as change the fate of marginal blastomeres to endoderm. Overexpression of casanova also restores endoderm markers in the absence of Nodal signalling. In addition, casanova efficiently restores later endodermal differentiation in these mutants, but this process requires, in addition, a partial activation of Nodal signalling.

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