CsLOB1 regulates susceptibility to citrus canker through promoting cell proliferation in citrus
| Autor: | Aihong Peng, Maxuel O. Andrade, Lanzhen Xu, Liu Wu, Qin Long, He Yongrui, Xiuping Zou, Yunuo Liu, Chen Shanchun, Meixia Du |
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| Rok vydání: | 2021 |
| Předmět: |
0106 biological sciences
0301 basic medicine Xanthomonas Cell division Plant Science Biology 01 natural sciences Xanthomonas citri Cell wall 03 medical and health sciences Expansin chemistry.chemical_compound Plant Growth Regulators Cell Wall Genetics Brassinosteroid Cell Proliferation Plant Diseases Plant Proteins Cell growth Gene Expression Profiling food and beverages Cell Biology Plants Genetically Modified Cell biology Plant Leaves 030104 developmental biology chemistry Citrus canker Disease Susceptibility Transcriptome Citrus × sinensis Citrus sinensis Signal Transduction 010606 plant biology & botany |
| Zdroj: | The Plant Journal. 106:1039-1057 |
| ISSN: | 1365-313X 0960-7412 |
| Popis: | Citrus sinensis lateral organ boundary 1 (CsLOB1) was previously identified as a critical disease susceptibility gene for citrus bacterial canker, which is caused by Xanthomonas citri subsp. citri (Xcc). However, the molecular mechanisms of CsLOB1 in citrus response to Xcc are still elusive. Here, we constructed transgenic plants overexpressing and RNAi-silencing of CsLOB1 using the canker-disease susceptible 'wanjincheng' orange (C. sinensis Osbeck) as explants. CsLOB1-overexpressing plants exhibited dwarf phenotypes with smaller and thicker leaf, increased branches and adventitious buds clustered on stems. These phenotypes were followed by a process of pustule- and canker-like development that exhibited enhanced cell proliferation. Pectin depolymerization and expansin accumulation were enhanced by CsLOB1 overexpression, while cellulose and hemicellulose synthesis were increased by CsLOB1 silence. Whilst overexpression of CsLOB1 increased susceptibility, RNAi-silencing of CsLOB1 enhanced resistance to canker disease without impairing pathogen entry. Transcriptome analysis revealed that CsLOB1 positively regulated cell wall degradation and modification processes, cytokinin metabolism, and cell division. Additionally, 565 CsLOB1-targeted genes were identified in chromatin immunoprecipitation-sequencing (ChIP-seq) experiments. Motif discovery analysis revealed that the most highly overrepresented binding sites had a conserved 6-bp 'GCGGCG' consensus DNA motif. RNA-seq and ChIP-seq data suggested that CsLOB1 directly activates the expression of four genes involved in cell wall remodeling, and three genes that participate in cytokinin and brassinosteroid hormone pathways. Our findings indicate that CsLOB1 promotes cell proliferation by mechanisms depending on cell wall remodeling and phytohormone signaling, which may be critical to citrus canker development and bacterial growth in citrus. |
| Databáze: | OpenAIRE |
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