Environmental Regulation of Lateral Root Emergence in Medicago truncatula Requires the HD-Zip I Transcription Factor HB1
Environmental Regulation of Lateral Root Emergence in Medicago truncatula Requires the HD-Zip I Transcription Factor HB1
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DOI：
10.1105/tpc.110.074823
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发表时间：
2010-07-01
期刊：
影响因子：
11.6
通讯作者：
Crespi, Martin
中科院分区：
文献类型：
--
作者：
Ariel, Federico;Diet, Anouck;Crespi, Martin
根结构对环境约束的适应是一个主要的农业特征，特别是在豆类中，豆类是世界上第三大作物。这种根的发育可塑性取决于侧根的形成。在模式豆科植物蒺藜苜蓿中，HD-Zip I转录因子HB 1在主根和侧根分生组织中表达，并受到盐胁迫的诱导。HB 1在M.蒺藜根改变其架构，而hb 1 TILLING突变体表现出增加侧根出现。电泳迁移率变动分析，启动子诱变，和染色质免疫沉淀-PCR分析表明，HB 1直接识别CAA-TAATTG顺式元件存在于一个LOB样（横向器官边界）基因，LBD 1，转录生长素调控的启动子。这些基因的表达响应脱落酸和生长素和他们的行为在hb 1突变体揭示了HB 1介导的抑制LBD 1在LR出现。M.蒺藜HB 1调节适应性发育反应，以最大限度地减少暴露于不利环境应力的根表面。
The adaptation of root architecture to environmental constraints is a major agricultural trait, notably in legumes, the third main crop worldwide. This root developmental plasticity depends on the formation of lateral roots (LRs) emerging from primary roots. In the model legume Medicago truncatula, the HD-Zip I transcription factor HB1 is expressed in primary and lateral root meristems and induced by salt stress. Constitutive expression of HB1 in M. truncatula roots alters their architecture, whereas hb1 TILLING mutants showed increased lateral root emergence. Electrophoretic mobility shift assay, promoter mutagenesis, and chromatin immunoprecipitation-PCR assays revealed that HB1 directly recognizes a CAA-TAATTG cis-element present in the promoter of a LOB-like (for Lateral Organ Boundaries) gene, LBD1, transcriptionally regulated by auxin. Expression of these genes in response to abscisic acid and auxin and their behavior in hb1 mutants revealed an HB1-mediated repression of LBD1 acting during LR emergence. M. truncatula HB1 regulates an adaptive developmental response to minimize the root surface exposed to adverse environmental stresses.