Scholarlink

<p>Cold-pretreatment (stratification) is widely employed to overcome seed dormancy and enhance germination, however, its underlying molecular mechanisms remain elusive. We tested the hypothesis that stratification alleviates the repression of α-amylase expression, a critical step for endosperm starch mobilization during germination. Stratification at 4&#xa0;°C effectively overcame dormancy in wild-type <i>Arabidopsis thaliana</i>, the ABA-catabolism mutant <i>cyp707a2</i>, the GA-insensitive mutant <i>sleepy1</i>, and the <i>cyp707a2&#xa0;sleepy1</i> double mutant, but failed to rescue the dormancy phenotype of the GA-biosynthesis mutant <i>ga3ox1</i>. Moreover, stratification markedly promoted starch hydrolysis by increasing both the transcript abundance and the enzymatic activity of α-amylase in freshly harvested seeds of wild-type and in those mutants exhibiting elevated endogenous ABA or treated with exogenous ABA. Concomitantly, stratification substantially suppressed the expression of <i>RGL2</i>, a DELLA protein that represses GA signaling, and <i>ABI5</i>, a key ABA-responsive transcription factor. Collectively, our data indicates that stratification initiates GA biosynthesis, thereby relieving RGL2-mediated repression of α-amylase expression. Secondly, stratification mitigates ABA-imposed inhibition of germination without alleviating the suppressive effect of ABA on post-germinative seedling development.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Stratification overcomes ABA-mediated seed dormancy by uncoupling RGL2/ABI5 inhibition from α-amylase expression

  • 期刊论文

  • 出版模式：

    开放获取

  • 发表日期：

    2026年6月22日

查看全文
  • Yuan Tian,
  • Qin-Lai Liu,
  • Mo-Xian Chen,
  • Ying-Gao Liu

摘要

Cold-pretreatment (stratification) is widely employed to overcome seed dormancy and enhance germination, however, its underlying molecular mechanisms remain elusive. We tested the hypothesis that stratification alleviates the repression of α-amylase expression, a critical step for endosperm starch mobilization during germination. Stratification at 4 °C effectively overcame dormancy in wild-type Arabidopsis thaliana, the ABA-catabolism mutant cyp707a2, the GA-insensitive mutant sleepy1, and the cyp707a2 sleepy1 double mutant, but failed to rescue the dormancy phenotype of the GA-biosynthesis mutant ga3ox1. Moreover, stratification markedly promoted starch hydrolysis by increasing both the transcript abundance and the enzymatic activity of α-amylase in freshly harvested seeds of wild-type and in those mutants exhibiting elevated endogenous ABA or treated with exogenous ABA. Concomitantly, stratification substantially suppressed the expression of RGL2, a DELLA protein that represses GA signaling, and ABI5, a key ABA-responsive transcription factor. Collectively, our data indicates that stratification initiates GA biosynthesis, thereby relieving RGL2-mediated repression of α-amylase expression. Secondly, stratification mitigates ABA-imposed inhibition of germination without alleviating the suppressive effect of ABA on post-germinative seedling development.