| Autor: |
Song, Qin, Kong, Lingfei, Yang, Jiarui, Lin, Minghui, Zhang, Yuqian, Yang, Xuerui, Wang, Xiaojing, Zhao, Zhengjie, Zhang, Meng, Pan, Jiarui, Zhu, Shunqin, Jiao, Bo, Xu, Changzheng, Luo, Keming |
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| Zdroj: |
Plant Journal; Apr2024, Vol. 118 Issue 1, p42-57, 16p |
| Abstrakt: |
SUMMARY: Drought stress caused by global warming has resulted in significant tree mortality, driving the evolution of water conservation strategies in trees. Although phytohormones have been implicated in morphological adaptations to water deficits, the molecular mechanisms underlying these processes in woody plants remain unclear. Here, we report that overexpression of PtoMYB142 in Populus tomentosa results in a dwarfism phenotype with reduced leaf cell size, vessel lumen area, and vessel density in the stem xylem, leading to significantly enhanced drought resistance. We found that PtoMYB142 modulates gibberellin catabolism in response to drought stress by binding directly to the promoter of PtoGA2ox4, a GA2‐oxidase gene induced under drought stress. Conversely, knockout of PtoMYB142 by the CRISPR/Cas9 system reduced drought resistance. Our results show that the reduced leaf size and vessel area, as well as the increased vessel density, improve leaf relative water content and stem water potential under drought stress. Furthermore, exogenous GA3 application rescued GA‐deficient phenotypes in PtoMYB142‐overexpressing plants and reversed their drought resistance. By suppressing the expression of PtoGA2ox4, the manifestation of GA‐deficient characteristics, as well as the conferred resistance to drought in PtoMYB142‐overexpressing poplars, was impeded. Our study provides insights into the molecular mechanisms underlying tree drought resistance, potentially offering novel transgenic strategies to enhance tree resistance to drought. Significance Statement: Here we demonstrate that PtoMYB142, a transcription factor, modulates gibberellin catabolism by directly regulating the expression of PtoGA2ox4, a key enzyme involved in gibberellin degradation. This regulatory pathway leads to a reduction in leaf size and an improvement in vessel features, which enhances water transport and reduces water loss in response to water stress. These novel insights into the molecular mechanisms underlying drought‐induced morphological changes in trees have significant implications for improving ecosystem resilience in water‐limited environments. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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