Yan Jiawen, Liu Zhihui, Wang Tongtong, Wang Ruoman, Wang Shuya, Chen Weijie, Suo Jinwei, Yan Jingwei, Wu Jiasheng
State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Hangzhou, Zhejiang, 311300, China.
State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Hangzhou, Zhejiang, 311300, China.
Plant Physiol Biochem. 2024 Feb;207:108436. doi: 10.1016/j.plaphy.2024.108436. Epub 2024 Feb 13.
Drought stress is a major abiotic stress which severely reduces the plant growth and limits agricultural productivity. Previous studies have demonstrated that lutein directly synthesized by the carotenoid epsilon-ring hydroxylase gene (LUT1) played crucial roles in regulating drought response. Notwithstanding the myriad studies on LUT1's response to drought stress in certain plant species such as Arabidopsis, the precise function mechanisms within tree species remain ambiguously understood. Our study reveals that under drought stress, TgLUT1, a novel LUT gene instrumental in β-lutein biosynthesis, was markedly up-regulated in Torreya grandis. Subcellular localization assay indicated that TgLUT1 protein was localized to chloroplasts. Phenotypic analysis showed that overexpression of TgLUT1 enhanced the tolerance of tomato to drought stress. Overexpressing of TgLUT1 increased the values of maximal photochemical efficiency of photosystem II (Fv/Fm), net photosynthetic rate (Pn) and non-photochemical quenching (NPQ), and reduced the accumulation of hydrogen peroxide (HO), malondialdehyde (MDA) content and electrolyte leakage percentage in response to drought stress. Furthermore, overexpression of TgLUT1 decreased the stomatal conductance to reduce the water loss rate exposed to drought stress. In addition, yeast one-hybrid assay, dual luciferase assay system and qRT-PCR results showed that TgWRKY10 down-regulated by drought stress inhibited the expression of TgLUT1 by directly binding to the TgLUT1 promoter. Collectively, our results show that TgWRKY10, down-regulated by drought stress, negatively regulates the expression of TgLUT1 to modulate the drought stress response. This study contributes to a more comprehensive understanding of LUT1's function in the stress responses of economically significant forest plants.
干旱胁迫是一种主要的非生物胁迫，严重降低植物生长并限制农业生产力。先前的研究表明，由类胡萝卜素ε-环羟化酶基因（LUT1）直接合成的叶黄素在调节干旱响应中起关键作用。尽管对拟南芥等某些植物物种中LUT1对干旱胁迫的响应进行了大量研究，但树种内的精确功能机制仍不清楚。我们的研究表明，在干旱胁迫下，一种参与β-叶黄素生物合成的新型LUT基因TgLUT1在榧树中显著上调。亚细胞定位分析表明，TgLUT1蛋白定位于叶绿体。表型分析表明，TgLUT1的过表达增强了番茄对干旱胁迫的耐受性。过表达TgLUT1增加了光系统II的最大光化学效率（Fv/Fm）、净光合速率（Pn）和非光化学猝灭（NPQ）的值，并减少了干旱胁迫下过氧化氢（HO）的积累、丙二醛（MDA）含量和电解质渗漏百分比。此外，TgLUT1的过表达降低了气孔导度，以降低干旱胁迫下的失水率。此外，酵母单杂交试验、双荧光素酶试验系统和qRT-PCR结果表明，干旱胁迫下调的TgWRKY10通过直接结合TgLUT1启动子抑制TgLUT1的表达。总的来说，我们的结果表明，干旱胁迫下调的TgWRKY10负向调节TgLUT1的表达，以调节干旱胁迫响应。这项研究有助于更全面地了解LUT1在具有经济意义的森林植物胁迫响应中的功能。
