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Abstract
背景回顾：Improving water use efficiency in crops is a significant challenge as it involves balancing water transpiration and CO2 uptake through stomatal pores.
主要发现：This study investigates the role of SlROP9, a tomato Rho of Plants protein, in guard cells and its impact on plant transpiration.
结果1-rop9突变提升WUE：The results reveal that SlROP9 null mutants exhibit reduced stomatal conductance while photosynthetic CO2 assimilation remains largely unaffected. Notably, there is a notable decrease in whole-plant transpiration in the rop9 mutants compared to the wild type, especially during noon hours when the water pressure deficit is high.
结果2-ROP9通过RBOHB影响WUE：The elevated stomatal closure observed in rop9 mutants is linked to an increase in reactive oxygen species formation. This is very likely dependent on the respiratory burst oxidase homolog (RBOH) NADPH oxidase and is not influenced by abscisic acid (ABA). Consistently, activated ROP9 can interact with RBOHB in both yeast and plants. In diverse tomato accessions, drought stress represses ROP9 expression, and in Arabidopsis stomatal guard cells, ABA suppresses ROP signaling. Therefore, the phenotype of the rop9 mutants may arise from a disruption in ROP9-regulated RBOH activity.
结果3-rop9不影响产量：Remarkably, large-scale field experiments demonstrate that the rop9 mutants display improved water use efficiency without compromising fruit yield.
结论：These findings provide insights into the role of ROPs in guard cells and their potential as targets for enhancing water use efficiency in crops.
摘 要
提升作物的水分利用效率是一个重大挑战，因为其涉及到途径气孔的水分蒸腾和二氧化碳吸收之间的平衡。本文研究了番茄SlROP9在保卫细胞中的作用及其对于植物蒸腾作用的影响。研究结果显示，SlROP9无效突变会导致气孔导度降低，但光合二氧化碳同化并不受影响。相比于野生型，rop9突变体整株的蒸腾作用显著下降，尤其是在正午水压最低的时刻。另外，rop9突变体中气孔闭合更多，这与ROS形成的增加有关。这很有可能是依赖于NADPH氧化酶RBOH，并不受到ABA的影响。与此一致的是，酵母和植物体内的蛋白互作实验均显示ROP9能够与RBOHB发生互作。在不同的番茄种质中，干旱胁迫能够抑制ROP9的表达，并且在拟南芥气孔保卫细胞中ABA抑制ROP信号转导。因此，rop9突变体的表型可能源自于受ROP9调控的RBOH活性的紊乱。重要的是，大规模的田间试验显示rop9突变体表现出水分利用效率增强但不影响果实产量的表型。本文的研究结果为ROPs在保卫细胞中的功能提供了新的视野，同时也为作物增强水分利用效率提供了潜在靶标。
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