Table_3_Identification of a highly drought-resistant pp7l hda6 mutant.xlsx

Plants have developed efficient strategies to counteract drought stress, including stomata closure, significant changes in nuclear gene expression, and epigenetic mechanisms. Previously, we identified Arabidopsis thaliana PROTEIN PHOSPHATASE7-LIKE (PP7L) as an extrachloroplastic protein that promotes chloroplast development. In addition, it was shown that PP7L is involved in high light and salt tolerance. Here, we demonstrate that the pp7l mutant can withstand prolonged periods of drought stress. Interestingly, despite impaired growth under standard growth conditions, photosynthetic efficiency recovers in pp7l mutant plants experiencing drought conditions. To assess the (post)transcriptional changes occurring in the pp7l mutant under different durations of drought exposure, we used an RNA-sequencing technique that allows the simultaneous detection of organellar and nuclear transcripts. Compared with the previously reported drought-responsive changes in the wild type, the drought-responsive changes in organellar and nuclear transcripts detected in the pp7l mutant were negligible. Our analysis of the data generated in this study and review and analysis of previous literature motivated us to create a pp7l hda6 (histone deacetylase 6) mutant, which exhibits remarkable drought resistance. Notably, the growth penalty associated with pp7l was alleviated in the double mutant, ruling out a dwarf effect on the drought-tolerant trait of this genotype. Future studies may consider that multiple loci and factors are involved in stress resistance and explore combinations of these factors to create even more resilient plants.

植物已演化出多种高效策略以抵御干旱胁迫，包括气孔关闭、核基因表达的显著改变以及表观遗传调控机制。此前，我们曾鉴定出拟南芥（Arabidopsis thaliana）的蛋白磷酸酶7类似蛋白（PROTEIN PHOSPHATASE7-LIKE，PP7L）为一种定位于叶绿体外部、可促进叶绿体发育的蛋白质。此外，已有研究表明PP7L参与植物的高光胁迫与盐胁迫耐受过程。本研究证实，pp7l突变体可耐受长期干旱胁迫。值得注意的是，尽管pp7l突变体在标准培养条件下生长受到抑制，但在干旱环境中其光合效率可恢复至正常水平。为探究不同干旱处理时长下pp7l突变体中发生的转录及转录后水平变化，我们采用了可同时检测细胞器与核转录本的RNA测序（RNA-sequencing）技术。与此前报道的野生型干旱响应转录变化相比，pp7l突变体中检测到的细胞器与核转录本的干旱响应变化可忽略不计。通过对本研究产生的数据进行分析，并结合既往文献的梳理与分析，我们构建了pp7l hda6（组蛋白去乙酰化酶6，histone deacetylase 6）双突变体，该双突变体表现出显著的干旱抗性。值得注意的是，双突变体中pp7l所带来的生长缺陷得到了缓解，这排除了该基因型干旱耐受性状受矮化效应影响的可能。未来的研究可关注参与胁迫耐受的多个基因位点与调控因子，并探索这些因子的组合应用，以培育出抗逆性更强的植物。