Frontiers Science Center for Cell Responses, College of Life Sciences, Nankai University, Tianjin, China.
College of Life Sciences, Shandong Agricultural University, Tai'an, Shandong, China.
Plant Cell Environ. 2024 Jul;47(7):2396-2409. doi: 10.1111/pce.14887. Epub 2024 Mar 22.
Stomatal movement is critical for water transpiration, gas exchange, and responses to biotic stresses. Abscisic acid (ABA) induces stomatal closure to prevent water loss during drought. We report that Arabidopsis CIPK8 negatively regulates ABA-mediated stomatal closure and drought tolerance. CIPK8 is highly enriched in guard cells and transcriptionally induced by ABA. Functional loss of CIPK8 results in hypersensitive stomatal closure to ABA and enhanced drought tolerance. Guard cell-specific downregulation of CIPK8 mimics the phenotype of cipk8 whereas guard cell-specific expression of a constitutive active CIPK8 (CIPK8) has an opposite effect, suggesting a cell autonomous activity of CIPK8. CIPK8 physically interacts with CBL1 and CBL9. Functional loss of CBL1 and CBL9 mimics ABA-hypersensitive stomatal closure of cipk8 whereas abolishes the effect of CIPK8, indicating that CIPK8 and CBL1/CBL9 form a genetic module in ABA-responsive stomatal movement. SlCIPK7, the functional homolog of CIPK8 in tomato (Solanum lycopersicum), plays a similar role in ABA-responsive stomatal movement. Genomic editing of SlCIPK7 results in more drought-tolerant tomato, making it a good candidate for germplasm improvement.
气孔运动对于水分蒸腾、气体交换和生物胁迫响应至关重要。脱落酸（ABA）诱导气孔关闭以防止干旱期间水分流失。我们报告称，拟南芥 CIPK8 负调控 ABA 介导的气孔关闭和耐旱性。CIPK8 在保卫细胞中高度富集，并受 ABA 转录诱导。CIPK8 的功能丧失导致对 ABA 的超敏性气孔关闭和增强的耐旱性。保卫细胞特异性下调 CIPK8 模拟了 cipk8 的表型，而组成型激活的 CIPK8（CIPK8）在保卫细胞中的特异性表达则具有相反的效果，表明 CIPK8 具有细胞自主活性。CIPK8 与 CBL1 和 CBL9 物理相互作用。CBL1 和 CBL9 的功能丧失模拟了 cipk8 的 ABA 超敏性气孔关闭，而消除了 CIPK8 的作用，表明 CIPK8 和 CBL1/CBL9 在 ABA 响应性气孔运动中形成遗传模块。番茄（Solanum lycopersicum）中 CIPK8 的功能同源物 SlCIPK7 在 ABA 响应性气孔运动中发挥类似作用。SlCIPK7 的基因组编辑导致番茄耐旱性增强，使其成为改良种质的良好候选者。
