Jing Yuanyuan, Liu Changhai, Liu Bingbing, Pei Tingting, Zhan Minghui, Li Chunrong, Wang Duanni, Li Pengmin, Ma Fengwang
State Key Laboratory of Crop Stress Biology for Arid Areas/Shaanxi Key Laboratory of Apple, College of Horticulture, Northwest A&F University, Yangling 712100, Shaanxi, China.
Tree Physiol. 2023 Jan 5;43(1):154-168. doi: 10.1093/treephys/tpac100.
Drought is a major abiotic stress limiting the growth and production of apple trees worldwide. The receptor-like kinase FERONIA is involved in plant growth, development and stress responses; however, the function of FERONIA in apple under drought stress remains unclear. Here, the FERONIA receptor kinase gene MdMRLK2 from apple (Malus domestica) was shown to encode a plasma membrane-localized transmembrane protein and was significantly induced by abscisic acid and drought treatments. 35S::MdMRLK2 apple plants showed less photosystem damage and higher photosynthetic rates compared with wild-type (WT) plants, after withholding water for 7 days. 35S::MdMRLK2 apple plants also had enhanced energy levels, activated caspase activity and more free amino acids, than the WT, under drought conditions. By performing yeast two-hybrid screening, glyceraldehyde-3-phosphate dehydrogenase and MdCYS4, a member of cystatin, were identified as MdMRLK2 interaction partners. Moreover, under drought conditions, the 35S::MdMRLK2 apple plants were characterized by higher abscisic acid (ABA) content. Overall, these findings demonstrated that MdMRLK2 regulates apple drought tolerance, probably via regulating levels of energetic matters, free amino acids and ABA.
干旱是一种主要的非生物胁迫，限制了全球苹果树的生长和产量。类受体激酶FERONIA参与植物生长、发育和胁迫反应；然而，FERONIA在干旱胁迫下苹果中的功能仍不清楚。在这里，苹果（Malus domestica）的FERONIA受体激酶基因MdMRLK2被证明编码一种定位于质膜的跨膜蛋白，并在脱落酸和干旱处理下显著诱导表达。与野生型（WT）植株相比，在停水7天后，35S::MdMRLK2苹果植株的光系统损伤较小，光合速率较高。在干旱条件下，35S::MdMRLK2苹果植株的能量水平也比野生型更高，半胱天冬酶活性被激活，游离氨基酸更多。通过酵母双杂交筛选，甘油醛-3-磷酸脱氢酶和半胱氨酸蛋白酶抑制剂家族成员MdCYS4被鉴定为MdMRLK2的相互作用伙伴。此外，在干旱条件下，35S::MdMRLK2苹果植株的脱落酸（ABA）含量较高。总体而言，这些发现表明MdMRLK2可能通过调节能量物质、游离氨基酸和ABA的水平来调节苹果的耐旱性。
