Peng Yuquan, Cao Haishun, Peng Zhaowen, Zhou Lijian, Sohail Hamza, Cui Lvjun, Yang Li, Huang Yuan, Bie Zhilong
Key Laboratory of Horticultural Plant Biology, Ministry of Education/College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, China.
Key Laboratory of Horticultural Plant Biology, Ministry of Education/College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, China; Institute of Facility Agriculture, Guangdong Academy of Agricultural Sciences, Guangzhou, China.
Plant Sci. 2023 Jan;326:111509. doi: 10.1016/j.plantsci.2022.111509. Epub 2022 Oct 22.
Grafting can improve the salt tolerance of many crops. However, critical genes in scions responsive to rootstock under salt stress remain a mystery. We found that pumpkin rootstock decreased the content of Na by 70.24 %, increased the content of K by 25.9 %, and increased the K/Na ratio by 366.0 % in cucumber scion leaves. RNA-seq analysis showed that ion transport-related genes were the key genes involved in salt stress tolerance in grafted cucumber. The identification and analysis of the expression of K transporter proteins in cucumber and pumpkin revealed six and five HAK5 members, respectively. The expression of CsHAK5;3 in cucumber was elevated in different graft combinations under salt stress and most notably in cucumber scion/pumpkin rootstock. CsHAK5;3 was localized to the plasma membrane, and a yeast complementation assay revealed that it can transport K. CsHAK5;3 knockout in hairy root mutants decreased the K content of leaves (45.6 %) and roots (50.3 %), increased the Na content of leaves (29.3 %) and roots (34.8 %), and decreased the K/Na ratio of the leaves (57.9 %) and roots (62.9 %) in cucumber. However, CsHAK5;3 overexpression in hairy roots increased the K content of the leaves (31.2 %) and roots (38.3 %), decreased the Na content of leaves (17.2 %) and roots (14.3 %), and increased the K/Na ratio of leaves (58.9 %) and roots (61.6 %) in cucumber. In conclusion, CsHAK5;3 in cucumber can mediate K transport and is one of the key target pumpkin genes that enhance salt tolerance of cucumber grafted.
嫁接可以提高许多作物的耐盐性。然而，在盐胁迫下接穗中响应砧木的关键基因仍是个谜。我们发现，南瓜砧木使黄瓜接穗叶片中的Na含量降低了70.24%，K含量增加了25.9%，K/Na比值增加了366.0%。RNA测序分析表明，离子转运相关基因是嫁接黄瓜耐盐胁迫的关键基因。对黄瓜和南瓜中钾转运蛋白的表达进行鉴定和分析，分别发现了6个和5个HAK5成员。盐胁迫下，不同嫁接组合中黄瓜CsHAK5;3的表达均升高，在黄瓜接穗/南瓜砧木组合中最为明显。CsHAK5;3定位于质膜，酵母互补试验表明它可以转运钾。在发根突变体中敲除CsHAK5;3会使黄瓜叶片（45.6%）和根（50.3%）中的钾含量降低，叶片（29.3%）和根（34.8%）中的钠含量增加，叶片（57.9%）和根（62.9%）中的K/Na比值降低。然而，在发根中过表达CsHAK5;3会使黄瓜叶片（31.2%）和根（38.3%）中的钾含量增加，叶片（17.2%）和根（14.3%）中的钠含量降低，叶片（58.9%）和根（61.6%）中的K/Na比值增加。总之，黄瓜中的CsHAK5;3可以介导钾转运，是增强嫁接黄瓜耐盐性的关键南瓜基因之一。
