Domestication has resulted in reduced salt tolerance in tomato. To identify the genetic components causing this deficiency, we performed a genome-wide association study (GWAS) for root Na+ /K+ ratio in a population consisting of 369 tomato accessions with large natural variations. The most significant variations associated with root Na+ /K+ ratio were identified within the gene SlHAK20 encoding a member of the clade IV HAK/KUP/KT transporters. We further found that SlHAK20 transports Na+ and K+ and regulates Na+ and K+ homeostasis under salt stress conditions. A variation in the coding sequence of SlHAK20 was found to be the causative variant associated with Na+ /K+ ratio and confer salt tolerance in tomato. Knockout mutations in tomato SlHAK20 and the rice homologous genes resulted in hypersensitivity to salt stress. Together, our study uncovered a previously unknown molecular mechanism of salt tolerance responsible for the deficiency in salt tolerance in cultivated tomato varieties. Our findings provide critical information for molecular breeding to improve salt tolerance in tomato and other crops.

中文翻译：

---

Na + / K +转运蛋白的变化导致番茄驯化期间耐盐性下降。

驯化导致番茄的耐盐性下降。为了鉴定导致这种缺陷的遗传成分，我们对369个番茄品种（自然变异较大）组成的群体中的根Na + / K +比例进行了全基因组关联研究（GWAS）。在编码进化枝IV HAK / KUP / KT转运蛋白成员的基因SlHAK20中鉴定出了与根Na + / K +比有关的最显着变异。我们进一步发现SlHAK20在盐胁迫条件下转运Na +和K +并调节Na +和K +稳态。发现SlHAK20的编码序列的变化是与Na + / K +比相关的致病变体，并赋予番茄耐盐性。番茄SlHAK20和水稻同源基因的敲除突变导致对盐胁迫超敏。一起，我们的研究发现了以前未知的耐盐分子机制，这是造成栽培番茄品种耐盐性不足的原因。我们的发现为分子育种提高番茄和其他农作物的耐盐性提供了关键信息。