|Yibo Cao, Ming Zhang, Xiaoyan Liang, Fenrong Li, Yunlu Shi, Xiaohong Yang, Caifu Jiang.Natural variation of an EF-hand Ca2+-binding-protein coding gene confers saline-alkaline tolerance in maize. DOI: 10.1038/s41467-019-14027-y|
Natural variation of an EF-hand Ca2+-binding-protein coding gene confers saline-alkaline tolerance in maize
Yibo Cao, Ming Zhang, Xiaoyan Liang, Fenrong Li, Yunlu Shi, Xiaohong Yang, Caifu Jiang
Sodium (Na+) toxicity is one of the major damages imposed on crops by saline-alkaline stress. Here we show that natural maize inbred lines display substantial variations in shoot Na+ contents and saline-alkaline (NaHCO3) tolerance, and reveal that ZmNSA1 (Na+Content under Saline-Alkaline Condition) confers shoot Na+ variations under NaHCO3 condition by a genome-wide association study. Lacking of ZmNSA1 promotes shoot Na+ homeostasis by increasing root Na+ efflux. A naturally occurred 4-bp deletion decreases the translation efficiency of ZmNSA1 mRNA, thus promotes Na+ homeostasis. We further show that, under saline-alkaline condition, Ca2+ binds to the EF-hand domain of ZmNSA1 then triggers its degradation via 26S proteasome, which in turn increases the transcripts levels of PM-H+-ATPases (MHA2 and MHA4), and consequently enhances SOS1 Na+/H+ antiporter-mediated root Na+ efflux. Our studies reveal the mechanism of Ca2+-triggered saline-alkaline tolerance and provide an important gene target for breeding saline-alkaline tolerant maize varieties. Saline-alkaline stress affects worldwide crops production, but the tolerance mechanisms have not been fully elucidated. Here, the authors show that EF-hand Ca2 + -binding-protein coding gene ZmNSA1 can regulate root H + efflux, Na + homeostasis, and saline-alkaline tolerance in maize.