Tissue-Specific Regulation of Na+ and K+ Transporters Explains Genotypic Differences in Salinity Stress Tolerance in Rice

作者：Juan Liu, Sergey N. Shabala, Lana Shabala, Meixue Zhou, Holger Meinke, Gayatri Venkataraman, Zhong‐Hua Chen, Fanrong Zeng, Quanzhi Zhao · 发表于：Frontiers in Plant Science · 年份：2019 · DOI：10.3389/fpls.2019.01361 · 被引用次数：110 · 研究领域：Plant Stress Responses and Tolerance、Aluminum toxicity and tolerance in plants and animals、Plant nutrient uptake and metabolism

Rice (Oryza sativa) is a staple food that feeds more than half the world population. As rice is highly sensitive to soil salinity, current trends in soil salinization threaten global food security. To better understand the mechanistic basis of salinity tolerance in rice, three contrasting rice cultivars – Reiziq (tolerant), Doongara (moderately tolerant), and Koshihikari (sensitive) were examined and the differences in operation of key ion transporters mediating ionic homeostasis in these genotypes evaluated. Tolerant varieties had reduced Na+ translocation from roots to shoots. Electrophysiological and qRT-PCR experiments showed that tolerant genotypes possessed 2-fold higher net Na+ efflux capacity in the root elongation zone. Interestingly, this efflux was only partially mediated by the plasma membrane (PM) Na+/H+ antiporter (OsSOS1), suggesting involvement of some other exclusion mechanisms. No significant difference in Na+ exclusion from the mature root zones was found between cultivars, and the transcriptional changes in the SOS signalling pathway genes in the elongation zone were not correlated with the genetic variability in salinity tolerance amongst genotypes. The most important hallmark of differential salinity tolerance was in the ability of the plant to retain K+ in both root zones. This trait was conferred by at least three complementary mechanisms: (1) its superior ability to activate H+-ATPase pump operation, both at transcriptional and functional levels; (2) r...