Soil salinisation is a major abiotic stress in agriculture, and is especially a concern for rice production because among cereal crops, rice is the most salt-sensitive. However, the production of rice must be increased substantially by the year 2050 to meet the demand of the ever growing population. Hence, understanding the biochemical events determining salt tolerance in rice is highly desirable so that the trait can be introduced in cultivars of interest through biotechnological intervention. In this context, an initial study on NaCl response in four Indica rice varieties showed a lower uptake of Na⁺ in the salt-tolerant Nona Bokra and Pokkali than in the salt-sensitive IR64 and IR29, indicating Na⁺ exclusion as a primary requirement of salt tolerance in the species. This was also supported by the following features in the salt-tolerant, but not in the -sensitive varieties: (1) highly significant NaCl-induced increase in the activity of PM-H⁺ATPase, (2) a high constitutive level and NaCl-induced threonine phosphorylation of PM-H⁺ATPase, necessary to promote its activity, (3) a high constitutive expression of 14-3-3 protein that makes PM-H⁺ATPase active by binding with the phosphorylated threonine at the C-terminal end, (4) a high constitutive and NaCl-induced expression of SOS1 in roots, and (5) significant NaCl-induced expression of OsCIPK 24, a SOS2 that phosphorylates SOS1. The vacuolar sequestration of Na⁺ in seedlings was not reflected from the expression pattern of NHX1/NHX1 in response to NaCl. NaCl-induced downregulation of expression of HKTs in roots of Nona Bokra, but upregulation in Pokkali also indicates that their role in salt tolerance in rice could be cultivar specific. The study indicates that consideration of increasing exclusion of Na⁺ by enhancing the efficiency of SOS1/PM-H⁺ATPase Na⁺ exclusion module could be an important aspect in attempting to increase salt tolerance in the rice varieties or cultivars of interest.

土壤盐渍化是农业中的主要非生物胁迫，并且特别是对水稻生产的关注，因为在谷物作物中，水稻对盐分最敏感。但是，大米的生产必须在2050年之前大幅增加，以满足不断增长的人口的需求。因此，非常需要了解决定水稻耐盐性的生化事件，以便可以通过生物技术干预将性状引入感兴趣的品种。在这种情况下，对四个four稻品种的NaCl响应的初步研究表明，耐盐的Nona Bokra和Pokkali的Na ⁺吸收量比盐敏感的IR64和IR29低，表明Na ⁺排除是该物种耐盐性的主要要求。耐盐品种中的以下特征也支持了这一点，但敏感性品种中却没有：（1）NaCl诱导的PM-H ⁺ ATPase活性显着增加；（2）高组成水平和NaCl诱导PM-H ⁺ ATPase的苏氨酸磷酸化，这是促进其活性所必需的；（3）14-3-3蛋白的高组成型表达，使PM-H ⁺ ATPase通过与C末端的磷酸化苏氨酸结合而具有活性最后，（4）根系中SOS1的高组成型和NaCl诱导表达，（5）Nas诱导的OsCIPK 24表达显着，是磷酸化SOS1的SOS2。NHX1 / NHX1响应NaCl的表达方式未反映出幼苗中Na ⁺的液泡螯合。NaCl诱导了Nona Bokra根中HKTs表达的下调，但Pokkali中的HKTs上调也表明它们在水稻耐盐性中的作用可能是特定品种的。研究表明，考虑娜的排除增加⁺通过增强SOS1 / PM-H效率⁺ ATP酶的Na ⁺排斥模块可能是一个重要方面，在试图增加在水稻品种或感兴趣的品种耐盐性。