Difference in root K+ retention ability and reduced sensitivity of K+-permeable channels to reactive oxygen species confer differential salt tolerance in three Brassica species.
Difference in root K+ retention ability and reduced sensitivity of K+-permeable channels to reactive oxygen species confer differential salt tolerance in three Brassica species.
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DOI：
10.1093/jxb/erw236
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发表时间：
2016-08
影响因子：
6.9
通讯作者：
Shabala S
中科院分区：
文献类型：
--
作者：
Chakraborty K;Bose J;Shabala L;Shabala S
这项工作提供了机制的解释之间的差异盐胁迫敏感性芸苔属植物，并将其与根质膜电位和细胞溶质K/Na比的调节芸苔属物种是已知的具有显着的跨和种内变异性的耐盐性，但赋予这种差异的细胞特异性机制仍然难以捉摸。本研究以三种芸苔属植物（B. napus，B. juncea和B. oleracea）进行测定。初步的根生长测定和活力染色表明，B。3个品种中，油菜的耐性最强，其次是B. juncea和B.甘蓝。在生理机制上，这种差异至少由三种互补的生理机制所决定：（1）质膜SOS 1-like Na+/H+交换体的表达和活性增加导致根系Na+排出能力增强;（2）胁迫诱导的H+-ATPase激活导致根系K+滞留能力增强;和（iii）降低B的灵敏度。油菜根系K+-活性氧通道（ROS）。后两种机制起主导作用，并赋予大部分的物种之间的差异盐敏感性。甘蓝型油菜植物也更有效地防止压力诱导的增加，在AKT 1，HAK 5和HKT 1转运蛋白基因的转录水平和表达上调。两者合计，我们的数据提供了这些物种之间的差异盐胁迫敏感性的机制解释，并揭示了关键离子转运系统的转录和翻译后调控参与根质膜电位和细胞溶质K/Na比的维持作为一个关键属性的耐盐性芸苔属物种。
This work provides the mechanistic explanation for differential salt stress sensitivity amongst Brassica species and links it with regulation of root plasma membrane potential and the cytosolic K/Na ratio Brassica species are known to possess significant inter and intraspecies variability in salinity stress tolerance, but the cell-specific mechanisms conferring this difference remain elusive. In this work, the role and relative contribution of several key plasma membrane transporters to salinity stress tolerance were evaluated in three Brassica species (B. napus, B. juncea, and B. oleracea) using a range of electrophysiological assays. Initial root growth assay and viability staining revealed that B. napus was most tolerant amongst the three species, followed by B. juncea and B. oleracea. At the mechanistic level, this difference was conferred by at least three complementary physiological mechanisms: (i) higher Na+ extrusion ability from roots resulting from increased expression and activity of plasma membrane SOS1-like Na+/H+ exchangers; (ii) better root K+ retention ability resulting from stress-inducible activation of H+-ATPase and ability to maintain more negative membrane potential under saline conditions; and (iii) reduced sensitivity of B. napus root K+-permeable channels to reactive oxygen species (ROS). The last two mechanisms played the dominant role and conferred most of the differential salt sensitivity between species. Brassica napus plants were also more efficient in preventing the stress-induced increase in GORK transcript levels and up-regulation of expression of AKT1, HAK5, and HKT1 transporter genes. Taken together, our data provide the mechanistic explanation for differential salt stress sensitivity amongst these species and shed light on transcriptional and post-translational regulation of key ion transport systems involved in the maintenance of the root plasma membrane potential and cytosolic K/Na ratio as a key attribute for salt tolerance in Brassica species.