Institute of Crop Science, Zhejiang University, Hangzhou 310058, China.
Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China.
Int J Mol Sci. 2019 Aug 22;20(17):4111. doi: 10.3390/ijms20174111.
In this work, the effect of drought on K uptake in root and its translocation from root to shoot was investigated using six barley genotypes contrasting in drought tolerance. Results showed that drought conditions caused significant changes in K uptake and translocation in a time- and genotype-specific manner, which consequently resulted in a significant difference in tissue K contents and drought tolerance levels between the contrasting barley genotypes. The role of K transporters and channels and plasma membrane (PM) H-ATPase in barley's adaptive response to drought stress was further investigated at the transcript level. The expression of genes conferring K uptake (, , , and ) and xylem loading () in roots were all affected by drought stress in a time- and genotype-specific manner, indicating that the regulation of these K transporters and channels is critical for root K uptake and root to shoot K translocation in barley under drought stress. Furthermore, the barley genotypes showed a strong correlation between H efflux and K influx under drought stress, which was further confirmed by the significant up-regulation of and . These results suggested an important role of plasma membrane H-ATPase activity and/or expression in regulating the activity of K transporters and channels under drought stress. Taken together, it may be concluded that the genotypic difference in drought stress tolerance in barley is conferred by the difference in the ability to regulate K transporters and channels in root epidermis and stele.
在这项工作中，使用六种在耐旱性方面存在差异的大麦基因型，研究了干旱对根吸收钾及其从根向地上部转运的影响。结果表明，干旱条件以时间和基因型特异性的方式导致钾吸收和转运发生显著变化，从而导致不同耐旱性大麦基因型之间的组织钾含量和耐旱性水平存在显著差异。进一步从转录水平研究了钾转运体和通道以及质膜（PM）H-ATPase 在大麦适应干旱胁迫中的作用。根中赋予钾吸收（、、、和）和木质部装载（）的基因的表达均受干旱胁迫的时间和基因型特异性影响，表明这些钾转运体和通道的调节对于大麦在干旱胁迫下的根钾吸收和根到地上部钾转运至关重要。此外，在干旱胁迫下，大麦基因型表现出 H 外排和 K 内流之间的强相关性，这进一步被 和 的显著上调所证实。这些结果表明，质膜 H-ATPase 活性和/或表达在调节干旱胁迫下 K 转运体和通道的活性中起重要作用。总之，可以得出结论，大麦对干旱胁迫耐受性的基因型差异是由根表皮和中柱中调节钾转运体和通道的能力差异决定的。
