National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi, 110067, India.
Funct Integr Genomics. 2019 Jul;19(4):587-596. doi: 10.1007/s10142-018-00653-0. Epub 2019 Feb 13.
Aquaporins are versatile proteins involved in several biological as well as molecular functions, and they have been extensively studied in various plant systems. Increasing evidences indicate their role in biotic and abiotic stresses, and therefore, studying these proteins in a naturally stress-tolerant crop would provide further insights into the roles of this important protein family. Given this, the present study was performed in foxtail millet (Setaria italica), a model plant for studying biofuel, stress tolerance, and C photosynthetic traits. The study identified 12 plasma membrane intrinsic proteins (PIPs), 11 tonoplast intrinsic proteins (TIPs), 13 NOD26-like intrinsic proteins (NIPs), and 3 small basic intrinsic proteins (SIPs) in foxtail millet. The identified proteins and their corresponding genes were characterized using in silico approaches such as chromosomal localization, analysis of gene and protein properties, phylogenetic analysis, promoter analysis, and RNA-seq-derived expression profiling. The candidate genes identified through these analyses were studied for their expression in response to abiotic stresses (dehydration, salinity, and heat) as well as hormone treatments (abscisic acid, methyl jasmonate, and salicylic acid) in two contrasting cultivars of foxtail millet. The study showed that SiPIP3;1 and SiSIP1;1 were differentially expressed in both the cultivars in response to stress and hormone treatments. Overexpression of these genes in a heterologous yeast system also demonstrated that the transgenic cells were able to tolerate dehydration as well as salt stress which suggests the involvement of these proteins in the tolerance mechanism. Overall, the present study provides insights into structure and organization of the aquaporin gene family in foxtail millet and highlights the potential candidate genes for further functional characterizations.
水通道蛋白是一类多功能蛋白，参与多种生物学和分子功能，在各种植物系统中得到了广泛研究。越来越多的证据表明它们在生物和非生物胁迫中的作用，因此，在一种天然耐受胁迫的作物中研究这些蛋白将进一步深入了解这一重要蛋白家族的作用。鉴于此，本研究在谷子（Setaria italica）中进行，谷子是研究生物燃料、胁迫耐受和 C 光合作用特性的模式植物。本研究在谷子中鉴定了 12 种质膜内在蛋白（PIPs）、11 种液泡膜内在蛋白（TIPs）、13 种 NOD26 样内在蛋白（NIPs）和 3 种小碱性内在蛋白（SIPs）。利用染色体定位、基因和蛋白特性分析、系统发育分析、启动子分析和 RNA-seq 衍生的表达谱分析等计算方法对鉴定出的蛋白及其相应基因进行了特征描述。通过这些分析鉴定出候选基因，并研究其在两种谷子品种对非生物胁迫（干旱、盐度和热）以及激素处理（脱落酸、茉莉酸甲酯和水杨酸）的响应中的表达情况。研究表明，SiPIP3;1 和 SiSIP1;1 在两种品种中对胁迫和激素处理的响应存在差异表达。这些基因在异源酵母系统中的过表达也表明，转基因细胞能够耐受干旱和盐胁迫，这表明这些蛋白参与了耐受机制。总的来说，本研究提供了谷子水通道蛋白基因家族结构和组织的见解，并强调了这些候选基因在进一步功能特征分析中的潜力。
