Gill Muhammad B, Zeng Fanrong, Shabala Lana, Zhang Guoping, Fan Yun, Shabala Sergey, Zhou Meixue
Department of Agronomy, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, China.
School of Land and Food, University of Tasmania, Hobart, TAS, Australia.
Front Plant Sci. 2017 Nov 16;8:1941. doi: 10.3389/fpls.2017.01941. eCollection 2017.
Waterlogging and salinity are two major abiotic stresses that hamper crop production world-wide resulting in multibillion losses. Plant abiotic stress tolerance is conferred by many interrelated mechanisms. Amongst these, the cell's ability to maintain membrane potential (MP) is considered to be amongst the most crucial traits, a positive relationship between the ability of plants to maintain highly negative MP and its tolerance to both salinity and waterlogging stress. However, no attempts have been made to identify quantitative trait loci (QTL) conferring this trait. In this study, the microelectrode MIFE technique was used to measure the plasma membrane potential of epidermal root cells of 150 double haploid (DH) lines of barley ( L.) from a cross between a Chinese landrace TX9425 and Japanese malting cultivar Naso Nijo under hypoxic conditions. A major QTL for the MP in the epidermal root cells in hypoxia-exposed plants was identified. This QTL was located on 2H, at a similar position to the QTL for waterlogging and salinity tolerance reported in previous studies. Further analysis confirmed that MP showed a significant contribution to both waterlogging and salinity tolerance. The fact that the QTL for MP was controlled by a single major QTL illustrates the power of the single-cell phenotyping approach and opens prospects for fine mapping this QTL and thus being more effective in marker assisted selection.
涝害和盐害是阻碍全球作物生产的两大主要非生物胁迫，造成了数十亿美元的损失。植物对非生物胁迫的耐受性由许多相互关联的机制赋予。其中，细胞维持膜电位（MP）的能力被认为是最关键的性状之一，植物维持高度负膜电位的能力与其对盐害和涝害胁迫的耐受性之间存在正相关关系。然而，尚未有人尝试鉴定赋予该性状的数量性状位点（QTL）。在本研究中，使用微电极MIFE技术测量了来自中国地方品种TX9425和日本麦芽品种Naso Nijo杂交的150个大麦（L.）双单倍体（DH）系在缺氧条件下表皮根细胞的质膜电位。在缺氧处理的植物中，鉴定出了表皮根细胞质膜电位的一个主要QTL。该QTL位于2H上，与先前研究报道的耐涝性和耐盐性QTL位置相似。进一步分析证实，膜电位对耐涝性和耐盐性均有显著贡献。膜电位QTL由单个主要QTL控制这一事实说明了单细胞表型分析方法的强大作用，并为该QTL的精细定位以及在标记辅助选择中更有效地应用开辟了前景。
