Cushman Kevin R, Pabuayon Isaiah C M, Hinze Lori L, Sweeney Megan E, de Los Reyes Benildo G
Department of Plant and Soil Science, Texas Tech University, Lubbock, TX, United States.
USDA-ARS, Crop Germplasm Research, College Station, TX, United States.
Front Plant Sci. 2020 Dec 8;11:588854. doi: 10.3389/fpls.2020.588854. eCollection 2020.
The abilities to mobilize and/or sequester excess ions within and outside the plant cell are important components of salt-tolerance mechanisms. Mobilization and sequestration of Na involves three transport systems facilitated by the plasma membrane H/Na antiporter (SOS1), vacuolar H/Na antiporter (NHX1), and Na/K transporter in vascular tissues (HKT1). Many of these mechanisms are conserved across the plant kingdom. While (upland cotton) is significantly more salt-tolerant relative to other crops, the critical factors contributing to the phenotypic variation hidden across the germplasm have not been fully unraveled. In this study, the spatio-temporal patterns of Na accumulation along with other physiological and biochemical interactions were investigated at different severities of salinity across a meaningful genetic diversity panel across cultivated upland The aim was to define the importance of holistic or integrated effects relative to the direct effects of Na homeostasis mechanisms mediated by , and Multi-dimensional physio-morphometric attributes were investigated in a systems-level context using univariate and multivariate statistics, , and path analysis. Results showed that mobilized or sequestered Na contributes significantly to the baseline tolerance mechanisms. However, the observed variance in overall tolerance potential across a meaningful diversity panel were more significantly attributed to antioxidant capacity, maintenance of stomatal conductance, chlorophyll content, and divalent cation (Mg) contents other than Ca through a complex interaction with Na homeostasis. The multi-tier macro-physiological, biochemical and molecular data generated in this study, and the networks of interactions uncovered strongly suggest that a complex physiological and biochemical synergy beyond the first-line-of defense (Na sequestration and mobilization) accounts for the total phenotypic variance across the primary germplasm of . These findings are consistent with the recently proposed Omnigenic Theory for quantitative traits and should contribute to a modern look at phenotypic selection for salt tolerance in cotton breeding.
植物细胞内外调动和/或隔离过量离子的能力是耐盐机制的重要组成部分。钠的调动和隔离涉及三种运输系统，分别由质膜H⁺/Na⁺逆向转运蛋白（SOS1）、液泡H⁺/Na⁺逆向转运蛋白（NHX1）以及维管组织中的Na⁺/K⁺转运蛋白（HKT1）介导。这些机制中的许多在植物界都是保守的。虽然陆地棉相对于其他作物具有显著更高的耐盐性，但导致种质间隐藏的表型变异的关键因素尚未完全阐明。在本研究中，在一个具有重要遗传多样性的陆地棉栽培群体中，研究了不同盐度严重程度下钠积累的时空模式以及其他生理和生化相互作用。目的是确定相对于由SOS1、NHX1和HKT1介导的钠稳态机制的直接作用而言，整体或综合效应的重要性。使用单变量和多变量统计、主成分分析和通径分析，在系统水平上研究了多维生理形态测量属性。结果表明，调动或隔离的钠对基线耐受机制有显著贡献。然而，在一个具有重要意义的多样性群体中观察到的总体耐受潜力的差异，通过与钠稳态的复杂相互作用，更显著地归因于抗氧化能力、气孔导度的维持、叶绿素含量以及除钙之外的二价阳离子（镁）含量。本研究中生成的多层次宏观生理、生化和分子数据以及所揭示的相互作用网络强烈表明，一线防御（钠的隔离和调动）之外的复杂生理和生化协同作用解释了陆地棉初级种质间的总表型变异。这些发现与最近提出的数量性状全基因理论一致，应该有助于以现代视角看待棉花育种中耐盐性的表型选择。
