Guerra Fernando P, Yáñez Alejandra, Matus Iván, Del Pozo Alejandro
Instituto de Ciencias Biológicas, Universidad de Talca, Talca 3460000, Chile.
Centro de Mejoramiento Genético y Fenómica Vegetal, Facultad de Ciencias Agrarias, Universidad de Talca, Talca 3460000, Chile.
Plants (Basel). 2021 Mar 12;10(3):539. doi: 10.3390/plants10030539.
Water deficit represents an important challenge for wheat production in many regions of the world. Accumulation and remobilization of water-soluble carbohydrates (WSCs) in stems are part of the physiological responses regulated by plants to cope with water stress and, in turn, determine grain yield (GY). The genetic mechanisms underlying the variation in WSC are only partially understood. In this study, we aimed to identify Single Nucleotide Polymorphism (SNP) markers that account for variation in a suite of WSC and GY, evaluated in 225 cultivars and advanced lines of spring wheat. These genotypes were established in two sites in the Mediterranean region of Central Chile, under water-limited and full irrigation conditions, and assessed in two growing seasons, namely anthesis and maturity growth periods. A genome-wide association study (GWAS) was performed by using 3243 SNP markers. Genetic variance accounted for 5 to 52% of phenotypic variation of the assessed traits. A rapid linkage disequilibrium decay was observed across chromosomes ( ≤ 0.2 at 2.52 kbp). Marker-trait association tests identified 96 SNPs related to stem weight (SW), WSCs, and GY, among other traits, at the different sites, growing seasons, and growth periods. The percentage of SNPs that were part of the gene-coding regions was 34%. Most of these genes are involved in the defensive response to drought and biotic stress. A complimentary analysis detected significant effects of different haplotypes on WSC and SW, in anthesis and maturity. Our results evidence both genetic and environmental influence on WSC dynamics in spring wheat. At the same time, they provide a series of markers suitable for supporting assisted selection approaches and functional characterization of genes.
水分亏缺是世界许多地区小麦生产面临的一项重大挑战。茎中水溶性碳水化合物（WSCs）的积累和再转运是植物为应对水分胁迫而调节的生理反应的一部分，进而决定籽粒产量（GY）。WSC变异背后的遗传机制仅得到部分了解。在本研究中，我们旨在鉴定单核苷酸多态性（SNP）标记，这些标记可解释225个春小麦品种和高代品系中一系列WSC和GY的变异。这些基因型在智利中部地中海地区的两个地点建立，分别处于水分受限和充分灌溉条件下，并在两个生长季节进行评估，即花期和成熟期。使用3243个SNP标记进行了全基因组关联研究（GWAS）。遗传方差占所评估性状表型变异的5%至52%。观察到各染色体间的连锁不平衡迅速衰减（在2.52 kbp时≤0.2）。标记-性状关联测试在不同地点、生长季节和生育期鉴定出96个与茎重（SW）、WSCs和GY等其他性状相关的SNP。属于基因编码区的SNP比例为34%。这些基因大多参与对干旱和生物胁迫的防御反应。一项补充分析检测到不同单倍型在花期和成熟期对WSC和SW有显著影响。我们的结果证明了遗传和环境对春小麦WSC动态的影响。同时，它们提供了一系列适合支持辅助选择方法和基因功能表征的标记。
