Pleiotropy Structures Plant Height and Seed Weight Scaling in Barley despite Long History of Domestication and Breeding Selection

Size scaling describes the relative growth rates of different body parts of an organism following a positive correlation.Domestication and crop breeding often target the scaling traits in the opposite directions.The genetic mechanism of the size scaling influencing the pattern of size scaling remains unexplored.Here,we revisited a diverse barley(Hordeum vulgare L.)panel with genome-wide single-nucleotide polymorphisms(SNPs)profile and the measurement of their plant height and seed weight to explore the possible genetic mechanisms that may lead to a correlation of the two traits and the influence of domestication and breeding selection on the size scaling.Plant height and seed weight are heritable and remain positively correlated in domesticated barley regardless of growth type and habit.Genomic structural equation modeling systematically evaluated the pleiotropic effect of individual SNP on the plant height and seed weight within a trait correlation network.We discovered seventeen novel SNPs(quantitative trait locus)conferring pleiotropic effect on plant height and seed weight,involving genes with function in diverse traits related to plant growth and development.Linkage disequilibrium decay analysis revealed that a considerable proportion of genetic markers associated with either plant height or seed weight are closely linked in the chromosome.We conclude that pleiotropy and genetic linkage likely form the genetic bases of plant height and seed weight scaling in barley.Our findings contribute to understanding the heritability and genetic basis of size scaling and open a new venue for seeking the underlying mechanism of allometric scaling in plants.

大麦芽期耐盐相关的同源和候选基因

土壤盐害影响了全球6%以上的陆地面积,并导致了大量的农作物减产。盐害主要通过渗透和离子胁迫抑制植物的生长和发育,而植物相应地通过渗透调节、转移或外排积累的钠和氯离子以增强适应性。目前,生产上尚未有实用、经济的方法治理盐害,因而最为可行的途径是增强植物自身的耐盐性。盐胁迫严重抑制种子萌发,而作为全球第四大禾谷类作物的大麦与其他谷物相比耐盐性更强。本文综述了大麦芽期耐盐性的遗传机制,总结了已报道的相关数量性状位点和功能基因,比对了拟南芥、大豆、玉米、小麦和水稻中耐盐候选基因在大麦中的同源基因并映射到参考基因组。此外,本文还讨论了三个耐盐功能基因家族的遗传多样性,包括脱水应答元件结合蛋白(DREB)、类体细胞胚胎发生受体激酶和水通道蛋白。上述三个基因家族在植物中都存在丰富的多样性,但DREB家族在大麦中的多样性高于水稻和小麦。后续研究中,芽期耐盐性的简便筛选方法仍有待开发,耐盐基因及相关机理机制仍需鉴定、验证,并整合到栽培品种中,以实现盐土上作物的生产。