Flanders Research Institute for Agriculture, Fisheries and Food (ILVO), Plant Sciences Unit, Caritasstraat 39, 9090, Melle, Belgium.
Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 927, 9052, Ghent, Belgium.
BMC Plant Biol. 2022 Dec 28;22(1):615. doi: 10.1186/s12870-022-03996-w.
Drought stress limits the production of soybean [Glycine max (L.) Merr.], which is the most grown high-value legume crop worldwide. Breeding for drought tolerance is a difficult endeavor and understanding the genetic basis of drought tolerance in soybean is therefore crucial for harnessing the genomic regions involved in the tolerance mechanisms. A genome-wide association study (GWAS) analysis was applied in a soybean germplasm collection (the EUCLEG collection) of 359 accessions relevant for breeding in Europe, to identify genomic regions and candidate genes involved in the response to short duration and long duration drought stress (SDS and LDS respectively) in soybean.
The phenotypic response to drought was stronger in the long duration drought (LDS) than in the short duration drought (SDS) experiment. Over the four traits considered (canopy wilting, leaf senescence, maximum absolute growth rate and maximum plant height) the variation was in the range of 8.4-25.2% in the SDS, and 14.7-29.7% in the LDS experiments. The GWAS analysis identified a total of 17 and 22 significant marker-trait associations for four traits in the SDS and LDS experiments, respectively. In the genomic regions delimited by these markers we identified a total of 12 and 16 genes with putative functions that are of particular relevance for drought stress responses including stomatal movement, root formation, photosynthesis, ABA signaling, cellular protection and cellular repair mechanisms. Some of these genomic regions co-localized with previously known QTLs for drought tolerance traits including water use efficiency, chlorophyll content and photosynthesis.
Our results indicate that the mechanism of slow wilting in the SDS might be associated with the characteristics of the root system, whereas in the LDS, slow wilting could be due to low stomatal conductance and transpiration rates enabling a high WUE. Drought-induced leaf senescence was found to be associated to ABA and ROS responses. The QTLs related to WUE contributed to growth rate and canopy height maintenance under drought stress. Co-localization of several previously known QTLs for multiple agronomic traits with the SNPs identified in this study, highlights the importance of the identified genomic regions for the improvement of agronomic performance in addition to drought tolerance in the EUCLEG collection.
干旱胁迫限制了大豆[Glycine max (L.) Merr.]的产量，大豆是全球种植面积最大的高价值豆科作物。培育耐旱品种是一项艰巨的任务，因此了解大豆耐旱性的遗传基础对于利用与耐旱机制相关的基因组区域至关重要。本研究在一个由 359 个欧洲育种种质组成的大豆种质资源库（EUCLGE 库）中进行了全基因组关联研究（GWAS）分析，以鉴定与大豆短期和长期干旱胁迫（SDS 和 LDS）响应相关的基因组区域和候选基因。
在长期干旱（LDS）实验中，与短期干旱（SDS）实验相比，干旱对大豆的表型影响更大。在所考虑的四个性状（冠层萎蔫、叶片衰老、最大绝对生长率和最大株高）中，SDS 实验的变异性在 8.4-25.2%之间，LDS 实验的变异性在 14.7-29.7%之间。GWAS 分析分别在 SDS 和 LDS 实验中鉴定了与四个性状相关的 17 个和 22 个显著的标记-性状关联。在这些标记所界定的基因组区域中，共鉴定到 12 个和 16 个具有特定抗旱相关功能的候选基因，包括气孔运动、根形成、光合作用、ABA 信号转导、细胞保护和细胞修复机制。其中一些基因组区域与先前已知的与耐旱性状相关的 QTL 共定位，包括水分利用效率、叶绿素含量和光合作用。
本研究结果表明，SDS 中缓慢萎蔫的机制可能与根系特征有关，而在 LDS 中，缓慢萎蔫可能是由于低气孔导度和蒸腾速率导致高 WUE。干旱诱导的叶片衰老与 ABA 和 ROS 反应有关。与 WUE 相关的 QTL 有助于干旱胁迫下生长速率和冠层高度的维持。与本研究中鉴定的 SNP 共定位的多个与多个农艺性状相关的 QTL，突出了所鉴定的基因组区域在提高 EUCLGE 库除耐旱性以外的农艺性能方面的重要性。
