Ecophysiology and Plant Productivity Laboratory, Instituto Federal Goiano-Campus Rio Verde, Rio Verde, Goiás, Brazil.
Department of General Biology, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil.
PeerJ. 2022 Mar 18;10:e13118. doi: 10.7717/peerj.13118. eCollection 2022.
Soybean is the main oilseed crop grown in the world; however, drought stress affects its growth and physiology, reducing its yield. The objective of this study was to characterize the physiological, metabolic, and genetic aspects that determine differential resistance to water deficit in soybean genotypes.
Three soybean genotypes were used in this study, two lineages (L11644 and L13241), and one cultivar (EMBRAPA 48-C48). Plants were grown in pots containing 8 kg of a mixture of soil and sand (2:1) in a greenhouse under sunlight. Soil moisture in the pots was maintained at field capacity until the plants reached the stage of development V4 (third fully expanded leaf). At this time, plants were subjected to three water treatments: Well-Watered (WW) (plants kept under daily irrigation); Water Deficit (WD) (withholding irrigation until plants reached the leaf water potential at predawn of -1.5 ± 0.2 MPa); Rewatered (RW) (plants rehydrated for three days after reached the water deficit). The WW and WD water treatments were evaluated on the eighth day for genotypes L11644 and C48, and on the tenth day for L13241, after interruption of irrigation. For the three genotypes, the treatment RW was evaluated after three days of resumption of irrigation. Physiological, metabolic and gene expression analyses were performed.
Water deficit inhibited growth and gas exchange in all genotypes. The accumulation of osmolytes and the concentrations of chlorophylls and abscisic acid (ABA) were higher in L13241 under stress. The metabolic adjustment of lineages in response to WD occurred in order to accumulate amino acids, carbohydrates, and polyamines in leaves. The expression of genes involved in drought resistance responses was more strongly induced in L13241. In general, rehydration provided recovery of plants to similar conditions of control treatment. Although the C48 and L11644 genotypes have shown some tolerance and resilience responses to severe water deficit, greater efficiency was observed in the L13241 genotype through adjustments in morphological, physiological, genetic and metabolic characteristics that are combined in the same plant. This study contributes to the advancement in the knowledge about the resistance to drought in cultivated plants and provides bases for the genetic improvement of the soybean culture.
大豆是世界上主要的油料作物；然而，干旱胁迫会影响其生长和生理机能，降低其产量。本研究的目的是描述决定大豆基因型对水分亏缺不同抗性的生理、代谢和遗传方面。
本研究使用了三个大豆基因型，两个品系（L11644 和 L13241）和一个品种（EMBRAPA 48-C48）。在温室的阳光下，将植物种植在装有 8 公斤土壤和沙子（2:1）混合物的盆中。当植物进入 V4 期（第三片完全展开的叶子）时，盆中的土壤湿度保持在田间持水量。此时，植物受到三种水分处理：充分浇水（WW）（每天浇水）；水分亏缺（WD）（停止浇水，直到植物达到清晨叶水势为-1.5 ± 0.2 MPa）；再浇水（RW）（水分亏缺后三天再浇水）。在 WW 和 WD 处理的第八天评估 L11644 和 C48 基因型，在中断浇水后的第十天评估 L13241 基因型。对于三个基因型，在重新浇水三天后评估 RW 处理。进行了生理、代谢和基因表达分析。
水分亏缺抑制了所有基因型的生长和气体交换。在胁迫下，L13241 中渗透调节剂的积累和叶绿素和脱落酸（ABA）的浓度更高。品系对 WD 的代谢调节是为了在叶片中积累氨基酸、碳水化合物和多胺。参与抗旱反应的基因的表达在 L13241 中被更强地诱导。总的来说，再浇水使植物恢复到与对照处理相似的条件。尽管 C48 和 L11644 基因型对严重水分亏缺表现出一定的耐受性和恢复力，但 L13241 基因型通过在同一植物中组合的形态、生理、遗传和代谢特征的调整，表现出更高的效率。本研究有助于提高对栽培植物抗旱性的认识，并为大豆文化的遗传改良提供基础。
