Adaptation to Water Stress in Soybean: Morphology to Genetics

Soybean (Glycine max L.) is the most important legume and oilseed crop. As a leguminous crop, it plays an irreplaceable role towards the sustainable agricultural system with biological nitrogen fixation. However, its production can be dramatically decreased by the occurrence of water stress. Water stress including drought and flooding induces the morpho-physiological and biochemical changes at different growth stages, which negatively affects the adaptability and yield of soybean. Genetic diversity that ensures productivity in challenging environment exists within germplasm, their wild relatives and species that are adapted to the water stress. The discovery of gene mapping, QTLs associated with root traits, slow canopy wilting, nitrogen fixation and flooding tolerance have accomplished significant progress in breeding programs. Identification of drought-responsive genes and transcription factors such as WRKY, DREBs, ERFs, ZIP, ZFP, MYB and NAC are valuable to ameliorate the water stress in soybean. Understanding the genetic mechanism using transcriptomic and proteomic approaches would be the ultimate choice for mitigating the water stress. Integration of well-designed soybean breeding program coupled with omic techniques would pave the way for developing drought and flooding resilient soybean cultivars