As a typical ancient tetraploid, soybean (Glycine max) is an important oil crop species and plays a crucial role in supplying edible oil, plant protein and animal fodder worldwide. As global warming intensifies, the yield of soybean in the field is often strongly restricted by drought stress. SNF1-related protein kinase 2 (SnRK2) and type A protein phosphatase 2C (PP2C-A) family members are core components of the abscisic acid (ABA) signal transduction pathway in plants and have been suggested to play important roles in increasing plant tolerance to drought stress, but genetic information supporting this idea is still lacking in soybean. Here, we cloned the GmSnRK2s and GmPP2C-A family genes from the reference genome of Williams 82 soybean. The results showed that the expression patterns of GmSnRK2s and GmPP2C-As are spatiotemporally distinct. The expression of GmSnRK2s in response to ABA and drought signals is not strictly the same as that of Arabidopsis SnRK2 homologous genes. Moreover, our results indicated that the duplicate pairs of GmSnRK2s and GmPP2C-As have similar expression patterns, cis-elements and relationships. GmSnRK2.2 may have a distinct function in the drought-mediated ABA signaling pathway. Furthermore, the results of yeast two-hybrid (Y2H) assays between GmSnRK2s and GmPP2C-As revealed that GmSnRK2.17, GmSnRK2.18, GmSnRK2.22, GmPP2C5, GmPP2C7, GmPP2C10 and GmPP2C17 may play central roles in the crosstalk among ABA signals in response to drought stress. Furthermore, GmPP2C-As and GmSnRKs were targeted by miRNA and validated by degradome sequencing, which may play multiple roles in the crosstalk between ABA and drought signals and other stress signals. Taken together, these results indicate that GmSnRK2s and GmPP2C-As may play a variety of roles in the drought-mediated ABA signaling pathway.
Keywords: PP2C-A; SnRK2; abscisic acid; drought stress; protein interaction; soybean.