A wild-allele GsPP2C-51-a1 enhances tolerance to drought stress in soybean and Arabidopsis.

key messageA wild-allele GsPP2C-51-a1 of Glyma.14g162100 was identified in SojaCSSLP5, back to wild soybean, conferring drought tolerance. Its functions were verified in transgenic hairy root soybeans and Arabidopsis under water deficit and ABA treatment. A population of wild soybean chromosome segment substitution lines (CSSLs), SojaCSSLP5, with NN1138-2 as the cultivated recurrent parent and N24852 as the wild donor parent, was used to identify drought-tolerant loci/segments from the donor. Relative shoot dry weight, a tolerance indicator, varied significantly among the parents and CSSLs. Six drought tolerance loci/segments were detected in SojaCSSLP5, including Gm14_LDB_21 with GsPP2C-51 (Glyma.14g162100) as one of the four possible genes. This gene belongs to the F1 clade of protein phosphatase 2C based on gene ontology annotation, qPCR, and previous research results. Glyma.14g162100 was traced back to the Chinese germplasm population, in which four alleles existed on the locus, with soja holding all four, and max holding only two without any new alleles emerging. N24852 and NN1138-2 hold a1 and a2, respectively. The GsPP2C-51 protein was located inside the nucleus. In transgenic hairy root composite soybean, the GsPP2C-51-a1 overexpressed plants maintained a higher leaf fresh weight (tolerance) under 15% PEG stress compared to the empty vector plants. This was strongly supported by improved tolerance, chlorophyll content, and a series of physiological responses in GsPP2C-51-a1 overexpressed Arabidopsis plants under water deficit and abscisic acid treatments. Thus, the wild-type allele GsPP2C-51-a1 (Glyma.14g162100a1) from N24852 positively regulates plant drought tolerance.