GmDNAJC7 from Soybean Is Involved in Plant Tolerance to Alkaline-Salt, Salt, and Drought Stresses

Soybean [Glycine max (L.) Merri.] is an important oilseed and food crop. In recent years, environmental degradation has accelerated soil alkalization, salinization, and water deficit, which have seriously threatened the soybean quality and yield. Chaperone DNAJ proteins play important roles in plant response to a number of abiotic and biotic stresses. Here, we investigated the function of a soybean DNAJ gene, GmDNAJC7, in plant tolerance to abiotic stresses. GmDNAJC7 gene expression was induced by alkaline-salt, salt, and drought treatments in soybean roots, suggesting its possible role in soybean response to these stresses. GmDNAJC7 overexpression improved the alkaline-salt tolerance of soybean composite plants, which showed a higher SPAD (Soil and Plant Analysis Development) value for chlorophyll content and leaf relative water content than the control plants after NaHCO3 treatment. Moreover, the GmDNAJC7 overexpressing Arabidopsis had a higher germination rate and average root length than the wild type and dnajc7 mutant, under NaHCO3, NaCl, and mannitol stresses, indicating that the ectopic expression of the GmDNAJC7 gene enhanced the alkaline-salt, salt, and drought tolerance in Arabidopsis. These findings suggest that GmDNAJC7 is involved in the alkaline-salt, salt, and drought tolerance in Arabidopsis and soybean. This study provides new insights into the role of DNAJ proteins in plant tolerance to abiotic stress.