The differential expression of soybean [Glycine max (L.) Merrill] WRKY genes in response to water deficit

• The soybean WRKY6, 46, 56, 106 and 149 genes presented a differential expression under water deficits conditions.
• The putative promoters of the genes analyzed are enriched of cis-elements which regulate the ABA-induced gene expression.
• The genes coexpressed with the WRKY genes analyzed are involved in stress response mechanisms.
• The GmWRKY56 and GmWRKY106 coexpression networks showed broad overlap.
• The GmWRKY106 emerges as candidate for genetic engineering strategies aiming to develop cultivars tolerant to dehydration.

Drought is today, and perhaps even more in the future, the main challenge for grain crops, resulting in a drastic yield reduction. Thus, it is of great interest to obtain soybean genotypes tolerant to water deficit. The drought tolerance trait is difficult to obtain through classical breeding due to its polygenic basis. In this context, genetic engineering is presented as a way to achieve this attribute. The ability to modulate the expression of many genes placed the transcription factors as promising biotechnological targets to develop stress tolerant cultivars. The WRKY proteins form a large family of transcription factors that are involved in important physiological and biochemical processes in plants, including the response to water deficit. In this study, the expression pattern determined by qPCR showed that, GmWRKY6, GmWRKY46, GmWRKY56, GmWRKY106 and GmWRKY149 genes are differentially expressed between a drought tolerant and a susceptible soybean genotype in water stress conditions. The in silico promoter and coexpression analysis indicate that these genes act in a stress physiological background.