Genome-Wide Identification and Characterization of the Soybean DEAD-Box Gene Family and Expression Response to Rhizobia.

DEAD-box proteins are a large family of RNA helicases that play important roles in almost all cellular RNA processes in model plants. However, little is known about this family of proteins in crops such as soybean. Here, we identified 80 DEAD-box family genes in the (soybean) genome. These genes were distributed on 19 chromosomes, and some genes were clustered together. The majority of DEAD-box family proteins were highly conserved in Arabidopsis and soybean, but and were specific to soybean. The promoters of these genes share -acting elements involved in plant responses to MeJA, salicylic acid (SA), low temperature and biotic as well as abiotic stresses; interestingly, half of the genes contain nodulation-related elements in their promoters. Microarray data analysis revealed that the genes were differentially expressed in the root and nodule. Notably, 31 genes were induced by rhizobia and/or were highly expressed in the nodule. Real-time quantitative PCR analysis validated the expression patterns of some genes, and among them, and were induced by rhizobia in root hair. Thus, we provide a comprehensive view of the DEAD-box family genes in soybean and highlight the crucial role of these genes in symbiotic nodulation.