Deciphering evolutionary dynamics of WRKY genes in Arachis species

BackgroundCultivated peanut (Arachis hypogaea), a progeny of the cross between A. duranensis and A. ipaensis, is an important oil and protein crop from South America. To date, at least six Arachis genomes have been sequenced. WRKY transcription factors (TFs) play crucial roles in plant growth, development, and response to abiotic and biotic stresses. WRKY TFs have been identified in A. duranensis, A. ipaensis, and A. hypogaea cv. Tifrunner; however, variations in their number and evolutionary patterns across various Arachis spp. remain unclear.ResultsWRKY TFs were identified and compared across different Arachis species, including A. duranensis, A. ipaensis, A. monticola, A. hypogaea cultivars (cv.) Fuhuasheng, A. hypogaea cv. Shitouqi, and A. hypogaea cv. Tifrunner. The results showed that the WRKY TFs underwent dynamic equilibrium between diploid and tetraploid peanut species, characterized by the loss of old WRKY TFs and retention of the new ones. Notably, cultivated peanuts inherited more conserved WRKY orthologs from wild tetraploid peanuts than their wild diploid donors. Analysis of the W-box elements and protein-protein interactions revealed that different domestication processes affected WRKY evolution across cultivated peanut varieties. WRKY TFs of A. hypogaea cv. Fuhuasheng and Shitouqi exhibited a similar domestication process, while those of cv. Tifrunner of the same species underwent a different domestication process based on protein-protein interaction analysis.ConclusionsThis study provides new insights into the evolution of WRKY TFs in Arachis spp.