Genome-wide investigation of WRKY gene family in pineapple: evolution and expression profiles during development and stress

Abstract

Based on the number of WRKY domains and the structure of their zinc-finger motifs, the WRKY proteins can be classified into three main groups (I–III), those with two WRKY domains belong to Group I, while those with one WRKY domain belong to Group II or III [4].Since the first WRKY gene, SPF1, was cloned from sweet potato [5], a large number of WRKY proteins have been experimentally identified from various plant species.[...]the pineapple can survive under drought conditions owing to the plant morphological features and its crassulacean acid metabolism.According to previous studies, variations in the WRKYGQK motif in WRKY domain might influence normal interactions of WRKY genes with downstream target genes, and therefore these three WRKY proteins might be worthy to further investigate their functions and binding specificities [41, 42].[...]lacking the pan-grass ρ WGD event during pineapple evolution might be a possible reason for the smaller amount of AcWRKY genes.[...]the variation in the number of group III WRKY genes was also a potential cause of the diversity of WRKY gene family size [31].