Working group session:
Functional Genomics
Presentation type:
poster
Authors:
Yin, Zujun ; Wang, Junjuan; Fu, Xiaoqiong; Wang, Delong; Fan, Weili; Wang, Shuai; Ye, Wuwei
Presenter:
Wang, Junjuan; Fu, Xiaoqiong; Wang, Delong; Fan, Weili; Wang, Shuai; Ye, Wuwei
Correspondent:
Yin, Zujun
Abstract:
Mitogen-activated protein kinase (MAPK) cascades are evolutionarily conserved signal transduction modules that are found in all eukaryotes. MAPKKKs (MAPK kinase kinases) are important components of the MAPK cascades, operate at the top levels of these cascades and have the most family members. This gene family has been investigated in Arabidopsis, rice and maize, but here has been no systematic investigation in cotton. Recently, the Gossypium raimondii genome was sequenced, which made it possible to identify all the MAPKKKs in this species. In this study, 78 MAPKKK genes were identified in G. raimondii by sequence comparison and signature motif searches. Most of MAPKKK proteins were predicted to be located in the nucleus and the cytoplasm. Based on phylogenetic analysis, MAPKKKs were classified into three subfamilies, of which 12 were ZIK genes, 22 were MEKK genes and 44 were Raf genes. The numbers and the conserved protein motifs within the subfamilies were similar to Arabidopsis and rice. The ZIK and MEKK genes displayed a scattered genomic distribution across 11 of the 13 chromosomes, whereas Raf genes were distributed across the entire genome. Gene structure analysis identified some losses or gains of exons during the evolution of these family genes. Their conserved patterns observed for introns and additional domains were consistent with the evolutionary relationships inferred from the phylogenetic analysis within subfamily. Furthermore, the expression pattern of MAPKKKs was analyzed in mature leaves and at the early fiber cell development stage. Sixty MAPKKK genes were expressed, of which 41 were strongly expressed in mature leaves. Twelve MAPKKK genes were more highly expressed in 3 days post-anthesis (DPA) ovules than in 0-DPA ovules. The tissue-specific expression patterns suggest their important roles in different tissues and at the developmental stage. Our results provide a foundation for future evolutionary and functional characterizations of MAPKKK genes in cotton and probably other Gossypium plants.