title: Genome-wide identification of mitogen-activated protein kinase gene family in Gossypium raimondii and the function of their corresponding orthologs in tetraploid cultivated cotton.
abstract: BACKGROUND
  Mitogen-activated protein kinase (MAPK) cascades play a crucial role in plant growth and development as well as biotic and abiotic stress responses. Knowledge about the MAPK gene family in cotton is limited, and systematic investigation of MAPK family proteins has not been reported.
  
  
  RESULTS
  By performing a bioinformatics homology search, we identified 28 putative MAPK genes in the Gossypium raimondii genome. These MAPK members were anchored onto 11 chromosomes in G. raimondii, with uneven distribution. Phylogenetic analysis showed that the MAPK candidates could be classified into the four known A, B, C and D groups, with more MAPKs containing the TEY phosphorylation site (18 members) than the TDY motif (10 members). Furthermore, 21 cDNA sequences of MAPKs with complete open reading frames (ORFs) were identified in G. hirsutum via PCR-based approaches, including 13 novel MAPKs and eight with homologs reported previously in tetraploid cotton. The expression patterns of 23 MAPK genes reveal their important roles in diverse functions in cotton, in both various developmental stages of vegetative and reproductive growth and in the stress response. Using a reverse genetics approach based on tobacco rattle virus-induced gene silencing (TRV-VIGS), we further verified that MPK9, MPK13 and MPK25 confer resistance to defoliating isolates of Verticillium dahliae in cotton. Silencing of MPK9, MPK13 and MPK25 can significantly enhance cotton susceptibility to this pathogen.
  
  
  CONCLUSIONS
  This study presents a comprehensive identification of 28 mitogen-activated protein kinase genes in G. raimondii. Their phylogenetic relationships, transcript expression patterns and responses to various stressors were verified. This study provides the first systematic analysis of MAPKs in cotton, improving our understanding of defense responses in general and laying the foundation for future crop improvement using MAPKs.
authors.affiliation: State Key Laboratory of Crop Genetics & Germplasm Enhancement, Hybrid Cotton R & D Engineering Research Center, MOE, Nanjing Agricultural University, Nanjing, 210095, Jiangsu Province, P. R. China. zhangxuey89@163.com.
authors.forename: Xueying
authors.initials: X
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Crop Genetics & Germplasm Enhancement, Hybrid Cotton R & D Engineering Research Center, MOE, Nanjing Agricultural University, Nanjing, 210095, Jiangsu Province, P. R. China. wangliman19861211@126.com.
authors.forename: Liman
authors.initials: L
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Crop Genetics & Germplasm Enhancement, Hybrid Cotton R & D Engineering Research Center, MOE, Nanjing Agricultural University, Nanjing, 210095, Jiangsu Province, P. R. China. intergoogle@126.com.
authors.forename: Xiaoyang
authors.initials: X
authors.lastname: Xu
authors.affiliation: State Key Laboratory of Crop Genetics & Germplasm Enhancement, Hybrid Cotton R & D Engineering Research Center, MOE, Nanjing Agricultural University, Nanjing, 210095, Jiangsu Province, P. R. China. cpcai@njau.edu.cn.
authors.forename: Caiping
authors.initials: C
authors.lastname: Cai
authors.affiliation: State Key Laboratory of Crop Genetics & Germplasm Enhancement, Hybrid Cotton R & D Engineering Research Center, MOE, Nanjing Agricultural University, Nanjing, 210095, Jiangsu Province, P. R. China. moelab@njau.edu.cn.
authors.forename: Wangzhen
authors.initials: W
authors.lastname: Guo
mesh_terms: D000595:Amino Acid Sequence; D032461:Chromosomes, Plant; D003001:Cloning, Molecular; D015870:Gene Expression; D020869:Gene Expression Profiling; D014644:Genetic Variation; D018745:Genome, Plant; D003368:Gossypium / Q000235:genetics*; D054884:Host-Pathogen Interactions; D020928:Mitogen-Activated Protein Kinases / Q000235:genetics*; D008969:Molecular Sequence Data; D005810:Multigene Family; D010940:Plant Proteins / Q000235:genetics*; D013312:Stress, Physiological; D057891:Tetraploidy; D020172:Verticillium / Q000502:physiology
chemical_list: D010940:Plant Proteins; D020928:Mitogen-Activated Protein Kinases