| MYC(myelocytomatosis)transcription factor is the core transcription factor in the response pathway of jasmonic acid hormones and has a variety of regulatory functions.The bHLH domain in MYC can bind to the G-box in the promoter of their target genes and plays a major role in the growth and development of JA plants.However,few studies have been reported about Camellia sinensis MYC gene family.Therefore,we identified 14 MYC genes in Camellia sinensis and analyzed these MYC genes by means of bioinformatics and further studies were carried out based on it.The main conclusions of this study are as follows:1.The information of the 14 MYC genes,containing their encoding protein length were from 313 to 1083 amino acids,with putative molecular weights(MWs)varying from 35.16 to 114.15 and isoelectric points(p I)ranging from 4.7 to 9.37 were presented.The result of sequence alignment showed that except CsMYC1.3 and Cs ASM.1,All the N terminal of MYC have basic-helix-loop-helix(bHLH)domain in Camellia sinensis.The MYC proteins of Arabidopsis thaliana,Oryza sativa and Camellia sinensis can be divided into five subfamilies.The MYCs of Camellia sinensis are mainly distributed in group I,II,IV and V subfamilies,and most of the MYCs in Camellia sinensis were more homology with those in Arabidopsis than Oryza sativa.Exon/Intron structures analysis revealed that the number of CsMYC exons varied from one to seven.Eight members in group V had no introns,only Cs TT8 in the group IV contained four exons;three members in group I,which have seven exons.MYCs in group II had a complex distribution of exons and introns,Cs ASM.1 had four exons,while Cs ASM.2 contained eight exons.Six motifs were identified.Motif 2,3,5 and 6 constitute the bHLH-MYC-N,while motifs 1 and 4 corresponded to HLH domains.Cis-element analysis suggests that CsMYCs play important role in plant growth,development,signal transduction,and regulates the metabolic process and response to abiotic stress.2.We used quantitative RT-PCR(qRT-PCR)to detect the four selected MYCs transcripts abundance in different tissues of tea plant cultivar Longjing 43,including include root,stem,apical bud,young leaf,mature leaf,old leaf,flower and fruit.The results showed that the four genes were expressed in the tissues and organs of tea tree.The expression levels of CsMYC2.1 and CsMYC2.3 were significantly higher than the other genes.CsMYC2.1 was highly expressed in root and apical bud,while CsMYC2.3 was highly expressed in apical bud,young leaf and root.CsMYC2.4 was highly expressed in flowers and fruits.The expression levels of CsMYC2.2 was low in all tissues.3.The subcellular localization result of CsMYCs showed that the four CsMYCs existed in the nucleus.CsMYC2.1 and CsMYC2.2 had transcriptional self-activation activities.The two-hybrid library screening using CsMYC2.1 as a bait,and representative candidate interaction proteins were verified,four of which were JAZ proteins(Cs JAZ1/3/7/8).The interaction between the MYC2 and JAZ proteins has been previously reported in other species,so the result is consistent with expectations.Y2 H and Bi FC were used to further verify the interaction between CsMYC2.1 and candidate proteins Cs JAZ3/7/8.These results not only enabled us to comprehensively understand the 14 CsMYC genes of Camellia sinensis,but also provided a research basis for further understanding the role of CsMYCs in the JA signaling pathway in Camellia sinensis. |
