Genome-Wide Identification And Expression Analysis Of Calcium-Dependent Protein Kinase And Its Related Kinase Gene Families In Melon(Cucumis Melo L.)

Melon is an agriculturally and economically important crop,which is widely cultivated in China.Heavy losses in melon production are frequently caused by various stresses.The calcium-dependent protein kinase(CDPK)is a ser/thr protein kinase that plays vital roles in plant growth,development,and responses to multiple stresses.CDPK and CRK genes were identified in the melon genome via bioinformatic analysis.Meanwhile,chromosome distribution,gene structure,phylogenetic syntenic analysis,duplication events and syntenic analysis also were performed.Furthermore,the expression levels of CmCDPKs and CmCRKs were conducted in different tissues and under various stimuli,such as biotic stress(Podosphaera xanthii),abiotic stress(salt and cold),and hormone(abscisic acid)treatment by qRT-PCR.We obtained some stress-tolerance genes for further research.The main results are as follow:1.A total of 18 CDPK genes and seven CDPK-related protein kinases(CRK)genes were identified in the melon genome,which were unevenly distributed across eleven chromosomes with an apparent exception for chromosome 3,and the largest number of CmCDPKs was located on chromosome 4.2.The Phylogenetic analysis and structure of CDPK and CRK genes in melon.The melon CDPK genes were clustered into four sub-groups.The CDPK genes in CDPK I-III contained seven or eight exons,respectively,and shared similar intron patterns.CmCDPK14 in CDPK IV carried 12 exons,which was significantly above that of CmCDPKs(with seven or eight exons)in the other three groups.However,it was similar to CRK genes.CDPK and CRK full-length protein sequences of melon,Arabidopsis,rice and tomato were used to construct a phylogenetic tree.One hundred and ten CDPKs from the four species were divided into four groups.Interestingly,group CDPK IV evidently clustered with CRK I on the phylogenetic tree.3.The duplication events and synteny analysis of melon and Arbidopsis CDPK and CRK.Two pairs of CmCDPKs were identified as segmental duplications.Twenty collinear gene pairs in CDPK genes and two collinear CRK genes were found between melon andArabidopsis.4.The expression profiles of CDPK and CRK genes in melon.The expression of CmCDPKs and CmCRKs were performed in different tissues and response to various stimuli.All the identified CmCDPKs and CmCRKs were expressed in at least one of the five tissues,whereas the expression level of CmCDPK3 was not detected in any of the five organs.Most of CmCDPKs and CmCRKs were down-regulated under powdery mildew and ABA treatment,but up-regualted under salt and cold stresses.Compared to other treatments,cold stress showed a stronger effect on the transcript levels of CmCDPKs and CmCRKs.The results indicated that CmCDPKs and CmCRKs play vital roles in response to stresses.5.The coding sequences of CmCDPK7,CmCDPK10 and CmCDPK15 were cloned,and then,liagted into pBI121 to construct expression vectors.