Cloning and Expression Analysis of MYB15 Genes from Citrus

Three MYB genes, including CmMYB15, PtMYB15 and ClMYB15, were cloned from seedlings of pomelo (Citrus maxima (Burm.) Merr.), trifoliate orange (Poncirus trifoliata (L.) Raf.) and lemon (Citrus limon (L.) Burm.f.), respectively, by in silico and reverse transcription PCR approaches. Results showed that the full length cDNA sequences of the three genes were 994, 992 and 988 bp, and encoded 267, 266 and 265 amino acids, respectively. The N-terminal of the three novel proteins contained two series of incomplete repeat MYB DNA-binding domains, suggesting that the three genes belonged to the R2R3 subclass of the MYB family. Moreover, the expression patterns of these genes were analyzed by real-time quantitative PCR (qRT-PCR) under the stress of ABA, drought, cold and salt.Results indicated that the expressions of the three MYB15 genes were induced by all stress treatments. However, their expression levels after stress differed among the citrus species.The results of this paper suggested that CmMYB15, PtMYB15 and ClMYB15 were members of the MYB gene family, and might play important roles in citrus in response to abiotic stress.