关键词: 棉花, GhMYB44, 开花时间, 表达量, 基因功能

Abstract: Flowering is an essential stage of flowering plants for determining the success of propagation. In the previous study, a MYB gene in D03 chromosome related to flowering time was found through genome-wide association study in Gossypium hirsutum. In this study, a MYB gene was cloned from Gossypium hirsutum, and two homologous genes were obtained and their amino acid sequences similarity was as high as 95%, which were named as GhMYB44a and GhMYB44b and  located in D03 and A02 chromosomes, respectively. GhMYB44a was 1 322 bp in length and contained 987 bp open reading frame (ORF). GhMYB44b was 1 313 bp in length with a 984 bp ORF. The theoretical isoelectric points of the two proteins were 8.93 and 9.15, respectively, and the sequence differences in the C-terminal caused significant differences in structure. Both GhMYB44a and GhMYB44b contained two MYB repeat domains and located in the nucleus, suggesting their roles as R2R3 type MYB transcription factors. GhMYB44a and GhMYB44b were expressed ubiquitously with the highest transcripts in the cotton leaves. GhMYB44a responded to PEG stress, and GhMYB44b responded to PEG and salt stresses. Overexpression of GhMYB44a and GhMYB44b promoted early-flowering of Arabidopsis, of which, the early flowering phenotype of 35S:GhMYB44a was more obvious.

Key words: cotton, GhMYB44, flowering time, expression level, gene function