陆地棉GhMYB1基因及启动子的克隆与干旱诱导下的表达分析OA

The MYB transcription factor family is one of the largest and most widely distributed gene fam-ilies in plants,playing critical roles in various biological processes including growth and development,disease resistance,and stress tolerance.In the previous study,the GhMYB1 transcription factor from upland cotton(Gossypium hirsutum L.)was found to interact with the elite promoter of the drought-responsive gene GhH-SP70-26,suggesting its potential involvement in drought response pathways.To investigate the drought-responsive characteristics of GhMYB1,we cloned its full-length coding sequence.The results revealed that its coding sequence was 1 244 bp in length,encoding a protein of 413 amino acids.Subcellular localization pre-diction indicated that GhMYB1 was targeted to the nucleus and belongs to the R2R3-type MYB transcription factor subfamily.Transcriptome data analysis showed that GhMYB1 exhibited the highest expression level in leaves compared with roots and stems in upland cotton,and its expression was induced by salt,heat and drought stresses,with the maximum transcript abundance at 12 h of drought treatment.To validate the expres-sion pattern of GhMYB1 under drought stress,quantitative real-time PCR(qRT-PCR)was performed to meas-ure its expression levels in leaves of drought-tolerant and drought-sensitive upland cotton accessions subjected to natural drought stress.The results demonstrated that GhMYB1 expression reached its peak at 7 days after drought treatment in both genotypes.To elucidate the regulatory mechanism underlying drought-induced ex-pression of GhMYB1,a 1 737 bp fragment of its promoter region was cloned.PlantCARE analysis revealed the presence of multiple cis-acting elements associated with stress responsiveness and phytohormone signaling.Fur-thermore,a pGhMYB1:GUSplant expression vector was constructed and transiently transformed into tobacco leaves.Compared with non-stressed controls,GUS activity gradually increased following 3 h and 12 h of man-nitol-simulated drought stress.Collectively,these findings indicated that GhMYB1 was responsive to drought stress in upland cotton and its promoter possessed drought-inducible activity,implying that GhMYB1 might play an important role in drought tolerance.This study could provide a solid theoretical foundation for further functional characterization of GhMYB1 and elucidation of its molecular regulatory mechanisms in drought stress responses.