Increased BnaMFT-transcript level is associated with secondary dormancy in oilseed rape (Brassica napus L.)

摘要

Brassica napus cultivars have little or no primary dormancy;however,they are prone to sec on dary dorma ncy in ducti on.Secondary dormant seeds can produce volunteer plants,which can result in genetic contamination,reduced quality and biosafety issues.However,informati on regarding the molecular mecha nism un derlyi ng sec on dary dormancy is limited.The MOTHER OF FT AND TFL1(MFT)gene,which is evolutionarily conserved in the plant kingdom,acts in a complex gene network in the seed dormancy or germination processes.In this study,we identified four B.napus genes that share high homology with AtMFT,named as BnaMFT.Analyses of c/s-acting elements showed that BnaMFT promoters contain multiple seed-specific regulatory elements,and various stress-and hormone-responsive elements.Further experiments validated that BnaMFTs were specifically expressed during seed maturation and in the dry seed,with peaks at 35-42 days after pollination.BnaMFTs were not sufficient for primary dormancy;however,they were significantly enhanced by secondary dormancy induction with PEG6000 treatment.Moreover,BnaMFTtranscripts were elevated by treatment with abscisic acid(ABA),which is known to be accumulated duri ng sec on dary dorma ncy.These results collectively suggest that increased BnaMFT tra nscription levels are associated with sec on dary dorma ncy inducti on in an ABA-depe ndent mariner in B.napus.