罗汉果成花转变过程中的生理与分子调控机制OA

[Objective]This study aimed to investigate the physiological and molecular regulatory mechanisms in-volved in floral transition of Siraitia grosvenorii,providing theoretical basis for establishing efficient flowering induction regulation technology and studying flower bud differentiation of Siraitia grosvenorii.[Method]The Qingpi variety of Siraitia grosvenorii was used as experimental material.After the full bloom period in late August 2023,terminal flower buds and terminal vegetative buds were collected to determine the contents of carbohydrates(soluble sugar,starch)and soluble protein,activities of antioxidant enzymes[peroxidase(POD),polyphenol oxidase(PPO),and phenylalanine ammonia-lyase(PAL)],and contents of endogenous hormones[indole-3-acetic acid(IAA)and abscisic acid(ABA)]. Meanwhile,based on real-time fluorescence quantitative PCR technology,the expression levels of 15 flowering-related genes in the two types of terminal buds.[Result]The soluble sugar content in terminal flower buds was extremely signifi- cantly lower than that in terminal vegetative buds(P<0.01),but there were no significant differences in the contents of starch and soluble protein between the two types(P>0.05,the same below).The activities of POD and PPO in terminal flower buds were significantly(P<0.05,the same below)or extremely significantly(P<0.0001)higher than those in the terminal vegetative buds,whereas PAL activity showed no significant difference.The IAA content in terminal flower buds was extremely significantly lower than that in terminal vegetative buds(P<0.0001),while the ABA content showed the opposite trend.Three trends were found in the expression of the 15 flowering-related genes in the two types of buds:ex- pression of 10 genes including SgFPA,SgFCA,and SgEFL3 of terminal flower buds was significantly or extremely sig- nificantly(P<0.01,P<0.001,P<0.0001)higher than those in terminal vegetative buds;conversely,the expression of SgFY and SgFLK genes was extremely significantly lower in terminal flower buds than in those of terminal vegetative buds(P<0.001,P<0.0001);no significant differences were found between the expression of SgFPF1 gene in the two types of terminal buds.[Conclusion]The floral transition of Siraitia grosvenorii exhibits complicated physiological and gene expression regulatory mechanisms.Soluble sugar may serve as a primary energy substance involved in the floral tran- sition.High activities of POD and PPO,along with the hormonal pattern of low IAA content amd high ABA content,may be closely related to the redox requirements and signal regulation of flower bud differentiation.Key flowering-related genes such as SgFPA,SgFCA,SgEFL3,SgFY,and SgFLK may participate in regulating the floral transition of Siraitia grosvenorii.