猕猴桃AcPAL家族基因的鉴定及在果实成熟过程的表达OA

Phenylalanine ammonia-lyase(PAL)plays an important role in plant growth and development as well as fruit ripening.To investigate the characteristics of the AcPAL gene family in kiwifruit(Actinidia chinensis)and their expression profiles during fruit ripening,a genome-wide identification of AcPAL genes was performed,followed by analyses of their sequence characteristics,encoded protein properties,promoter cis-acting elements,gene structures,and phylogenetic relationships.Quantitative real-time PCR(qRT-PCR)was employed to detect the expression patterns of these genes in different tissues and during fruit ripening.The results were as follows:(1)A total of seven kiwifruit AcPAL genes were identified and designated as AcPAL1-AcPAL7,respectively.The proteins encoded by the AcPAL family genes consisted of 706-722 amino acids,and all of them were stable acidic proteins.These proteins possess the conserved domain(PLN02457)and active site motif(GTITASGDLVPLSYIA).(2)Chromosomal localization and collinearity analyses revealed that one tandem duplication event and ten segmental duplication events were the major driving forces for the expansion of the AcPAL family members.(3)Phylogenetic tree analysis indicated that all AcPAL family members clustered within the dicotyledon clade and showed a close genetic relationship with CsPAL proteins from Camellia sinensis.(4)The promoters of AcPAL family genes contained various cis-acting elements involved in light response,stress response,hormone response,as well as growth and development regulation.(5)qRT-PCR results showed that different AcPAL members exhibited differential expression patterns in roots,stems,leaves,flowers and fruits of kiwifruit.Notably,four members(AcPAL2,AcPAL3,AcPALA and AcPAL5)were significantly up-regulated during postharvest fruit ripening.This expression pattern was consistent with the marked increase in PAL enzyme activity,and their expression was induced by abscisic acid(ABA).These findings provide candidate genes and a theoretical basis for further investigation into the functions of AcPAL genes in the formation of postharvest fruit quality in kiwifruit.