Studies On The Accumulation Of Pigment In Plum Fruit And The Molecular Mechanism Of Anthocyanin And Carotenoid Synthesis

A comparative study of the main pigments in 9 different plum varieties was conducted.At the same time,the plum ‘Cuihongli'(red peel,yellow flesh)and ‘Qiangcuili'(yellow-green peel and flesh)with 4 years were used to study the changes of the quality,contents of chlorophyll,anthocyanin and carotenoid,the expression of structural genes related to anthocyanin and carotenoid synthesis during the growth stages.The sequence of PAL,UFGT,PDS,LCYB and ZEP of ‘Cuihongli' and ‘Qiangcuili' were cloned by using homologous sequence method.The main results were as follows:1.Among the 9 plumes,only the atropurpureus peel,red peel and red flesh could detect the anthocyanin,which main components were cyanidin-3-O-glucoside and cyanidin-3-O-rutinoside,the darker the color,the higher the anthocyanin contents.Both peel and pulp,green varieties had the highest chlorophyll and carotenoid contents,and purple-black varieties had the highest flavonoid contents.2.With the development of ‘Cuihongli' and ‘Qiangcuili',the fruit weight,diameter and soluble sugare contents increased,titratable acid contents decreased,Vc contents decreased first and then increased.Compared with ‘Qiangcuili',‘Cuihongli' was smaller,soluble sugar contents were higher,titratable acid contents were lower,sugar to acid ratio were higher.Thus,‘Cuihongli' have brighter color,better taste and better nutrition.3.At the early stage of fruit development,both peel and pulp of ‘Cuihongli' and‘Qiangcuili' were all green,chlorophyll was the main color substance.With the fruit growth,the chlorophyll contents decreased,the carotenoid contents first decreased and then increased.The anthocyanin contents only in the peel of ‘Cuihongli' had been accumulating,which was the main pigment that made it atropurpureus.and which main components were cyanidin-3-O-glucoside and cyanidin-3-O-rutinoside.The pulp of‘Cuihongli' and both peel and pulp of ‘Qiangcuili' might be affected by chlorophyll,carotenoid,flavonoid and other pigments.4.The expression of structural genes related to anthocyanin biosynthesis were analyzed in ‘Cuihongli' and ‘Qiangcuili'.The results showed that the expression ofPsUFGT gene was not detected in the peel and pulp of young friut and in the pulp of early fruit expansion of ‘Qiangcuili',the expression of PsPAL,PsCHS,PsCHI,PsF3 H,PsDFR,PsANS and PsUFGT genes could be detected in other peel and pulp,with low levels in pulp.Correlation analysis showed that the expression of PsPAL,PsCHS,PsF3 H,PsANS and PsUFGT were positively correlated with anthocyanin contents,and the expression PsPAL and PsUFGT were significant positively correlated with anthocyanin contents.5.The expression of structural genes related to carotenoid biosynthesis were analyzed in ‘Cuihongli' and ‘Qiangcuili'.The results showed that the expression of PsPSY,PsPDS,PsZDS,PsLCYB and PsZEP in peel were higher than that in pulp at the early stages of fruit development,at the later stage,the expression in pulp were similar to that in peel or even higher.Correlation analysis showed that the expression of PsPDS,PsLCYB and PsZEP genes had positive correlations with carotenoid contents,and the correlation between PsPDS gene expression and carotenoid contents reached a significant level.6.The sequence of PAL,UFGT,PDS,LCYB and ZEP of ‘Cuihongli' and ‘Qiangcuili'.were cloned by using homologous sequence method.And the length of PAL was 2160 bp encoding 719 amino acids,UFGT was 1428 bp encoding 475 amino acids,PDS was 1722 bp encoding 573 amino acids,LCYB was 1515 bp encoding 504 amino acids,ZEP was1986 bp encoding 661 amino acids.The amino acid sequences in two plums were completely same of LCYB and ZEP,one amino acid differed of PAL and PDS,three amino acids differed of UFGT.The phylogenetic tree analysis showed the genetic distance of Prunus salicina and Prunus mume,Prunus armeniaca,Prunus persica,Prunus avium was shorter,and the genetic relationship was closer.