Studies On The Accumulation Of Carotenoids And The Expression Of Related Genes In Plum

Recent years,there have been few studies on the content and components of carotenoids as well as the expression of related genes,but there are great differences in the accumulation of carotenoids between different plum varieties.In this experiment,the contents and components of carotenoids and the expression of related genes in the biosynthesis pathway of carotenoids in mature period of various plum species were compared and studied.At meanwhile,the accumulation rules of carotenoids and the expression of related genes were also analyzed in peel and pulp of ‘Cuihongli’(The peel is purplish red and the pulp is yellow)and ‘Qiangcuili’(The peel is green and the pulp is greenish yellow)during development,the apparent coloration of which has a significant difference.The main results are as follows:1.The contents of carotenoids were significantly higher in the peel of different plum varieties than those in the pulp,with the highest contents in ‘Naili’ and the lowest in‘Konglongdan’.Except for the absence of β-cryptanthin and α-carotene accumulation in the peel of ‘Konglongdan’ and the absence of α-carotene accumulation in ‘Angenuo’,most of the plum varieties had 5 kinds of carotenoids in peel: Lutein,Zeaxanthin,β-cryptoxanthin,carotene,α-carotene and β-carotene,among which the main components is Lutein.Except the absence of β-carotene in pulp of ‘Konglongdan’ pulp,most plum species have the accumulation of Lutein and β-carotene in the pulp,among which β-carotene is the main component.Also,there is a little accumulation of zeaxanthin in the pulp of ‘Naili’ ‘Heibaoshi’‘Yinhongli’ ‘Meili’ ‘Angenuo’,and the accumulation of β-cryptoxanthin is detected in the pulp of ‘Heibaoshi’.2.In the peel of different plum varieties at maturity,the expression of PSY was higher than other genes,while the expression of NSY and CCD4 were very low.At maturity,there was a significant negative correlation between the expression of CCD4 and β-cryptoxanthin,α-carotene and β-carotene in the peel of different plum varieties.The total amount of carotenoids in peel was positively correlated with the expression of PSY,LCYB,LCYE,while negatively correlating with the expression of NCED.3.The carotenoid content of ‘Cuihongli’ and ‘Qiangcuili’ both showed a decreasing trend during development,and the carotenoid content of ‘Qiangcuili’ was lower than that of‘Cuihongli’.There are five kinds of carotenoids in the fruit of ‘Cuihongli’ and ‘Qiangcuili’:Lutein,Zeaxanthin,β-cryptoxanthin,carotene,α-carotene and β-carotene,among which Lutein is the key component.Except for β-cryptoxanthin(the lowest component),the other components are gradually reduced with the development of the fruit,and there is no accumulation of α-carotene in the pulp of ‘Cuihongli’.In the pulp of ‘Cuihongli’,the β-cryptoxanthin only accumulated at the young fruit stage,expansion stage,the semi-red stage and the mature stage.In the pulp of ‘Qiangcuili’,β-cryptoxanthin began to accumulate at the rapid expansion stage,and α-carotene only accumulated at the young fruit stage.4.In ‘Cuihongli’ and ‘Qiangcuili’,DXS regulated the accumulation of carotenoids mainly by affecting the accumulation of Lutein,α-carotene and β-carotene,showing a positive correlation with the total content of carotenoids in ‘Qiangcuili’,while not significantly in ‘Cuihongli’.There was a positive correlation between LCYB and Lutein,while LCYE showed a significant negative correlation with content of Lutein.The relative expression of DXR,PSY,PDS,ZDS,ZISO,CRTISO,LCYE,BCH,VDE and ZEP was significantly higher in the semi-red period of ‘Cuihongli’ peel than in other periods.The expression of ZISO and NSY had a significant effect on the synthesis of ‘Cuihongli’carotenoids;the expression of DXS in ‘Qiangcuili’ was significantly positively correlated with its carotenoid content,while the expression of CCD4 showed a significant negative correlation.