Integrated metabolome and transcriptome analysis revealed carotenoid metabolism difference in pepper(Capsicum annuum L.)yellowing mutants under different light quality

Light is an important environmental factor for plant growth and development,different light qualities have different regulatory effects on plants.To investigate the effect of light quality on plants,we determined the physiological characteristics,transcriptome and metabolome analysis of pepper yellowing mutants yl1 treated with blue,red,green,and purple light.Results showed that the leaf of yl1 was obviously yellowing,and the contents of chlorophyll,carotenoid and net photosynthetic rate in yl1 were significantly decreased under purple light.A total of 31,853 genes were quantified under blue,red,green and purple light.The genes related to carotenoid metabolism pathway such as PSY,LUT5 and VDE were significantly increased,while the expression levels of chlorophyll synthesis related genes POR and CAO were significantly decreased under purple light.At the same time,21 carotenoid pathway metabolites were detected under the four light different lights,and 10 metabolites were more abundant in pepper leaves.α-carotene,β-carotene,lutein,neoxanthin,α-cryptoxanthin andβ-cryptoxanthin were significantly accumulated under blue,red and green light.However,zeaxanthin and antheraxanthin were accumulated in large quantities under purple light.After silencing the CaVDE gene under purple light,leaf etiolation degree was significantly weakened,chlorophyll,carotenoids and net photosynthetic rate were significantly increased,and the accumulation of zeaxanthin and antheraxanthin was significantly decreased.These results provide a reference for analyzing the changes of carotenoid components induced by VDE in purple light and provide new insights into the mechanism of leaf color change in plants.