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

Abstract

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 <italic>yl1</italic> treated with blue, red, green, and purple light. Results showed that the leaf of <italic>yl1</italic> was obviously yellowing, and the contents of chlorophyll, carotenoid and net photosynthetic rate in <italic>yl1</italic> 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 <italic>PSY, LUT5</italic> and<italic> VDE</italic> were significantly increased, while the expression levels of chlorophyll synthesis related genes <italic>POR</italic> and <italic>CAO</italic> were significantly decreased under purple lught. At the same time, twenty-one carotenoid pathway metabolites were detected under the four light, and ten metabolites were more abundant in pepper leaves. <italic>α</italic>-carotene, <italic>β</italic>-carotene, lutein, neoxanthin, <italic>α</italic>-cryptoxanthin and <italic>β</italic>-cryptoxanthin were significantly accumulated under blue, red and green light. However, zeaxanthin and antheraxanthin were accumulated in large quantities under purple light. After silencing <italic>CaVDE</italic> 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 <italic>VDE</italic> in purple light and provide new insights into the mechanism of leaf color change in plants.