Abstract:

Carotenoids are the most widely distributed class of pigments in nature,which endow plants flowers,fruits and other organs with bright colors.The synthesis process of carotenoids contains a variety of metabolic enzyme genes.In order to reveal the molecular mechanism of carotenoid accumulation in yellow peeled zucchini,lay a foundation for further studying the function of carotenoid synthase gene in zucchini,this study identified zucchini carotenoid anabolism family genes based on the zucchini genome database,and further screened and cloned the key enzyme genes for carotenoid synthesis and metabolism by publicly published transcriptome data and qRT-PCR verification.The results showed that 48 carotenoid metabolizing enzyme gene members were detected in zucchini genome;and two key genes PSY1 and LCYE2 were screened out and showed different expression during the different developmental stages based on the transcriptome data of Sweet REBA/Lady Godiva.qRT-PCR analysis also showed that, except for PSY1 gene 0 d and LCYE2 gene 2 d, the relative expression of PSY1 and LCYE2 in different developmental stages of yellow peeled zucchini were significantly higher than that of white peeled zucchini.The full-length CDS of PSY1 and LCYE2 genes were cloned and sequencing analyzed from white and yellow peeled zucchini,respectively,which suggested that PSY1 genes of both materials were 51 bp more than the predicted coding sequence in zucchini reference genome,and were all consistent with the published sequence of PSY gene(GenBank number:XM_023695146.1),while the sequences of LCYE2 gene was not significantly different from the reference genome.Phylogenetic tree analysis showed that zucchini PSY1 was homologous to the reported Cucurbita moschata PSY(JN176311.1)with the best similarity as high as 98.80%.

Key words: Zucchini, PSY1, LCYE2, qRT-PCR, Gene clone