The Assembly of Purple-red Spinach Provides Insight into the Mechanism of Betalain Biosynthesis

Abstract

Purple-red spinach is a unique cultivar with rich in betalains, which has been used for food colorants and is beneficial for human health. In view of the lack of genomic inforamtion of purple-red spinach genome and promote the idetification of betalian gene, we presented the genome of purple-red spinach with Nanopore ultra-long and illumina sequencing platform. The contig N50 size was 2.2Mb and 99.33% contig sequence was anchored to the six chromosomes, totaling 878.83Mb. The purple-red genome constitues 74.15% repeat sequence and harbors 26020 protein-coding genes. We also comprehensively identified candidate genes in betalain biosynthesis pathway in spinach. Moreover, a combined transcriptomic and BSA analysis uncovered a key betalain gene, FUN_002594, which regulated the color and betalain content of leaf. Our data present a valuable resource for facilitating molecular breeding programs of spinach and shed novel light on unique attributes, as well as the modulation of betalain biosynthesis.