Genome-Wide Identification, Characterization and Expression Analysis of Mango (Mangifera indica L.) chalcone synthase (CHS) Genes in Response to Light

Abstract

Light is one the most important environmental factors regulating the accumulation of specific metabolites in plants, such as flavonoid. Chalcone synthase (CHS) is the key rate-limiting enzyme of the flavonoid biosynthesis pathway, while little is known about the CHS genes in mango (Mangifera indica L.). Therefore, the aim of the study was to obtain the genome-wide identification of the CHS genes in mango and screen the light-responsive family members. In this study, a total of 21 CHS genes were identified from the mango genome, and most of the members contained the Cys-His-Asn triad and the CHS/STS signature motif. Most of the MiCHS genes were located on chromosomes 2 and 4, and seven pairs of tandem duplication genes and five pairs of segmental duplication genes were detected among the MiCHS members. The expression of MiCHSs showed a tissue-specific pattern and was not correlated with the flavonoid or anthocyanin accumulation in cultivars with different peel colors. MiCHS4, MiCHS16 and MiCHS17 were found to respond to preharvest and postharvest UV-B plus visible light treatments, which exhibited no significant relationship with the light-responsive cis-acting element distribution in the promoter region. Our results are helpful and can be used to further study the function of MiCHS genes in light-induced flavonoid biosynthesis in mango.