Cloning and Characterization of Three Sugar Metabolism Genes (LBGAE, LBGALA, and LBMS) Regulated in Response to Elevated CO2 in Goji Berry (Lycium barbarum L.).

Yaping Ma,Handong Gao,Lihua Song,Vangimalla R Reddy,Bing Cao,Mura Jyostna Devi

doi:10.3390/plants10020321

Abstract

The composition and content of sugar play a pivotal role in goji berry (Lycium barbarum L.) fruits, determining fruit quality. Long-term exposure of goji berry to elevated CO2 (eCO2) was frequently demonstrated to reduce sugar content and secondary metabolites. In order to understand the regulatory mechanisms and improve the quality of fruit in the changing climate, it is essential to characterize sugar metabolism genes that respond to eCO2. The objectives of this study were to clone full-length cDNA of three sugar metabolism genes—LBGAE (Lycium barbarum UDP-glucuronate 4-epimerase), LBGALA (Lycium barbarum alpha-galactosidase), and LBMS (Lycium barbarum malate synthase)—that were previously identified responding to eCO2, and to analyze sequence characteristics and expression regulation patterns. Sugar metabolism enzymes regulated by these genes were also estimated along with various carbohydrates from goji berry fruits grown under ambient (400 μmol mol−1) and elevated (700 μmol mol−1) CO2 for 90 and 120 days. Homology-based sequence analysis revealed that the protein-contained functional domains are similar to sugar transport regulation and had a high sequence homology with other Solanaceae species. The sucrose metabolism-related enzyme’s activity varied significantly from ambient to eCO2 in 90-day and 120-day samples along with sugars. This study provides fundamental information on sugar metabolism genes to eCO2 in goji berry to enhance fruit quality to climate change.

Highlights

Goji berry (Lycium barbarum) is a perennial shrub and belongs to the genus Lycium of the family Solanaceae, called wolfberry
Three sugar metabolism-related genes LBGAE (Lycium barbarum uridine diphosphate (UDP) glucuronate 4-epimerase), LBGALA (Lycium barbarum alpha-galactosidase) and LBMS (Lycium barbarum malate synthase) upregulated to elevated CO2 were selected from a previous transcriptome profiling study of goji berry [9]
This study demonstrates that the elevated CO2 levels affected the enzyme involved in the sucrose metabolism and quality of goji berry fruit by reducing its sugar components

Summary

Introduction

Goji berry (Lycium barbarum) is a perennial shrub and belongs to the genus Lycium of the family Solanaceae, called wolfberry. With the increasing demand due to its medicinal properties, more attention has been paid to improve the fruit quality of the goji berry. The LBP (Lycium barbarum polysaccharide) is the most abundant group of active ingredients in goji berry fruit, containing several monosaccharides that are influenced by several environmental factors [2,3]. Elevated atmospheric CO2 concentration is beneficial for photosynthesis and can directly affect the growth and development of plants [5,6,7]. Prolonged elevated atmospheric CO2 levels were shown to negatively affect goji berry fruit quality with reduced flavonoid, carotenoid, total sugars and polysaccharides, which might be related to photosynthesis acclimation [9]

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