English

Abstract

Photosynthetic characteristics and expression patterns of the photosynthesis-related genes in the high-yield mulberry variety E’Sang 1 (E1) and normal mulberry variety Husang 32 (H32) were investigated in this study. The observation of daily variation of photosynthesis in E1 and H32 indicated that the peak of net photosynthetic rate(Pn)inE1 variety was significantly higher than that inH32 (P <0.05). Meanwhile, the Pn-PAR and Pn-Ci responses of E1 and H32 were evaluated, and the results showed that the carboxylation efficiency and compensation saturation point were much higher in E1 rather thanH32. Importantly, the photosystem II actual photochemical efficiency and photochemical quenching coefficient in the leaves of E1 were significantly higher than those in H32 (P<0.05). Also, the activity of RuBP in E1 was higher than that in H32 (P >0.05). Based on the RNA-seq data, a total of 3,356 differentially expressed genes (DEGs) were detected among different time points between E1 and H32. Of these, 1,136 DEGs were involved in the metabolic pathways, including three main photosynthesis-related metabolic pathways (i.e., carbon fixation in photosynthetic organisms, carbon metabolism, and porphyrin and chlorophyll metabolism). Meanwhile, 10 novel DEGs related to photosynthesis were detected, and four potential key genes of them could account for the differences in net photosynthetic rate and yield betweenH32 and E1.This study could provide important insights into the molecular breeding of mulberry varieties with high photosynthetic efficiency and contribute to understanding the genetic mechanism of photosynthesis.© 2021 Friends Science Publishers