勃氏甜龙竹DbFRK2和DbHXK5基因的克隆、表达与功能初探OA

Fructokinase and hexokinase are key plant enzymes that catalyze fructose phosphorylation and playing central roles in glycolysis,and carbohydrate metabolism.To explore the potential functions of DbFRK2 and DbHXK5 in sweetness formation of Dendrocalamus brandisii bamboo shoots,this study cloned DbFRK2 and DbHXK5 using reverse transcription-polymerase chain reaction(RT-PCR).Gene expression patterns were analyzed using quantitative real-time polymerase chain reaction(qRT-PCR),and fructose content and related metabolic enzyme activities were measured across various developmental stages of bamboo shoots.The results revealed that the open reading frame of DbFRK2 is 993 bp in length,encoding a protein of 331 amino acids.This protein contains conserved domains characteristic of the pfkB carbohydrate phosphofructokinase family,including three substrate-binding regions,six ATP-binding sites,and the PLN02323 conserved domain.Phylogenetic analysis indicated that DbFRK2 shares a close relationship with the fructokinase gene in Lolium rigidum.DbHXK5 possesses an open reading frame of 1 422 bp,encoding a protein of 474 amino acids.This protein contains the complete ASKHA_NBD_HK_plant domain,confirming its classification within the plant hexokinase family.It shows the mostly close relationship to Phyllostachys edulis in phylogenetic analysis.qRT-PCR results demonstrated that both DbFRK2 and DbHXK5 expression levels,as well as FRK and HXK enzyme activities,increased progressively during bamboo shoot development.While fructose content gradually decreased.These findings suggest that DbFRK2 and DbHXK5 may be involved in regulating fructose metabolism in bamboo shoots.This study provides a foundation for further elucidating the functions of DbFRK2 and DbHXK5 in sugar metabolism in Dendrocalamus brandisii,thereby offering theoretical support for the improvement of bamboo shoot quality and guidance for production practices.