Identification And Expression Pattern Analysis Of IbCWIN Gene Family Members In Sweet Potato

Sweet potato is an important food,feed,industrial raw material crop and a new type of bio-energy crop.Cell wall sucrose invertase(CWIN)is a key enzyme for sucrose metabolism in plant sources and sink.However,there are few studies on the members and functions of the Ib CWIN gene family in sweet potato.This study uses bio-informatics methods to identify the Ib CWIN gene family,and analyzes the physical and chemical properties,conserved domains,phylogenetic relationships,promoter elements,and tissue-specific expression patterns of family members.Using three different types of sweet potatoes as materials,the content of sucrose,total soluble sugar,and starch in different tissues at different growth and development stages was determined,in order to have a further understanding of the coordination of sweet potato photosynthesis and source-sink relationship at the genetic level.The main results are as follows:(1)There are 10 Ib CWIN genes in sweet potato,which are distributed on 8chromosomes.They all contain the Glyco＿32 conserved domain and the same or similar conserved motif.They belong to the glycosyl hydrolase gene family GH32.The Ib CWIN gene family encodes 442-1115 amino acids,the protein molecular weight ranges from 49.56-124.44 k D,and the isoelectric point is 5.0-9.1.Ib CWIN gene family promoters contain many types of cis-acting elements.Phylogenetic tree analysis found that the Ib CWIN gene family is adjacent to Me CWINV1,At CWINV6;Me CWINV3,Me CWINV4,and Me CWINV6 genes.It is speculated that the Ib CWIN gene family has similar functions to these genes.(2)Fluorescent quantitative PCR results showed that Ib CWIN gene family was expressed in different tissues of sweet potato,and there were many expression patterns.Ib CWIN1,Ib CWIN5,Ib CWIN6,Ib CWIN7,Ib CWIN8,Ib CWIN9 and Ib CWIN10 were highly expressed in aboveground parts;Ib CWIN2 and Ib CWIN4 were highly expressed in the underground part.In addition,the expression levels of Ib CWIN4,Ib CWIN5,Ib CWIN6,Ib CWIN7 and Ib CWIN9 in Eshu 6 and Eshu 11 roots were higher than those in Fucaishu 18 roots.In pot experiment,Ib CWIN2,Ib CWIN3 and Ib CWIN9 were highly expressed in the underground part,and the same trend of starch content was that Ib CWIN2 and Ib CWIN9 were expressed more in the tuberous root than in other tissue parts.It is speculated that the highly expressed genes in different tissues play an important role in the transformation and synthesis of sucrose and starch.The results of field experiment were different from those of pot experiment,which suggested that the expression of Ib CWIN gene family was related to sweet potato genotypes and environmental factors.(3)The leaf,petiole and stem were closely related to the accumulation and transportation of sucrose and total soluble sugar in three types of sweet potato.In the change of starch content,there was a significant or extremely significant positive correlation between tuberous roots and fibrous roots,stems and leaves at different stages,but there was no significant correlation between above ground starch content.In the process of root starch accumulation rate change,high starch type and edible type sweet potato were better than vegetable type sweet potato in the regulation of root starch accumulation.(4)Sucrose,total soluble sugar and Ib CWIN1 in root tubers of three types of sweet potato;Starch and Ib CWIN4,Ib CWIN5,Ib CWIN6,Ib CWIN9 had extremely significant or significant positive correlation.Sucrose and total soluble sugar were significantly correlated with Ib CWIN2,Ib CWIN5,Ib CWIN7;There was a significant negative correlation between starch and total sugar content.Based on the results of pot experiments,Ib CWIN4、Ib CWIN5 and Ib CWIN6 may be closely related to sucrose and total soluble sugar content in sweet potato,and Ib CWIN2,Ib CWIN4,Ib CWIN5,Ib CWIN6 and Ib CWIN9 may be closely related to starch content of root tuber.