Cloning And Functional Analysis Of StSWEET In Potato

Potato is one of the four major crops in China.The transport of photosynthetic products sugar provides a material basis for the formation of potato tubers.Long-distance transportation and unloading of assimilation products in potato leaves is a key link.The SWEET can transport carbohydrates in both directions and also plays an important role in growth and development,metabolic processes and stress.In this study,based on the potato double haploid genome-wide database as a data source,combined with the Arabidopsis and tomato SWEET gene family,the potato StSWEET family was identified and systematic bioinformatics analysis,and the expression profiles of StSWEET family in different tissues of potato were studied.The expression of StSWEET gene family under the biotic and abiotic stress of Qingshu 9 potato.Based on the expression,the StSWEET11 and StSWEET16 b genes were homologously cloned and functionally analyzed.1.This study analyzed 33 genes in the potato StSWEET family,named StSWEET1-StSWEET17;and clustered 29 genes of the published tomato SlSWEET family and 35 genes of the Arabidopsis AtSWEET family.The SWEET family has been clustered into four subfamilies,6 in the first subfamily,32 in the second subfamily,51 in the third subfamily,19 in the potato SWEET family,and only 2 in the fourth subfamily.Most of the genes in the potato belong to the third subfamily.Gene structure analysis showed that the number of introns in each open reading frame was different,and its structure was conservative.The StSWEET gene family is clustered on 10 potato chromosomes,and chromosomes 10 and 11 are not distributed,the StSWEET12 d gene has not yet been mapped.The StSWEETs protein family has 10 conserved motifs,and proteins in the same subfamily contain similar conserved motifs that have similar functions in each subfamily.Promoter predictive analysis indicated that potato SWEET protein is associated with cell growth,development,secondary metabolism,and response to biotic and abiotic stresses.2.Using qRT-PCR technology to analyze the expression profiles of different tissues of potato StSWEET gene family in Qingshu 9.Studies have shown that most of the StSWEET gene family is specifically expressed in different tissues,and the specific expression in a certain tissue may be involved in the growth and development of the tissue,regulating the corresponding functions.The StSWEET11 gene is highly expressed in leaves,and the StSWEET16 b gene is highly expressed in flowers.The expression of StSWEET10 c was highest in roots and StSWEET12 e was low.In stems,StSWEET1 h was highly expressed and StSWEET1 f was the lowest;StSWEET11 was higher in leaves and StSWEET17 was the lowest;StSWEET1e was highly expressed in flowers and StSWEET1 f was lower in expression;StSWEET1d was higher in tubers and StSWEET12 e was expressed low level;StSWEET12c is highly expressed in stolons,while StSWEET17 is low in expression.3.The expression of the potato StSWEET gene family under the biotic stress(leaf-leaved leaves of the late blight pathogen)and abiotic stress(glucose,fructose and sucrose treatment)of the potato was detected by qRT-PCR.Studies have shown that the StSWEET11 gene responds to the growth of late blight pathogens and is also sensitive to sucrose;StSWEET16b gene is closely related to the growth of late blight pathogens and slightly sensitive to fructose and sucrose.Under the induction of Phytophthora infestans,StSWEET10 c and StSWEET10 d reached the highest expression at 24 h,especially the expression of StSWEET11 was significantly up-regulated.The expression levels of StSWEET1 d,StSWEET1e,StSWEET2 b,StSWEET10a and StSWEET12 b have a downward trend.In the process of sugar stress,StSWEET3,StSWEET10 b,StSWEET2c,StSWEET16 b and StSWEET16 c were down-regulated after glucose stress;StSWEET12c was up-regulated after glucose and fructose stress,but down-regulated after sucrose stress;StSWEET16a was only in fructose stress after the upward adjustment.In the stem,StSWEET16 a,StSWEET17,StSWEET1 e and StSWEET10 a were up-regulated after glucose stress;under the stress of fructose and sucrose,StSWEET11,StSWEET1 b,StSWEET12e,StSWEET1 f,StSWEET12d,StSWEET1 c and StSWEET1 d were up-regulated.In the leaves,StSWEET1 i,StSWEET10c and StSWEET2 a were up-regulated after sucrose stress,and StSWEET2 c was down-regulated after sucrose stress.4.Based on the gene expression,the StSWEET11 and the StSWEET16 b genes were cloned in Qingshu 9.Its StSWEET11 has a CDS of 903 bp,encodes 301 amino acids,has a molecular weight of 33591.42 Da,and has an isoelectric point of 9.29.It has seven transmembrane domains and contains two MtN3/saliva conserved domains.StSWEET16 b has a CDS of 786 bp,encodes 262 amino acids,has a molecular weight of 28,838.13 Da,and has an isoelectric point of 9.66.It has six transmembrane domains and contains a conserved domain of MtN3/saliva.The expression vectors of StSWEET11 and StSWEET16 b genes were constructed by Gateway technology,respectively.Genetically transformed tobacco was mediated by LBA4404 Agrobacterium competent,and 52 transformed seedlings were obtained from StSWEET11 gene;48 transformed seedlings were obtained from StSWEET16 b gene.