Analysis On The Function Of PbSOT Genes In Regulation Sugar Accumulation In Pear Frutis

The sugar content of pear fruit is the most important factor to evaluate the intrinsic properties of fruit.The transport and accumulation of sugar in fruit is mainly controlled by sugar transporter regulation.Studying sugar transporters related to sugar accumulation in fruits has a great influence on understanding the sugar storage mechanism and changing fruit quality.Based on the published genome-wide sequences of various species,this study identified and analyzed the evolutionary expression pattern of sorbitol transporter(SOT)gene family in pear genome by bioinformatics method,and studied the expression of PbSOT gene in pear and its sugar content.Accumulation correlation,identified PbSOT gene family members closely related to fruit sugar accumulation,further verified the transport function of SOT by transcriptome sequencing analysis,Arabidopsis protoplast subcellular localization and hormone treatment,the results are as follows:1.Based on the genome-wide data of six Rosaceae fruit tree species of apple,black raspberry,plum,peach,pear and strawberry,the members of the Rosaceae fruit tree sorbitol transporter(SOT)gene family were identified and studied by bioinformatics method.Chromosome localization,promoter and sequence characteristics,evolutionary relationships,etc.,and related analysis of gene structure,physical and chemical properties.63 SOT gene family members were isolated from six Rosaceae fruit species,63 genes were clustered into 4 groups,group Ⅰ and group Ⅲ were pome fruits(pear and apple),and groupⅡ was stone fruit(peach and plum).Group Ⅳ contains all six Rosaceae fruit trees.The 24 SOT genes of Pear are mainly involved in tandem,near-end and discrete replication,which is different from the replication of other Rosaceae fruit trees.By qRT-PCR analysis,the PbSOT6/20 gene in group Ⅳ was most strongly expressed in pear leaves,shoots,flowers,fruits and seeds.Compared with other SOT genes,the expression pattern of PbSOT6/20 was more strongly correlated with the sorbitol accumulation pattern in pear fruit.Exogenous sorbitol at low concentration(100 mg/g)induced PbSOT6/20 expression in pear fruit,but did not induce PbSOT6/20 expression in leaves.The above results indicate that PbSOT6/20 is involved in the accumulation of sorbitol in pear fruit and plays an important role in the transfer of sorbitol from source to reservoir.This study provides a new understanding of the SOT gene-mediated transport of sorbitol in pears.2.Sorbitol is the main component of soluble sugar in pear fruit.In order to study the effect of SOT on the transport of sorbitol source pool,this experiment uses"Cuiguan" as the material,with 6 different stages of Crested Petiole,leaves,fruit stems and fruit.On the one hand,the soluble sugar content was determined at different stages of four different tissues.On the other hand,24 groups of samples were subjected to transcriptome sequencing analysis,and the SOT gene regulated by the sorbitol source pool was screened and verified by real-time PCR.Six genes with transport functions PbSOTl/2,PbSOT6/20,PbSOT3,PbSOT13,PbSOT19/21 and PbSOT22 were screened.It is speculated that the gene PbSOT6/20 transfers intracellular sorbitol to the outside of the cell,while PbSOTl/2,PbSOT3,PbSOT13,PbSOT1 9/21 and PbSOT22 transfer sorbitol from the cell to the cell.Subcellular localization indicates that PbSOT6/20 and PbSOT22 are localized on the cell membrane.At the same time,a silencing TRV2-PbSOTs vector and a super-expressing PSAK277-PbSOTs vector were constructed.3.Using Cuiguan as the material,in the first year,the fruits were treated with IAA and ABA at concentrations of 0.1 mg/L、1 mg/L、10 mg/L、100 mg/L and 1000 mg/L in the five stages of fruit development.Treatment to explore the effects of hormone treatment on fruit development and maturity.The results showed that the soluble sugar content in the mature fruit was increased by treatment with 1 mg/L and 10 mg/L of ABA hormone at 30 days and 45 days after flowering.At the same time,the fruits were treated with IMA at 1 mg/L、10 mg/L and 100 mg/L 30 days and 45 days after flowering,and the content of sorbitol and sucrose in the mature fruits was significantly increased.The second year was treated with 1 mg/L、10 mg/L ABA,and 1mg/L、10 mg/L、100 mg/LIAA at 30 days and 45 days after flowering,of which 10 mg/L ABA-treated fruit was at maturity.The content of fructose,sorbitol and glucose increased,and the fruit sorbitol content was higher than that of the control fruit at 95 days after flowering,and the content of fructose and sorbitol increased in 10 mg/L IAA treated fruit.At 95 days after flowering,the fructose and sorbitol content in the fruit has increased.