Functional Analysis Of SlPT1,a Tomato High-affinity Phosphate Transporter Gene By VIGS

Phosphorus is a large number of elements required for plant growth.Tomato(Solanum lycopersicum)is one of the world's most important vegetable crops,and low phosphorus stress can seriously affect tomato yield and quality.The high affinity phosphorus transporter PHT1 gene family is an important gene that regulating phosphorus transport.Based on the analysis of the sequence and expression pattern of the tomato PHT1 gene family,VIGS-mediated gene transient s ilencing method was used to detection the total phosphorus content,chlorophyll content,total root length,total root area,Root cap ratio and other effects.The specific results are as follows:1.A total of 8 high-affinity phosphotransporter gene family members were found in the tomato genome database,named as Sl PT1-Sl PT8,and their conservation,evolutionary relationship and chromosomal location was analysis.we was found that the members of the gene family had high stability,and both of them contained the conservative structural domain GGDYPLS ATIMS E of the PHT1 family,and 8 genes were distributed on chromosomes 3,6 and 9.2.The expression patterns of 8 members in normal phosphorus and low phosphor us treatment were studied.The results showed that the expression of Sl PT1 gene in roots,stems and leaves of plants was signif icantly increased in the roots of low-phosphorus plants.Sl PT2 gene was up-regulated in low-phosphorus plant roots and not detected in stems and leaves.Sl PT6 gene was mainly expressed in low-phosphorus roots,and its expression in stems and leaves was low.Sl PT7 gene was abundantly expressed in roots;Sl PT3,Sl PT5 gene weak expression in roots,stems and leaves,and did not inc rease in low phosphorus environment.Sl PT4 and Sl PT8 genes were not detected in plant.The expression level of Sl PT1 gene was signif icantly increased when phosphorus was low,suggesting that Sl PT1 gene may have a signif icant influence on phosphorus transport in tomato.Therefore,this paper selected Sl PT1 gene for follow-up study.3.The TRV-Sl PT1 silencing expression vector was successfully constructed and infected with tomato two-leaf and one heart seedlings.Wild type(WT)and infected TRV empty vector(TRV)plants were used as controls.A total of 15 plants of gene silenced Sl PT1 were obtained by q RT-PCR detected,and the silenc ing efficiency was 38.1%-83.7%4.The effect of Sl PT1 gene silencing on plant growth was examined.The results showed that in normal phosphorus treatment,wild-type plants(WT),TRV empty vector plants(TRV),and Sl PT1 gene-silenced plants(Sl PT1)had total phosphorus content in roots,stems and leaves,total root length,plant height and stem diameter was no significant difference between them,and the total root area of Sl PT1 plants was significantly lower than that WT and TRV plants,which was lower than 10.6% and 8.2% respectively.In the low phosphorus treatment,the phosphorus content was significantly lower than that of WT and TRV plants,which was 37.1% lower than that WT plants,and the difference was not significant in stems and leaves.The total root length and total root area of Sl PT1 plants were signif icantly lower than those of TRV plants,which were 38% and 18.2% lower than those of TRV plants,respectively.The chlorophyll b and chlorophyll a/b of Sl PT1 plants were significantly lower than those of WT plants.The above results indicated that silencing of Sl PT1 gene caused a significant decrease in total phosphorus content,total root length,total root area and other indicators of tomato roots under low phosphorus stress,and also indicated that in low phosphorus,plants increased total roots length and total root area to improve the efficiency of phosphorus absorption by plants.