| Iron is a necessary trace mineral element for normal life activities of plants.It is a component of cytochrome and iron-sulfur protein.Iron can also promote the synthesis of chlorophyll,promote plant growth and flower formation,and improve fruit quality and yield.Iron deficiency will seriously affect plant growth,reduce fruit yield and quality.However,studies on iron nutrition,metabolism and its molecular mechanism in Pomology are extremely rare.In recent years,with the rapid development of grape industry,the problem of iron deficiency and chlorosis of grape has become an urgent problem to be solved,especially in the calcareous soil producing areas in northern China.The molecular mechanism of iron uptake,translocation and distribution in grape is still unknown.Therefore,cloning and functional analysis of iron uptake,translocation and distribution genes in grape can further clarify its molecular mechanism,and provide theoretical basis for solving iron deficiency or mining iron efficient utilization of Grape Germplasm resources.In this experiment,the wine grape variety ‘ Maselan ’ of Yantai Academy of Agricultural Sciences was used as the material to screen and identify iron absorption,transport and distribution genes in grape genome by homologous cloning method,and the detailed characteristics of genes and their coding proteins of each family were analyzed by using a variety of bioinformatics software.Real time fluorescent quantitative PCR was used to analyze the expression patterns of various family genes in different tissue parts of grape at different stages and the response to iron deficiency stress.The main results are as follows:1.The iron content of ‘Maselan’ grape fruit increased at first and then decreased at different development stages,and the iron content of mature fruit was higher than that of young fruit.2.After the experiment of iron deficiency stress on tissue culture seedlings of‘ Maselan ’ grape,the results of iron staining showed that there was still a small amount of iron in the root,the iron in the stem and leaf decreased significantly,and there was almost no iron distribution in the leaf.3.In this study,53 members of FRO,IRT,FRDL,FPN,YSL,FER,PIC,VIT,IREG,NRAMP1 family genes related to iron uptake,translocation and distribution were cloned from grape by homologous cloning method.4.The gene families related to Fe uptake in grape include FRO family and IRT family.There are six members of the FRO family in grape.The expression levels of FRO2 and FRO3 in grape leaves were the highest,and the expression levels of FRO5 in grape fruit at hard core stage were the highest.Under the condition of iron deficiency,the expression level of FRO2 was significantly up-regulated in the roots of grape seedlings,the expression level of FRO3 was up-regulated in the leaves and stems,and the expression level of FRO4 was down regulated in the leaves.There are ten members of the IRT family in grape.Among the IRT family genes,IRT7 had the highest expression level in grape leaves and fruits.Under the condition of iron deficiency,the expression level of IRT1 in the roots of grape seedlings was significantly up-regulated,and the expression levels of IRT4 and IRT7 in the leaves were significantly up-regulated.5.There are FRDL family,FPN family and YSL family related to Fe translocation in grape.There are six members of the FRDL family in grape.Among the FRDL family genes,FRDL2 had the highest expression level in grape leaves and fruits,and the expression level in mature fruit was significantly higher than that in other stages.The expression level of FRDL2 in roots,stems and leaves of grape seedlings was significantly down regulated under iron deficiency.There are three members of the FPN family in grape.Among the FPN family genes,the expression level of FPN3 was the highest in young leaves,and increased in different fruit development stages.The expression level of FPN1 was slightly lower than that of FPN3 in mature fruits.Under iron deficiency condition,the expression levels of FPN1 in roots,stems and leaves of grape seedlings were significantly up-regulated,and the expression levels of FPN3 in leaves were up-regulated.There are ten members of the YSL family in grape.The relative expression level of YSL4 was the highest in young leaves of grape.The relative expression level of YSL2 in young fruit and fruit of color transformation stage was higher than that in other stages.The relative expression level of YSL4 was the highest in mature fruit.The expression level of YSL4 in grape seedling leaves was significantly up-regulated under iron deficiency.6.FER family,PIC gene,VIT family,IREG family and NRAMP1 family are related to Fe distribution in grape.There are four members of the FER family in grape.Among the FER family genes,FER3 had the highest expression level in the old leaves,and the highest expression level in the mature fruits.The expression levels of FER2 and FER3 in grape seedling leaves were significantly up-regulated under iron deficiency.The expression level of PIC gene in grape leaves was higher than that in fruit.The expression level of PIC in grape seedling leaves was significantly up-regulated under iron deficiency.There are three members of the VIT family in grape.In Vitis vinifera,the expression level of VIT2 was the highest in young leaves,VIT2 was the highest in fruit of color transformation stage,and VIT3 was the highest in fruit of mature stage.The expression level of VIT2 in the roots of grape seedlings was significantly upregulated under iron deficiency.There are three members of the FRO family in grape.Among the genes of grape IREG family,the expression level of IREG1 in young leaves was the highest,and the highest expression level was in fruit during color transformation period.The expression level of IREG3 in old leaves was the highest,and the highest expression level was in fruit during mature period.The expression level of IREG1 in grape seedling leaves was significantly up-regulated under iron deficiency.There are seven members of the NRAMP family in grape.Among the NRAMP1 family genes,NRAMP1-4 had the highest expression level in the old leaves of grape,the highest expression level in the whole grape fruit,and the highest expression level in the mature fruit.The expression of NRAMP1-1 was significantly up-regulated in the stem and root of grape seedlings under iron deficiency. |
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