| Wheat is one of the most important food crops in the world. Its biomass and economic yield mainly depend on the photosynthesis of leaves. Chlorophyll is the important pigment involved in photosynthesis in plant chloroplasts. Chlorophyll metabolism is influenced when certain location of plant genome occur aberrance, which lead to change of leaf color. Albino mutant of wheat play an important role in researching photosynthesis of higher plants, biosynthesis of chlorophyll, genetic differentiation and development of chloroplast. Therefore it’s important in the theoretical research of photosynthesis regulatory mechanism in order to increase the photosynthesis ability and economic efficiency of crops.In this paper, a albino mutant designated "M6", was identified from wheat variety CN19. Genetic action of the albino gene character was analyzed by using the F1 and F2 progenies from it crossed with normal green original parent CN19. Furthermore, the albino gene was mapped preliminarily through the DNA extraction, PCR and polyacrylamide gel electrophoresis, SSR labeling method for positioning, screening polymorphism markers. Otherwise, M6 and CN19 were taken as materials and we employ suppression subtractive hybridization technique characterized by high specificity and output rate to construct SSH cDNA library and obtain positive clones through differentially screening. Then we analyzed the differentially ESTs.This results could be the basis for making photosynthesis regulatory mechanism further understood. The main results were summarized as follows:1. The albino mutant M6 has been crossed with normal plant CN19, seeding of F1 behaved green, seeding of F2 appeared separation of leaf color. The separation ratio of green and albino fitted for 3:1 by x2-test, which suggested that the albino trait of M6 was controlled by one pair of recessive nuclear gene.2. With SSR molecular marker, two sets of Xgwm and Xwmc wheat SSR markers analyze the polymorphisms among polymorphic primers M6, CN19 and F2 population of M6/CN19 and CN19/M6. The results show that:By analysis using Joinmap4.0 software, Xgwm611, Xwmc557, Xwmc581, Xcfa2040 were linked to the albino gene, which was located on the wheat 7BL chromosome. Each marker’characters genotypes and molecular genotype trajectory were in accord with the theoretical ratio of 1:2:1. The order of marker on wheat 7B is Xgwm611, Xwmc557, Xwmc581, Xcfa2040. The genetic distance of albino gene to the primers were 1.3cM,0.4cM, 2.1cM, 8.0cM。 The gene was rough mapped between SSR marker Xwmc581 and Xcfa2040.3. We extract the mRNA of the materials M6 and CN19 to build a forward and reverse SSH cDNA library. M6 was used as tester, CN19 as the driver in forward SSH cDNA library. CN19 was used as tester;, M6 as the driver in reverse SSH cDNA library. The results showed that the forward library obtained a total of 27 effective ESTs sequence, BLAST analyses indicated that 17 ESTs were known functional sequences or coding sequences were highly similar,10 ESTs were unknown functional and couldn’t find similar sequences, all of them were uniESTs.3 ESTs were mapped on wheat 7BL,1 EST was mapped on 7AS. Photosynthesis and metabolism related sequences accounted for 26%,4% ESTs were involved in transportation,11% in transcriptional regulation and 22% in resistance and defense,37% ESTs were found no significant similarities. Reverse library obtained a total of 35 effective ESTs sequences which 24 ESTs were known functional sequences or sequences encoding highly similar products,11 ESTs couldn’t find similarities in GenBank,6 ESTs were multi-copy sequences,4 ESTs were found similarities, but functions are unclear,1 EST mapped on 7BL.49% of the ESTs sequences related to photosynthesis and metabolism,6% related to cell signaling,3% related to transcriptional regulation, cell growth/apoptosis accounted for 11%, others’ function were unknown.The function of ESTs related to photosynthesis had been analyzed briefly. |
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