Inheritance Of A Leaf Color Mutant In Maize

Corn is the most important source of food and feed raw materials in the world. Its biomass and economic yield mainly depend on the photosynthesis of leaves. The chlorophyll is an important pigment for photosynthesis. Therefore it is very important in the theoretical research of photosynthesis regulatory mechanism to map and clone new photosynthetic-related genes and research their function. Through the gene engineering approach the photosynthesis ability and economic efficiency of crops may be significantly increased.In this study the mutation of chlorophyll biosynthesis comes form the natural mutant in maize inbred lines 444. The mutation 444 crossed with normal inbred line 9058, then their progenies were used to process genetic analysis,and discover and fine mapping two genes which controlled the leaf color of the mutation 444. The results were obtained as following:1. From measured the chlorophyll relative content of the mutation 444 in different temperature, identified that the mutation was mutated in the step of chlorophyll biosynthesis and the phenotype of the mutation was impact by the temperature. Under the low temperature(18℃), it was the albino seedling. Under the 28℃, it was the yellow seedling. But when it was under the higher temperature(32℃above), the seedling closed to green.2.The different generation form normal maize inbred line 9058 and mutation 444 was used to phenotypic and molecular analysis. Identified two genes which existed epistatic dominance interaction controlled the leaf color in the two inbred line's generation under the low temperature. Then named the two genes respectively as al(albino leaf) and yl(yellow leaf).3.The molecular marker technique was used in the F2 population. So al was rough mapped between SSR marker bnlg1064 and umc1026 which genetic distance was 1.9cM, physical distance was 2.2Mb, contained 20 BACs. Gene yl was rough mapped between SSR marker bnlg1672 and umc2160 on chromosome 7, which physical distance was 6.0Mb, contained 54 BACs. The epistatic dominance interaction of the two genes was confirmed fron the rough mapping and then laid the foundation for the fine mapping and map-based clone.4.Under the rough mapping, the population of 2141 plants was used to find the recombinant plants for the gene al, and obtained 26 plants. And then 385 plants for the gene yl, obtained 65 plants. The bioinformatics technique was used to develop many useable marks in the two main regions. By detecting these recombinants plants, the gene al was mapped on AC183307 or AC194339, the physical interval was 200kb. The gene yl was mapped between mark 7CH15-22 and 7CH22-4, which contained 10 BACs and it's physical interval was 1200Kb.