| Biosynthesis of chlorophyll is a very complicated process. Chlorophyll metabolism is influenced when certain location of plant genome occur aberrance, which lead to change of leaf color. Leaf color mutants not only in the biosynthesis of chlorophyll, chloroplast structure, function, genetics, and cell differentiation and development of genetic transformation, gene expression and regulation studies of great significance, but also as a morphological marker in the production of practical application.In this paper, a yellow-green mutant, designated as "ygl80", was Chemical mutated from rice line 10079. The morphological characters, agricultural traits and physiological characteristics of this yellow-green mutant were studied. Genetic action of the yellowing character was analyzed by using the F1 and F2 progenies from ygl80 crossed with normal green original parent 10079 and other line ZF802. Furthermore, this mutant gene was mapped preliminarily with microsatellite and InDel marker. The results are as follows:1. The phenotype character of yellow-green mutant ygl80 is that leaf color is yellow-green. Furthermore, plant becomes short, the number of tiller reduces. The whole plant of this mutant embodies yellow-green character from the start of seedling to heading.2. The photosynthetic pigment content of ygl80 decreased significantly at two different growth stages, i.e.seedling and booting stage, compared with that of 10079. The chlorophyll content decreased by 76.49%,54.59%. The carotenoid content decreased by 49.42%,41.18%. The chlorophyll a and chlorophyll b contents decreased by 72.29%,49.69% and 91.75%,71.74%, respectively.3. The combinations of ygl80 crossed with two normal green varieties were used in genetic analysis. The result showed that leaf color of each F1 progenies represented normal green, and segregation ratio of normal green seedlings to yellow-green seedlings fitted the expected ratio of 3:1 in each F2 population, which suggested that the yellowing trait of ygl80 was controlled by one pair of recessive nuclear gene.4. The F2 population of ZF802/ygl80 was used as the mapping population. The genomic DNA of parent ZF802 and ygl80 were amplified with 350 pairs of primers of microsatellite markers well-distributed on 12 pairs of rice chromosomes. The DNA pools of green seedlings and yellow-green seedlings were amplified with the microsatellite primers with parental polymorphism, and then the genomic DNA of the F2 individuals amplified with the primers displaying polymorphism between the two pools. The results showed that the mutant gene of ygl80 was mapped on the long arm of rice chromosome 5. It located between RM169,RM289and RM430. The genetic distances from the target gene to the markers RM169,RM289 and RM430 were 10.9 cM,10.9 cM and 11.9 cM, respectively. Finally, We designed 23 pairs of by using the rice genome data, amplification results showed that the mutant gene was located between Ch5-163-1 and Ch5-164-4. The genetic distances were 0.24 cM and 0.39 cM, and the physical distance between the two InDel makers was 110 kb. So, it was designated ygl80, temporarily.The MAPMARKER was used as linkage analysis and the part molecular linkage map of yellowing mutational gene was constructed. |
