Genetic Analysis And Gene Mapping Of A Semi-dominant Rolled Leaf Mutant Erll In Rice (Oryza Sativa L.)

Rice is one of the most significant food crops in China as well as in the world. Leaf morphologyis the main focus of plant type breeding, changes of which will have impacts on many physiologicalcharacteristics including photosynthesis and stress resistance, and then the growth and even the yieldformation may be influenced. With the completion of the rice genome sequence and the rapiddevelopment in disciplines related to molecular biology, the nature of rice growth and development canbe understood in molecular level. Leaf morphological genes in rice, especially genes related to rolledleaf, plays key roles in ideal plant type breeding, high-yield breeding as well as varietal improvement inrice. An extreme rolled leaf mutant (erl1) was selected from an established rice mutant library, thengenetic analysis, morphological observation, gene mapping and primary functional analysis were carriedout in this research. The main results were summarized as follow:1. The leaf of erl1rolled inward extremely from seedling to maturity stage, with plant heightshortening and leaf color darkening. The leaf morphological of the heterozygote was half-rolled,and there was no significant difference from the wild type.2. Crosses were made between erl1and3indica varieties including TN1、ZF802、NJ06. The F1plantswere all half-rolled, while the F2plants showed phenotypic segregation, with extreme-rolled,half-rolled and normal leaf morphologies. The ratio of these three phenotypes in each F2populationwas consistent with the1:2:1ratio of Mendelian inheritance. The results of genetic analysisshowed that this mutant trait was a qualitative trait controlled by a semi-dominant gene.3. Comparison of plant morphologies between the erl1and the wild type WYJ7shows that the lengthof internode in erl1was shorter and the number of node was less than the wild type.Theinvestigation of Panicle traits were conducted, which shows that the number of filled grains perpanicle, the number of primary branch, the number of second branch and the thousand grain weightof the erl1were all reduced significantly, compared with the wild type.4. The analysis of chlorophyll content in the leaf showed that the score of SPAD, the content ofchlorophyll a and chlorophyll b in the erl1leaf were all increased significantly, when comparedwith the wild type.5. The cell structure of the erl1leaf was observed by paraffin section, which showed that the vasculartissue had a disordered arrangement and the sclerenchyma cells near abaxial side were replaced bythe mesophyll cells.6. Through map-based cloning, the ERL1was delimited to a51kb region on the chromosome12, inwhice there were five open reading frames. And sequencing analysis showed that the third genehad a base substitution from G to A, which led to changing of amino acids from Gly to Glu.