Genetic Analysis And Gene Cloning Of A Leaf Tip Rumpled Mutant In Rice

The leaf is a vital place for photosynthesis and respiration in rice (Oryza sativa L.) and directly affecting the yield of rice. The related genes of regulating the leaf shapes were isolated and cloned by using the mutant of leaf shape in rice, which is making for not only analyzing the regulation mechanism of development and controlling of leaf form, but also conducive to molecular design breeding in plant type in rice. We use the chemical mutagenesis of EMS to process the typical and quality japonica varieties(Oryza sativa L. ssp. Japonica) and then get a homozygous mutant of the leaf tip corrugation and distortion, temporarily named Leaf Tip Rumpled (ltr1) in this study. The mutant of Itrl has the phenotypes that except the tip of the leaves are obviously the distortion, besides most veins blade shrinks to bend. Based on the morphological investigation, cellular structure observation, genetic analysis, gene localization and cloning and functional analysis of research in the mutant of ltr1, We has had a series of results, as follows:1. The cytology study that the shrinks parts of ltr1mutant leaves and of the corresponding parts of its wild type japonica blades, shows that disorder distributed at vascular and developed unusual at bulliform cell and sclerenchymatous cell, may be an important reasons for the phenotype of the tip shrinks and distortion in the Itrl mutant.2. The analysis results based on the ltr1-sll1double mutant, show that the role of the LTR1and SLL1in the process and development of leaves shape in rice, are respectively belonged to the different regulation pathways, and independent influence of the leaf form built.3. The Itrl mutant was crossed to two japonica varieties Nipponbare, WYJ7and three different indica varieties including93-11、ZF802、TN1and NJ06, constructing the genetic population. All of the F1plants have normal leaf shape and the ratio of normal leaf plants to leaf tip rumpled mutant plants in F2population fitted3:1. The results of genetic analysis show that the leaf tip rumpled mutant character was controlled by a single recessive gene.4. Used map-based cloning technology, the caused gene LTR1was located in the preliminary between RM6318and RM1920in chromosome2, and the genetic distance were4.1cM and2.7cM. To further expand after group will eventually LTR1fine mapping in two STS mark between STS-N12and CAPS-N20, and the physical distance is about12.3KB in this candidate area. According to relevant website forecast, only one open reading frame located within the LTR1anchored region and its function is unknown.5. Sequencing and comparing the sequence in the anchored area between the mutant Itrl and wild type Nipponbare, the results indicated that the coding areas have two bases(CT) deletion, and the transcription terminate caused by moving yards mutations in the Itrl mutant. Therefore, we speculated that the change in the phenotype of leaf shape caused by the moving yards mutation in the ltr1mutant, and the gene of LTR1is a new control gene for the development of leaf shape in rice.