Genetic Analysis And Fine Mapping Of ESl0in Rice (Oryza Saliva L.)

Leaves were the main places of plant photosynthesis, and it was also an important source of organs.Rice leaf senescence was directly affected by the photosynthetic efficiency of rice, and had a greatinfluence on rice yield. In recently, with the development of rice genome sequencing and modernmolecular biotechnology, more and more science researchers were started to pay attention to themolecular mechanism of leaf senescence, and had achieved many important results. People want toreveal the molecular mechanism of leaf senescence to breeding high yield potential of rice varieties. Inthis study, an early senescence (es10) mutant of rice (Oryza sativa L.) by mutagenesis of ethylenemethylsulfonate (EMS) treatment from Nipponbare was identified, and from phenotype andphysiological to show the ES10mutant caused multifaceted changed of rice. Map-based cloning methodwas used to construct gene mapping, and it will facilitate the positional cloning and shed light on theresearch on molecular mechanism of leaf early-senescence and service the agricultural production. Themain results of this research were as follow:1. From seeding stage，the leaves of mutation es10become yellow gradually, and with the growth anddevelopment of the area of leaf yellowing, the leaf margin and tip appears dead. From mature stage，mutation es10showed short stature, high tillering, long growing period and self infertility. The plantshowed a typical early-senescence.2. The content of chlorophyll and carotene in the mutant was lower than wild-type. However, the ratioof the content of chlorophyll a and chlorophyll b was not changed. SPAD-value also proved thisresult.3. Scanning electron microscope (SEM) showed that leaf surface of mutant es10were smoother thanwild-type, and it lacked the siliceous protuberance around stomata in leaf. Transmission electronmicroscope (TEM) showed that chloroplasts of mutant es10grow abnormally，and the number ofchloroplasts in mutant es10were less than wild-type. Moreover, chloroplasts arrangement of mutantes10was disordered, and osmiophilic particles were increased.4. Genetic analysis showed that mutant es10was a new early-senescence mutant and controlled by arecessive gene. It was different from the gene including dwl1, es-t, and es-n, which have been foundalready.5. Map-based cloning method was used to map the gene on the long arms of chromosome10betweenmarker M1and M2, and the genetic distance was9.1cM. Another seven polymorphicmarkers were developed for fine mapping, and the gene was finally fine delimited in a43-kbinterval, with six open reading frames by bioinformatics prediction.