Gene Cloning Of A Lesion Mimic And Premature Senescence Mutant 8318 And Genetic Identification Of A Dwarf Tillering Mutant 8485 In Rice

1.Gene cloning of a lesion mimic and premature senescence mutant 8318 in riceAt present,the main cultivated rice varieties in China are facing the bottleneck of increasing yield.The occurrence of leaf lesions and premature senescence have a great impact on the yield and quality of rice.Therefore,the study on the mechanism of premature senescence of leaf lesions in rice will help to regulate the senescence process of rice and improve the yield of rice.The mutant 8318 used in this experiment is a stable genetic lesion mimic and premature senescence mutant induced by ethyl methylsulfonate(EMS)from the restorer Lehui 188(188R)of Indica rice.The mutant began to produce brown lesions at the middle and late booting stages and then gradually withered from the tip to the base of the leaf.Compared with wild type,the plant height,effective panicle,panicle length,grain number per panicle,1000-grain weight,seed setting rate and yield per plant of 8318 mutant decreased by 13.5%,32.1%,10.5%,42.9%,3.6%,24.2% and 66.3%,respectively.At heading stage,the content of photosynthetic pigments and total content of 8318 mutant decreased compared with 188 R.Genetic analysis showed that 8318 mutant were controled by a pair of recessive nuclear genes;The F2 generation of 8318 mutant crossed with Oryza sativa L.cv.Nipponbare was used as the genetic mapping population,and the mutant gene was initially located between the newly developed In Del marker L1 and L3 with a physical distance of 1460 Kb.A gene related to the traits of the material was screened in the mapping interval based on high-throughput sequencing results.The full length of the gene was 1793 bp,including two exons and one intron,and the full length of CDS is 1056 bp,encodes a protein consisting of 351 amino acids.This gene has not yet been reported,being tentatively named 8318.The function complementary vector of p C1300-8318 gene was constructed,and the gene 8318 was confirmed to be transfected into the mutant by PCR detection.The T0 generation positive transgenic plants did not show the phenotype of lesion mimic and premature senescence,which preliminarily verified the function of the gene.2.Genetic identification of a dwarf tillering mutant 8485 in riceThe improvement of rice yield per unit area has always been an important direction of rice research,among which the improvement of rice plant type plays an important role in breeding high-yield varieties.Tillering is an important trait that determines rice yield.Nowadays,increasing rice yield is stepping into a bottleneck.The number of effective panicles is one of the three main factors that constitute rice yield.The quantity and quality of effective panicles are one of the main driving forces to ensure the continuous and steady increase of rice yield.Therefore,it is particularly important to explore the regulation network of rice tillering-related genes and tillering development.The experimental material 8485 was a stable inherited dwarf tiller mutant induced by EMS chemical mutagenesis of indica rice variety 188 R.Only the main stem and 0~2 tillers of the mature 8485 mutant could develop into effective panicles,while the other short tillers could not elongate and distort,failure or extremes poor to produce seeds.F2 generation from the hybrid of 8485 and188 R was used as the Genetic analysis population.According to the phenotypic isolation in the field,it is speculated that the 8485 mutation may be controlled by a pair of recessive nuclear genes.