Fine Mapping And Cloning Of A Palea Defective 1(PD1) Gene Mutant And Hairy Leaf HL1 Gene In Rice

Spikelet is one of the important storage organs of photosynthetic product in rice.Spikelet development directly affect the grain yield and rice quality.Here,we reported a palea defective mutant pd1 that found from the selfing progenies of indica cv.93-11 after 60 Co y ray treatment.pd1 flower only has four stamen,whereas pollen fertility was not affected.pd1 palea showed smaller and flatter like leaf,that caused lemma excessively bent inward.pd1 plants only have 46%seed setting rate and 21.6 g 1000-grain weight,that lead to its loss of two-thirds of grain yield.Scanning electron microscope(SEM)analysis revealed that pd1 mutation reduced the size of epidermic cell and the number of fibrous sclerenchyma cells both in palea and lemma.Somenone before has serveried analyze the genetic factor analyze of this mutant,and pd1 was finally narrowed to a 69 Kb region between RM11239 and RM11245 on chromosome 1,containing 10 ORFs.On these basis,we contanted sequence alignment and found that the cloned 9 ORFs were no difference between 93-11 and mutant,the retrotransposon protein ORF3 failed to clone and was expect;we also carried out qRT-PCR analysis and found that ORF3 was no expression between 93-11 and mutant.It was suggested to be an unknown genetic factor involved in the development of rice spikelet.The trichome on the leaf could protect plant on a certain extent becase it could strengthen resistance in plants against abiotic threatens such as high temperatures and drought tolerance and it also could enhance plants resistance tobiotic factors including insect and pathogenic bacteria.We chose a hairy leaf indica cultivar SWWR and two non-hairy japonica culivar Nipponbare and Ning1 as experimental materials in this study.Someone before has made LOC_Os06g44750 as HL1 candidate gene,which has two nucleotide substitution and a continuous deletion between SWWR and Nipponbarer on chromosome 6.On this basis,this study checked it,then exlarged HL1 on a 73.1 Kb interval between newly developed InDel markers WB31 and WB35.There were 8 ORFs,which contained LOC_Os06g44750 as ORF7.12 non-hairy rice culiva and 3 hairy leaf rice were sequenced and alignment in dicated there has difference of ORF7 in hairy leaf rice and non-hairy.Through qRT-PCR analysis of 8 ORFs,we found ORF7 has expression in SWWE and has no expression in Nipponbare and Ning1.On these basis,ORF7 was very likely to be the candidate gene,hence we conducted over-expression vector and complementary-expression vector,then transformed them to the Nipponbare and conducted preliminary functional analysis.