Genetic Analysis And Gene Mapping Of A Small Organ Mutant So1 In Rice

Plant organ size is an important factor affecting the yield,and it is also an essential biological system for studying cell cycle and cell division.As the main food crops and important model plants,rice has provided the genetic resources and theoretical basis for the study of the genetic and molecular mechanism of organ development.Strigolactones(SLs)is a new type of plant hormone.It can inhibit the occurrence of plant branching,and with cytokinin,auxin regulated plant branching development jointly decided to plant the plant type.At present,the new biological function of SLs is still being discovered.In this study,a spontaneous mutant sol was used as the research object,and we found that the SO1 gene was controlled by the regulation of cell cycle and the biosynthesis of the.The main results of this paper are as follows:1,sol phenotype analysis:Compared with the wild type,from the beginning of tillering stage,its performance significantly increased tiller number,smaller overall whole organ,such as plant height is shorter,shorter Spike length,leaves become more soft,thin,short and small,grain length and width become smaller.the underground root shortening phenotype.2,Analysis of agronomic traits:Mutant sol except the tiller number was significantly more than the wild-type R30,other agronomic traits such as plant high,spike length,average number of grains per spike,primary branch number per panicle,grain long,grain width,1000 grain weight and seed setting rate were significantly reduced.3,Stem cytology observation:Compared with the wild type,sol longitudinal stem cell length and cell number were than R30 reduce 14.8%and 44.5%,the mutant stem relationship is mainly due to caused by the reduction of the number of cells.4,The results of SEM observation of spikelet outer epidermal:Compared with the wild type,the cell length and width of spikelet outer epidermal cell was reduced around 18.4%and 13%in sol,and the number of longitudinal and horizontal cell was increased 14.2%and 4.4%.It is showed that the reduction of the cell width is caused by the decrease of the main cell width.5,Genetic analysis and gene mapping:the sol organ small character is controlled by a single recessive nuclear gene.Mapping-based cloning showed that the mutation responsible for the sol phenotype was located in a 76.8kb region on Chr.4.Sequencing results showed that:Mutant sol in the second exon of the HTD1 gene has a 8bp base insertion,and caused premature stop code was identified.The results of the cosegregation test showed that the mutant was coseparated from the small organ.So we make sure that HTD1(LOC_Os04g46470)is the candidate gene.6,Expression profile analysis of candidate genes:SOI in all tissues of rice were expressed,and the young tissue is higher than the amount of expression of mature tissue,especially in the stem and sheath secondary meristem expression was the highest.This is consistent with the results obtained from the LOC_Os04g46470 expression profile on the eFP Browser Rice site.7,SO1 function preliminary analysis results:The results confirmed that SO1 was involved in the process of SLs biosynthesis and signal transduction,and played a decisive role in the process of its biosynthesis.8,sol formation mechanism preliminary exploration:The experimental show that,the rate of cell proliferation and expansion of sol were obviously less than those of the wild type,leading to very significantly reduce the number of cells,eventually forming organs smaller phenotype.9,During the course of mutant screening of aberrant Cd accumulation in rice grain,we found that Cd concentration in sol was about 2.8 folds to WT when with lmg/Kg Cd addition.