| Germplasm resources are the important material basis for rice breeding.In order to obtain elite germplasm resources,weedy rice in Guangdong province were extensively collected in this study.And then,representative weedy rice resources germplasm were selected out as materials for researches.The genetic diversity of morphological characters,seed storability and salt tolerance at different stages,and the molecular genetic diversity of representative weedy rice resources germplasm had been analyzed.The genes related salt tolerance in one of weedy rice materials,ZJ3,with resistance to salt stress,had been mined through the digital gene expression profile based on RNA-seq.The main results are as follows:1.One hundred and sixty nine weedy rice resources were collected from different regions in Guangdong province.These materials came from seven different regions of Guangdong.Among which Zhanjiang region collections were the most,following by Chaoshan region and Jiangmen region.The materials collected from Huizhou-heyuan-meizhou area were the least.2.The results of investigation of morphological characters of 40 representative resources showed that,the number of tillers ranged from 9.60 to 17.80,with an average of14.31 and a coefficient of variation of 15.20%.Plant height was between 94.90 cm and135.26 cm,with an average value of 114.25 cm and a coefficient of variation of 8.76%.The heading time ranged from 59.7d to 75.5d,with an average value of 69.49 d and a coefficient of variation of 6.27%.The effective panicle number was between 6.70 and 13.60,with an average value of 10.17 and a coefficient of variation of 17.90%.Grain length ranged from5.35 mm to 10.92 mm,with an average of 8.16 mm and a coefficient of variation of 12.85%.The grain width was between 2.26 mm and 3.19 mm,with an average of 2.61 mm and a coefficient of variation of 9.51%.The grain length-width ratio was between 2.06 and 4.75 with an average of 3.12 and the coefficient of variation was 18.13%.Some materials had strong shattering and some materials were not easy to shatter.There were materials with long awn,short awn or unawn.The color of shell was yellow,brown or spotted.The color of seed coat was red,black or white.3.The analysis of storage properties of 17 different germplasm resources through artificial aging showed that,after artificial aging for 30 days,there were 8 materials with more than 50% germination rate.After artificial aging for 40 days,there were two materials with germination rate of more than 30%.The analysis of salt tolerance of 17 different germplasm materials at bud seedling stage,seedling stage and tilling stage showed that,under the salt stress concentration of 0.5%Na Cl and 1%Na Cl,the materials ZJ3,ZJ2 and CS1 had strong salt tolerance at the seedling stage and seedling stage.The salt tolerance of ZJ3 and JM1 was strong at tillering stage under salt stress at 0.5%Na Cl and 0.8%Na Cl concentrations.4.The analysis of molecular genetic diversity of 40 weedy rice resources in Guangdong province using SRAP markers showed that,141 polymorphic alleles were detected with 22 primer pairs of SRAP markers,ranging from 4 to 9 polymorphic alleles amplified for each pairs of primers,with an average of 6.4.The polymorphic allele percentage was22.22%～87.5%,and the average was 64.39%.The average of genetic distance between materials within the region was less than the mean genetic distance between all materials,and also less than the mean genetic distance between materials in difference regions.The result of clustering by genetic distance showed that 40 weedy rice materials could be clustered into 8 categories with 0.12 value of the genetic distance as the threshold.5.The results of gene expression differences analysis of the weedy rice materials,ZJ3,with resistance to salt stress and the variety Jinnongsimiao,with lower resistance to salt stress,between treatment and control through digital gene expression profiles based on RNA-seq at seedling stage with 0.5% Na Cl salt stress showed that,(1)1322 expression difference genes were detected in the weedy rice ZJ3 treated with salt stress(T1)compared to the ZJ3 not treated with salt stress(CK1),of which 1073 genes were up-regulation expression,and 249 genes were down-regulation expression.Compared to the control CK2,Jinnongsimiao not treated with salt stress,a total of 1222 expression difference genes were detected in T2,Jinnongsimiao treated with the salt stress.And among them,373 genes were up-regulated and 849 genes were down-regulated.A total of 644 expression difference genes were detected in T1 compared to T2,among which 564 were up-regulated and 80 were down-regulated.(2)Among the differentially expressed genes between ZJ3 treated with 0.5%Na Cl and control,Jinnongsimiao treated with 0.5% Na Cl and control,261 of them were the same difference expression genes,and 1061 were specific expression difference genes in T1(ZJ3 treated with salt stress),and There were 961 differentially expressed specific genes in T2(Jinnongsimiao treated with salt stress).(3)There were 145 differentially expressed specific genes in ZJ3 treated with 0.5% Na Cl compared to Jinnongsimiao treated with 0.5%Na Cl.The result of GO analysis showed that,the functions of these differentially expressed specific genes mainly include metabolic process,cell process,localization and stimulation reaction,cell components,cells,organelles,catalytic activity,binding and transport activity.6.twenty five genes related to salt tolerance were screened out of 145 differentially expressed specific genes in ZJ3 treated with 0.5% Na Cl.Those were including 1transcription factor gene(DREB2)and other 24 genes functioned as oxidoreductase,protein kinase,nucleic acid triphosphatase,UDP-glucosetransferas,phosphorylase,cation transportor and phenylpropanoid biosynthetic process.The q PCR analysis of 7 genes out of them showed that,compared with those in control,4 genes in ZJ3 treated with salt stress were significantly differentially expressed and they were up-regulated,which were similar to the results of the digital gene expression profile analysis.Compared with those in Jinnongsimiao,The relative expression level of 3 genes,Os01g0206700(serine/threonine protein kinase gene),Os02g0167300(nucleoside triphosphatase gene)and DREB2(DRE binding transcription factors 2 gene)were significantly different in ZJ3 treated with salt stress and their expression were up-regulated those were same as the results of digital gene expression profiles based on RNA-seq.The results in this study showed that,for weedy rice materials in Guangdong,there were high genetic diversity of morphological characters,salt tolerance and seed storability.The molecular genetic diversity was of certain degree.145 differentially expressed specific genes and 25 genes related salt tolerance genes of ZJ3 were mined also,these results are of great significance for the further research and utilization of weed rice resources in Guangdong... |
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