RESUMO
Salinity is a major environmental stress to plants. In this study, the ability of plants to tolerate salt was investigated by studying growth, physiological characteristics, and expression levels of genes related to the salt-stress response in the salt-tolerant rice mutant (Till-II-877), which was derived from γ-ray irradiation. Compared to plants grown under normal conditions, the height and root length of wild type (WT) were reduced by approximately 40 and 29% following exposure to salt stress for 3 weeks, whereas Till-II-877 line showed 29 and 23% reductions in plant height and root length, respectively. No significant changes were observed in total chlorophyll content, and the malondialdehyde content of the mutant increased less than that of the WT under salt treatment. Gene expression was compared between the WT and mutant lines using microarray analysis. An unbiased analysis of the gene expression datasets allowed us to identify the pathways involved in salt-stress responses. Among the most significantly affected pathways, changes in gene expression were observed in α-linolenic acid and linoleic acid metabolism (in lipid metabolism), fructose and mannose metabolism and glycolysis-gluconeogenesis (in carbohydrate metabolism), cysteine and methionine metabolism (in amino acid metabolism), and carbon fixation (in the energy metabolism of photosynthetic organisms) under salt stress. These results show that the differential response of plants subjected to salt stress was due to changes in multiple metabolic pathways. These findings increase our understanding of the effects of salt stress in rice and may aid in the development of salt-tolerant rice cultivars.
Assuntos
Regulação da Expressão Gênica de Plantas , Genoma de Planta , Mutação/genética , Oryza/genética , Oryza/fisiologia , Estresse Fisiológico/genética , Carotenoides/metabolismo , Clorofila/metabolismo , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Ontologia Genética , Genes de Plantas , Malondialdeído/metabolismo , Redes e Vias Metabólicas/efeitos dos fármacos , Redes e Vias Metabólicas/genética , Oryza/efeitos dos fármacos , Oryza/crescimento & desenvolvimento , Cloreto de Sódio/farmacologia , Estresse Fisiológico/efeitos dos fármacos , Transcrição Gênica/efeitos dos fármacosRESUMO
This study evaluated the chemical and genetic diversity of high-seed-yield sorghum germplasms from Korea, the United States, and South Africa. We identified significant differences in the chemical contents of whole plants at the heading stage in all cultivars, including differences in crude protein, fat, fiber, ash, neutral detergent fiber, acid detergent fiber, mineral, and fatty acid contents. Our results suggest that Banwoldang is the most appropriate cultivar for roughage because of its high protein yield. We identified significant differences in the tannin, flavonoid, amylose, mineral, crude fat, fatty acid, and 3-deoxyanthocyanin contents in the whole grain from all cultivars, but not in the mineral or crude fat contents. Tannin levels were generally low. IS645 contained the highest levels of flavonoids and linolenic acid compounds, and Moktak had the highest amylose and deoxyanthocyanidin content in the grain. To assess genetic diversity, we used 10 simple sequence repeat (SSR) primer sets to identify 38 alleles with 3-8 alleles per locus. Based on phylogenetic analysis of the SSR markers, the sorghum cultivars were divided into three major groups. Comparison of clusters based on chemical compositions with those based on SSRs showed that the groups formed by the three native Korean cultivars clustered similarly in molecular dendrograms. Association analysis was conducted for the 10 SSR marker; 48 chemical and growth traits were present for two marker traits (seed color and whole plant fatty acid content) with significant marker-trait associations. These markers could be used to select sorghum cultivars for breeding programs.
Assuntos
Loci Gênicos , Variação Genética , Filogenia , Sementes/genética , Sorghum/genética , Alelos , Antocianinas/metabolismo , Cruzamentos Genéticos , Ácidos Graxos/metabolismo , Flavonoides/metabolismo , Repetições de Microssatélites , Melhoramento Vegetal , Proteínas de Plantas/metabolismo , República da Coreia , Sementes/metabolismo , Sorghum/classificação , Sorghum/metabolismo , África do Sul , Taninos/metabolismo , Estados UnidosRESUMO
Under certain circumstances, transposable elements (TE) can create or reverse mutations and alter the genome size of a cell. Sorghum (Sorghum bicolor L.) is promising for plant transposon tagging due to its small genome size and its low content of repetitive DNA. We developed a marker system based on targeted region amplification polymorphisms (TE-TRAP) that uses the terminal inverted repeats (TIRs) of transposons. A total of 3816 class 2 transposons belonging to the PIF/Harbinger family were identified from the whole sorghum genome that produced five primers, including eight types of TIRs. To define the applicability and utilization of TE-TRAP, we used 21 individuals that had been bred after ɤ-ray irradiation. In total, 31 TE-TRAP, 16 TD, and 21 AFLP primer combinations generated 1133, 223, and 555 amplicons, respectively. The percent polymorphic marker was 62.8, 51.1, and 59.3% for the TE-TRAP, TD, and AFLP markers, respectively. Phylogenetic and principal component analyses revealed that TE-TRAP divided the 21 individuals into three groups. Analysis of molecular variance suggested that TE-TRAP had a higher level of genetic diversity than the other two marker systems. After verifying the efficiency of TE-TRAP, 189 sorghum individuals were used to investigate the associations between the markers and the ɤ-ray doses. Two significant associations were found among the polymorphic markers. This TE-based method provides a useful marker resource for mutation breeding research.
Assuntos
Elementos de DNA Transponíveis/genética , Filogenia , Melhoramento Vegetal , Sorghum/genética , Relação Dose-Resposta à Radiação , Raios gama , Marcadores Genéticos , Genoma de Planta/efeitos da radiação , Mutação , Sorghum/crescimento & desenvolvimento , Sorghum/efeitos da radiaçãoRESUMO
Comparative genomic hybridization (CGH) is a powerful tool used to analyze changes in copy number, polymorphisms, and structural variations in the genome. Gene copy number variation (CNV) is a common form of natural diversity in the genome, which can create new genes and alter gene structure. Thus, CNVs may influence phenotypic variation and gene expression. In this study, to detect CNVs, we irradiated rice seeds with gamma rays (300 Gy) and selected two dwarf mutagenized plants, GA-III-189 and -1052, in the M3 generation. These plants were subjected to CGH analysis using Agilent's RICE CGH array. Most of the CNVs identified were less than 10 kb in length. We detected 90 amplified and 18 deleted regions in GA-III-189, and 99 amplified and 11 deleted regions in GA-III-1052. Of note, CNVs were located on chromosome 12 in both GA-III-189 and -1052, which contained 39 commonly amplified regions in 29 genes. The commonly amplified genes included six genes encoding F-box domain-containing proteins. Alterations in these F-box domain-containing genes were confirmed by quantitative RT-PCR. Integration of CGH and gene expression data identified copy number aberrations and novel genes potentially involved in the dwarf phenotype. These CGH and gene expression data may be useful for uncovering the mechanisms underlying the dwarf phenotype.
Assuntos
Hibridização Genômica Comparativa , Raios gama , Mutação/efeitos da radiação , Oryza/genética , Oryza/efeitos da radiação , Variações do Número de Cópias de DNA , Raios gama/efeitos adversos , Expressão Gênica , Estudos de Associação Genética , FenótipoRESUMO
Seed shattering of wild plant species is thought to be an adaptive trait to facilitate seed dispersal. For rice breeding, seed shatter-ing is an important trait for improving breeding strategies, particularly when developing lines use interspecific hybrids and introgression of genes from wild species. We developed F3:4 recombinant inbred lines from an interspecific cross between Oryza sativa cv. Ilpoombyeo and Oryza rufipogon. In this study, we genetically analyzed known shat-tering-related loci using the F3:4 population of O. sativa/O. rufipogon. CACTA-AG190 was significantly associated with the shattering trait CACTA-TD according to bulked segregant analysis results, and was found in the qSH-1 region of chromosome 1. Fine genetic mapping of the flanking regions around qSH-1 based on CACTA-AG190 revealed multiple-sequence variations. The highest limit of detection based on quantitative trait locus analysis was observed between shaap-7715 and a 518-bp insertion site. Two other quantitative trait locus analyses of seed-shattering-related loci, qSH-4 and sh-h, were performed using simple sequence repeat and allele-pecific single nucleotide polymor-phism markers. Our results can be applied for rice-breeding research, such as marker-assisted selection between cultivated and wild rice.