RESUMO
Waxy starch has an important influence on the qualities of breads. Generally, grain weight and yield in waxy wheat (Triticum aestivum L.) are significantly lower than in bread wheat. In this study, we performed the first proteomic and phosphoproteomic analyses of starch granule-binding proteins by comparing the waxy wheat cultivar Shannong 119 and the bread wheat cultivar Nongda 5181. These results indicate that reduced amylose content does not affect amylopectin synthesis, but it causes significant reduction of total starch biosynthesis, grain size, weight and grain yield. Two-dimensional differential in-gel electrophoresis identified 40 differentially expressed protein (DEP) spots in waxy and non-waxy wheats, which belonged mainly to starch synthase (SS) I, SS IIa and granule-bound SS I. Most DEPs involved in amylopectin synthesis showed a similar expression pattern during grain development, suggesting relatively independent amylose and amylopectin synthesis pathways. Phosphoproteome analysis of starch granule-binding proteins, using TiO2 microcolumns and LC-MS/MS, showed that the total number of phosphoproteins and their phosphorylation levels in ND5181 were significantly higher than in SN119, but proteins controlling amylopectin synthesis had similar phosphorylation levels. Our results revealed the lack of amylose did not affect the expression and phosphorylation of the starch granule-binding proteins involved in amylopectin biosynthesis.
Assuntos
Amilopectina/biossíntese , Amilose/biossíntese , Triticum/metabolismo , Sequência de Aminoácidos , Grão Comestível/crescimento & desenvolvimento , Grão Comestível/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Regulação Enzimológica da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Redes e Vias Metabólicas , Modelos Moleculares , Fosforilação , Proteínas de Plantas/química , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Proteômica , Especificidade da Espécie , Amido/metabolismo , Sintase do Amido/química , Sintase do Amido/genética , Sintase do Amido/metabolismo , Triticum/genética , Triticum/crescimento & desenvolvimentoRESUMO
OBJECTIVE: To investigate the effect of salt stress on DNA methylation in Isatis indigotica. METHODS: Methylation sensitive amplification polymorphism (MSAP) approach was used in this study. RESULTS: By using 15 pairs of selective primers combinations, a total of 632 MSAP bands were obtained in Isatis indigotica genome under salt stress. In all, 44 (6.9%) CCGG sites displayed cytosine methylation changes under salt stress. Among these sites, 31(4.9%) CCGG sites underwent hypermethylation changes and 13 (2.0%) CCGG sites underwent demethylation changes. CONCLUSION: This result provides evidence for DNA methylation remodeling occurring immediately after salt stress affects Isatis indigotica.
Assuntos
Metilação de DNA , Isatis/efeitos dos fármacos , Cloreto de Sódio/farmacologia , Estresse Fisiológico , Primers do DNA , DNA de Plantas/genética , Epigênese Genética , Isatis/genética , Técnicas de Amplificação de Ácido Nucleico/métodos , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/genética , Polimorfismo GenéticoRESUMO
Fluorescence in situ hybridization (FISH) and double FISH experiments were carried out to ascertain the chromosomal distribution patterns of the 45S and 5S ribosomal DNAs in the three species of Cucurbitaceae. Five pairs of 45S rDNA loci and two pairs of 5S rDNA signals were detected on chromosomes of Cucurbita moschata Duch. Luffa cylindrical Roem. contained five pairs of 45S rDNA loci and one pair of 5S rDNA loci. In Benincasa hispida Cogn., two pairs of 45S rDNA sites and one pair of 5S rDNA site were detected. In this species, 5S rDNA and one pair of the 45S loci were collocated closely in chromosome 7S. 45S rDNA chromosomal distribution patterns were highly conserved among the three species, althoufh their number varied markedly. The 5S rDNA sites on chromosomes among the three species were highly polymorphic. We further discussed differentially evolutionary processes of 45S and 5S rDNA in plant genomes.
