Project description: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.
Project description:To identify genes involved in the OsDIS1-mediated drought-responsive pathway, we performed microarray analysis of the OsDIS1 overexpression and wild-type plants under both normal and drought stress conditions using the Agilent rice Genechip. Seven-day-old plants of the OsDIS1 overexpression line 9-4-2 as well as the wild-type plants were used in the drought treatment. OsLEA3 was used as a positive control for the drought treatment. Genes with more than two-fold changes in the overexpression plants compared with the wild-type plants were selected. The expression pattern of some differentially expressed genes was further confirmed by real-time PCR. The OsDIS1 overexpression 9-4-2 plants and the wild-type plants were cultured on 1/2 MS medium plus 3% sucrose for seven days. About half of the plants were sampled as the untreated control for RNA isolation, and the rest were transferred with 1/2 MS medium onto filter papers to induce drought stress. When the leaves of the OsDIS1 overexpression plants began to show drought stress phenotypes, we collected leaves for RNA isolation. OsLEA3 was used as a positive control for the drought treatment.