Project description:Arsenic (As) contamination of rice grains affects millions of people worldwide. In this study, we found that sulfur application (20As+120S) decreased As concentration in rice grains by 44 % compared to grains without sulfur application (20As+0S). Importantly, sulfur application decreased arsenate [As(V)] and arsenite [As(III)] concentration in rice grains significantly, while there was no significant effect on dimethylarsenate (DMA) concentration. To elucidate the molecular basis of As accumulation in rice grains, we performed Illumina sequencing to acquire the differentially expressed genes induced by arsenate and sulfur treatments. By contrast with the control, the expression of 1,000 genes was found to be changed significantly, with 46 genes up-regulated and 954 genes down-regulated in grains grown in arsenate-contaminated soil (20As+0S). Between samples of control and arsenate together with sulfur treatment (20As+120S), 1,169 genes expressed significantly differently, with 16 genes up-regulated and 1,153 genes down-regulated. Sulfur application significantly changed the expression of genes involved in As metabolism in rice grains, significantly down-regulated phosphate transporter gene OsPT23 and aquaporin gene OsTIP4;2, while ABC transporter genes (OsABCG5, OsABCI7_2 and OsABC6) and phytochelatin synthase genes (OsPCS1, OsPCS3 and OsPCS13) were up-regulated. These results provide an insight into the molecular basis of how sulfur assimilation regulates As accumulation in rice grains.
Project description:We performed Illumina sequencing to acquire the differentially expressed genes induced by arsenate and sulfur treatments. We found that sulfur (S) application reduced As concentration of rice grains harvested at 20 days after anthesis (DAA). By contrast with the control, the expression of 1001 genes were found to be significantly changed, 46 genes up-regulated and 954 genes down-regulated in the 20As grains. 1169 genes expressed significantly differently between the samples of control and 20As+120S, with 16 genes up-regulated and 1153 genes down-regulated. Among the differentially expressed genes (DEGs) regulated by As and S treatment, there were 10 DEGs encoding phosphate transporter, and 24 DEGs encoding aquaporin transporter. Some genes involved in As detoxification, such as ABC transporter, glutathione S-transferase and phytochelatin synthase were up-regulated by sulfur treatment. The results provide an insight into the molecular basis of how sulfur application regulates As accumulation in rice grains. Arsenic (As) was artificially added to soil with 20 mg/kg As (Na2AsO4.12H2O, 20As), another treatment was 20As+120S, sulfur (S) were supplied artificially with 120 mg/kg (Na2S2O3•5H2O) to the As-added soil (20As+120S).
Project description:Rice (Oryza sativa L.) is the main staple food for nearly half of the world’s population. Cereals, especially rice is deficient in micronutrients such as Fe. However, rice genotypes differ in grain Fe concentration (Panda B, et.al. Am J Plant Sci. 2014;5:2829-41. doi: 10.4236/ajps.2014.518299). The present study is focused on identification of gene(s) involved in Fe accumulation in developing rice grain through high throughput RNA-seq technology and to understand the basis of differential Fe accumulation in developing rice grain. Two cultivars of rice viz. Sharbati (high Fe) and Lalat (low Fe) differing in grain iron concentration were used in the study. Root and grain transcriptome sequences of these two cultivars (at mid-grain filling stage) were generated using RNA-Seq (Illumina Hiseq 2000 platform). For each genotype, on an average 9.7 and 7 Gb data was generated for grain and root samples, respectively. The short reads were aligned against the Nipponbare reference genome (IRGSP build 5.0), thereby successfully mapping 95% and 67% of the reads from grain and root samples, respectively. Genes known to be involved in Fe metabolism were analyzed for expression. Among the genes coding for phytosiderophore synthesizing enzymes, OsNAS1 and OsNAAT2 showed higher expression in the grains of Sharbati while OsDMAS1 had higher expression in its root. Of the 18 yellow-stripe like (YSL) genes in rice, only 11 were found to be expressed in the two cultivars. Out of these, 2 (OsYSL2 and OsYSL 8) were up-regulated in the grains of Sharbati highlighting their importance in the uptake of Fe from soil and its accumulation in the developing grain. Two other genes (OsFRO1 and OsIRT1) known to be involved in Fe uptake by the root were also found to be highly expressed in the root of Sharbati. Our findings suggest that higher grain iron concentration of cv. Sharbati might be due to higher expression of key Fe transporters (viz. OsYSL2, OsYSL8 and OsITR1) and root membrane bound OsFRO1, which give an advantage in terms of absorption, transport and assimilation of Fe by this cultivar as compared to the low iron containing cultivar, Lalat.
Project description:Deficiency of alcohol dehydrogenase 2 reduces arsenic in paddy-field rice grains by suppressing silicate transporters during reproductive stage