Gene Expression Of Rice Responding To Cd, BSM And The Co-contamination Of Cd-BSM Stress

With the increase of Bensulfuron-methyl (BSM) and cadmium (Cd) in the soil due to the widely using of sulfonylurea herbicides and the continuously accumulating of heavy metal elements in China, the molecular mechanisms of the co-contamination of BSM and Cd stress on rice are still unknown. In this study we investigated the expression of genes and proteins in rice roots effected by Cd, BSM and the co-contamination of Cd-BSM stress using gene-chip and proteomic techniques. Feng Meizhan was employed as the experimental material. The main results were summarized as follows:1. The effect of Cd, BSM and the co-contamination of Cd-BSM on rice growthThe results indicated that the optimum concentration of Cd was 5mg/L, which could inhibit the growth of rice (such as the length of roots and the rice height) and the inhibition to roots was more severe. However, BSM did not inhibit the rice growth at the concentration of 0.1mg/L. When the same concentration of BSM and coexisted with Cd, the inhibitions to rice were less slight than that of Cd singlely. It seemed that BSM could relieve the toxicity of Cd to some extend.2. The effect of Cd, BSM and the co-contamination of Cd-BSM on proteome in riceThe results of proteome showed that Cd, BSM and the co-contamination of Cd-BSM stress had significant effects on proteome in rice roots. The expressions of considerable amount of proteins were inhibited or induced by Cd, BSM and the co-contamination of Cd-BSM stress.The analysis of the category and function of stress-induced proteins showed that different proteins were induced in response to Cd, BSM and the co-contamination of Cd-BSM stress.F1-ATPase, endonuclease,70kDa heat shock protein, S-adenosyl-L-homocysteine hydrolase, NAD-dependent malate dehydrogenase, metalloenzyme superfamily, Rossmann-fold NAD(P)(+)-binding proteins, glutamine synthetase and adenosine kinase were induced by Cd in Feng Meizhan rice roots.70kDa heat shock protein, metalloenzyme superfamily, Rossmann-fold NAD(P)(+)-binding proteins, glutamine synthetase and adenosine kinase were induced by BSM in Feng Meizhan rice roots.F1-ATPase, metalloenzyme superfamily, Rossmann-fold NAD(P)(+)-binding proteins, glutamine synthetase and triosephosphate isomerase were induced by the co-contamination of Cd-BSM in Feng Meizhan rice roots.3. The effect of Cd, BSM and the co-contamination of Cd-BSM on gene expression in riceThe results of geng-chip showed that the expression of different genes were induced (ratio>2) in response to Cd,BSM and the co-contamination of Cd-BSM, which were signal receptor genes, transcription genes of intracellular signaling, detoxifying enzyme genes, synthesis of secondary metabolites and antibiotics genes, course of disease and other resistance genes, hormones and growth regulatory genes, group-transfer and material transport-related genes, metabolic and regulatory genes. The number and the type of genes induced by Cd,BSM and the co-contamination of Cd-BSM were different.4. Comparing the genes induced by Cd,BSM and the co-contamination of Cd-BSM in rice rootsMost genes were induced either by Cd or by BSM stress in rice roots. Many genes were specifically induced by Cd, BSM or the co-contamination of Cd-BSM stress. Metallothionein-like and detoxification genes, large number of sulfate permease and transporter related genes were specifically induced by Cd stress. A lot of heat shock protein genes, complete ethylene signal transduction pathway related genes and ubiquitin domain containing protein related gengs were specifically induced by BSM stress. Some genes specifically induced by Cd and anothers were also induced by the co-contamination of Cd-BSM stress in rice roots, which was a possible molecular pathway for BSM to relieve the toxicity of Cd to rice.