| Rice stripe disease is one of the most important rice diseases in China. The disease is induced by Rice stripe virus (RSV), which is transovarily transmitted in the circulative persistent manner by Laodelphax striatellus. Highly viruliferous insects were obtained in this study. Rice plants from two lines with nearly identical genetic background but different susceptibly to RSV were inoculated with these insects. GC-MS was employed to analysis metabolic profiling of the two rice lines before and after RSV infection, aiming to investigate the mechanisms underlying RSV pathogenesis.Small brown planthoppers (Laodelphax striatellus) were collected from Yunnan and screened to obtain highly viruliferous insects. Biological inoculation experiments indicated that the incidence of disease of rice plants inoculated with the screed insects reached 90%. Further, progenies derived from these insects without artificial selection pressure can induce a high disease incidence, indicating that the insects obtained in this study were highly viruliferous and genetically stable. Rice seedlings of WuSan and KT95-418 were inoculated with these insects. Diseased plants with symptoms typical of RSV infection were further verified using RT-PCR.Metabolites of the diseased and healthy rice plants of the two lines were extracted. The metabolites were detected using the GC technique. The results demonstrated: the contents of metabolites of the four samples are not high. However, the retention time various to a great extent; using diseased KT95-418 rice plants as control, it was determined that metabolites with the retention time 3.176, 3.566, 11.538, 12.244, 16.216 and 17.985 (min) might be associated with RSV susceptability, while those with the retention time 3.453, 5.739, 5.831, 8.052, 10.155, 19.272 and 23.842 might be related to RSV resistance. Finally, using GC-MS, ion current chromatogram of volatile components of the four samples were obtained. The relative standard deviation (RSD) analysis of the peak area indicated that the relative deviation was small. This ensured that following analysis could be carried out. Through Software analysis and spectrum library retrial, it was found that there were 12 kinds of endogenous metabolites in WS, 11 in WSB, 9 in WB and 14 in WBB. Five kinds of metabolites were shared between WS and WSB and 6 between WB and WBB. 4 kinds of metabolites existed in all four samples. Contents of metabolites were analysised through calculation of the relative peak area. The results showed that contents of the four metabolites shared by all four samples vary between each other. 2, 4-dimethyl-Benzaldehyde with the retention time 10.53 correlated with virus susceptibly while 3-methyl-Phenol and 2-(2-Methylvinyl) thiophene with the retention time 7.59 and 10.53 correlated with disease resistance. Finally, the PCA method was used to conduct pattern recognition of this process. The results showed that variation existed between metabolic profiling of the two rice lines with different susceptibly to RSV. Metabolites of the healthy plants of the two lines vary greatly. But in diseased plants, the variation was less significant. Variation between healthy and diseased plants was more significant in KT95-418 than in WS. The phenomena might be responsible for the more significant resistance to RSV in KT95-418 than in WS. Among them, metabolites with retention times 7.59, 10.53 and 10.73 (min) varied greatly between the four samples and and could be used as an indicator to distinguish RSV responses of WS and KT95-418. In all, the analysis suggested that 2, 4-dimethyl-Benzaldehyde might be related to rice susceptibility to RSV, while 3-methyl-Phenol and 2-(2-Methylvinyl) thiophene might be involved in rice resistance to RSV. |
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