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A Research on Soil Transmission Medium of Rice Stripe Virus

Author: WanYu
Tutor: YangShiHu
School: Nanjing Agricultural College
Course: Crop Genetics and Breeding
Keywords: rice rice stripe virus soil transmission intermediary agent of soil transmission Chryseobacterium aquaticum
CLC: S435.111.42
Type: Master's thesis
Year: 2010
Downloads: 5
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Abstract

Rice stripe virus (rice stripe) is cause from the rice stripe virus (rice stripe virus, RSV), is currently an important virus disease in China’s rice production,which is widely distributed, largely harmed and occurring heavy. In recent years, rice production in China posed a serious threat, and huge economic losses, half the rice crops do not have harvest. RSV has become the one of the major diseases of rice production in Jiangsu Province.Major food producing areas in Jiangsu Province are mostly rice-wheat cropping system of two crops a year dominated in recent years, rice stripe disease endemic in the Huaihe significantly worsening trend. Wheat stripe virus and rice stripe virus caused by the same virus, which was also suggested that the years of the rotation, alternating two kinds of disease, prompted the outbreak of rice stripe disease or aggravated(Zhu J L et al,2008). Since the research report of rice stripe virus in China, the academic community generally recognized that the rice stripe virus is an insect-borne disease transmission,which is transmissed by Laodelphaxstriatellu,so the transmission of the disease are all concentrated in the Laodelphaxstriatellu.But the efficient high-strength pesticides and insecticidal measures year after year does not seem to be able to stop the trend of the disease increasing in recent years.We are note that rice stripe disease is not only have the trend of increasing year by year but also has some soil-borne diseases similar characteristics from the experimental fields of rice-wheat crop rotation for many years.In order to determine whether the sense of rice stripe virus disease have the existence of soil-borne method except the Laodelphaxstriatellu sucking in virus transmission.We are isolated and purified 42 different morphological characteristics of strains, including 7 species of actinomycetes,3 species of mould,32 species of bacteria,from successive years of rice stripe disease by high incidence in the soil pool of Nanjing Agricultural University.We are examining all of these strains by PCR primers in RSV-CP gene, it was discovered that a bacterial strain can be able to amplified single and clear 990bp±the specific bands,which is same to amplified from RNA of diseased rice leaves with the incidence of RT-PCR products, while the remaining strains are all no corresponding PCR product.This strain was sent to two different commercial sequencing companies naming bacterial 16S-rRNA sequencing, the consequences of two companies were all the Chryseobacterium aquaticum sp.nov.100% homology, so we are determine the strain is Chryseobacterium aquatic genus Chryseobacterium.We are carry on the 8 rice seedlings root inoculated aquatic Chryseobacterium tests.using pot root inoculation method,which contain seven rice stripe virus disease susceptible varietise(Nipponbare,R109,Wuyugeng) and one rice stripe virus disease resistance varietise(IR36).We are daily observations after inoculation the Chryseobacterium aquaticum. After root inoculating with this bacterial liquid, the results showed that three susceptible rice cultivars in all 7 individual experiments appeared typical symptoms of rice stripe and the incidences of disease plant 4weeks after inoculating was 18.1-25% and 22% in average, the time of onset lasing for 10 days. In contrast, the incidences of disease plant in non-inoculation control plantlets was only 0-2.5% and 0.96% in average.the different rice stripe virus disease susceptible varietise is not much fluctuation at different times, basically about 20%. rice stripe virus disease resistance varietise IR36 whether or not inoculated is not diseased.This indicates that the Chryseobacterium can really induce rice stripe virus-induced disease by the method of root inoculating.and the resistant variety also showed good resistance by the method of root inoculating about its resistance of stripe disease gene.In order to determine whether the vaccination of aquatic Chryseobacterium strains after the disease is being stripe virus disease, we tested all the plants carriing out by RT-PCR examination, determine whether there is any strain stripe virus.The results showed that the incidence of all inoculated plants not only have the same symptoms with the natural field strains disease, and its diseased leaves using the RSV virus CP gene primers can be extended out a single clear bands of 990 bp, using the RSV virus SP gene primer can be extended out of 500bp bands, these bands were sequenced by the outgoing commercial company,and it is the corresponding stripe virus sequence. The non-inoculated control and the plants of non-typical leaf curl symptoms after inoculated is not have PCR product, except the very few plant can expand out the two bands.

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CLC: > Agricultural Sciences > Plant Protection > Pest and Disease Control > Crop pests and diseases and their prevention > Cereal crop pests and diseases > Rice pests and diseases > Disease > Transgression ( pass ) an infectious agent harmful > Rice sheath blight
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