Geographic Distribution Of RSMV In Southern China And Its Effects On Vector Leafhopper

Rice stripe mosaic virus(RSMV),which was first discovered in Luoding of Guangdong province in 2015,is a tentative new description virus of the genus Cytorhabdovirus in the famliy Rhabdoviruses,and it is transmitted by Recilia dorsalis with a protracted manner.Rice stripe mosaic disease caused by the virus poses a potential threat to the rice production in China.Due to the RSMV is a latest type of rice virus,its prevalence and distribution are not yet clear.Therefore,this research established a molecular detection method for RSMV,conducted extensive field investigations in southern China,and explored the effects of viruses on the life parameters of Recilia dorsalis.The main results of research in this paper are as follows:1.We established a twofold RT-PCR molecular detection method for Rice stripe mosaic virus and Rice gall dwarf virus.As the early symptoms caused by RSMV and Rice gall dwarf virus(RGDV)infecting rice are similar and can be transmitted by Recilia dorsalis.This study established a dual RT-PCR method that can simultaneously detect two viruses to achieve rapid detection of the in vivo rate of infection by mediator insects and rapid identification of early rice disease.This method can detect RSMV and RGDV from single-headed Recilia dorsalis or a total RNA extract equivalent from to 0.001 mg of diseased leaf samples.The proportion of Recilia dorsalis carrying both the RSMV and RGDV viruses in the ward is high,which will lead to compound infections of the two rice diseases.2、This research preliminarily clarified the distribution and incidence of RSMV in Southern China.We have conducted a field survey of the occurrence of rice stripe mosaic disease in early rice and late rice in southern China from 2017 to 2018 in two consecutive years.The results show that Pathogenic strains can be seen in the southwestern of Guangdong and eastern of Guangxi,as well as in the central of Hainan,among of which some areas in western Guangdong are more severely affected.Among them,the diseased plants in Luoding Guangdong province were compound infection by RSMV and RGDV,and the composite infection rate was 80.88%(165/204).3.We have systematically surveillance the toxic of leafhopper in some areas.The results that Recilia dorsalis have a high proportion of carry two virus RSMV and RGDV in ward.Among them,In 2017 to 2018 years wintering period RSMV virus rate is 63.33%~100% of Taiping Town,and RGDV virus rate is 23.33%~90.00%.In 2017 to 2018 years wintering period RSMV virus rate is 43.33%~100% of Luoping Town,and RGDV virus rate is 26.78%~73.33%.In 2017 to 2018 years wintering period RSMV virus rate is 46.78%~90.00% of Luojing Town,and RGDV virus rate is 6.78%~66.78%.Meanwhile,the N.cincticeps also has a high toxic rate(average 44.77%)in the ward,but indoor transmission tests have failed to confirm the ability of the leafhopper to RSMV.4.It is preliminarily revealed that RSMV has an adverse effect on the growth of Recilia dorsalis,but it has a stimulating effect on leafhopper fecundity.at 25℃,compared with the virus-free leafhopper,the virus-infected nymph developmental duration was prolonged for 0.97 days,and the adult longevity was shorted by 3.8 days,the number of filial generation is risen(add 47.41%).There is no significant change the male and female proportion in the progeny population with virus-infected leafhopper.The above results provide a basic date for further revealing pathogenesis of rice stripe mosaic disease,and provide basis for making prediction and prevention and control measures of the disease.