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Southern rice black streaked dwarf virus(SRBSDV) is vectored by white-backed planthopper(WBPH),Sogatella furcifera,in a circulative,propagative,and persistent manner.To better understand the relationship of virus- vector- host plant and the transmission mechanism of WBPH,this study evaluated the direct effects of SRBSDV on the feeding behavior of WBPH and determined the feeding behavior of viruliferous WBPH in relation to SRBSDV inoculation.The third to fifth- instar nymphs of WBPH were allowed to feed for 48 hours on SRBSDV- infected rice plants,and then reared on the healthy seedlings for 8- 15 days.Electronic penetration graph(EPG) was used to monitor the feeding behavior of both the non-viruliferous and viruliferous WBPH for 12 hours.Fifteen- 22 days after the recording,total RNA was isolated from rice plant and used to determine whether or not the rice plant had been infected by RT- PCR.EPG showed that the duration of the 1st phloem contact(N4) was 15 times longer in viruliferous WBPH than in non- viruliferous WBPH.The mean duration of watery salivation(N4- a) of viruliferous WBPH was significantly longer than that of nonviruliferous WBPH.Meanwhile,the stepwise- backward logistic regression model showed that the total duration of N4 was the most significant variable(P= 0.019) positively correlated with SRBSDV inoculation,which was followed by the number of N4- a(> 10min) preceding N4- b(P =0.034).The study revealed that SRBSDV modified the feeding behavior of WBPH in a direct way and enhanced the inoculation efficiency.Salivation into phloem region might be the most important stylet activity for the inoculation of SRBSDV.
Southern rice black streaked dwarf virus (SRBSDV) is vectored by white-backed planthopper (WBPH), Sogatella furcifera, in a circulative, propagative, and persistent manner. To better understand the relationship of virus- vector- host plant and the transmission mechanism of WBPH, this study evaluated the direct effects of SRBSDV on the feeding behavior of WBPH and determined the feeding behavior of viruliferous WBPH in relation to SRBSDV inoculation. Third to fifth-instar nymphs of WBPH were allowed to feed for 48 hours on SRBSDV- infected rice plants, and then reared on the healthy seedlings for 8- 15 days. Electronic penetration graph (EPG) was used to monitor the feeding behavior of both the non-viruliferous and viruliferous WBPH for 12 hours. Fifteen- 22 days after the recording, total RNA was isolated from rice plant and used to determine whether or not the rice plant had been infected by RT-PCR. EPG showed that the duration of the 1st phloem contact (N4) was 15 times longer in viruliferous WBPH than in non- viruliferous WBPH was mean longer of watery salivation (N4- a) of viruliferous WBPH was significantly longer than that of nonviruliferous WBPH. Meanwhile while the stepwise- backward logistic regression model showed that the total duration of N4 was the most Significant variable (P = 0.019) positively correlated with SRBSDV inoculation, which was followed by the number of N4- a (> 10min) preceding N4- b (P = 0.034). The study revealed that SRBSDV modified the feeding behavior of WBPH in a direct way and enhanced the inoculation efficiency .alternative into phloem region might be the most important stylet activity for the inoculation of SRBSDV.