Virulence Variation Of The Brown Planthopper (Nilaparvata Lugens) On Multi-generational Resistant Rice Variety Mudgo

In this paper,virulence variation of the brown planthopper Nilaparvata lugensafter feeding on multi-generational resistant rice variety Mudgo was studied.BPH from suspectiblerice variety TN1 was selected to raiseon resistant rice Mudgo with resistant gene Bph1.The body weight of eclosion female BPH,the gain of body weight in 48 h,the amount of honeydew excrement in 48 h and the number of offspringsat different generations raised on Mudgowere investigated.At the same time,female BPH 1-8 days after eclosion were collected,the ovary was observed and ovarian RNAs were extracted.Three genes related to ovary development exuperantia,mago nashi and Angiotensin-convertingenzyme(ACE)were selected for real-time fluorescence quantification.The results showed that the ecologicalcharactersof short-wings female BPH were significantly decreased in the first generation after raised on Mudgo;The weight gain and the honeydew excrement in 48 h in the first generation were significantly lower than the control group,while there was no significant difference between the other generations and the control group;Compared with the control group,the body weight of eclosion female BPH from 1st to 4th generation were significantly decreased,however,there was no significant difference between the first four generations.The body weight of eclosion female BPH from 4th to 6th generations had no significant difference.The number of offsprings of the short-wings BPH decreased significantly in the first generation.The offspring was no significant difference between 2nd to 4th generations but significantly fewer than the control group.There was no significant difference between 5th to 7th generations and had no significant difference with the control group as well.The development of ovary was significantly affected after feeding on resistant rice Mudgo.The ovarian volume of the first generation of BPHwas smaller and the whole development was delayed.With the increase of feeding time,the ovarian development gradually returned to normal.Until to the 7th generation,ovarian development speeds up and the size of ovary showed no significant difference with the control group.After raised on resistant rice Mudgo,the relative expression of each gene(exu,mag,ACE)of the short wings female BPH was inhibited.Similar to the ecological characteristics,the relative expression of each gene reached a stable state in 4-6th generations,and with the increase of feeding time,the relative expression of each gene gradually approached the level of control group.exu and ACE of 1-3rd generations were highly expressed on the first day of eclosion.exu of 4-6thgeneration had a same peak value on the fifth day of eclosion as the control group while the expression of ACE gradually approached that of the control group.The relative expression of exu and ACE all reached their control group levels in 6th generation.