Effects Of B. Tabaci Resistance On The Transmission Of TYLCV, As Well As TYLCV On B. Tabaci Host Selectivity

Bemisia tabaci (Gennadius), Hemiptera. Aleyrodidae, Stenorrhyncha, is one of the world wide agricultural pests, and be considered a complex species. Bemisia tabaci B and Q are the most widely distributed andt damaging biotypes in the species. Bemisia tabaci B invaded to China in the1990s, while Q was found in the year of2003in Yun Nan province. In resent years, tomato yellow leaf curl virus outbreaks in vast areas of our country transmitted by whitefly, and seriously damaged the production of tamato.Nowadays, the way of control Whitefly is mainly dependent on chemical pesticides, and it has developed resistance to a wide array of insecticides due to the; frequently used of insecticides in the main agricultural areas in our country. In order to comprehensive clarify the Biotic and abiotic factors that affected the spread of TYLCV, This paper systematically studied the effected of resistance in acquisition, retention, and transmission of TYLCV; and the impact of TYLCV for whitefly to insecticides; TYLCV whitefly impact on host selectivity. The results have important theoretical and practical significance for revealing the mechanism of TYLCV fast spreads and outbreaks in our country recent years; and sustainable governance of Whitefly and TYLCV. The main contents and conclusions are as follows:1、The feature of thiamethoxam resistance and sensitive biotype B in acquisition, retention, and transmission of TYLCVBy comparing the ability of thiamethoxam resistance and sensitive biotype B in acquisition, retention, and transmission of TYLCV, It was found that there were no significant differences on access to TYLCV rate between resistant and susceptible biotype B B. tabaci strains, but the relative expression levels of TYLCV in vivo resistant strains was significantly higher than the sensitive strain; If susceptible or resistant biotype B Bemisia tabaci strains has obtained virus, both of them can held it for hole life in the body, but its expression level in the body will slowly decrease; There were no significant differences in transmitting efficiency of TYLCV between resistant and sensitive B biotype Bemisia tabaci strains adults. However. it was found that the relative expression of TYLCV in the infested plants by it by quantitative PCR found that the relative expression of TYLCV was much more higher in the resistant strains infecting plants than that in the susceptible, and the greater the number of whiteflies, the greater the difference.The study defined the role of thiamethoxam resistance in the spread of TYLCV by Bemisia tabaci B biotype2、The impact for whitefly infected with TYLCV to insecticidesDetermination the toxic of experiment biotype B, TYLCV-infected biotype B, biotype Q and TYLCV-infected biotype Q four whitefly populations to bifenthrin, acetamiprid, chlorantraniliprole, thiamethoxam and Avermectin by agar moisturizing law. The results show that both the B or Q-biotype, after TYLCV infection, have reduced the sensitivity to the five insecticides, in particular to thiamethoxam and abamectin sensitivity decreased significantly, While B biotype LC50values to thiamethoxam decreased by2.889, and the Q biotype LC50values to thiamethoxam and avermectin decreased by7.876and2.145times respectively. Through analysis and comparison of B and Q biotype sensitivity to bifenthrin, acetamiprid, Chlorantraniliprole, thiamethoxam and avermectin five agents, the results show that relative to the Q biotype populations, B biotype showed much more sensitive to these five agents.3、Thermal tolerance of thiamethoxam resistance and sensitive of Bemisia tabaci biotype BBy comparing the mortality between thiamethoxam resistance and sensitive biotype B Bemisia tabaci in the short-term temperature and pressure, as well as the relative expression of HSP40, HSP70and HSP90, it was found that the susceptible Bemisia tabaci significantly sensitive to thermal than that of thiamethoxam resistant Bemisia tabaci biotype B, And at35℃, The relative expression levels of HSP70in thiamethoxam resistance strain was much lower than that in the susceptible strain.The study provide a certain molecular mechanisms basis for the heat tolerance to thiamethoxam resistant and susceptible B. tabaci4%TYLCV whitefly impact on host selectivityBy comparing health biotype B (TYLCV free), infected B biotype (TYLCV infection), non-virus Q biotype (TYLCV free) and infected Q biotype (TYLCV infection) on the health and TYLCV infected tomato plants preferences, it was found that TYLCV-free B. tabaci Q preferred to settle on TYLCV-infected tomato plants over healthy ones. TYLCV-free B. tabaci B, however, preferred healthy tomato plants to TYLCV-infected plants. In contrast, TYLCV-infected B. tabaci, either B or Q, did not exhibit a preference between TYLCV-infected and TYLCV-free tomato plants. Based on gas chromatography-mass spectrometry (GCMS) analysis of plant terpene volatiles, significantly moreb-myrcene, thymene,b-phellandrene, caryophyllene,(1)-4-carene, and a-humulene were released from the TYLCV-free tomato plants than from the TYLCV-infected ones. The results accordance with the invasion of Q biotype bemisia tabaci and the outbreaks of TYLCV in time, it indicate that the invasion of Q biotype bemisia tabaci have more closer relations than B biotype bemisia tabaci for the outbreaks of TYLCV.In summary, this paper closely the actual production for the spread of whitefly and TYLCV, for the first time to study the effects of whitefly to thiamethoxam resistance and TYLCV spread, the first time to find the phenomenon of whitefly to thiamethoxam resistance is more tolerant to environmental temperature, as well as the mechanism of Q biotype is more easy to transmit TYLCV...