Breeding Of Insect-resistant Rice Lines And Field Screening Of Attractants For Anagrus Nilaparvatae Based On Herbivore-induced Rice Volatiles

Our previous results found that compared to wild type (WT) plants, rice lines with silencing of the linalool synthase gene OsLIS, which released less amount of linalool, were more attractive to rice brown planthopper (BPH) Nilaparvata lugens (Sta1), whereas were less attractive to the egg parasitoid of rice planthoppers Anagrus nilaparvatae;lines with silencing of OsTPS3, which emitted less amount of (E)-β-caryophyllene, showed a reduction in attractiveness to BPH, white-backed plant hopper (WBPH) Sogatella furcifera (Horvath) and the parasitoid. Moreover, via indoor and primary outdoor experiments,3single chemicals (Linalool, cis-3-hexenal and cis-3-hexenyl acetate) and one mixed blend (Linalool, cis-3-hexenal, cis-3-hexenyl acetate plus MeSA) were found to be attractive to the parasitoid and thus enhance the parasitism of BPH eggs. To develop new techniques for controlling BPH, some researches on breeding of insect-resistant rice lines and screening of attractants for Anagrus nilaparvatae based on herbivore-induced rice volatiles, by combining genetic engineering and field bioassay. were carried out. The main results are as follows:Using Agrobacterium-based transformation system containing a vector with two T-DNA, lines containing hpt Ⅱ and the target gene are obtained,26of which are lines over-expressing OsLIS and4of which are lines silencing OsTPS3. By PCR screening for the progenies of these lines, rice lines only containing the target gene can be obtained.Based on the previous result, we choose one single chemical linalool and one blend (Linalool, cis-3-hexenal, cis-3-hexenyl-aceate plus MeSA) to test their effect on the population density of BPH and the parasitism of BPH eggs by the parasitoid A. nilaparvatae. To a certain degree, both linalool and the blend were attractive to BPH nymphs, while repellent at early stage and attractive at later stage to BPH adults. Linalool seems has an inhibitory role for BPH oviposition. Both linalool and the blend were attractive to Anagrus nilaparrvatae to some content, which was consistent with the previous results.These findings are of significance for the development of new techniques for controlling rice planthoppers, such as combining lines expressing OsLIS and lines silencing OsTPS3to implement push-pull strategy, breeding lines that repel rice planthoppers and attract natural enemies, and so on, thus improving the management of rice planthoppers.