Study Of Tree Herbivore-induced Rice Resistance Against Rice Blast

In this study,we conducted three rice pests namely stem bore(Chilo suppressalis),leaf folder(Cnaphalocrocis medinalis)and phloem-feeding insect(Nilaparvata lugens)with different feeding strategies and the rice pathogen that hemibiotrophic pathogen(Magnaporthe oryzae)to explore the effect of the rice feeding by C.suppressalis,N.lugens and C.medinalis respectively on the rice blast.At the same time,the contents of SA,JA and ET in rice leaves changed by rice plant herbivores and rice blast were also carried out.Futhermore,the experiment of SA and JA verified the resistance to the rice blast.The prime target is to reveal the biochemical mechanism of the rice plant resistance induced by herbivores pre-infested on the rice blast.The main results were summarized as follows:1.The effect of feeding by rice insects on rice blast studies revealed that significant less number of lesions were observed on rice plants that had been pre-infested by C.suppressalis and N.lugens than those that had not been infested by insects.In contrast,there was no statistical difference between rice plants pre-infested by C.medinalis and uninfested control plants.2.The results of contents of SA,JA and ET in rice leaves challenged by rice plant herbivores and rice blast showed that feeding by C.suppressalis alone increase responses involving SA and JA,but not ET.Likewise,feeding by N.lugens alone also increase responses involving SA and JA,but not ET.M.oryzae infection induced a similar response of rice plants as C.medinalis;a significant decrease of SA,a significant increase of JA,but unchanged of ET.3.The experiment of SA and JA spraying showed that pretreatment with 8Mm SA strongly decrease the number of typical blast lesions,but pretreatment with 0.1 Mm JA has no effect on the number of typical blast lesions.So,SA is involved in the rice blast resistance.In summary,this study provides valuable insight into the effects of insects with different feeding strategies pre-infestation on the prevalence of second attacker rice blast M.oryzae in rice.We proved SA pathway mainly participate in the rice plant mediated herbivore-pathogen interactions.These provide an important scientific evidence of the future disease control in rice.