OsRCI-1gene Regulates Rice Physiology And Brown Planthopper Defense Analysis

Plant lipoxygenase(LOXs,linoleate: oxygen oxidoreducatase,EC 1.11.11.12)is the first key synthase in the Oxylipins pathway,which is involved in regulating plantsdefenses against biotic or abiotic stresses.Monocotyledonous plant rice(Oryza sativa)is an important staple crop in the world,while ricebrownplanthpper(BPH),Nilaparvatalugens(St?l),one of the most important pests of rice,which feeds on rice phloem sap and cause serious loss of rice yield in Asia.Based on our previous work,in this paper the function of OsRCI-1 in regulating rice physiologicaland biochemical characteristics by reverse genetics were performed,mainly including the function and mechanism of OsRCI-1 involved in three-levels nutritional relation ship between rice,BPH,Anagrus nilaparvatae and growth and development of rice.The results were as follows:(1)Rice lipoxygenase gene OsRCI-1 is involved in the regulation of rice growth and development.Overexpression of OsRCI-1 gene in rice could promoted the growth of rice seedling in early stage;whilerice with overexpresion of OsRCI-1 got lower production compared to wild-tpye rice,on the contrary,inhibiting OsRCI-1 expression in rice could decrease rice height and increase rice yield.(2)TheOsRCI-1 gene positively regulates the direct defense of rice against brown planthopper.The activity of catalase in overexpression OsRCI-1 gene rice plants increased after BPH treatment than control.Overexpression OsRCI-1 gene rice plants treated with LOX inhibitors could change the feeding and oviposition behavior of brown planthopper,and weakened the resistance of overexpression OsRCI-1 gene rice to brown planthopper.(3)Increasment of repellent agaisnt BPH in overexpression of OsRCI-1 gene rice at least partly attribute to enhancement of rice volatile such as GLVs.When treated rice with different concentrations of methyl jasmonate(MeJA),cis-3-Hexen-1-ol,cis-3-Hexenal,and their mix mixture,and 2-heptanone and 2-heptanol,the treatment with cis-3-hexenol,or Mix mixture could decrease feeding selection and ovipsotion selection of BPH,butvolatiles(2-heptanone,and 2-heptanol)only affected oviposition selection of BPH.(4)OsRCI-1 gene plays an important role in rice indirect defense positivly.In Lab,results showed that over-expression of OsRCI-1 rice increased the parasitism rate of the rice wasp;exogenous SHAM could reduce the parasitism rate of BPH eggs on over-expression of OsRCI-1 rice,wild type rice treated with exogenous cis-3-Hexenal,2-heptanone,Mix mixture respectively could significantly enhancethe parasitization rate of BPH eggs by Anagrus nilaparvatae.In field only cis-3-Hexenal and 2-heptanone showed significant attracting activity to parasitic wasps Anagrus nilaparvatae in with different concentrations.