利用水稻次生代谢产物防治害虫已成为研究热点,但是对水稻自身抗性的机制知之甚少。在这项研究中,对两组水稻(T1,有害虫;T2,无害虫)进行了代谢组学分析,表明脂肪酸,生物碱,和酚酸在T1显著上调。上调的代谢产物(p值<0.1)富含亚油酸代谢,萜烯,哌啶,和吡啶生物碱生物合成,α-亚麻酸代谢,和色氨酸代谢.筛选出T1中6种显着上调的差异代谢物:N-反式-阿魏酸-3-甲氧基酪胺(1),N-反式-阿魏酰基酪胺(2),N-反式-对-香豆酰基酪胺(3),N-顺式-阿魏酸酪胺(4),N-苯基乙酰基-L-谷氨酰胺(5),和苯甲酰胺(6)。测定了这6种不同代谢产物的昆虫生长抑制活性,结果表明,化合物1具有最高的活性,显著抑制了二化星的生长59.63%。化合物2-4对二化星的生长也表现出良好的抑制作用,而其他化合物则无显著影响。RNA-seq分析表明,幼虫暴露于化合物1上调了真核生物中核糖体生物发生显着富集的基因,细胞周期,核糖体,和其他途径。下调的基因在代谢途径中显著富集,氧化磷酸化,柠檬酸盐循环(TCA循环),和其他途径。从上述显著富集的通路中筛选出18个上调基因和15个下调基因,并通过实时定量PCR进行验证。测定幼虫暴露于化合物1时解毒酶(谷胱甘肽S-转移酶(GST);UDP-葡糖醛酸转移酶(UGT);和羧酸酯酶(CarE))的活性,这表明GST的活性被化合物1显著抑制,而UGT和CarE酶的活性没有显著变化。由UPLC-MS测定,T1组和T2组化合物1的含量分别为8.55ng/g和0.53ng/g,分别,这表明害虫显著诱导了化合物1的合成。化合物1可能通过抑制二化星的解毒酶活性和代谢来增强水稻抗虫性,以及促进细胞增殖影响其正常的生长发育过程。本文初步阐明了水稻抗虫的化学生态机理。
The use of secondary metabolites of rice to control pests has become a research hotspot, but little is known about the mechanism of rice self-resistance. In this study, metabolomics analysis was performed on two groups of rice (T1, with insect pests; T2, without pests), indicating that fatty acids, alkaloids, and phenolic acids were significantly up-regulated in T1. The up-regulated metabolites (p-value < 0.1) were enriched in linoleic acid metabolism, terpene, piperidine, and pyridine alkaloid biosynthesis, α-linolenic acid metabolism, and tryptophan metabolism. Six significantly up-regulated differential metabolites in T1 were screened out: N-trans-feruloyl-3-methoxytyramine (1), N-trans-feruloyltyramine (2), N-trans-p-coumaroyltyramine (3), N-cis-feruloyltyramine (4), N-phenylacetyl-L-glutamine (5), and benzamide (6). The insect growth inhibitory activities of these six different metabolites were determined, and the results show that compound 1 had the highest activity, which significantly inhibited the growth of Chilo suppressalis by 59.63%. Compounds 2-4 also showed a good inhibitory effect on the growth of Chilo suppressalis, while the other compounds had no significant effect. RNA-seq analyses showed that larval exposure to compound 1 up-regulated the genes that were significantly enriched in ribosome biogenesis in eukaryotes, the cell cycle, ribosomes, and other pathways. The down-regulated genes were significantly enriched in metabolic pathways, oxidative phosphorylation, the citrate cycle (TCA cycle), and other pathways. Eighteen up-regulated genes and fifteen down-regulated genes from the above significantly enriched pathways were screened out and verified by real-time quantitative PCR. The activities of detoxification enzymes (glutathione S-transferase (GST); UDP-glucuronosyltransferase (UGT); and carboxylesterase (CarE)) under larval exposure to compound 1 were measured, which indicated that the activity of GST was significantly inhibited by compound 1, while the activities of the UGT and CarE enzymes did not significantly change. As determined by UPLC-MS, the contents of compound 1 in the T1 and T2 groups were 8.55 ng/g and 0.53 ng/g, respectively, which indicated that pest insects significantly induced the synthesis of compound 1. Compound 1 may enhance rice insect resistance by inhibiting the detoxification enzyme activity and metabolism of Chilo suppressalis, as well as promoting cell proliferation to affect its normal growth and development process. The chemical-ecological mechanism of the insect resistance of rice is preliminarily clarified in this paper.