Functional Study of Cytochrome P450 Enzymes from the Brown Planthopper ( Nilaparvata lugens Stål) to Analyze Its Adaptation to BPH-Resistant Rice

Plant metabolites are important to world food security in terms of maintaining sustainable yield and providing food with enriched phytonutrients. Here we report comprehensive profiling of 840 metabolites and a further metabolic genome-wide association study based on ∼6.4 million SNPs obtained from 529 diverse accessions of Oryza sativa. We identified hundreds of common variants influencing numerous secondary metabolites with large effects at high resolution. We observed substantial heterogeneity in the natural variation of metabolites and their underlying genetic architectures among different subspecies of rice. Data mining identified 36 candidate genes modulating levels of metabolites that are of potential physiological and nutritional importance. As a proof of concept, we functionally identified or annotated five candidate genes influencing metabolic traits. Our study provides insights into the genetic and biochemical bases of rice metabolome variation and can be used as a powerful complementary tool to classical phenotypic trait mapping for rice improvement.

Jasmonates (JAs) act as conserved elicitors of plant secondary metabolism. JA perception triggers extensive transcriptional reprogramming leading to the concerted activation of entire metabolic pathways. This observation inspired numerous quests for 'master' regulators capable of enhancing the production of specific sets of valuable plant metabolites. Many transcription factors (TFs), often JA-activated themselves, with a role in the JA-modulated regulation of metabolism were discovered. At the same time, it became clear that metabolic reprogramming is subject to complex control mechanisms integrated in robust cellular networks. In this review, we discuss current knowledge of the effect of JA-modulated TFs in the elicitation of secondary metabolism in the model plant Arabidopsis (Arabidopsis thaliana) and a range of medicinal plant species with structurally divergent secondary metabolites. We draw parallels with the regulation of secondary metabolism in fungi and consider the remaining challenges to map and exploit the transcriptional machineries that drive JA-mediated elicitation of plant secondary metabolism. Copyright © 2012 Elsevier Ltd. All rights reserved.

Planthoppers are highly destructive pests in crop production worldwide. Brown planthopper (BPH) causes the most serious damage of the rice crop globally among all rice pests. Growing resistant varieties is the most effective and environment-friendly strategy for protecting the crop from BPH. More than 19 BPH-resistance genes have been reported and used to various extents in rice breeding and production. In this study, we cloned Bph14, a gene conferring resistance to BPH at seedling and maturity stages of the rice plant, using a map-base cloning approach. We show that Bph14 encodes a coiled-coil, nucleotide-binding, and leucine-rich repeat (CC-NB-LRR) protein. Sequence comparison indicates that Bph14 carries a unique LRR domain that might function in recognition of the BPH insect invasion and activating the defense response. Bph14 is predominantly expressed in vascular bundles, the site of BPH feeding. Expression of Bph14 activates the salicylic acid signaling pathway and induces callose deposition in phloem cells and trypsin inhibitor production after planthopper infestation, thus reducing the feeding, growth rate, and longevity of the BPH insects. Our work provides insights into the molecular mechanisms of rice defense against insects and facilitates the development of resistant varieties to control this devastating insect.