Resistance of rice to insect pests mediated by suppression of serotonin biosynthesis

Abstract

Rice is one of the world's most important foods, but its production suffers from insect pests, causing losses of billions of dollars, and extensive use of environmentally damaging pesticides for their control. However, the molecular mechanisms of insect resistance remain elusive. Although a few resistance genes for planthopper have been cloned, no rice germplasm is resistant to stem borers. Here, we report that biosynthesis of serotonin, a neurotransmitter in mammals, is induced by insect infestation in rice, and its suppression confers resistance to planthoppers and stem borers, the two most destructive pests of rice. Serotonin and salicylic acid derive from chorismate. In rice, the cytochrome P450 gene CYP71A1 encodes tryptamine 5-hydroxylase, which catalyses conversion of tryptamine to serotonin. In susceptible wild-type rice, planthopper feeding induces biosynthesis of serotonin and salicylic acid, whereas in mutants with an inactivated CYP71A1 gene, no serotonin is produced, salicylic acid levels are higher and plants are more insect resistant. The addition of serotonin to the resistant rice mutant and other brown planthopper-resistant genotypes results in a loss of insect resistance. Similarly, serotonin supplementation in artificial diet enhances the performance of both insects. These insights demonstrate that regulation of serotonin biosynthesis plays an important role in defence, and may prove valuable for breeding insect-resistant cultivars of rice and other cereal crops.

Plant‐mediated interactions among above‐ground and below‐ground life stages of a root‐feeding weevil

“…Further work will also be needed to identify the biochemical responses involved in interactions among different life stages of RWW on rice. Recent work on herbivore-induced resistance in rice has focused on volatile emission from herbivore-injured plants and by increased production of amino acid derivatives such as serotonin (Yuan et al, 2008;Lu et al, 2018).…”

Current understanding of the molecular players involved in resistance to rice planthoppers

“…These mutants were more resistant to BPH than the susceptible wild‐type rice. More BPHs were found on the wild‐type rice plants than on the mutants by 55% . By knocking out the CYP71A1 via the CRISPR‐Cas9 genome editing technique, rice plants became resistant to BPH .…”

Current and Future Prospects of Plant Breeding with CRISPR/Cas

“…Contamination of arable land among abiotic stresses has created the need to prevent crop toxic heavy metals from accumulating. varieties with low concentration of cadmium, radiocesium, and arsenic have been developed by breeder OsARM1, OsNramp5 [53][54][55]. increased powdery mildew resistance available [48].…”