Effects of jasmonic acid-induced resistance in rice on the plant brownhopper, Nilaparvata lugens Stål (Homoptera: Delphacidae)

It has been established that jasmonate and its pure derivative, Jasmonic Acid can induce the emission of volatiles similar to those induced by herbivory which fed on the plant. Although the effects of induced resistance on chewing insects have been extensively studied, relatively little is known about their potential effects on phloem-feeding insects such as brown planthoppers. We studied the pattern of within-plant preference in the brown planthopper, Nilaparvata lugens (Stål) (BPH) (Homoptera: Delphacidae) and its consequences for offspring performance on the host-plant Oryza sativa L. (Taebaegbyeo variety) regarding the role of induced resistance of rice plants to hopper feeding. The present study examined the effects of induced resistance on the feeding (food assimilation and digestion), development, egg hatchability and survival. In this study, induced resistance was activated in rice using a foliar application of synthetic jasmonic acid (JA) (low 2.5 mM and high 5 mM). Induced resistance significantly reduced the longevity and egg hatchability of the adult N. lugens, as well as the percentage of nymphs surviving to maturity (only at high dose). This study also observed N. lugens food utilization, in order to evaluate the potential influence of induced resistance on N. lugens feeding behavior. The quantity of food ingested and assimilated by N. lugens on JA treated rice plants was significantly affected at the high dose of JA. These results indicate that JA application induces systemic defenses in rice that have a direct negative impact on N. lugens survivorship. At high concentration (5 mM) several abnormalities possibly related to defective moulting, were observed along with malformed eggs. These findings expand our knowledge the effects of JA-dependent defenses on phloem-feeding insects.