Herbivory by Striped Stem Borer Triggers Polyamine Accumulation in Host Rice Plants to Promote Its Larval Growth

Abstract

Polyamines (PAs) are ubiquitous low-molecular-weight aliphatic polycations in all living organisms, which are crucial for plant response to abiotic and biotic stresses. The role of PAs in plant disease resistance has been well documented. However, their involvement in plant–pest interactions remains unclear. Here, the role of PAs in rice against striped stem borer (SSB, Chilo suppressalis Walker), a destructive pest in rice production worldwide, was investigated. SSB larval infestation led to a substantial accumulation of free putrescine (Put) in rice seedlings, which was in parallel with an elevated expression of host PA biosynthesis genes Arginine Decarboxylase1 (ADC1) and ADC2. Moreover, SSB larval oral secretion application with wounding further raised the transcripts of ADC1 and ADC2 in rice compared with wounding treatment alone. The larval growth on both rice plants and artificial diet was promoted by the exogenous application of PA and inhibited by a PA biosynthesis inhibitor. On the other hand, the rice defense responses, including polyphenol oxidase (PPO) and peroxidase (POD) activities, as well as protease inhibitor level, were enhanced by a Put supplement and reduced by an ADC inhibitor. Our results indicate that SSB herbivory triggers polyamine accumulation in host rice plants, which is beneficial to SSB in rice–SSB interaction.

Metabolically Tailored Selection of Ornamental Rose Cultivars through Polyamine Profiling, Osmolyte Quantification and Evaluation of Antioxidant Activities

“…Furthermore, hydrogen peroxide produced via PA catabolism may play a role in triggering hypersensitive reactions, as well as modulating defense gene expression through the activation of serine/threonine kinases from the MAPK group which can lead to cell death [59]. Additionally, it may contribute to strengthening and thickening the cell wall, thereby aiding in the prevention of fungal or insect attacks [60]. In addition to their involvement in generating ROS, PAs play a significant role in plant immunity and the amplification of pattern-triggered immunity (PTI) responses [24].…”