Silicon Protects Rice Plants Against Striped Stem Borer by Disturbing Herbivory-Induced Putrescine Accumulation

Silicon (Si) protects plants against insect herbivores; however, the underlying mechanisms remain unclear. Polyamines (PAs) play a crucial role in plant–insect interactions. Here, the involvement of Si in putrescine (Put) metabolism and its role in rice resistance against striped stem borer (SSB, &l...

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Main Authors: Hao Zhang, Xiaodong Liu, Cunyan Li, Linzhi Fang, Chaoyue Gai, Rensen Zeng, Qiongli Wang, Yuanyuan Song, Daoqian Chen
Format: Article
Language:English
Published: MDPI AG 2025-07-01
Series:Plants
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Online Access:https://www.mdpi.com/2223-7747/14/13/2066
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Summary:Silicon (Si) protects plants against insect herbivores; however, the underlying mechanisms remain unclear. Polyamines (PAs) play a crucial role in plant–insect interactions. Here, the involvement of Si in putrescine (Put) metabolism and its role in rice resistance against striped stem borer (SSB, <i>Chilo suppressalis</i> Walker) were investigated. The results showed that SSB larval infestation led to a substantial accumulation of free Put in rice seedlings. Si application increased rice resistance against SSB and repressed the SSB attack-induced accumulation of Put, in parallel with a decreased expression of Put biosynthesis genes encoding arginine decarboxylase (<i>ADC1</i> and <i>ADC2</i>). Moreover, Si application had no significant effect on the wounding-induced expression of <i>ADC1</i> and <i>ADC2</i>, but attenuated the further elevation in the transcription of <i>ADC1</i> and <i>ADC2</i> induced by SSB larvae oral secretion. Simultaneously, Si addition reduced the Put and spermidine contents in SSB-attacked plants. Furthermore, the exogenous application of Put attenuated Si-enhanced resistance against SSB larvae, whereas exogenous D-arginine, an inhibitor of ADC, showed similar effects to Si on rice resistance against SSB. Our findings indicate that Si improves rice resistance to SSB, at least partly by reducing herbivory-stimulated putrescine accumulation.
ISSN:2223-7747