Abstract
Abstract
Brown planthopper (Nilaparvata lugens, BPH) is a major pest that severely limits rice production. Although plant defense against BPH involves complex metabolic and structural responses, the role of non-protein amino acids (NPAAs) in this process remains poorly understood. Here, we demonstrate that (R)-β-tyrosine functions as a key defense metabolite that enhances rice resistance to BPH. Exogenous application and genetic manipulation across different rice backgrounds revealed that (R)-β-tyrosine does not directly affect insect survival but instead acts through host-mediated mechanisms. Transcriptomic, histological, and physiological analyses showed that (R)-β-tyrosine promotes the expression of phenylpropanoid pathway genes, leading to increased lignin accumulation, enhanced mechanical strength, and reinforced physical barriers that restrict BPH feeding. Mechanistically, we identify the JA-inducible transcription factor OsMYB72 as a key activator of OsTAM1, the enzyme catalyzing β-tyrosine biosynthesis, thereby linking JA signaling to (R)-β-tyrosine accumulation. This JA-OsMYB72-OsTAM1 module coordinates β-tyrosine production with downstream phenylpropanoid metabolism, promoting lignin deposition and reinforcing structural defense against BPH. Together, our findings establish a link between NPAA metabolism and lignin-associated structural defense, offering insight into metabolite mediated plant resistance to piercing-sucking herbivores.