Wound-induced transcriptional dynamics in rice

Herbivore attacks or some pathogen infections typically begin with wounding of plant tissues, yet the transcriptional dynamics of wound-induced responses in the monocot rice remain incompletely understood. Here, we conducted a time-series transcriptome analysis of mechanically wounded rice leaves. Temporal expression patterns were observed even in untreated plants, particularly at dusk. To identify differentially expressed genes (DEGs), we compared wounded and unwounded (control) plants at corresponding time points. Jasmonate-related genes, including 18 biosynthetic and 13 catabolic genes, were significantly up-regulated. Consistently, jasmonic acid (JA) and jasmonoyl-L-isoleucine were rapidly accumulated in wounded tissues within 1 h, followed by JA catabolites after 3 h. Weighted gene co-expression network analysis of upregulated DEGs revealed early- and late-responsive gene modules. Early-expressed genes included putative regulators such as transcription factors, kinases, abscisic acid pathway components, and small peptide-coding genes, while late-responsive genes were primarily involved in specialized metabolite biosynthesis (e.g., phenylpropanoids). Targeted metabolomic analysis showed that most phenolamides were highly accumulated in wounded leaves, whereas flavonoid levels were decreased, likely due to altered metabolic flux in the phenylpropanoid pathway. Comparative analysis of leaf folder (LF) larvae- and wound-induced transcriptomes revealed that only 42% of wound-upregulated DEGs responded to LF feeding, suggesting that LF larvae partially suppress wound responses in rice. This study provides a valuable resource for understanding wound-associated biotic stress responses in rice.