Genome-wide characterization of the cassava lipoxygenase gene family reveals MeLOX12 as a key regulator of JA-mediated resistance to Tetranychus urticae

• Genome-wide identification of LOX genes in cassava reveals 16 gene members which belong to six phylogenetic subgroups. • Several MeLOX genes are strongly induced in resistant cultivars during two-spotted spider mite attack. • Knock-down of MeLOX12 reduces jasmonic acid accumulation and defense gene expression. • MeLOX12 plays a pivotal role in cassava resistance against mite infestation. Lipoxygenase (LOX), a key rate-limiting enzyme in jasmonic acid (JA) biosynthesis, plays pivotal roles in various biological processes, particularly in plant defense against insect pests. However, the mechanisms by which LOX mediates cassava ( Manihot esculenta ) resistance to the two-spotted spider mite (TSSM) remain poorly understood. In this study, we observed that several genes participating in JA biosynthesis were significantly up-regulated in resistant cultivars following TSSM infestation. Among these, LOX exhibited the most robust induction. We employed a genome-wide characterization of the MeLOX gene family in cassava, identifying 16 distinct members. Phylogenetic analysis revealed that these MeLOX genes were classified into six subgroups, clustering with several well-characterized defense-related AtLOXs from Arabidopsis thaliana . Furthermore, cis-element identification and conserved motif prediction suggested that these MeLOX genes are likely associated with biotic stress in cassava. To examine the potential link between LOX expression as well as TSSM resistance, we suppressed the most highly induced gene via virus-induced gene silencing (VIGS). Knockdown of MeLOX12 in the TSSM-resistant cassava SC9 down-regulated the transcription of other JA biosynthesis genes, and reduced the JA accumulation, which could ultimately lead to a significant decline in TSSM resistance. Our findings demonstrate that MeLOX12 is a critical gene governing cassava resistance to TSSM, providing valuable insights for future breeding programs and pest management strategies.