Genome-wide analysis of lectin genes in Pinellia ternata reveals PtPTA109 as a novel gene conferring strong resistance to bacterial soft rot and aphid infestation

Though the genome-wide identification of gene families provides a powerful approach for discovering novel functional genes, the lectin gene family in Pinellia ternata (Thunb.) Breit., an important medicinal plant in the Araceae family, has not been systematically characterized. Lectins are carbohydrate-binding proteins that play pivotal roles in plant defense by recognizing and binding to foreign carbohydrates. In this study, a genome-wide analysis of P. ternata lectin genes ( PtPTAs ) was conducted , and their resistance to bacterial soft rot and aphid infestation was evaluated through expression profiling and overexpression assays. A total of 167 PtPTAs were identified and classified into six subfamilies based on their conserved domains and phylogenetic analysis. Further, six PtPTAs showing notable expression patterns in transcriptome data and reverse transcription quantitative real-time PCR results were selected for functional validation. Overexpression of these genes significantly reduced the lesion area caused by the soft rot pathogen, Pectobacterium carotovorum subsp. carotovorum in P. ternata leaves ( P < 0.05), with PtPTA109 showing the strongest resistance of 88%. Moreover, four of the six PtPTAs , except PtPTA106 and PtPTA116, significantly inhibited aphid infestation ( P < 0.05), with PtPTA102 and PtPTA109 exhibiting particularly high aphid escape rates (>40%). Furthermore, the overexpression of PtPTA109 in Arabidopsis substantially enhanced plant tolerance to both soft rot pathogen and aphids, probably attributed to the accumulation of salicylic acid in transgenic plants. These findings have systematically identified and characterized PtPTA109 as a novel dual-resistance gene, which could be exploited in green pest management and molecular breeding of P. ternata .