Serine proteinase inhibitors fromNicotiana benthamiana, a non-preferred host plant, inhibit the growth ofMyzus persicae(green peach aphid)

Abstract

AbstractThe green peach aphid (Myzus persicae) is a severe agricultural crop pest that has developed resistance to most current control methods, requiring the urgent development of novel strategies. Plant proteinase inhibitors (PINs) are small proteins that protect plants against pathogens and/or herbivores, likely by preventing efficient protein digestion. We identified 67 protease genes in the transcriptomes of threeM. persicaelineages (USDA-Red, G002, and G006). Comparison of gene expression levels in aphid guts and whole aphids showed that several proteases, including a highly expressed serine protease, are significantly overexpressed in the guts. Furthermore, we identified three genes encoding serine protease inhibitors (SerPIN-II1,2, and3) inNicotiana benthamiana, which is a non-preferred host forM. persicae. Using virus-induced gene silencing (VIGS) with a tobacco rattle virus (TRV) vector and overexpression with a turnip mosaic virus (TuMV) vector, we demonstrated thatN. benthamiana SerPIN-II1andSerPIN-II2cause reduced survival and growth, but do not affect aphid protein content. Similarly,SerPIN-II3overexpression reduced survival and growth, andserpin-II3knockout mutations, which we generated using CRISPR/Cas9, increased survival and growth. Whereas protein content was significantly increased in aphids fed onSerPIN-II3overexpressing plants, it was decreased in aphids fed onserpin-II3mutants. Together, our results show that three PIN-IIs fromN. benthamiana, a non-preferred host plant, effectively inhibitM. persicaesurvival and growth, thereby representing a new resource for the development of aphid-resistant crop plants.