Recently, the research team led by Prof. Li Yiping from our college’s Research Center of Fruit Tree Pests and Green Prevention published an online research paper titled "Trypsin-encoding gene function of efficient star polycation nanomaterial-mediated dsRNA feeding delivery system of Grapholita molesta" in Pest Management Science. This study screened out the key trypsin gene in the midgut digestive enzymes of Grapholita molesta using transcriptome technology and analyzed its function using optimized SPc nanocarrier-mediated RNAi technology. It was found that the trypsin gene GmolTrypsin9 can serve as a target gene for the control of Grapholita molesta, providing an important theoretical reference for the subsequent development of RNAi biological pesticides. Ph.D student Lv Dongbiao and postdoctoral researcher Dr. Kassen Kuanysh from our college are the co-first authors of this paper, while Profs. Li Yiping and Dr. Yuan Xiangqun are the co-corresponding authors.
Grapholita molesta is an important worldwide pest of fruit trees, severely damaging the tender shoots and fruits of Rosaceae fruit trees such as peach, pear, apple, and plum, causing significant economic losses to fruit production. Trypsin is an important hydrolytic digestive protease in the midgut of insects, playing a crucial role in digestion, growth, and development of insects. Based on previous transcriptome data analysis of Grapholita molesta feeding on hosts such as peach, pear, apple, and plum, this study screened and identified key trypsin genes and analyzed the characteristics of the trypsin GmolTrypsin9 gene. By conducting experiments on the stability of dsRNA and the protective effect of SPc nanocarriers on target genes, the optimal dosage of SPc nanocarrier-mediated RNAi feeding method was optimized and screened, resulting in the development of an efficient and convenient new method to verify the function of target genes in Grapholita molesta. After using this method to interfere with trypsin GmolTrypsin9, it was found that the activities of trypsin and chymotrypsin in the midgut of Grapholita molesta larvae were significantly reduced, leading to prolonged larval stages and reduced pupal weight, severely affecting their growth and development. The results indicate that the trypsin gene GmolTrypsin9 in Grapholita molesta is an important insect digestive enzyme gene that can serve as a target for the development of RNAi biological pesticides, possessing significant application value.
The role of GmolTrypsin9 in the growth and development of Grapholita molesta
This research marks another new development for the research team following their publication on the global invasive pest Spodoptera frugiperda titled "Dynamics of gut microflora across the life cycle of Spodoptera frugiperda and its effects on the feeding and growth of larvae" in Pest Management Science in 2023. This research was funded by the General Program of the National Natural Science Foundation of China (31871971, 32172409) and the Major Science and Technology Special Project of Shaanxi Province (2020zdzx03-03-02).Original link：https://pubmed.ncbi.nlm.nih.gov/38970236/
