Recently, Niu Dongdong’s research group from the School of Plant Protection of Nanjing Agricultural University and the Hailing Jin team of the University of California, Riverside jointly published the title”Spray-induced gene silencing for disease control is dependent” in Plant Biotechnology Journal. on the efficiency of pathogen RNA uptake” research paper. The study compared the absorption efficiency of dsRNA by pathogenic fungi, oomycetes and non-pathogenic fungi, and found that Botrytis cinerea, Sclerotinia, Rhizoctonia solani, Aspergillus niger and Verticillium dahlia can effectively absorb dsRNA, which is beneficial The fungus Trichoderma viride has a low absorption efficiency of dsRNA, while Colletotrichum gloeosporioides cannot absorb dsRNA. Phytophthora infestans has a low absorption efficiency of dsRNA, and the different cell types and developmental stages of pathogens also affect the absorption efficiency of dsRNA (Figure 1).
The green prevention and control of crop diseases is of great significance to ensuring my country’s food security and sustainable agricultural development. In recent years, with the gradual in-depth study of the biological functions of small RNAs, it has been discovered that small RNAs have key regulatory functions in the interaction between plants and pathogens. Among them, cross-border regulation of small RNAs has become a research hotspot in the field, and the mechanism of small RNA shuttle transport has been realized. An important theoretical breakthrough in the field, and gradually developed Spray-Induced Gene Silencing (SIGS) based on cross-border RNAi technology. SIGS is a method of in vitro synthesis of double-stranded RNA (dsRNA) targeting target pathogenic factors and sprayed on the surface of plants to inhibit the occurrence of diseases and achieve green prevention and control of diseases. However, the theoretical basis of SIGS for preventing and controlling crop diseases is still unclear.
Figure 1. YFP-dsRNA labeled with fluorescein Detect the absorption efficiency of dsRNA by various fungi
Through the detection of disease prevention effect, it is found that SIGS has a good control effect on pathogens with high dsRNA absorption efficiency, and can significantly inhibit the occurrence of diseases. On the contrary, SIGS cannot inhibit the pathogenicity of pathogens with low absorption efficiency or inability to absorb dsRNA. In addition, in order to test the persistence of the protective effect of dsRNA on crops, the study tested the effects of controlling tomato gray mold in different time periods after dsRNA treatment, and found that dsRNA treatment still has good disease prevention against gray mold after 7 days. The effect (Figure 2) shows that SIGS has broad application prospects in the prevention and control of field diseases.
At present, there have been successful cases of SIGS-mediated disease control. This study found that the absorption efficiency of dsRNA by pathogens is the bottleneck in the application of SIGS. In the future, how to further optimize the delivery vector or other ways to improve the absorption efficiency of pathogenic bacteria to dsRNA, so as to expand the application field of SIGS. In addition, how to enhance the stability of RNA in the environment is also crucial for the application of SIGS to prevent and control field diseases.
Figure 2. SIGS mediates the persistence of plant protection
Associate Professor Niu Dongdong from the School of Plant Protection, Nanjing Agricultural University and Professor Hailing Jin from the University of California, Riverside are the co-corresponding authors of the paper. Nanjing Agricultural University is the first to complete the paper. Qiao Lulu, a graduated doctoral student, is the first author of the thesis. The research was funded by projects such as the Jiangsu Provincial Agricultural Science and Technology Independent Innovation Fund.