RNAi-based control of plant root pathogens

• Applicant: Professorin Dr. Aline Koch
• Subject Area: Plant Breeding and Plant Pathology
• Term: from 2016 to 2018
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 321722509

RNAi is known as a conserved integral part of gene regulation present in all eukaryotes that utilizes noncoding double-stranded (ds)RNAs to direct the silencing of gene expression. This natural phenomenon can be exploited to control agronomically relevant plant diseases. The in planta expression of dsRNAs that specifically targets genes in a harmful pathogen/predator can be utilized to confer resistance and therefore protection from infection. This biotechnological method was termed host-induced gene silencing (HIGS). A vast number of studies on HIGS in plant-pathogen interactions have been published, which reflects the relevance of this emerging field and its great potential in plant protection. Recently, we demonstrated that HIGS of essential fungal ergosterol biosynthetic genes is a highly efficient strategy to control the growth and development of the phytopathogenic fungus Fusarium graminearum. While these results provided proof-of-concept that RNAi-based plant protection is an effective strategy to control diseases caused by devastating necrotrophic pathogens, the broad applicability of this transgenic approach remains questionable due to the persisting weak acceptance of GMO strategies for food and feed production in many countries. Therefore, we established an RNAi-based crop protection strategy using direct spray applications of noncoding double-stranded RNA to target pathogens, termed spray-induced gene silencing (SIGS).The present application addresses the question, based on our experience of HIGS and SIGS strategy development to control Fusarium diseases on leaves as well as ears, whether we can efficiently control plant root pathogens, such as Fusarium culmorum and Magnaporthe grisea, using the non-transgenic SIGS approach. Diseases of cereal crops caused by phytopathogenic fungi of the genus Fusarium as well as Magnaporthe lead to great shortages in global grain production. The extensive application of systemic fungicides in the field has led to the development of reduced sensitivity, or even resistance to conventional fungicides, in many plant pathogenic fungi. These alarming developments demonstrate that novel strategies in pathogen and pest control are urgently required. Agrobiotechnological strategies such as SIGS that will be assessed in this proposal will provide essential information on a fundamentally new plant protection strategy, thereby opening novel avenues for improving crop yields in an environmentally friendly and sustainable manner.

• DFG Programme: Research Grants