RNA silencing approaches for identifying pathogenicity and virulence elements towards engineering crop resistance to plant pathogenic fungi

Over the past several years, RNA interference (RNAi) has emerged as a powerful genetic tool that is being exploited not only in fundamental research for the assessment of gene functions, but also in various fields of applied research in medicine and agriculture. In plants, RNAi strategies have the potential to allow manipulation of various aspects of food quality and nutritional content, but also for plant protection. In the study of plant–fungus interactions, a comprehensive understanding of pathogenic mechanisms based on information from genome sequences demands advanced genomics tools and infrastructure. In order to make use of the plethora of information yielded by the rapidly increasing fungal pathogen genome sequencing studies, there is a growing need to achieve gene function assessment amenable to high-throughput techniques. Targeted gene disruption is effective but may not be feasible in certain fungi because of lack of transformation protocols or their life styles. RNAi techniques offer an alternative but, in contrast to other biological systems, only few studies have reported the use of RNAi to explore gene function in plant pathogenic fungi. In this review, we summarize a variety of options using RNAi techniques that have become available to study gene function for high-throughput phenotypic screening of virulence and pathogenicity factors in plant fungi. The identification of such genes can be exploited for the protection of crops against fungal pathogens.