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Title: Applications of plant biotechnology to protect crop plants from fungal infection

Petr Karlovsky

Georg-August-University Goettingen, Germany

Biography

Petr Karlovsky is professor and head of Molecular Phytopathology and Mycotoxin Research Section of the University of Göttingen in Germany. Petr studied biochemistry and obtained his PhD degree in the Institute of Biophysics in Brno, Czech Republic. After his studies he worked as a postdoctoral researcher at universities in Goettingen and Hohenheim in Germany and as a visiting professor at the University of Connecticut in Storrs, USA. In 1999 he moved from academia to industry, assuming the position of Research Manager for Disease Resistance with DuPont/Pioneer Hi-Bred in Johnston, IA and Newark, DE in the USA. In 2001 he accepted professor position at the University of Goettingen. Since then he acted as Vice President of the Society for Mycotoxin Research, was nominated for two Expert Groups of ILSI (Brussels, Belgium), and joined editorial boards of Mycotoxin Research, Journal of Phytopathology and PLOS ONE and the advisory board of Amity Institute of Microbial Sciences in New Delhi, India. He served as a reviewer for granting agencies of Austria, Czech Republic, Germany, Israel, Portugal, Singapore, Switzerland and USA and was awarded a guest professorship by Zhejiang University in Hangzhou, China, and a Senior Visiting Fellowship by the Institute of Advanced Studies, Bologna, Italy. Petr Karlovsky co-authorized 133 scientific publications listed by Clarivate Analytics (Web of Science) and more than 200 abstracts and is listed as co-inventor on several patents. He lives with his wife in Berlin, Germany.

Abstract

Biotechnology provides indispensable tools for plant protection. Plant cell cultures, in vitro selection for resistance, embryo rescue, protoplast fusion, double haploids and other techniques have advanced resistance breeding long before genetic engineering became feasible in crop plants. Although these techniques are still being used, plant biotechnology is often understood as a synonym for the use of genetically engineered (GM) crops, which will be the focus of this presentation. Many strategies for genetic engineering of crops for resistance against pathogens exist but only few were developed to maturity. Production of enzymes digesting fungal cell walls in GM crops was historically the first strategy, inspired by natural defence of plants. Antimicrobial peptides followed with a ramification to peptides from sources that might frighten consumers (scorpions) and to non-enzymatic effects of enzymes (lysozyme). Fusion proteins consisting of antimicrobial peptides and pathogen-specific antibodies attracted considerable attention, promising to prevent Fusarium head blight in wheat.

Enzymatic detoxification of fungal virulence factors was coined in the 1980th in Japan, targeting fusaric acid. Although fusaric acid acts as a virulence factor in many diseases, in planta detoxification as a resistance strategy has yet to be demonstrated. Detoxification was however exploited successfully against pathogens producing oxalic acid and turned out to be one of the most efficient GM-based resistances available against fungi, entering patent portfolios of major breeding companies. The detoxification of mycotoxin deoxynivalenol was shown to protect grain crops from Fusarium infection. First fungal genes were used; the industrial development of GM wheat resistant to Fusarium failed due to a wrong choice of the gene. More recently genes of plant origin have been employed for the detoxification of deoxynivalenol.

Apart from rendering crops resistant to fungal infection, detoxification of fungal metabolites may improve food safety status of crops when the targeted compounds are mycotoxins. A detoxification strategy aiming at the reduction of exposure to mycotoxin fumonisin was developed by a major seed company to maturity but the GM varieties have not been commercialized, apparently because of concerns about the effect of negatively loaded keywords "GM" and "mycotoxin" on public perception. A surprising effect of a strategy targeting maize pests was discovered in Iowa and confirmed in many countries since: GM maize producing Bt protein, protecting the plant from pests, benefit from significantly reduced content of fumonisins and other mycotoxins.

The most recent strategy of genetic engineering of crops for resistance is transkingdom gene silencing by RNA interference. The efficiency is surprisingly high but there are concerns about the stability of the strategy because fungal mutants impaired in RNA interference are supposed to break the resistance fast. Finally, CRISPR/CAS equipped plant biotechnology with the capability to edit plant genomes in situ in a precise way, offering new options for the enhancement of plant native defence especially against biotrophic pathogens. While in Europe irrational fears and anti-GM lobbies essentially prevented applications of GM in plant production, plant biotechnology will continue advancing plant production in North America, Africa and on the Asian continent.