A genetic approach to crop protection

• Ein genetischer Ansatz für den Pflanzenschutz

Spencer, David; Conrath, Uwe (Thesis advisor); van Dongen, Joost Thomas (Thesis advisor)

Aachen : RWTH Aachen University (2022, 2023)
Dissertation / PhD Thesis

Dissertation, RWTH Aachen University, 2022

Abstract

Plants rely on constitutive and inducible defence mechanisms to fight pathogens and to produce the resources for human diet and bioeconomy. Today, crop protection is at a crossroads where changes to the climate require alternative strategies to ensure food security. Exploiting the genetic traits of plant immunity provides a valuable toolbox for developing new approaches for resistance breeding. In this thesis, the antifungal activity in the phyllosphere of the common sunflower (Helianthus annuus L.) to the Asian soybean rust agent Phakopsora pachyrhizi has been assessed. The so-called nonhost resistance of sunflower to P. pachyrhizi comprises the induced biosynthesis and secretion of coumarins to the surface of its leaves. In addition, proteins that are constitutively present in the sunflower phyllosphere seem to be involved in defence. I identified several of them in an exoproteomic analysis of sunflower leaf washes. Furthermore, I demonstrated that the coumarin secretion machinery of sunflower can be transferred to Nicotiana benthamiana, and likely other crops as well, by heterologous expression of the ATP-binding cassette transporter HaABC. As a result, transiently transformed N. benthamiana leaves exhibit enhanced inhibition of P. pachyrhizi spore germination in the phyllosphere. To fully exploit the potential of genetic approaches for crop protection, public acceptance and political will needs to be encouraged by evidence-based debate. This work seeks to exemplify how studying one specific nonhost plant-pathogen interaction can potentially be of value for sustainable food production.