Abstract
The hemibiotrophic fungus Zymoseptoria tritici, responsible for Septoria tritici blotch, is currently the most devastating foliar disease on wheat crops worldwide. Here, we explored, for the first time, the ability of rhamnolipids (RLs) to control this pathogen, using a total of 19 RLs, including a natural RL mixture produced by Pseudomonas aeruginosa and 18 bioinspired RLs synthesized using green chemistry, as well as two related compounds (lauric acid and dodecanol). These compounds were assessed for in vitro antifungal effect, in planta defence elicitation (peroxidase and catalase enzyme activities), and protection efficacy on the wheat-Z. tritici pathosystem. Interestingly, a structure-activity relationship analysis revealed that synthetic RLs with a 12 carbon fatty acid tail were the most effective for all examined biological activities. This highlights the importance of the C12 chain in the bioactivity of RLs, likely by acting on the plasma membranes of both wheat and Z. tritici cells. The efficacy of the most active compound Rh-Est-C12 was 20-fold lower in planta than in vitro; an optimization of the formulation is thus required to increase its effectiveness. No Z. tritici strain-dependent activity was scored for Rh-Est-C12 that exhibited similar antifungal activity levels towards strains differing in their resistance patterns to demethylation inhibitor fungicides, including multi-drug resistance strains. This study reports new insights into the use of bio-inspired RLs to control Z. tritici.
Highlights
Wheat is one of the most produced and consumed crops worldwide along with maize and rice
Wheat is susceptible to various pathogenic agents, Septoria tritici blotch (STB), caused by the hemibiotrophic fungus Zymoseptoria tritici, is considered as the most impacting foliar disease on wheat and is of major concern for wheat production worldwide
We conclude that 12 carbon is the optimum fatty acid tail length for both ether and ester-RLs regarding their direct activity against Z. tritici
Summary
Wheat is one of the most produced and consumed crops worldwide along with maize and rice. For the 2018–2019 period, the Food and Agriculture Organisation estimated that global wheat production reached 732.1 million tons [1]. This crop is cultivated in many different geoclimatic areas and ecosystems, and it is vastly used for human food as well as livestock feed. Wheat is susceptible to various pathogenic agents, Septoria tritici blotch (STB), caused by the hemibiotrophic fungus Zymoseptoria tritici, is considered as the most impacting foliar disease on wheat and is of major concern for wheat production worldwide. 70% of fungicides applied in the European Union are used for the control of this disease, for a cost of approximately 1.2 billion dollars per year [2,3]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
