Title : Induction of volatile organic compounds in wheat plants following infection by different rhizoctonia pathogens
Abstract:
The most popular means of plant protection is the chemical method, but this control is often connected with the need for repeating chemical treatments. Thus, eco-friendly strategies should be developed where, under the European Green Deal, aromatic plants and their repellent properties seem to constitute a good alternative. In earlier studies, we have shown that insect injury, bacteria infestation and pathogen infection induce plant volatile organic compounds (VOCs) emission, which can provide defensive functions to plants. In this study, Triticum aestivum L. (Poaceae) cv. ‘Jenga’ wheat plants were intentionally infected with one of four Rhizoctonia species (R. cerealis, R. solani, R. zeae, and R. oryzae). The soil was inoculated by the pathogens during sowing, whereas shoots were inoculated at stage BBCH 33. In greenhouse experiments, we measured VOCs from wheat 3, 7 and 11 days following stem infestation, or 42 days following soil inoculation of Rhizoctonia spp. VOC emissions were found to be largest on days 7 or 11 post-stem inoculation (>3 days post-stem inoculation >42 days post-soil inoculation). T. aestivum infected by pathogens induced five common green leaf volatiles (GLVs), namely (Z)-3-hexenal = (Z)-3-HAL, (E)-2-hexenal = (E)-2-HAL, (Z)-3-hexen-1-ol = (Z)-3- HOL, (E)- 2-hexenol = (E)-2-HOL, (Z)-3-hexen-1-yl acetate = (Z)-3-HAC], six common terpenes (β-pinene = β-PIN, β-myrcene = β-MYR, Z-ocimene = Z-OCI, linalool = LIN, benzyl acetate = BAC, β-caryophyllene = β-CAR), and indole = IND. We found that R. cerealis infested T. aestivum emitted the largest amounts of (Z)-3-HAL and (Z)-3- HAC, while T. aestivum infested by R. solani released the largest amount of LIN (7 or 11 days following stem infestation). VOCs released by the T. aestivum after R. cerealis (AGD I) and R. solani (AG 5) infestations were significantly larger in comparison to R. zeae (WAG-Z) and R. oryzae (WAG-O) for the volatiles (Z)-3-HAL, (E)-2- HAL, (Z)-3-HOL, (E)-2-HOL, (Z)-3-HAC, β-PIN, β-MYR, and LIN. With the exception of (E)-2-HOL, β-MYR, LIN, BAC, β-CAR, the other VOCs were emitted in similar amounts by infected T. aestivum 3 days following stem and soil inoculation. The quantities of induced VOCs were higher at days 7 and 11 than at 3 days post-infection, and greater when T. aestivum was infected with Rhizoctonia on the stem base than through the soil.
Audience Take Away:
- Eco-friendly strategies should be developed, and we propose the use of aromatic plants with repellent properties as a viable and beneficial alternative. Assessing the insect dose response to plant volatile organic compounds can reveal a range of concentrations over which herbivore attraction or repellence may occur. This may lead to novel, sustainable methods of pest and environmental control.
- New trends and/or solutions in Chemical Ecology are of importance for the future of plant protection. The intensive reduction of typical pesticides lead us to new environmental-friendly approach in plant protection. The audience will learn that the we as the humanity have to focus much more on the on the nature observation than invest funds in new formulas synthetizing.
- Among main target groups are:
-farmers
-policy makers (regional, national and EU level)
-pest control industry
-scientists - Farmers will be the crucial end users of the project results. Although they are a diverse target group, the outcomes of the project can be used in any farm. Hence, it must be assumed that all people and companies involved in agricultural plant production will be among the groups of recipients. In essence, there are three main farm groups within the EU are semi-subsistence farms, where a large proportion of the food produced is used to feed farmers and their families, small and medium-sized farms that are generally family-run businesses, and large agricultural enterprises, which more often have some legal form or are cooperatives.
- Biochemical pesticides are naturally occurring substances that control pests by non-toxic mechanisms, whereas conventional pesticides directly kill or inactivate the pest. Biochemical pesticides include substances that interfere with mating, such as insect sex pheromones, as well as various scented plant extracts that attract insect pests to traps and are effective in very small quantities. In consequence, biopesticides are usually inherently less toxic than conventional pesticides and generally affect only the target pest and closely related organisms. Moreover, when used as a component of Integrated Pest Management (IPM), these programs can significantly reduce the use of conventional pesticides. Owing to the continuous evolution of the resistance to conventional chemicals, there is a need for intensive research on the biopesticide development. Of note is that the costs for the development and the registration of the biopesticide are comparatively lower. However, a successful biopesticide development can only be obtained through interdisciplinary research involving entomology, genetics, molecular biology, biochemistry, agronomy, plant pathology, analytical chemistry and ecology.
- The humanity soon or later will follow the observation and application of the processes in the nature. The market and job opportunities will explode in the coming future.
- Yes, it is. Personally I will be happy to collaborate with any other institutions.
- Concerning the significance of the project outcomes, it has to be mentioned, that these will be in line with EU and worldwide policy, global market trends and finally, yet importantly, the real needs of end users. As it was highlighted during International Year of Plant Health in 2020, plant pests are responsible for losses of up to 40% of crops globally, and for trade losses in agricultural products worth over USD 220 billion each year. It is of therefore of utmost importance for all people and entities engaged in food production to have sound plant protection products. Our proposed multitool solution will have a game-changing impact on the IPM market and farming systems. Furthermore, the global bio-insecticides market size is projected to grow at a CAGR of 15.8% from an estimated value of USD 2.2 billion in 2020 to reach USD 4.6 billion by 2025. The increasing area under organic cultivation and growing concerns toward the impact of pesticide use on biodiversity is leading to the growth of the bioinsecticide industry. The role of IPM practices in biological crop protection has been gaining importance worldwide.
- The presentation might help other scientific departments in grant application or in solid communication and collaboration with presenter.
- While numerous factors influence pest management decisions, reported barriers include, among others: (i) the absence of non-chemical alternatives, (ii) lack of knowledge on pesticides and alternatives, (iii) biased information from chemical companies, and (iv) an insufficient advisory service on judicious pesticide use. A crucial way to mitigate these barriers would be the dissemination and communication of project results as well as integrating the farmers’ communities within the project from the very beginning (regional centres for pest risk management as a citizen science approach).
- I want to tackle the natural plants’ defense system with the cooperation to Asian scientific groups.
