London: Researchers have demonstrated that unique fungi strengthen the "immune systems" of wheat and bean plants against aphids. Fungi enter and influence the amount of a plant's own defences, resulting in fewer aphids.
The results, published in the journal New Phytologist, could serve to reduce agricultural insecticide use. "In order for us to really use fungi to control agricultural pests in the future, we need to understand the mechanisms and processes behind their activity. So, it's very exciting that we have managed to advance a step closer", said researcher Nicolai Vitt Meyling, Associate Professor from the University of Copenhagen.
Certain fungi are able to establish a close rapport with plants that results in fewer insect infestations and thereby less damage to crops. Until now, it was unclear how these fungi could be used to reduce insect infestations. The researchers studied three types of fungi to compare their effects against aphid infestations on wheat and bean plants.
"It turned out that two of these fungi were able to effectively reduce aphid infestations by establishing themselves in plant roots and tissues," the researcher said. "By combining greenhouse-based experiments with advanced chemical analyses, we can see that the fungi cause plants to increase production of their own natural defences, thus strengthening plant immune systems. This translates into fewer aphids, which would otherwise weaken a plant," the researcher added.
"According to the researcher, when aphids suck up plant sap, plants lose energy, to the detriment of their root networks and overall growth.
However, when fungi-treated plants were attacked by aphids, they were able to compensate by increasing root growth, so that they didn't lose growth potential. Plants left untreated with the fungi couldn't compensate for the attacks. The researchers "treated" wheat and bean plants by applying fungal spores to seed, from which the plants were then germinated and cultivated. They then added a few aphids and observed how many more aphids.