We rely heavily on plants, which are often exposed to pesticides or fungicides to control insects or fungal diseases, for example. But pests and pathogens may evolve and change to overcome such control measures. Or the chemicals can have a variety of undesirable effects and impacts beyond their targets. But there may be a way to create a kind of resistance to some threats, like a kind of vaccine for plants. This approach triggers a type of plant immune defense, so that a plant can respond more effectively when it encounters a threat. The work has been reported in Frontiers in Science.
“While induced resistance has been studied for decades, its exploitation in crop protection has only recently begun to gain momentum,” said study co-author Brigitte Mauch-Mani, a Professor at the University of Neuchâtel. “We argue in favor of a holistic approach to crop protection, which combines multiple strategies to deliver tailored solutions. Induced resistance sits in the heart of such an integrated approach.”
Many crops are now genetically modified so that they will resist the effects of a pesticide. But pests may eventually evolve so that these pesticides are ineffective. But if plants are themselves changed so that they have better protection against pests or pathogens, such pesticides may no longer be as necessary.
Plants might generate and release compounds that attract natural predators of certain pests. Another method is known as defense priming, in which plants are exposed to a stressful event, which induces defense mechanisms. If a similar problem arises again, the plant then reacts more robustly. Defense priming in plants seems to last so long that it's passed down to the next generation.
These induced resistance strategies don't usually shield plants completely, so they have to be combined with other efforts, and carefully controlled so that plant biology is not compromised.
“Induced resistance is the result of a complex network of developmental and environmental pathways in the plant,” explained Mauch-Mani. “So safe and efficient exploitation of induced resistance is not as straightforward as the introgression of a single gene or spraying a single pesticide. We will need case-by-case evaluation of the optimal growth conditions, crop germplasm, and agricultural practices to capitalize on induced resistance’s multifaceted benefits.”
Induced resistance may not only help reduce the threats posed by pests. Other types of induced resistance could improve plant health or nutrition, and may help plants adapt to a changing climate.
Scientists may also be able to learn more about how these mechanisms are imprinted and passed onto the next generation. These processes might then be exploited to improve food production in new ways.
“We strongly believe that fundamental research into induced resistance will be critical for the transition towards a truly sustainable food supply,” said Mauch-Mani. “However, there is an urgent need for better communication between discovery-focused research and other stakeholders who have the expertise to translate discovery into application."
Sources: Frontiers, Frontiers in Science
