Helping potatoes help themselves: inducing plant defences

Figure 3. Sources of induced systemic resistance in plants include beneficial bacteria and fungi on the plant roots, as well as abiotic compounds such as silicon, methyl jasmonate and chitin/chi- tosan. While microbes can produce signalling compounds directly, abiotic compounds stimulate production by the plant. While these compounds can have a range of effects, their key function is to turn on defence genes throughout the plant.

Just like us, plants have evolved sophisticated mechanisms to defend themselves against pests and pathogens. One of the most intriguing strategies is 'Induced Systemic Resistance' (ISR). Specific microbes or environmental triggers can activate the plant defences, improving its ability to ward off attack or cope with stress. And we can help that happen.

ISR occurs when defensive genes are activated throughout the plant and can be triggered by:

• Presence of a pathogen

• Damage caused by a pathogen or insect to the plant cells

• Beneficial fungi and / or bacteria in the root zone

• Physical stress

• Abiotic (non-biological) compounds such as chemicals, plant hormones or volatiles

Stimulation of ISR may therefore be another tool in the kitbag helping to protect potato crops from the destructive effects of the environment, pests, and pathogens.

Read more about ISR in Issue 13 of PotatoLink magazine.