Resistance

Question 1

What is the primary difference between qualitative resistance and quantitative resistance?

Answer 1

Qualitative resistance is a type of resistance that is conferred by a single gene mutation, leading to a large, clear-cut effect. Quantitative resistance involves the combined small effects of changes in multiple genes, resulting in a continuous spectrum of resistance.

Question 2

What are the other names for qualitative and quantitative resistance?

Answer 2

Qualitative resistance is also known as monogenic resistance, while quantitative resistance is also known as polygenic resistance.

Question 3

Which fungicide group is associated with resistance caused by single-step mutations, and what is an example of such a mutation?

Answer 3

Group 11 - QoIs are associated with resistance from single-step mutations. The most common and complete resistance-causing mutation is G143A.

Question 4

What is the FRAC group and name of the fungicide group associated with resistance that is a multi-step process?

Answer 4

The fungicide group is Group 3 - Demethylation Inhibitors (DMIs), which are also known as triazoles.

Question 5

What are the different mechanisms that contribute to DMI resistance?

Answer 5

DMI resistance can occur through a combination of mechanisms, including a mutation in the CYP51 gene, overexpression of the CYP51 gene, and enhanced efflux of the fungicide from the cell

Question 6

How many single-step mutations are mentioned for Group 11 - QoIs, and what do they cause?

Answer 6

Three single-step mutations are mentioned: G143A, F129L, and G137R. The G143A mutation results in complete resistance

Question 7

What is a key difference in the type of resistance development between QoIs and DMIs?

Answer 7

Resistance to QoIs often develops from single-step mutations with a large effect, while resistance to DMIs is a multi-step process involving various mechanisms.

Question 8

Which fungicide group listed has a high risk of qualitative resistance?

Answer 8

Group 11 - QoIs have a high risk of developing qualitative resistance due to the effect of single gene mutations like G143A.