A recent paper, first-authored by Gonçalo Laureano and headed by Andreia Figueiredo – respectively, PhD student and principal investigator at the Grapevine-Pathogen Systems (GPS) Lab, at Ciências ULisboa – presents a study  using a Plasmopara viticola – the microorganism responsible for the downy mildew disease in grapevine – strain capable of suppress the defense mechanisms conferred by a specific defense gene, the Rpv3, in grapevine. This paper was published in the journal Cells and the work on it reported is part of Catarina Gouveia’s thesis, co-supervised by Ana Rita Matos, both from the Environmental and Molecular Plant Physiology, respectively MSc Student and researcher. Read the BioISI Digest below to know more.

What was the starting point that led to the current research?

We had previously shown that jasmonic acid (JA) signaling is important to define the outcome of grapevine-P. viticola interaction. As JA is synthesized in the chloroplast from a pool of free C18:3, we have tried to understand if fatty acids and lipid modulation could be important in a successful grapevine defense response. Based on the results that we had we hypothesize that activation of this signaling/defense pathway could be associated to specific traits in grapevine, particularly to the existing Resistance to Plasmopara viticola loci (Rpvs). Rpvs are currently established as important markers in grapevine breeding towards P. viticola resistance.

In this work we have shown that the activation of grapevine defense throughout JA and lipid signaling pathways may be specifically related to an Rpv3 background.

What is the main finding reported in this paper?

The genetic background has a strong influence in the resistance degree against downy mildew, in each grapevine variety, by the presence of specific defense genes. In our study we used a Plasmopara viticola strain capable of suppress the defense mechanisms conferred by a specific defense gene, the Rpv3. The Rpv3 is present in the tolerant variety used as well as in the resistant, but this one besides harboring the Rpv3 present another one, the Rpv12. Our findings showed that defense mechanisms triggered by lipids, called lipid signaling events, seems to be specific to the Rpv3.

If you had to explain the main finding to a 5-year-old child, how would you do it?

Just like people and animals, different plants can be strong or weak against sickness. Some plants can fight off sickness easily, some can get sick but recover, and others are very weak and can’t get better once they’re sick. The reason some plants are stronger is because they have special things inside them that protect them. In this study, we found out what those special things are that help plants stay healthy when they get a sickness called downy mildew.

Why is it important for the scientific community and for society at large?

In viticulture, to prevent yield and quality losses the current strategy relies on the intensive application of phytochemicals, which leads to negative effects, such as pollution, biodiversity loss and health problems. The seek for a sustainable viticulture has led to the development of breeding programs, that aims at improving agronomic traits such as resistance to pathogens.  However, the process of obtaining hybrids is extremely time-consuming and laborious. In addition, the emergence of new strains of P. viticola has been challenging the resistance of these hybrids. Therefore, a deeper knowledge of grapevine defense mechanisms is essential, not only to accelerate breeding processes, but also to define more sustainable disease control measures.

What are the next steps?

We proposed that could be a link between the genetic background of the grapevine and activation of a lipid signaling pathway as a defense strategy against Plasmopara viticola. To further prove this hypothesis, more genotypes with different Rpv backgrounds should be analysed.

Find out more about GPS Lab here 

Read the full paper here.