Giving plants sustained resistance via genetic research

  Agrosystems Research
  Plant Breeding
  Biointeractions and Plant Health
  Biometris
  Bioscience
  Research facilities
  Projects
  Sustainable production and climate change
  Global crop production
  Developing cropping systems that require lower inputs
  More efficient utilisation of nitrogen and phosphate without leaching
  Disease suppressiveness of soil reduces pesticides use
  Silt vegetables, seaweed and sea fish from one mixed silt farm
  Making crops resistent to insects
  Giving plants sustained resistance via genetic research
  Making plants suitable for poor or silty soils
  Biological control reduces consumption of chemical pesticides
  DNA techniques for exact detection of pests and diseases
  New techniques can overcome objections genetic modification
  Crop protection only where really needed
  Drought-tolerant potatoes on the horizon
  Restricting large harvest losses caused by viruses
  Predicting when cereals are containing fungal toxins
  Making plants suitable for a different climate
  Better detection of exotic organisms
  Effect of climate change on land use
  Effect of climate change on genetic variation within a species
  Farmers think about consequences of climate change for their farm
  Climate change increases chance of harvest failures by pests and diseases
  Health
  Plant-based raw materials
  Systems biology

Lily cultivars show a wide variation in their resistance to Fusarium. Use of a DNA marker allows early and simple prediction whether a lily plant is resistant.

Pest or disease control would not, or hardly, be required if plants would have a sustained resistance to pests and diseases. Scientists of Plant Research International are developing these plants with a sustained resistance by unravelling the resistance mechanisms at gene level.

Many plant pathogens, from viruses, bacteria and fungi through to insects, are capable to break through plant defence mechanisms. They are affecting the crop and this leads to yield loss. But there are always plants that are not or hardly affected; they are inherently resistant.

Our scientists are making use of this phenomenon. They are searching wild species for resistance genes and transfer these to the susceptible species by means of crossing. In the progeny they are investigating which regions in the genome play a role in resistance and subsequently which genes in that region are responsible. They also want to know why one gene does give resistance whereas another does not. This might enable them to amend genes in such a way that they will give an even better resistance.

Stacking genes
Sometimes one gene is sufficient to make a plant resistant. But in practice this usually is found to be unsustainable because the pathogen can easily break such resistance. Our scientists are therefore ‘stacking’ several resistance genes.
And there are also genes that are only causing partial – or field - resistance. Combination of different genes that give partial resistance (also called Quantitative Trait Loci or QTLs) can yet enable the plant to keep his enemies at bay. The scientists are investigating which and how many genes are at least required to make a plant resistance to a specific pest or disease.

Switching off genes is a third option. Here one can think of genes that are coding for the proteins a virus needs to be able to infect the plant. These genes are called S (susceptibility) genes. It is known that viruses of which those S genes have been switched off have difficulty in infesting a plant. This will therefore lead to sustainable resistance. The scientists have demonstrated that this mechanism is also working for some fungi. But time will have to learn whether this is also a lasting effect. Resistance by S genes does, incidentally, often lead to plant yield losses.

Analysing pest or disease
Making plants resistant also tells the scientists how pests and diseases themselves are functioning; the proteins excreted by fungi to infect the plant are an example. Once our scientists know which protein this is, they can – as it were – make the plant immune to that particular protein.

This requires the scientists to analyse many plants for possible resistance. The sooner it is clear whether the plant is really resistant the better. This is why the scientists are continually developing new tests for sooner getting decisive answers. In this way they can see in an early stage, often already at seedling level, whether the resistance is really there and whether it is effective.

  
Print this page

Contact
Richard Visser
Plant Breeding
business card
»  more Contact