Researchers at Umeå University in Sweden and Wageningen University & Research in The Netherlands have discovered how plants can defend themselves against aphids. The findings may help to reduce the use of insecticides and improve sustainability of agriculture.
During her doctorate, Karen Kloth studied aphid feeding behavior on different varieties of the model plant Arabidopsis thaliana, collected from 350 different locations on the northern hemisphere. Together with other Dutch researchers, she built a video-tracking platform to measure how often aphids penetrated the plants and were feeding.
On resistant plants, the aphids were feeding less from the sugar-rich sap than on susceptible plants. This behavior was associated with one specific plant gene, coding for a protein with unknown function. In Benedicte Albrectsen’s lab at the Umeå Plant Science Centre, the researchers studied where in the plant the protein was located. They transformed plants with a fluorescent version of the protein, and found that the protein coats the inside of the vessels where sugar-rich sap is transported. Further experiments showed that aphids had a slower sap ingestion and produced fewer offspring on resistant plants.
The researchers think that the protein might occlude the narrow food canal of the aphid. At high temperatures, plants produced more of the protein and were more resistant to aphids. In addition, plants with the protein had another advantage: they were able to produce more seeds during heat stress.
Kloth, who has been working on this study for six years, is optimistic about the new resistance gene and what it would mean for plant breeders.
“In the beginning, we did not know if the video platform would work,” she says. “We kept the aphids in an artificial environment, and it is debatable whether this represents whole plants in natural conditions. When the first results confirmed that we had indeed found a new resistance gene, I was really excited.”
Natural plant resistance to aphids and better tolerance to heat stress are of interest for plant breeding companies. Breeding crops with effective resistance proteins can help to reduce insecticide application and yield losses due to hot conditions. In the long term, this research could help to produce more sustainable fruits and vegetables.
The study was recently published in the journal “Plant Cell.”