According to Penn State researchers, plants can trigger a "leaky-gut syndrome" (permeability of the intestinal mucosa) in insects as part of a multi-pronged strategy to protect themselves from ingestion. By better understanding of plant defense, the results could contribute to the development of new pest control methods.
"We have found that a combination of physical and chemical defense mechanisms in maize plants can disrupt the gut barrier of fall worms and allow intestinal microbes to penetrate their body cavities," said Charles Mason, a postdoctoral fellow in entomology. "This can cause septicemia, which can kill the insect or simply trigger an immune response that can weaken the insect."
Researchers culled case worms in the lab and vaccinated them with one of three species of naturally occurring intestinal bacteria. They fed the insects with one of three types of maize ̵
The scientists found that the presence of all three intestinal bacteria types was the ability of the worms to reduce larvae to damage maize plants, especially when other defense mechanisms such as elongated trichomes and enzymes were present that can perforate both intestinal linings. The types of intestinal bacteria, however, differed in the extent to which they weakened the insects. The findings are published in the July 22 issue of Proceedings of the National Academy of Sciences .
"Our results show a mechanism by which some plants use the intestinal flora of insects in conjunction with their own defense against them," said Mason.
Gary Felton, a professor and head of the Department of Entomology, noted that the findings should have broad implications for understanding the environmental function of plant defense.
"In our study, all of the different plant defense mechanisms, such as leaf trichomes and plant enzymes, require certain gut microbes to defend against herbivores." said. "Our results predict that the variation in plant defense efficacy in nature is largely due to the variability observed in the insect gut microbial communities."
The team said the findings could help inform the development of insect-resistant plants.
"It may be beneficial to" stack "plant defense mechanisms targeting the insect gut to create a" leaky gut "that exposes the insect to microbial attacks on its immune system," Mason said.
Caterpillars protect against predators from sticky poisonous plants
Charles J. Mason el al., "Plant Defense Interacts with Enteric Insect Bacteria Inducing a Bowel Syndrome," PNAS (2019). www.pnas.org/cgi/doi/10.1073/pnas.1908748116
Plants defend themselves against insects by triggering a "leaky gut syndrome" (2019, July 22)
retrieved on July 22, 2019
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