Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

The herbivore dilemma: How corn plants fights off simultaneous attacks

09.02.2016

Maize plants may face a metabolic tradeoff when defending against both aphids and caterpillars

Corn seedlings are especially susceptible to hungry insect herbivores, such as caterpillars and aphids, because they lack woody stems and tough leaves. So what's a tender, young corn plant to do?


Herbivorous insects feeding on a corn stalk.

Photo by Meena Haribal

A recent study by Professor Georg Jander's group at the Boyce Thompson Institute (BTI), finds that corn plants may make serious trade-offs when defending themselves against multiple types of insects. Some corn varieties make themselves more vulnerable to aphids after generating defensive compounds against nibbling caterpillars. The results, which appear in the journal Molecular Ecology, may lead to the development of corn plants that are naturally more resistant to certain insects.

"It's like a metabolic dilemma," said Vered Tzin, a first author and postdoctoral scientist in the Jander laboratory. "When caterpillars are feeding, there's a change in the metabolic pathway that makes chemical defense compounds that protects the plants from caterpillars. But when we studied aphids, it seems like the same compounds that make the plants caterpillar-resistant have the potential to make them aphid-susceptible."

Corn plants face an onslaught of different herbivorous insects that chew on leaves, pierce and suck out sap or plant cell fluids, bore into stems or consume the roots. Researchers estimate that insects consume 6-19 percent of the world corn crop each year, while also spreading bacteria and viruses between plants.

To defend against these attacks, corn plants have both physical and chemical defense mechanisms. To ward off aphids, plants make callose, a carbohydrate that can seal off openings between cells and to stop aphids from sucking out the sap from the tissues through their needle-like stylet. Callose formation is triggered by a defensive compound called DIMBOA. In the event of a caterpillar attack, plants produce a compound called MBOA that deters their feeding. Both MBOA and DIMBOA are in the same metabolic pathway and come from a molecule called a benzoxazinoid.

Because both defensive compounds come from the same parent molecule, the researchers suspected that feeding by one group of insects, such as chewing caterpillars, might affect the plant's ability to fight off another group, like aphids.

To test this idea, the researchers grew corn seedlings of a common variety, called B73, and exposed some to caterpillars. They then seeded them with aphids and counted the number of offspring that the aphids produced on pristine plants, compared to previously nibbled ones. The aphids consistently produced more offspring on corn that had been pre-chewed by caterpillars.

But, when the researcher tested other corn varieties, individual results would vary. They repeated the experiment with 17 different lines of corn from around the world. Like B73, some varieties supported more aphid offspring after a caterpillar feeding, while the pre-feeding reduced the number of aphids or had no effect on other varieties.

The variation they saw is likely due to the evolutionary history of the different corn varieties. Aphids tend to be more common in temperate areas, such as the Midwest, where they spread barley yellow dwarf virus and cereal yellow dwarf virus, while caterpillars are a larger problem in tropical areas. Different varieties likely arose from breeding programs aimed at fighting off the threats that corn faces in different environments.

To identify genes that may play a role in this interaction, the researchers bred B73 plants with another variety called Ky21, which hosted fewer aphid offspring after caterpillar feeding. Using a genetic approach, they identified three genome regions, on chromosomes 1, 7 and 10, that appear to have a significant impact on a corn plant's aphid susceptibility. By breeding for specific genetic variations that naturally reduce caterpillar and aphid damage, scientists can develop new crop varieties that will require fewer pesticide applications.

In the future, the Jander group plans to use a similar approach to see how corn plants respond to simultaneous attacks from other types of insects and pests that attack different plant tissues.

"We can use a genetic approach to ask ecological questions and try to understand how a plant responds to two organisms," said Tzin, pointing out that most plant-insect research focuses on the plant's response to one type of insect at a time. "We should use more genetic tools to answer ecological questions."

###

Media Relations Contacts: Patricia Waldron (607-254-7476, pjw85@cornell.edu) or Kitty Gifford (607-592-3062, kmg35@cornell.edu)

To learn more about Boyce Thompson Institute (BTI) research, visit the BTI website at http://bti.cornell.edu.

Connect online with BTI at http://www.facebook.com/BoyceThompsonInstitute and http://www.twitter.com/BTIScience.

About Boyce Thompson Institute

Boyce Thompson Institute is a premier life sciences research institution located in Ithaca, New York on the Cornell University campus. BTI scientists conduct investigations into fundamental plant and life sciences research with the goals of increasing food security, improving environmental sustainability in agriculture and making basic discoveries that will enhance human health. Throughout this work, BTI is committed to inspiring and educating students and to providing advanced training for the next generation of scientists. For more information, visit http://www.bti.cornell.edu.

Media Contact

Patricia Waldron
pjw85@cornell.edu
607-254-7476

 @BTIscience

http://bti.cornell.edu 

Patricia Waldron | EurekAlert!

More articles from Life Sciences:

nachricht New photocatalyst speeds up the conversion of carbon dioxide into chemical resources
29.05.2017 | DGIST (Daegu Gyeongbuk Institute of Science and Technology)

nachricht Copper hydroxide nanoparticles provide protection against toxic oxygen radicals in cigarette smoke
29.05.2017 | Johannes Gutenberg-Universität Mainz

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Strathclyde-led research develops world's highest gain high-power laser amplifier

The world's highest gain high power laser amplifier - by many orders of magnitude - has been developed in research led at the University of Strathclyde.

The researchers demonstrated the feasibility of using plasma to amplify short laser pulses of picojoule-level energy up to 100 millijoules, which is a 'gain'...

Im Focus: Can the immune system be boosted against Staphylococcus aureus by delivery of messenger RNA?

Staphylococcus aureus is a feared pathogen (MRSA, multi-resistant S. aureus) due to frequent resistances against many antibiotics, especially in hospital infections. Researchers at the Paul-Ehrlich-Institut have identified immunological processes that prevent a successful immune response directed against the pathogenic agent. The delivery of bacterial proteins with RNA adjuvant or messenger RNA (mRNA) into immune cells allows the re-direction of the immune response towards an active defense against S. aureus. This could be of significant importance for the development of an effective vaccine. PLOS Pathogens has published these research results online on 25 May 2017.

Staphylococcus aureus (S. aureus) is a bacterium that colonizes by far more than half of the skin and the mucosa of adults, usually without causing infections....

Im Focus: A quantum walk of photons

Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.

The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....

Im Focus: Turmoil in sluggish electrons’ existence

An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.

We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...

Im Focus: Wafer-thin Magnetic Materials Developed for Future Quantum Technologies

Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.

Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Marine Conservation: IASS Contributes to UN Ocean Conference in New York on 5-9 June

24.05.2017 | Event News

AWK Aachen Machine Tool Colloquium 2017: Internet of Production for Agile Enterprises

23.05.2017 | Event News

Dortmund MST Conference presents Individualized Healthcare Solutions with micro and nanotechnology

22.05.2017 | Event News

 
Latest News

New insights into the ancestors of all complex life

29.05.2017 | Earth Sciences

New photocatalyst speeds up the conversion of carbon dioxide into chemical resources

29.05.2017 | Life Sciences

NASA's SDO sees partial eclipse in space

29.05.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>