Source: PENNSYLVANIA STATE UNIVERSITY submitted to NRP
CATERPILLAR SPIT DECREASES GREEN LEAF VOLATILE EMISSION, A PLANT STRESS RESPONSE
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
COMPLETE
Funding Source
Reporting Frequency
Annual
Accession No.
1015430
Grant No.
2018-67011-28028
Cumulative Award Amt.
$95,000.00
Proposal No.
2017-06899
Multistate No.
(N/A)
Project Start Date
Apr 15, 2018
Project End Date
Apr 14, 2020
Grant Year
2018
Program Code
[A7101]- AFRI Predoctoral Fellowships
Recipient Organization
PENNSYLVANIA STATE UNIVERSITY
408 Old Main
UNIVERSITY PARK,PA 16802-1505
Performing Department
Entomology
Non Technical Summary
Insects are notorious crop pests; plant damage and control measures to protect plant health are estimated to cost the US economy billions of dollars annually. Despite constant assault, nearly all green plants respond to stress and damage by rapidly emitting GLVs. Because of this immediate response to stress, these molecules are believed to be an important system for plant defense responses. The GLVs are available to be utilized as information signals in plant-based interactions with herbivores, carnivores, and neighboring plants within an ecosystem. Our preliminary data suggest several strategies employed by the oral secretions of caterpillar herbivores to block the biosynthesis of GLVs. Since GLVs are important as signaling molecules in plant stress response, the change or loss of that signal is important to the health of the plant and by association, the health of the herbivore. Here we propose that GLV biosynthesis is blocked by both protein and non-protein components of caterpillar oral secretions; one method being the prevention of hydroperoxide lyase activity during GLV biosynthesis by a heat stable component in the regurgitant. The long term goal of this project seeks to determine how the loss of the GLV signal benefits caterpillar herbivores. By elucidating the role of these compounds for plant defense and resistance signaling, we can better utilize these mechanisms to deter crop pests and increase crop yields.
Animal Health Component
(N/A)
Research Effort Categories
Basic
100%
Applied
(N/A)
Developmental
(N/A)
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
21131101130100%
Goals / Objectives
Since green leaf volatiles (GLVs) are signaling molecules in the plant stress response, the change or loss of that signal is important with respect to the health of the plant and, by association, the health of the herbivore. The primary goal of this project is to determine how the manipulation of the GLV signal benefits caterpillars. The objectives of this project are the following:1. Determine the strategies by which caterpillar oral secretions alter GLV emission from species-appropriate host plants.2. Identify the heat stable elicitor of (Z)-3-hexenal reduction from Manduca sexta regurgitant.3. Determine the step in the GLV biosynthetic pathway that is blocked by the heat stable elicitor from M. sexta regurgitant.
Project Methods
To assay the GLVs emitted from different plants (maize, tobacco, and collards) and treatments (different caterpillar species' oral secretions) during this experiment, we employ the use of a ground tissue assay. The results will be evaluated through gas-chromatography-flame ionization detection (GC-FD) and gas chromatography-mass spectrometry (GC-MS). To identify the heat-stable effector, we will use purification columns and high performance liquid chromatography (HPLC).

Progress 04/15/18 to 04/14/20

Outputs
Target Audience:Recently, there has been an increased interest in the role of green leaf volatiles (GLVs) in the environment and in plant defense responses. The target audience that was the focus of the research and data collectedduringthis project was those researchers in the fields of plant physiology and chemical ecology. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?This project has provided numerous opportunites for training and professional development. The PD has presented research from this project at a nation and international conference, as well as published a portion of this research in a peer-reviewed scientific journal (additional manuscripts are in preparation). This project has also provided opportunities for collaboration among the PD and other researchers who are experts in their fields. The PD has also gained considerable technical experience in volatile collection a How have the results been disseminated to communities of interest?The results have been disseminated to communities of interest (researchers in the fields of plant-insect interactions and chemical ecology) through publication in peer-reviewed scientific journals and presentation at both theInternational Society of Chemical Ecology and Entomological Society of America national meetings. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? Aim 1 was accomplished and published in Environmental Entomology in 2019. We have made significant progress in the acheivement of Aim 2, the characterization of the heat stable effector of (Z)-3-hexenal emission (which has been termed the hexenal trapping molcule - HALT). We have also made progress on Aim 3 in determing the step in the GLV biosynthetic pathway which is blocked by the HALT effector. The HALT effector likely directly affects the (Z)-3-hexenal molecule itself, preventing the emission of this compound during damage. These data indicate that the GLV signal is potentially deleterious to caterpillar fitness, since their oral secretions may have up to three effectors to alter the emission of GLVs from their host plant species. Each of these effectors act at different points along the GLV biosynthetic pathway. Preliminary data from these objectives has been presented at both the International Society of Chemical Ecology and Entomological Society of America national meetings, and additional papers are in preparation.

Publications

  • Type: Theses/Dissertations Status: Under Review Year Published: 2020 Citation: Jones AC, Caterpillar The Effects of Caterpillar Oral Secretions on Green Leaf Volatile (GLV) Emissions. State College, PA. Pennsylvania State University, 2020. p. 114
  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Jones AC, Cofer TM, Seidl-Adams, Tumlinson JH. 2019. 2019. Oral Presentation. Lepidoptera possess diverse mechanisms to suppress green leaf volatile emissions Entomological Society of America. St. Louis, MO
  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Jones AC, Seidl-Adams, Tumlinson JH. 2019. Oral Presentation The differential activity of an insect effector between Trichoplusia ni and Pieris rapae on collards Entomological Society of America, Eastern Branch. Blacksburg, VA.


Progress 04/15/18 to 04/14/19

Outputs
Target Audience:The target audiencethat was the focus ofthis projectfor its durationisprimarily those researchers in the fields of plant physiology and chemical ecology. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?This project provided training and professional development at two conferences. These experiences provided valuable opportunities to present data andnetwork with other researchers in my field. How have the results been disseminated to communities of interest?The results of this project have been disseminated to researchers in the plant biology and chemical through a publication and presentations at a national and international conference. What do you plan to do during the next reporting period to accomplish the goals?To accomplish the remaining goals, I plan to complete experiments that elucidate the nature of the heat stable elicitorof (Z)-3-hexenal and work closely with collaborator Hans Alborn to identify it. I will also continue experiments to better determine the setp in the GLV biosynthetic pathway that the heat stable elicitor blocks.

Impacts
What was accomplished under these goals? Aim 1 was publishedin Environmental Entomology. Continuing work is being done on aims 2 and 3. Research from this project has been presented at the International Society of Chemical Ecology and Entomological Society of America national meetings.

Publications

  • Type: Journal Articles Status: Published Year Published: 2019 Citation: Jones AC, Seidl-Adams I, Engelberth J, Hunter CT, Alborn H, Tumlinson JH. Herbivorous Caterpillars Can Utilize Three Mechanisms to Alter Green Leaf Volatile Emission. Environmental entomology. 2019 Jan 19;48(2):419-25.