CAP'N'COLLAR ISOFORM C: THE MEDIATOR FOR ALLELOCHEMICAL INDUCTION OF CYP321A1 IN HELICOVERPA ZEA?

• Sponsoring Institution: National Institute of Food and Agriculture
• Project Status: COMPLETE
• Funding Source: HATCH
• Reporting Frequency: Annual
• Accession No.: 1001470
• Project Start Date: Oct 1, 2013
• Project End Date: Sep 30, 2018
• Program Code: [(N/A)]- (N/A)

Recipient Organization
UNIVERSITY OF ARIZONA
888 N EUCLID AVE
TUCSON,AZ 85719-4824

Performing Department
Entomology

Non Technical Summary
Insect herbivores cause billions of dollars in damage to crops annually. Control of insect pests still largely depends on conventional, harmful insecticides. Novel and environmentally benign methods of crop protection are urgently needed to address these concerns. Understanding how insect herbivores utilize plant defense toxins as signals to escalate their counter-defense genes such as plant toxin-metabolizing P450s (e.g. CYP321A1 in the cotton bollworm) for overcoming plant defenses may lead to novel, bio-rational control methods. Based on our preliminary data, we hypothesize that plant toxin-induced overproduction of the cotton bollworm counter-defensive CYP321A1 is positively regulated byCap`n'Collar isoform C (CncC),a protein factor capable of binding to specific nucelotide sequences (calld cis elements) upstream of the target genes it regulates.We will test this central hypothesis by combinations of cell culture and transfection, dual luciferase reporter gene assays, RT-PCR cloning, loss- and gain-of-function analyses, and in vivo RNA interference (RNAi).If this hypothesis is supported, this project will provide a detailed mechanistic understanding of how cotton bollworm and other herbivores disarm plant defenses. This knowledge can be used to design and develop novel, environmentally benign and more effective pest control strategies and approaches.

Animal Health Component

5%

Research Effort Categories

Basic

90%

Applied

5%

Developmental

5%

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
211	3110	1130	100%

Knowledge Area
211 - Insects, Mites, and Other Arthropods Affecting Plants;

Subject Of Investigation
3110 - Insects;

Field Of Science
1130 - Entomology and acarology;

Keywords

allelochemicals

cap`n'collar isoform c

induction

signaling pathway

herbivores

helicoverpa zea

Goals / Objectives
To determine if the XRE-fla mediates induction of CYP321A1 by the ARE-Nrf2 signaling pathway markers (DEM, tBHQ) and other allelochemicals. To examine if induction of CYP321A1 by allelochemicals, tBHQ, and DEM is due to elevated ROS stress resulting from these compounds; To prove that CncC is the activator for allelochemical induction of CYP321A1.

Project Methods
This project will test our hypotheses by combinations of cell culture and transfection, dual luciferase reporter gene assays, RT-PCR cloning, loss- and gain-of-function analyses, and electrophoresis mobility shift assays (EMSA).

Progress 10/01/13 to 09/30/14

Outputs
Target Audience:Scientists, Professionals and students work in plant-insect interactions, gene regulation and pest control. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?This project has trained 1 graduate student and 1 visiting postdoc scholar. Several undergraduate students learned some lab techniques such as insect rearing, cell culture, and molecular cloning. How have the results been disseminated to communities of interest?Two papers published. Also presented the data in professional meetings. What do you plan to do during the next reporting period to accomplish the goals?This year, we bascially finished Objective 1. We will be going to accomplish objective 2.

Impacts
What was accomplished under these goals? How polyphagous herbivores up-regulate their counter defense genes in response to a broad range of structurally different allelochemicals remains largely unknown. To test whether this is accomplished by having more allelochemical-response elements or the similar number of functionally more diverse elements, we mapped out the cis-acting elements mediating the induction of the allelochemical-metabolizing CYP321A1 from the generalist Helicoverpa zea by xanthotoxin and flavone, two structurally distinct allelochemicals with very different encounter rate by this species. Seven xanthotoxin-responsive elements were localized by analyzing promoter activities of varying length of CYP321A1 promoter in H. zea fatbody cells. Compared with the 5 flavone-responsive elements mapped out previously, there are four common elements (1 essential element, 2 enhancers, and 1 negative element) mediating induction of CYP321A1 by both of the two allelochemicals. The remaining four elements (3 enhancers and 1 negative element), however, only regulate induction of CYP321A1 by either of the two allelochemicals. Co-administration of the two allelochemicals resulted in an induction fold that is significantly lower than the expected additive value of the two allelochemicals. These results indicate that xanthotoxin- and flavone-induced expressions of CYP321A1 are mediated mainly by the functionally more diverse common elements although the allelochemical-unique elements also play a role.

Publications

• Type: Journal Articles Status: Published Year Published: 2014 Citation: Zhang, C., Wong, A., Zhang, Y., Ni, X. & Li, X. 2014. Common and unique cis-acting elements mediate xanthotoxin and flavone induction of the generalist P450 CYP321A1. Nature Scientific Reports 4:6490.
• Type: Journal Articles Status: Published Year Published: 2014 Citation: Ni, X., Lei, Z., He, K., Li, X., Li, X. & Xu, W. 2014. Integrated pest management is the lucrative bridge connecting the ever emerging knowledge islands of genetics and ecology. Insect Science. 21 (5): 537540.