CONTROL OF PREHARVEST AFLATOXIN CONTAMINATION IN MAIZE THROUGH HOST INDUCED GENE SILENCING

• Sponsoring Institution: Agricultural Research Service/USDA
• Project Status: NEW
• Funding Source: USDA COOPERATIVE AGREEMENT
• Reporting Frequency: Annual
• Accession No.: 0427547
• Project No.: 6054-42000-025-08S
• Project Start Date: Sep 1, 2014
• Project End Date: Sep 30, 2016

Project Director
CARY J W

Recipient Organization
UNIVERSITY OF ARKANSAS
(N/A)
FAYETTEVILLE,AR 72703

Performing Department
(N/A)

Non Technical Summary
(N/A)

Animal Health Component

(N/A)

Research Effort Categories

Basic

50%

Applied

50%

Developmental

0%

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
712	1219	1102	10%
712	1510	2010	62%
712	1810	1102	18%
712	1830	2010	10%

Knowledge Area
712 - Protect Food from Contamination by Pathogenic Microorganisms, Parasites, and Naturally Occurring Toxins;

Subject Of Investigation
1219 - Edible tree nuts, general/other; 1510 - Corn; 1810 - Cottonseed; 1830 - Peanut;

Field Of Science
1102 - Mycology; 2010 - Physics;

Keywords

aspergillus

flavus

maize

host-induced

gene

silencing

rnai

aflatoxin

transgenic

Goals / Objectives
Host-induced gene silencing (HIGS) is promising new technology in which the pathogen is directed by the host plant to down-regulate the expression of its own genes. HIGS technology does not require that the host plant express a foreign protein so food and feed produced from resistant lines of transgenic maize should be more acceptable to regulatory agencies and consumers. Silencing constructs expressed in plants can knock-down the expression of fungal genes required for successful invasion and toxin production. The goal of the proposed research is to control preharvest aflatoxin contamination in maize through identification of Aspergillus flavus genes involved in fungal growth, development and toxin production to be targeted for silencing by an ribonucleic acid interference (RNAi)-mediated mechanism in transgenic host plants.

Project Methods
Utilizing information obtained from Aspergillus (A.) flavus proteomic and genomic studies we will identify candidate fungal genes that are required for successful invasion and aflatoxin production during the A. flavus-maize interaction. Ribonucleic acid interference (RNAi) vectors targeting these candidate genes will be constructed and initially assayed in A. flavus for efficacy in knockdown of target gene expression. Efficacious constructs will then be optimized for expression in maize and binary RNAi constructs subsequently introduced into maize. Seed from transgenic lines will be assayed by polymerase chain reaction based techniques for presence of the transgene as well as expression of the hairpin ribonucleic acid (RNA). Seed from positive lines will be used in kernel screening assays (KSAs) to determine if expression of target fungal gene(s) is significantly downregulated leading to decreased fungal growth and aflatoxin production. Maize lines demonstrating significant resistance to A. flavus growth and toxin production will have their seed bulked and used further as breeding material.