Gene expression analysis of Aspergillus flavus during colonization of peanut varieties

• Grant number: 12/50189-0
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: July 01, 2012
• End date: June 17, 2014
• Field of knowledge: Agronomical Sciences - Food Science and Technology - Food Science
• Principal Investigator: Benedito Corrêa
• Grantee: Patricia Zorzete
• Host Institution: Instituto de Ciências Biomédicas (ICB). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

The peanut (Arachis hypogeal L.) is one of the most important oilseed is the fourth most produced, second only to soybeans, cotton and canola. In Brazil, Sao Paulo is the largest producer, contributing about 70-80% of national production estimated at 120-150 thousand tons. Economic losses are related to aflatoxin contamination, it is difficult to control due to the influence of climatic conditions such as humidity and temperature. However, the highest concentações aflatoxin are associated with the growth of Aspergillus flavus in inadequate storage conditions. The need for good management practices and use of varieties more resistant to contamination by pests become increasingly present. Known as high-oleic varieties have higher durability (storage time) and better nutritional quality. The study aims to evaluate the expression profile of 14 genes directly or indirectly involved in the biosynthesis of aflatoxins B1 and B2 and also involved in regulating the same, the technique of Real Time RT-PCR. 30 are used strains of A. flavus isolated from grain and peanut shells, between field and storage in the region of Tupa. AH strains have been classified by morphological criteria and by sequencing the ITS region of rDNA. The profile of expression of these genes are related to the range of high oleic peanut (CCL 503) having about 80% oleic acid in its composition and the conventional peanut (Runner) with approximately 40% oleic acid. The study of the potential of toxigenic strains of A. flavus used will be necessary to compare the results of aflatoxin production and gene expression between the two varieties of peanuts. (AU)