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Investigations on aflatoxin contamination in groundnut caused by aspergillus flavus (link ex. fries) and its management using pgpr (plant growth-promoting rhizobacteria)

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Relation http://oar.icrisat.org/8905/
 
Title Investigations on aflatoxin
contamination in groundnut
caused by aspergillus flavus (link ex.
fries) and its management
using pgpr (plant growth-promoting
rhizobacteria)
 
Creator Raviteja, M
 
Subject Groundnut
 
Description Aflatoxin contamination is a qualitative problem in groundnut (Arachis
hypogaea L.) occurring at both pre-and post-harvest stages. These aflatoxins are
secondary metabolites produced by Aspergillus flavus and A. parasiticus and have
carcinogenic, hepatotoxic, teratogenic and immuno-suppressive effects. Use of plant
growth-promoting rhizobacteria (PGPR) is a viable and sustainable option in managing
aflatoxin problem in groundnut. The objectives of our present study were to evaluate
the prevalence of A. flavus infection and aflatoxin contamination in groundnut oil
mills/traders of Telangana and Andhra Pradesh (AP); differentiate toxigenic and
atoxigenic strains using cultural methods; identify a superior PGPR (Pseudomonas
fluorescens) isolate and determine its mode of inhibition on A. flavus and aflatoxin
contamination. Pod samples were collected from eight selected oil mills/traders in
Mahaboobnagar, Rangareddy, Nizamabad, Karimnagar (Telangana); and Anantapur
(AP) districts and A. flavus infection was enumerated. Further, aflatoxin contamination
in kernels was estimated by indirect competitive ELISA. A total of 24 A. flavus isolates
were obtained from the collected pod samples. These isolates were identified as
toxigenic/atoxigenic using cultural detection methods on Yeast extract sucrose (YES)
media and coconut agar medium (CAM). Ten native P. fluorescens isolates from
groundnut rhizosphere were isolated and screened against A. flavus by dual culture and
in vitro seed colonization (IVSC) assays. Superior PGPR isolate (Pf7) against mold
infection and aflatoxin contamination was screened for determining its mode of
inhibition using scanning electron microscopy (SEM). In Telangana, kernel infection
by A. flavus ranged from 42 (Mahaboobnagar) to 90.7% (Nizamabad). After
Nizamabad, samples from Rangareddy district recorded up to 90% kernel infection. In
AP, Tadimarri mandal recorded kernel infection up to 29.3%, whereas Tadipatri
recorded up to 59.3%. Aflatoxins in kernels from these mills in Telangana were highest
in Rangareddy (1205.2 μg kg-1) followed by Karimnagar (365.5 μg kg-1). Oil mills of
Nizamabad and Mahaboobnagar have recorded aflatoxins to a tune of 4.9 and 11.5 μg
kg-1in Telangana
 
Date 2015
 
Type Thesis
NonPeerReviewed
 
Format application/pdf
 
Language en
 
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Identifier http://oar.icrisat.org/8905/1/M%20Raviteja.pdf.pdf
Raviteja, M (2015) Investigations on aflatoxin contamination in groundnut caused by aspergillus flavus (link ex. fries) and its management using pgpr (plant growth-promoting rhizobacteria). Masters thesis, Professsor Jayashankar Telangana State Agricultural University.