Aflatoxin in Chili Peppers in Nigeria: Extent of Contamination and Control Using Atoxigenic Aspergillus flavus Genotypes as Biocontrol Agents

Across sub-Saharan Africa, chili peppers are fundamental ingredients of many traditional dishes. However, chili peppers may contain unsafe aflatoxin concentrations produced by Aspergillus section Flavi fungi. Aflatoxin levels were determined in chili peppers from three states in Nigeria. A total of 70 samples were collected from farmers’ stores and local markets. Over 25% of the samples contained unsafe aflatoxin concentrations. The chili peppers were associated with both aflatoxin producers and atoxigenic Aspergillus flavus genotypes. Efficacy of an atoxigenic biocontrol product, Aflasafe, registered in Nigeria for use on maize and groundnut, was tested for chili peppers grown in three states. Chili peppers treated with Aflasafe accumulated significantly less aflatoxins than nontreated chili peppers. The results suggest that Aflasafe is a valuable tool for the production of safe chili peppers. Use of Aflasafe in chili peppers could reduce human exposure to aflatoxins and increase chances to commercialize chili peppers in premium local and international markets. This is the first report of the efficacy of any atoxigenic biocontrol product for controlling aflatoxin in a spice crop.

Identification of Differently Regulated Proteins after Fusarium graminearum Infection of Emmer (Triticum dicoccum) at Several Grain Ripening Stages

This study was conducted to improve the knowledge of molecular processes involved in the interaction between Fusarium graminearum and emmer in the course of grain ripening. Emmer plants were artificially inoculated with a F. graminearum spore suspension at anthesis. In the course of grain ripening from milk ripe to plant death stage, grains at four phenological growth stages were collected for analysis. The infection degree was evaluated based on the F. graminearum DNA content in emmer grain infolding tissues (glumes and rachis). For proteome analysis the albumin and globulin fractions of emmer grains, consisting of proteins with various functions related to the development and stress response, were analysed regarding the changes due to Fusarium infection by two-dimensional gel electrophoresis. Altogether, forty-three proteins affected by infection were identified by mass spectrometry. Enzymes detoxifying reactive oxygen species were regulated at all developmental stages. In the early stage of grain development, the abundance of proteins related to stress response, such as 2-Cys peroxiredoxin, a chitinase, a xylanase inhibitor and a spermidine synthase was increased. During later stage of grain development, the abundance of stress-related proteins, such as chitinases, heat shock proteins and an α-amylase inhibitor-like protein, decreased. During all ripening stages, but especially during medium milk stage (BBCH 75) and soft dough stage (BBCH 85), the abundance of proteins related to carbon metabolism, starch and protein biosynthesis as well as photosynthesis increased due to F. graminearum infection. At the plant death stage (BBCH 97) the abundance of only two proteins related to metabolism decreased.