IDENTIFICATION AND ENHANCEMENT OF SEED-BASED BIOCHEMICAL RESISTANCE IN CROPS TO AFLATOXIN PRODUCING PATHOGENS
Location: Food and Feed Safety Research
Title: The Use of Neutron Tomography for the Structural Analysis of Corn Kernaels
Submitted to: Journal of Cereal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 2, 2007
Publication Date: June 15, 2008
Citation: Cleveland IV, T.E., Hussey, D.S., Chen, Z.Y., Jacobson, D.L., Brown, R.L., Carter Wientjes, C.H., Cleveland, T.E., Arif, M. 2008. The Use of Neutron Tomography for the Structural Analysis of Corn Kernels. Journal of Cereal Science. 48:517-525.
Interpretive Summary: Aflatoxins are poisons produced by the fungus, Aspergillus flavus, after it infects agricultural commodities, such as corn. Since aflatoxins in food and feed are regulated, enhanced ability to visualize corn kernels, especially those infected by Aspergillus flavus, could contribute significantly towards growers producing a safe and more profitable crop. A research collaboration between ARS-SRRC, Food and Feed Safety Research Unit and the National Institute of Standards and Technology (NIST) used a non-destructive technique called neutron tomography to analyze corn kernels to distinguish well-known kernel anatomical structures and to distinguish between different types and treatments of kernels. It was found that this technique could identify many anatomical structures in kernels. It was also found that differences could be detected between aflatoxin-susceptible kernels that had been infected by Aspergillus flavus and those that were uninfected. This study demonstrated the usefulness of neutron tomography for the structural analysis of corn. Use of this technique could lead to a greater understanding of the fungal infection process as it pertains to resistance and susceptibility, and could enhance the development of corn lines resistant to Aspergillus flavus. Growing these lines commercially could lead to greater protection of food and feed, as well as decreased financial losses to growers.
Neutron tomography was examined as a technique for non-destructively analyzing the internal structure of dried corn kernels. The study had two goals: first, to determine if the analysis could distinguish well-known anatomical features of the kernels; and second, to determine if it could distinguish between different types and treatments of kernels. Specifically, kernels which were infected vs. uninfected with the aflatoxin producing fungus Aspergillus flavus were analyzed. Two different varieties of corn were used: VA35 (susceptible to A. flavus infection) and GT-MAS:gk (resistant). It was found that neutron tomography could distinguish many anatomical features of the kernels, including the scutellum, endosperm, aleurone, pericarp, pedicel, coleorhizae, radical, plumule and coleoptile. Furthermore, differences were detected between susceptible kernels that had been infected and those that were uninfected. Infected kernels were found to have lower neutron attenuation in the scutellum and embryo regions, possibly caused by lower hydrogen concentrations due to fungal degradation. No systematic structural differences were detected between resistant control and resistant inoculated kernels, as expected. This study indicated that neutron tomography could be a useful technique for the structural analysis of corn, and possibly other grains or small biological objects.