Xu, H. and Annis, S. and Linz, J. and et al, . (2000) Infection and colonization of peanut pods by Aspergillus parasiticus and the expression of the aflatoxin biosynthetic gene, nor-1, in infection hyphae. Physiological and Molecular Plant Pathology, 56 (5). pp. 185-196.
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Abstract
The a¯atoxigenic fungi, Aspergillus ¯avus and A. parasiticus infect a wide variety of crops, all of which produce oil-rich seed. A histological study of the host±pathogen interaction between peanut, Arachis hyphogea, and A. parasiticus was performed in a system where peanuts remained attached to the plant and were inoculated without wounding. For infection studies, a genetically-tagged strain of A. parasiticus, G5, was engineered to harbor the b-glucuronidase (GUS) reporter gene under control of the nor-1 promoter from the a¯atoxin biosynthetic pathway. There was a similar temporal pattern of a¯atoxin B1 production and appearance of GUS activity in cultures of A. parasiticus G5. This strain was used to follow infection and a¯atoxin production during colonization of undamaged, drought-stressed peanuts. The fungus colonized all tissues of the peanut pod and appeared to gain ingress through the corky layer of the pericarp. Both intra- and inter-cellular colonization were observed. Fungal colonization of the cotyledons resulted in visible depletion of storage bodies within cells. Two morphologically distinct types of hyphae, wider hyphae and narrower hyphae, were seen throughout the pod tissues. Statistical analysis revealed that the narrower hyphae were signi®cantly more likely to produce GUS activity than wider ones. GUS activity was found in hyphae infecting the pericarp, embryo and cotyledons indicating expression of a¯atoxin biosynthetic genes in these tissues. Interestingly, GUS activity was not observed in the hyphae colonizing the testa.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | Aspergillus parasiticus, Aspergillus flavus, Arachis hypogea L., aflatoxin, GUS, peanut pod |
| Author Affiliation: | Department of Botany and Plant Pathology, Michigan State University, East Lansing, MI 48824, U.S.A., |
| Subjects: | Plant Protection |
| Divisions: | Groundnut |
| Depositing User: | Mr Siva Shankar |
| Date Deposited: | 08 Aug 2012 05:19 |
| Last Modified: | 08 Aug 2012 05:19 |
| Official URL: | http://dx.doi.org/10.1006/pmpp.2000.0265 |
| URI: | http://eprints.icrisat.ac.in/id/eprint/7240 |
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