Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 1998 Jan 6;95(1):388-93.
doi: 10.1073/pnas.95.1.388.

Cryptic speciation and recombination in the aflatoxin-producing fungus Aspergillus flavus

D M Geiser  1 , J I Pitt, J W Taylor
Affiliations

Cryptic speciation and recombination in the aflatoxin-producing fungus Aspergillus flavus

D M Geiser et al. Proc Natl Acad Sci U S A. .

Abstract

Aspergillus flavus, like approximately one-third of ascomycete fungi, is thought to be cosmopolitan and clonal because it has uniform asexual morphology. A. flavus produces aflatoxin on nuts, grains, and cotton, and assumptions about its life history are being used to develop strategies for its biological control. We tested the assumptions of clonality and conspecificity in a sample of 31 Australian isolates by assaying restriction site polymorphisms from 11 protein encoding genes and DNA sequences from five of those genes. A. flavus isolates fell into two reproductively isolated clades (groups I and II). The lack of concordance among gene genealogies among isolates in one of the clades (group I) was consistent with a history of recombination. Our analysis included five strains of the closely related industrial fungus A. oryzae, all of which proved to be clonally related to group I.

PubMed Disclaimer

Figures

Figure 1
Figure 1
(A) Strict consensus of the 72 MP trees inferred from the restriction site data for the 17 different multilocus genotypes (A–Q). The arrow indicates the internal branch separating groups I and II. (B) UPGMA (10) distance analysis of the same data. The arrow indicates the same branch highlighted in A, which is the longest branch on the tree (branch lengths shown are proportional to those inferred from the data). ∗, Genotype “C” represents A. flavus isolates 1–10, 5–2, and 17–4, as well as A. oryzae isolates NRRL 447, 448, 449, and 469. “Q” represents that of A. oryzae isolate NRRL 483.
Figure 2
Figure 2
One MP tree from each of the five gene regions sequenced. CI, consistency index; RI, retention index, RC, rescaled consistency index. Numbers below branches represent bootstrap values based on 500 replicates. Only values ≥70% are shown. The 16 different A. flavus multilocus genotypes are represented by letters. Isolates used representing each multilocus genotype: A, 1–22; B, 1–9 (B1) and 5–1 (B2); C, 17–4; D, 1–26; E, 1–29; F, 3–2; G, 4–2; H, 12–4; I, 7–2; J, 7–3; K, 7–4; L, 11–1; M, 12–3; N, 13–4; O, 14–1; and P, 14–2. GenBank accession numbers are AF036768-787 (amdS12); AF036788-807 (benA56); AF036808-830 (omt12); AF036831-850 (pecA12); and AF036851-870 (trpC13).
Figure 3
Figure 3
Partition homogeneity test results.
See this image and copyright information in PMC

References

    1. Squire R A. Science. 1981;214:877–880. - PubMed
    1. Klich M A, Pitt J I. A Laboratory Guide to Common Aspergillus Species and their Teleomorphs. Division of Food Processing, North Ryde, NSW, Australia: Commonwealth Scientific and Industrial Research Organization; 1988.
    1. Kurtzman C P, Smiley M J, Robnett C J, Wicklow D T. Mycologia. 1986;78:955–959.
    1. Dvorackova, I. Aflatoxins and Human Health (CRC, Boca Raton, FL).
    1. Wogan G N. Cancer Res. 1992;52:2114s–2118s. - PubMed

Publication types

Associated data

LinkOut - more resources