21277379
not annotated - annotated - LINNAEUS only
Independent duplications of alpha-amylase in different strains of Aspergillus oryzae.
Aspergillus oryzae is a filamentous fungus that has arisen through the ancient domestication of Aspergillus flavus for making traditional oriental foods and beverages. In the many centuries A. oryzae has been used for fermenting the starch in rice to simple sugars, it has undergone selection for increased secretion of starch-degrading enzymes. In particular, all A. oryzae strains investigated thus far have two or more copies of a gene encoding alpha-amylase, whereas A. flavus has only one. Here we investigate the duplications leading to these copies in three A. oryzae strains. We find evidence of at least three separate duplications of alpha-amylase, an example of parallel evolution in a micro-organism under artificial selection. At least two of these duplications appear to be associated with activity of transposable elements of the Tc1/mariner class. Both involve a 9.1 kb element that terminates in inverted repeats, encodes a putative transposase and another putative protein of unknown function, and contains an unusual arrangement of four short internal imperfect repeats. Although "unusual Mariners" of this size have previously been identified in A. oryzae, Aspergillus fumigatus and Aspergillus nidulans, this is the first evidence we know of that at least some of them are active in modern times and that their activity can contribute to beneficial genetic changes.
Ann file
T1 Species 66 84 Aspergillus oryzae
N1 Reference T1 Taxonomy:5062
T2 Species 88 106 Aspergillus oryzae
N2 Reference T2 Taxonomy:5062
T3 Species 184 202 Aspergillus flavus
N3 Reference T3 Taxonomy:5059
T4 Species 278 287 A. oryzae
N4 Reference T4 Taxonomy:5062
T5 Species 453 462 A. oryzae
N5 Reference T5 Taxonomy:5062
T6 Species 559 568 A. flavus
N6 Reference T6 Taxonomy:5059
T7 Species 653 662 A. oryzae
N7 Reference T7 Taxonomy:5062
T8 Species 1264 1273 A. oryzae
N8 Reference T8 Taxonomy:5062
T9 Species 1275 1296 Aspergillus fumigatus
N9 Reference T9 Taxonomy:746128
T10 Species 1301 1321 Aspergillus nidulans
N10 Reference T10 Taxonomy:162425
T11 Species 331 335 rice
N11 Reference T11 Taxonomy:4530 Oryza sativa