Evolution of the aflatoxin gene cluster |
| |
Authors: | K C Ehrlich |
| |
Institution: | (1) Southern Regional Research Center, ARS, USDA, 1100 R.E. Lee Blvd., New Orleans, LA 70124, USA; |
| |
Abstract: | WhyAspergillus species produce aflatoxin remains an unsolved question. In this report we suggest that evolution of the aflatoxin biosynthesis
gene cluster has been a multistep process. More than 300 million years ago a primordial cluster of genes allowed production
of anthraquinones that may have served as insect attractants to facilitate spore dispersal. Later adaptive evolutionary steps
introduced genes into the cluster that encoded enzymes associated with fungal virulence. These genes may have allowed the
otherwise saprophytic fungi to be better able to colonize living plants. Later, genes for production of aflatoxins B1 and
G1 were added to the basal cluster. Loss of the ability to produce aflatoxin G1 occurred with the divergence ofA. flavus, a species that, perhaps, was more successful than its ancestors at colonizing plants. This logical progression in evolutionary
development of the aflatoxin biosynthetic cluster fits the phylogenetic data as well as known chemical reactivity of the initially
formed anthraquinone polyketide metabolites. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|