Telomere-to-telomere assembled and centromere annotated genomes of the two main subspecies of the button mushroom Agaricus bisporus reveal especially polymorphic chromosome ends

Summary

This research provides the first complete genetic blueprint of two varieties of the common button mushroom. By comparing their DNA sequences, scientists discovered important differences in how these mushrooms reproduce and pass on their genetic material to offspring. This knowledge has practical implications for mushroom breeding and cultivation. Impacts on everyday life: – Improved understanding enables better breeding of commercial mushrooms – Could lead to development of new mushroom varieties with enhanced traits – Helps optimize mushroom farming techniques and productivity – Provides insights that could benefit breeding of other food crops – Advances our knowledge of how organisms inherit and mix genetic material

Background

Agaricus bisporus, the most cultivated edible mushroom worldwide, exists in two main subspecies – var. bisporus and var. burnettii. The var. bisporus has a secondarily homothallic life cycle with recombination restricted to chromosome ends, while var. burnettii is heterothallic with recombination distributed more evenly across chromosomes. Complete genome sequences are needed to understand the relationship between genomic makeup and these different lifestyles.

Objective

To generate and compare complete telomere-to-telomere genome assemblies of both A. bisporus subspecies, with special focus on annotating centromeres and analyzing the distribution of genetic recombination.

Results

The genomes of both subspecies were largely co-linear, with chromosome ends showing the most differences in gene content between subspecies. Each chromosome contained a single large cluster of repeats at consistent positions, comprising nearly 50% of all repeats and likely representing centromeres. These repeat regions were heavily methylated. The mapping population confirmed an even distribution of crossovers in var. burnettii meiosis, contrasting with var. bisporus where recombination is restricted to chromosome ends.

Conclusion

The study produced exceptionally complete and well-annotated genomes of both A. bisporus subspecies, revealing important insights into centromere structure and recombination patterns. The findings demonstrate the value of high-quality genome assemblies for understanding genetic components underlying different life cycles in fungi.
Scroll to Top