A Physical Map of the 1-Gigabase Bread Wheat Chromosome 3B

TLDR

Wheat feeds 35 % of the world’s population and lacks sequence‑based tools to accelerate improvement. The study aimed to construct a BAC‑based integrated physical map of wheat chromosome 3B. A chromosome‑specific BAC library was used to assemble 82 % of chromosome 3B into 1 036 contigs anchored with 1 443 molecular markers. The resulting map provides a template for the remaining wheat chromosomes and demonstrates the feasibility of constructing physical maps in large, complex, polyploid genomes with a chromosome‑based approach.

Abstract

As the staple food for 35% of the world's population, wheat is one of the most important crop species. To date, sequence-based tools to accelerate wheat improvement are lacking. As part of the international effort to sequence the 17-billion-base-pair hexaploid bread wheat genome (2n = 6x = 42 chromosomes), we constructed a bacterial artificial chromosome (BAC)-based integrated physical map of the largest chromosome, 3B, that alone is 995 megabases. A chromosome-specific BAC library was used to assemble 82% of the chromosome into 1036 contigs that were anchored with 1443 molecular markers, providing a major resource for genetic and genomic studies. This physical map establishes a template for the remaining wheat chromosomes and demonstrates the feasibility of constructing physical maps in large, complex, polyploid genomes with a chromosome-based approach.