Genetic diversity, distribution and domestication history of the neglected GGAtAt genepool of wheat

Ekaterina D. Badaeva, Fedor A. Konovalov, Helmut Knüpffer, Agostino Fricano, Alevtina S. Ruban, Zakaria Kehel, Svyatoslav A. Zoshchuk, Sergei A. Surzhikov, Kerstin Neumann, Andreas Graner, Karl Hammer, Anna Filatenko, Amy Bogaard, Glynis Jones, Hakan Özkan & Benjamin Kilian 

Theoretical and Applied Genetics; March 2022; vol. 135: 755–776

Key message

We present a comprehensive survey of cytogenetic and genomic diversity of the GGA^tA^t genepool of wheat, thereby unlocking these plant genetic resources for wheat improvement.

Abstract

Wheat yields are stagnating around the world and new sources of genes for resistance or tolerances to abiotic traits are required. In this context, the tetraploid wheat wild relatives are among the key candidates for wheat improvement. Despite its potential huge value for wheat breeding, the tetraploid GGA^tA^t genepool is largely neglected. Understanding the population structure, native distribution range, intraspecific variation of the entire tetraploid GGA^tA^t genepool and its domestication history would further its use for wheat improvement. The paper provides the first comprehensive survey of genomic and cytogenetic diversity sampling the full breadth and depth of the tetraploid GGA^tA^t genepool. According to the results obtained, the extant GGA^tA^t genepool consists of three distinct lineages. We provide detailed insights into the cytogenetic composition of GGA^tA^t wheats, revealed group- and population-specific markers and show that chromosomal rearrangements play an important role in intraspecific diversity of T. araraticum. The origin and domestication history of the GGA^tA^t lineages is discussed in the context of state-of-the-art archaeobotanical finds. We shed new light on the complex evolutionary history of the GGA^tA^t wheat genepool and provide the basis for an increased use of the GGA^tA^t wheat genepool for wheat improvement. The findings have implications for our understanding of the origins of agriculture in southwest Asia.

See: https://link.springer.com/article/10.1007/s00122-021-03912-0

Figure 1: Generalized idiogram and nomenclature of the A^t- and G-genome chromosomes. The C-banding pattern is shown on the left, the pSc119.2 (red) and pAesp_SAT86 (green) pattern on the right side of each chromosome. 1–7—homoeologous groups; S—short arm, L—long arm. The numerals on the left-hand side designate putative positions of C-bands/FISH sites that can be detected on the chromosome arm; C-bands specific for the ARA-1 group are shown with pink numerals, C-bands specific for the ARA-0 group are indicated by green numerals. Red asterisks on the right-hand side indicate C-bands that were considered for the ‘chromosomal passport’.