Unique genetic adaptive genes identified in new barley study
Project name
Genomic Signatures of barley breeding for environmental adaptation to the new continents
Project code
UMU1806-002RTX
Clipper and Stirling
A team of researchers led by Prncipal Research Scientist Professor Chengdao Li from the Department of Primary Industries and Regional Development (DPIRD) and Murdoch University, have undertaken a study looking at the genomes of two early barley varieties bred in Australia, named Clipper and Stirling, and compared them to other varieties from Europe and North America.
The researchers first compared Clipper and Stirling with 5 European and North American barleys and examined gene Presence/Absence variants.
Australian barleys contain 3893 unique genes.
Most of the genes are associated with circadian rhythm and response to light intensity.
In Australia, the growing season is determined by soil moisture availability.
This is different from many areas throughout Europe and North America, as barley is grown over the summer half of the year with frequent rainfall.
Researchers further examined 56 barleys from Australia, Europe and North America, comparing them to the Clipper reference sequence to look at evolutionary relationships.
Australian barley was more diverse to European barley than North American.
The various genetic patterns across chromosomes may reflect the breeding selection targeting different genomic regions in Australia and North America.
In Australia, scientists focused on developing barley plants that grow quickly and start flowering early, which helps the plants adapt to variable sowing dates but also avoid dry and very hot weather as they mature.
In Europe and North America, the sowing dates are relatively fixed, but Australian barley sowing dates depend on when the rain comes.
By choosing barley plants that flower early and are sensitive to daylight, specific gene variations related to when the plant grows were favored and became more common in the Australian varieties.
These included key environmental adaptive genes such as those coding for light perception, photoperiod, and development.
While Australian barley, although sharing a lot of European background, has adapted due to the different gene segments in important genes for flowering and environmental perception, and these have been fixed through breeding.
Gene insights
The next steps in the study saw researchers further compare the genomes of 7 barley cultivars from Australia, Europe and North America.
Researchers looked for the gene segments of 10 potential genes that may be associated with flowering time and responsiveness to photoperiod.
Professor Chengdao Li said among the 10 genes, 5 genes with a dominant haplotype and 2 with a distinctive haplotype in Australian varieties were identified.
This haplotype is dominant in Australian varieties. While all European and North American cultivars carry a different gene segment/haplotype.
Further analysis showed some Australian barley types share a similar genetic makeup with African barley but not European.
This comparison suggests Australia's barley obtained some genetic variations from Africa to adapt dry and hot environment in Australia, which is dramatically different from the European environments, Professor Li said.
The path to resilient crops
Australian barley is photoperiod-sensitive, which is beneficial in growth conditions that require barley to flower at a time with reliable rainfall, irrespective of the sowing date.
In tests where barley was planted at different times, Australian barley consistently flowered around the same date, regardless of when it was planted, unlike European varieties.
This sensitivity to day length gives Australian barley an advantage in areas where rainfall is scarce and unpredictable when it's planted, and where there's likely to be hot weather during maturation.
Barley adaptation in the Australian environment involves selecting and improving pre-existing genetic variants within the European gene pool.
Breeding activities have also introduced non-European haplotypes, e.g. African barley for drought and heat tolerance.
Selection for suitably adapted barley varieties in Australia has led to the fixation of several genes in flowering regulatory pathways.
Australian varieties are dominated by one haplotype in each gene.
Identifying these genes and haplotypes deepens the understanding of how breeding selections have shaped the genome architecture in Australian barley to what it is now.
The research also provided an insight of how to breed new barley for the future changing climates.
Contact
Chengdao Li
Western Barley Genetics Alliance Director
E: chengdao.li@dpird.wa.gov.au
P: (08) 9368 3843