A team of scientists led by Royal Botanic Gardens Victoria researchers has decoded the genome of the golden wattle (Acacia pycnantha), a woody shrub or tree occurring in south-eastern Australia and is the country’s floral emblem. The genome assembly will be a valuable resource for all studies involving the genus Acacia, including the evolution, conservation, breeding, invasiveness, and physiology of the genus, and for comparative studies of legumes. The results appear in the journal PLoS ONE.
The golden wattle (Acacia pycnantha), showing inflorescences and phyllodes. Image credit: Dan Murphy.
Acacia is the largest and most widespread genus of plants in the Australian flora, with 1,071 species (1,082 accepted species globally).
It occupies and dominates a diverse range of environments, with an equally diverse range of forms.
For a genus of its size and importance, Acacia currently has surprisingly few genomic resources.
“Acacia has surprisingly little genome data, as the technical analyses is very time consuming,” said Dr. Todd McLay, a postdoctoral researcher at Royal Botanic Gardens Victoria.
“It took us just over three years to sequence, but with advancements in technology, it is getting faster to do this type of work.”
“The golden wattle DNA was sequenced into millions of fragments that were then assembled like a giant jigsaw puzzle using high-performance computing housed in the National Herbarium of Victoria.”
The golden wattle genome was found to be made of 814 million DNA bases and included nearly 48,000 genes. In comparison, humans have larger genomes with 3.1 billion bases of DNA but fewer genes.
Comparative genomics identified suites of gene families that are more diverse with respect to other plants, and which can be associated with greater adaptability.
One of these gene families is involved in flowering time and may drive the characteristic synchronous flowering of Acacia associated with the onset of spring.
“An Acacia genome is a strategic resource for the study of genomic adaptations leading to the continent-wide success of the genus, and subsequently for advancing our understanding of the evolution of the Australian flora and its biomes,” the researchers said.
“It is also a key resource for conservation genomics of species of Acacia, invasion genomics, ethnobotany, and forestry.”
The authors now plan to investigate the relationships between all wattle species, using the genome to understand genes involved in the adaptation of wattles to the diverse range of environments in Australia.
They are also planning on sequencing many more native Australian plant genomes.
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T.G.B. McLay et al. 2022. A genome resource for Acacia, Australia’s largest plant genus. PLoS ONE 17 (10): e0274267; doi: 10.1371/journal.pone.0274267
