BATTLING viruses in garlic plants is the bold new field being tackled by a group of Australian university researchers.
It is notoriously difficult to get virus-free garlic anywhere in the world. In fact there can be up to 10 or 12 viruses in infected plants, with most garlic plants hosting at least six viruses
But University of Queensland plant virologist associate professor John Thomas understanding the suite of viruses and their impact could help increase output for Aussie growers.
Dr Thomas said all Australian commercial garlic varieties have viruses, which doesn't seem to affect taste or nutrition.
"But does have an impact on the crop's yield," Dr Thomas said.
Dr Thomas is joined in the quest to nut out these viruses by UQ colleagues Dr Stephen Harper and associate professor Andrew Geering, the Department of Agriculture and Fisheries' Dr Kathy Crew and PhD candidate Sari Nurulita.
Ms Nurulita's doctoral study aims to develop reliable virus detection tests and investigate why both superior and inferior garlic plants share the same viral profile.
"Garlic is a vegetatively propagated crop, and once it's been infected, all the progeny are infected," Dr Thomas said.
"It's also possible for the crop to collect more viruses in the field, but not lose any plants."
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He said in previous work led by Dr Harper and funded by the Australian Centre for International Agricultural Research, researchers grew higher performing bulbs among virus-infected garlic crops.
"Through breeding selections over generations, Dr Harper was getting three times the yield from the best selections," Dr Thomas said.
"However, Ms Nurulita's work shows these elite garlic selections are still infected by the virus complement and we don't know why that is occurring."
Ms Nurulita is also investigated the viruses concentrations using next-generation sequencing, and mapped the full genomes of the viruses.
"I did not find any significant differences in the viruses levels and was unable to determine a clear-cut difference between the two different lines of elite and poor performing garlic seed," Ms Nurulita said.
Dr Thomas said the team had also tried tissue culture propagation to generate virus-free garlic but without success.
"We think maybe gene silencing is happening naturally in the plant," he said.
"It may depend on which virus gets the upper hand in a particular clove, or the order they are infected in.
"There are so many different possibilities and it's not a simple matter.
"But we are going to look at absolute levels of virus to see whether we can determine if gene silencing is responsible."
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