This Seminar was presented by Richard Buggs from Royal Botanic Garden Kew and was based around the genomics of trees and how to best ensure trees that are currently under threat from diseases such as ash dieback can be best saved.
What are the main threats?
Richard Buggs focused on a disease called ash dieback which is a fungal disease that blocks the water transport system in ash trees which leads to leaf loss and the eventual death of the tree.
The disease was first found in Poland in 1992 and has since spread across Europe, first being identified in Britain in 2012.
Summer is the best time to identify symptoms of ash dieback as during autumn and winter the trees will naturally be shredding their leaves. Symptoms include:
- Tips of shoots become black and shrivelled
- Blackened, dead leaves
- The veins and stalks of leaves turn brown
- From July to October white fruiting bodies can be found on blackened leaf stalks
The other threat Richard eluded to is that caused by the Emerald ash borer, which is a beetle native to north-eastern Asia that feeds on ash species. Females lay eggs in bark crevices on ash trees, and the larvae feed underneath the bark of the ash, causing the ash tree to die within two to three years.
What can we do?
There are a number of proposed solutions to prevent the rapid spread of ash dieback.
One such proposal involves cutting down trees that are identified as having ash dieback to prevent this tree from spreading the disease.
Another solution includes breeding native tolerant ash trees based on their phenotype. This would therefore result in ash trees being grown that are resistant to the disease and thus would not be affected by the spread of ash dieback.
Broad leaved trees, such as ash, have relatively small genome sizes, with ash sitting at 0.9 Gbp (billion base pairs). This therefore makes the genome easy to work with, making the identification of ash dieback resistant trees viable.
Due to the relatively small genome size of ash trees and other broad leaved trees, methods such as trans-genetics become viable, which is the transfer of genetic information across families, allowing for disease resistant genes to be passed from tree species to tree species.
Ash trees were studied to detect different abilities to resist the emerald ash borer. Trees that had resistance and were evolutionary different were compared and the similarities were proposed as candidate genes for resistance. Two such candidate genes were found. This is a good example of how the genomic comparison of trees could allow for such threats to trees to be eliminated in the future, or at least allow the threat to be managed.
My thoughts
I really enjoyed the seminar presented by Richard. Genomics is an area of Biology that I take great interest in, and seeing how its application can be used in the real world to solve real issues was very useful to me. This seminar re-enforced my interest in genomics and helped me to see how important genomics is to the future.
Thomas Nicholls 