Unlocking the Power of Plants

Our features writer Abigail Carruthers (Tanners) gives us an insight into her amazing work at Kew Gardens. Kew Gardens is the world leader in plant science and conservation, as well as having some spectacular gardens. I was privileged to work there this year for a while, in the Jodrell Laboratory. If you have visited, you will remember the extensive gardens and huge trees; or perhaps the highlight of your visit was the glasshouses? There is something exciting about entering and being transported to exotic lands. Enter the Princess of Wales Conservatory, walk through the desert, with a huge variety of cacti, succulents and trees such as the baobab. Then, through some doors, and into the hot, damp, tropical rainforest. Here, if you are lucky, you might even spot a lizard or a chameleon! There is always something new to encounter when exploring Kew. My favourite part is the Mediterranean Garden. Narrow paths lead past olive trees, the Cork Oak and Italian Cypress, and that distinctive ‘Mediterranean’ smell lingers in the air. Behind the scenes at Kew, vital work is going on in horticulture and science. Plants and fungi are needed to support every ecosystem, providing food and shelter for animals and humans. Kew works to protect plants and fungi and uncover their potential uses. Horticulturists find out the growing conditions needed by very rare plants. For example, café marron is a wild relative of the coffee plant that grows on a tiny island in the Indian Ocean. It was thought to be almost extinct. Samples were found and sent to Kew. At Kew, horticulturists managed to get the plant to root and eventually produce fruit. New plants were sent back to their natural habitat to re-establish a stable wild population. Kew is home to the largest plant collection in the world. 5,000 living plants, including 14,000 trees, make up the ‘living collection’. The Herbarium houses dried plant

specimens and in the DNA bank, samples are kept in freezers to be used in analyses. Kew’s sister site, Wakehurst Place, the wild botanic garden in Sussex, keeps the Millennium Seed Bank. Here, 2.4 million seeds are stored, retaining plant diversity in case it is lost in the wild. Kew’s scientific research includes finding new species, identifying plants threatened with extinction, investigating disease, collecting wild relatives of crop plants and much more. After lockdown, the Jodrell opened up again. My research was in molecular biology, looking at plant DNA. DNA is the code that determines the structure and function of all living organisms. It is made up of a chain of molecules called nucleotides. In short, these are written as a series of the letters A, C, T and G. Genes are short pieces of DNA that determine which proteins are made, which in turn govern the plant (or animal’s appearance). Individuals of a certain plant species have similar genes, therefore similar DNA sequences. Thus, plants that are closely related to each other look similar, just as we look similar to our close family. DNA sequencing is the process of finding out what this series of letters are. DNA is first extracted from the plant, then a sequencer produces the series of letters (although it is a bit more complicated than that!). This sequence can then be used to identify the species. This is the same basic process that would have occurred if you were to have an ancestry DNA test. Last month, Kew published the ‘State of the World’s Plants and Fungi’ report, which covers a huge breadth of very important research. One part identified new species with potential uses as crops, energy providers or medicine. Currently, just a few species make up the majority of our diet. With a rising human population and threats of climate change, it is important to increase the diversity of the food plants we eat. Like crops, very few species are used to make biofuel. The challenge is growing crops for biofuel on land that is unsuitable to grow food. Fuel crops must be grown sustainably and used in a way that minimises carbon emissions. The answer to diseases such as cancer, diabetes and dementia are plants. This is only one of the many reasons for not clearing rainforests. What if the cure for cancer was in the patch that was just cut down? Some developments have been made in this area. For example, a compound found in apple inspired a class of drugs called the flozins, developed to control blood glucose levels in diabetics. The Pacific Yew produces a compound that has been developed to use in some chemotherapy. There is so much more, and if you are interested, I would encourage you to read the report in full. You can find it on the Kew website, or contact me for a copy. Overall, from magnificent gardens to cutting-edge plant research, Kew is a hive of activity in all things plant and fungi and well worth a visit!