When we say ‘eat your greens’, we are mostly talking about sprouts, cabbages and kale. We know these vegetables are good for us, even if they are not our favourite! These vegetables belong to a much larger family of plants known as Brassicas, which include turnips, mustard and oilseed rape (Brassica napus) which is used to make cooking oil and salad dressings. So, Brassicas are really important crops grown throughout the world and an essential source of vitamins for many. It is even claimed that some brassicas can help protect against illnesses such as cancer.
But Brassicas need protection from diseases that can affect their yield and quality. In the past, chemicals have been widely used to control diseases of Brassicas and many other crops such as wheat and potatoes. But chemicals can be harmful to the environment, and they are also expensive for many to use. To find better ways of controlling diseases in the future, we have been exploring the natural genetic potential of crop plants.
The science described in our paper is known as translational research, taking discoveries from ‘model plants’ and applying them to crop species. In our case, the model was a tiny weed plant called Arabidopsis thaliana which has been widely studied by many throughout the world. Model plants are used because they have lots of useful characteristics that make it easier to make new scientific discoveries. We wanted to apply new findings into Brassica crop species.
It had been previously shown in Arabidopsis that necrosis and ethylene-inducing like peptides (NLPs) can induce defence responses such as reactive oxygen species that improve disease resistance. NLPs are proteins present in lots of microbes including many disease-causing microbes on crops. So, we wanted to see if they also induced defence responses in Brassica crop species. We revealed that most brassica species could recognise NLPs apart from one – Brassica oleracea which includes cabbages, kales and sprouts – which was very surprising to us.
But not all individuals within a single Brassica species could detect NLPs. We drilled down into Brassica NLP perception using grey mould disease, caused by Botrytis cinerea, as a trigger. In B. napus plants, we compared resistance to grey mould disease between: B. napus plants that could recognise NLPs; and those in the same species that could not. We found that there was no difference between them which was a different result to what we were expecting from the model plant. We think the reason is that there was a lot of genetic diversity in our plants which might have masked the effect of NLP recognition and we can study this further in the future. Overall, we show that translational research can improve understanding of biological processes in crop species and can also produce surprising results.
Henk-jan Schoonbeek, Hicret Asli Yalcin, Rachel Burns, Rachel Emma Taylor, Adam Casey, Sam Holt, Guido Van den Ackerveken, Rachel Wells and Christopher J. Ridout published this study in Plant Pathology:
TITLE IMAGE: Photograph demonstrating iconic Brassica plants: the oil from canola/oilseed rape (Brassica napus) resting on the leaves of kale (Brassica oleracea). All images used with permission of the author.