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Graham Noctor: Understanding plant stress

Researcher portraits Article published on 12 July 2019 , Updated on 24 September 2020

Graham Noctor is a researcher in plant biology at the Institute of Plant Sciences - Paris-Saclay. He has just been appointed senior member of the French University Institute. With his team, he studies the mechanisms of plant adaptation to constraining environments that cause "stress". In particular, the researcher is exploring the consequences of their exposure to a CO2-rich atmosphere in the context of current and future climate change.

"Just like humans, plants can experience stress that may appear as symptoms of suffering or disease, but this stress can also make the plant stronger, more resilient," says Graham Noctor, leader of the Climate Change and Redox Signaling team at the Institute of Plant Sciences - Paris-Saclay (IPS2). "Stress is linked to a lack of water, and temperatures that are either too low or too high, a polluted atmosphere, or attacks by other harmful organisms. All stresses affect the reliability, quality, or yield of plants, and the main purposer here is to identify the signalling mechanisms that make them more resilient."

However, the accumulation of reactive oxygen species (free radicals) plays an important role in all these stresses, and is controlled by the antioxidant system. "My research is therefore focused on the cellular signalling that is linked to it. Knowing that the plant's antioxidant system is even richer than that of humans or animals at the chemical and molecular levels, I am trying to understand this complexity to identify the most important components."

Impact of CO2

More recently, Graham Noctor's team has begun to study the relationship between CO2 levels and plant stress as part of the ANR HIPATH project (2018-2022), which he coordinates at the national level. "We know that the increase in CO2 in the atmosphere will have unpredictable effects on the climate. But let us imagine that more CO2 could be beneficial to plants, because by absorbing it, they transform it into carbohydrates. In general, the more they "consume", the more they photosynthesize and the better they grow," explains the researcher. But if the relationship between CO2, photosynthesis and growth is very well studied in France and internationally, the link between CO2 levels and stress is much less so. Will the increase in CO2 change the plant's resistance to stress? "This is a very important issue for agriculture and therefore for humans. As with any study on the impact of future CO2 levels, definitive answers are not easy to provide. It is hard to carry out experiments spread over several decades that would simulate the reality of the slow and continuous increase in atmospheric CO2. But it is certain that, without global political change, CO2 will continue to rise. Nevertheless, we must try to provide some initial answers to this question, which has not been sufficiently studied yet! »

An Englishman in Saclay

After defending his thesis and completing a first post-doc in England, Graham Noctor arrived at INRA Versailles in the 1990s to complete a second one. Then he returned to his native country. Encouraged by Pierre Gadal, professor at the Université Paris-Sud, to apply in France, he passed his HDR exam in 1998 and obtained a teaching and research position three years later.

Today, with a rate of 5 to 6 publications per year, Graham Noctor is one of Saclay's most cited researchers (Highly Cited Researcher from Clarivate Analytics). His recent appointment at the French University Institute (IUF) rewards twenty years of research and will allow him to devote more time to it for five years.