Coping with stress: how plants survive extreme weather

It’s too hot outside for human comfort. Luckily we can avoid the sun and keep ourselves sufficiently hydrated. But how about plants? Rooted to the ground as they are, they need different tactics to cope with weather extremes. “Plants are resilient by necessity,” says Dr Rashmi Sasidharan. “That’s exactly what fascinates me about them.” Her research group at Utrecht University  focuses on the way plants cope with environmental stressors like drought and flooding. With extreme weather on the rise, her research is now more relevant than ever.

Plants cannot run away from extreme weather, so they need tremendous plasticity and sophisticated environmental sensing machinery

Prolonged periods of hot, dry weather like the present heatwave are becoming more common globally. While it is hot and dry in Europe, other parts of the world are experiencing the opposite, with heavy rainfalls resulting in floods and inundation of large areas of land. For plant life, these are challenging conditions. Where some species thrive, others may not survive. This provides a challenge for human food crops. “Take rice for instance, with its rare capacity to thrive in inundated areas,” says Sasidharan. “We flood rice paddies on purpose to kill weeds that can’t survive long under water, thereby using one species’ coping mechanism to kill the other.” While rice copes well with flooding, it does not deal so well with drought. How do crops cope with multiple stressors? This is one of the research questions of the Sasidharan group. 

The fundamental nature of her work is what drives Sasidharan. Initially trained in biochemistry and biotechnology, her PhD took her into the world of plants. She was mostly interested in proteins and enzymes when her PhD project brought her into the fascinating area of cell-wall modifying proteins in plants. From that moment, she was hooked to plant research. “The resilience and environmental plasticity of plants fascinated me from the start”, she recounts. Now, ten years later, she leads a research group in this field. Plants are by necessity very perceptive of even the smallest changes in their environment. “They cannot run away”, laughs Sasidharan, “so they need tremendous plasticity and sophisticated environmental sensing machinery.”
 

Fundamental research with societal relevance

Sasidharans research group at Utrecht University has a strong focus on fundamental research. Inducing various stressors to plants in controlled environments allow the researchers to better understand how plants respond to them and by which mechanisms they become resilient. Her research ultimately helps improve food crops. “If you are a farmer and your crops have somehow made it through a drought period and then your fields are flooded, you want to know how to protect your plants.” To investigate how plants deal with stressors being thrown at them, a controlled lab experiment provides insight. “Aside from our fundamental research, we also tie up with applied research institutes, where they identify crop varieties that work best in the field and distribute them to farmers.” One such institute is the non-profit International Rice Research Institute (IRRI)’ with headquarters in the Phillipines, which aims to develop climate resilient strains of rice. Sasidharan’s group is investigating the mechanisms by which some rice weeds are becoming more tolerant to flooding. “While helping IRRI with a new weed management protocol, we get to elucidate new flood tolerance mechanisms, that’s a win-win.” 

Making plants more resilliant

Adapting plants to be able to cope with our changing climate can be done through selective breeding. This is a long and tedious process that can be done much faster using modern gene-editing tools. Genetic modification is strictly regulated however and is not allowed in Europe, which can be a bump in the road for the translation of fundamental research. “In the lab, we use model species such as Arabidopsis (Sand rocket).  Once we figured out a mechanism, we ask ‘does this mechanism hold in commercially relevant species like tomato, potato, maize’?  These do not always translate directly and may require some genetic tweaking. Introducing a new traits or genes potentially very interesting for research and development, but at the moment it is banned. A major challenge for crop researchers is to get the knowledge of genetic modification techniques such as gene-editing to the general public, thereby making people more aware and less afraid of it. “It is most likely a necessity if we want our crops to survive climate change in the long run,” says Sasidharan. One way is to educate the younger generation and equip them with the knowledge and communication tools to further spread the message. She does this through her teaching in  the 3^rd year bachelor course ‘Food Forward’ where there is a heavy emphasis on science communication. 

Predictable patterns dissapear

We see the climate obviously changing. Decades ago when the weather was predictable farmers could adjust to it, planting and harvests could be reliably planned. That is now out of the window. We lose a lot of food due crop losses in the field and extreme weather fluctuations are increasingly frequent. Crops in the field commonly experience several stresses. In the ideal world we would have a crop variety that can do it all but there is no magic bullet. The research community is focusing on identifying common elements of the major stresses. Can we find something that could make our crops at least resilient to those common elements? If we can develop varieties that can sustain some of the yield and not a complete loss is already a win.