Water deficit and salt stress are two major environmental stresses for plants. Salt decreases crop yield and as soil salinity increases worldwide, this causes a problem for agriculture. Luckily, plants can adapt their growth to environmental conditions. In our lab, we are investigating the responses of plants to salinity stress and water deficit from different angles.

The most easily visible changes in plant growth occur above ground, but the first contact with salt happens between the soil and the root system. Research in our lab has shown how flexible this root system is and how it reshapes during salt stress. Our lab discovered that the main root can change direction when it encounters salt, a process called halotropism. Data from  our lab also showed that there are different strategies of reshaping root architecture in response to salt. These different strategies result in a different ratio of lateral and main root length. But how are plants able to alter their growth, how do they sense the salt and what are the implications for salt tolerance?

Many thanks to Dutch Science Foundation NWO (both fundamental and applied science domain projects), CSC, ERA-Net, Nuffic and ERC-Consolidator (Sense2SurviveSalt) for supporting our research.

The research continues with these questions:

How is root architecture remodeled during salt and water stress and how do root responses to salt contribute to stress tolerance of plants?

How are Na+ ions sensed by plants? What is the molecular mechanism that sets in motion all downstream responses that are mounted when plants encounter salinity?

How is the balance between cellular Na+ and K+ levels maintained in the presence of an overwhelming amount of Na+ ions during salt stress?

What is the role of auxin transport and local auxin biosynthesis and conjugation in root and shoot developmental responses to salt stress?

What are the gene regulatory networks that guide developmental responses to salt and water stress?

Our lab uses approaches that include natural variation screening and genetics, stress physiology, gene editing, mutant screening, cellular microscopy, and biochemical approaches. To screen stress physiology, we have developed a time-lapse imaging system that can continuously measure the differences in growth. The species we work on: Arabidopsis (of course!), tomato, the halophyte S. parvula, and potato.

A selection of our publications:

  • van Zelm, E., Zhang, Y. and Testerink, C. Salt Tolerance Mechanisms of Plants. Annual Review of Plant Biology 71: 403-433 (2020) http://www.annualreviews.org/eprint/VN2EH6PPXYXVDSWUTZEM/full/10.1146/annurev-arplant-050718-100005
  • Kawa, D., Meyer, A. J., Dekker, H. L., Abd-El-Haliem, A., Gevaert, K., Van De Slijke, E., Maszkowska, J., Bucholc, M., Dobrowolska, G., de Jaeger, G., Schuurink, R. C., Haring, M. A., and Testerink, C. SnRK2 protein kinases and mRNA decapping machinery control root development and response to salt. Plant Physiology 182: 361-377 (2020)
  • Deolu-Ajayi, A. O., Meyer, A. J., Haring, M. A., Julkowska, M. M., & Testerink, C. Genetic Loci Associated with Early Salt Stress Responses of Roots. iScience 21, 458-473 (2019).
  • Korver, R. A., Koevoets, I. T. & Testerink, C. Out of Shape During Stress: A Key Role for Auxin. Trends in Plant Science 1–11 (2018).
  • Julkowska, M. M. et al. Genetic Components of Root Architecture Remodeling in Response to Salt Stress. The Plant Cell 29, 3198–3213 (2017).
  • Van der Does, D. et al. The Arabidopsis leucine-rich repeat receptor kinase MIK2/LRR-KISS connects cell wall integrity sensing, root growth and response to abiotic and biotic stresses. PLoS Genet. 13, e1006832 (2017).
  • van den Berg, T., Korver, R. A., Testerink, C. & Ten Tusscher, K. H. W. J. Modeling halotropism: a key role for root tip architecture and reflux loop remodeling in redistributing auxin. Development 143, 3350–62 (2016).
  • Julkowska, M. M. et al. Capturing Arabidopsis root architecture dynamics with ROOT-FIT reveals diversity in responses to salinity. Plant Physiol. 166, 1387–402 (2014).
  • Galvan-Ampudia, C. S. et al. Halotropism is a response of plant roots to avoid a saline environment. Curr. Biol. 23, 2044–50 (2013).

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