Role of steroids in frost hardening of winter wheat
Project National Science Centre (Poland): 2013/09/B/NZ9/01653
Project leader: dr hab. Anna Janeczko (Department of Developmental Biology)
Colaborators: prof. dr hab. Maria Filek (Department of Developmental Biology), dr Michał Dziurka (Department of Developmental Biology), dr Ewa Pociecha (Agricultural Uniwersity in Krakow), dr Barbara Jurczyk (Agricultural Uniwersity in Krakow), dr Agata Siwek (Jagiellonian University).
The aim of the work was to study the biochemical and physicochemical mechanisms of the activity of steroid regulators (brassinosteroids, progesterone) in winter wheat that was exposed to low temperatures. Brassinosteroids are steroid hormones in plants while progesterone is mammalian steroid hormone but is also present in plants, although its role is only partly explained. Cold hardening induces frost tolerance and prepares winter crops to survive winter during vegetation. In our experiments, seedlings of six winter wheat cultivars were cold hardened (3 weeks) at 5 oC and then exposed to frost. Application of brassinosteroid (24-epibrassinolide) and progesterone before cold hardening reduced frost damage in the plants proving protective role of these steroids. The endogenous brassinosteroid content increased in winter wheat during cold hardening while content of progesterone decreased. A higher amount of brassinosteroids (but not progesterone) was accompanied by a higher level of frost tolerance of cultivars of winter wheat. The information about dependency of brassinosteroid content in plants and level of frost tolerance of winter wheat cultivars can be important for breeders for selection of new cultivars - more resistant to stress. Brassinosteroids and progesterone are important for regulation of the antioxidant system in winter wheat during cold hardening. Steroids did not affect the content of the stress hormone (ABA) but changed content of gibberellins. Studies of the membranes, which were performed on a Langmuir trough, showed an increase in the value of the parameter that indicates differences in membrane compressibility (resulting from stronger interactions between the molecules in the membranes). This suggests that 24-epibrassinolide and progesterone are incorporated into the lipid layer and that similar to sterols stabilise the interaction between lipids, which may be important step for better frost tolerance. Brassinosteroids may be recommended to use in agriculture for preparation of agrochemicals improving plant resistance to frost.
Janeczko A., Oklestkova J., Novak O., Śniegowska-Świerk K., Snaczke Z., Pociecha E. 2015. Disturbances in production of progesterone and their implications in plant studies. Steroids 96: 153–163.
Filek M., Rudolphi-Skórska E., Sieprawska A., Kvasnica M., Janeczko A. 2017. Regulation of the membrane structure by brassinosteroids and progesterone in winter wheat seedlings exposed to low temperature. Steroids 128: 37-45.
Janeczko A., Dziurka M., Pociecha E. 2018. Increased leaf tocopherol and β-carotene content is associated with the tolerance of winter wheat cultivars to frost. Journal of Agronomy and Crop Sciences, 204:594-602.
Janeczko A. 2019. Brassinosteroids in cereals - presence, physiological activity and practical aspects. Chapter 3 (pp. 62-92) in: S. Hayat et al. (eds.), Brassinosteroids: Plant Growth and Development, Springer Nature Singapore Pte Ltd. (Invited chapter). https://doi.org/10.1007/978-981-13-6058-9_3
Janeczko A., Pociecha E., Dziurka M., Filek M., Jurczyk B., Libik-Konieczny M., Oklestkova J. Novak O., Pilarska M., Rudolphi-Skórska E., Sadura I., Siwek A. 2019. Changes in content of steroid regulators during cold hardening of winter wheat - steroid physiological/biochemical activity and impact on frost tolerance.Plant Physiology and Biochemistry 139:215-228.