Mutants of barley with disturbances of synthesis and signaling of brassinosteroids in studies of temperature stress
Leader: dr hab. Anna Janeczko (Department of Developmental Biology)
Cooperation: workers of IPP PAS: prof. dr hab. Maria Filek (Department of Developmental Biology), dr Michał Dziurka (Department of Developmental Biology), dr Magdalena Ryś (Department of Developmental Biology), dr Marta Libik-Konieczny (Department of Stress Biology); Msc Iwona Sadura others: dr Ewa Pociecha (Agricultural University in Krakow), dr Barbara Jurczyk (Agricultural University in Krakow), dr Damian Gruszka (Silesia University)
Too high or too low temperatures not only in animals and people, but also in plants are the stress-causing factor. The effects of temperature stress (such as frost) are particularly dangerous for crops, and are associated with a decrease in yield. However, due to the flexibility of metabolism, all living organisms have to some extent the ability to acclimate to adverse thermal conditions. Like in humans, steroid hormones play an important role in the regulation of plant metabolism. Plant steroid hormones are called brassinosteroids (BR) and they help, among others, protect cells from the effects of stress. The implementation of this project has provided theoretical material that shows some of the mechanisms of brassinosteroid action in plants. So far, many directions of action of BR (in terms of temperature stress) have been established in studies where BR were exogenously applied on plants (i.e. via spraying). The research carried out as part of the project, using semi-dwarf barley mutants with biosynthetic and perception BR disorders, shows that BR are one of the factors involved in regulating the hormonal balance (influencing the level of other hormones) and membrane lipid composition (and properties). BR may also participate in barley in the production of heat shock protective proteins (HSP) and key membrane proteins (aquaporin - HvPIP and H+-ATPase) by regulating both at the level of transcript accumulation and protein accumulation. Temperature (20, 5, 27oC) is however an important factor affecting the directions of biochemical-physiological changes induced by BR. BR deficit and BR perception disorders were associated in barley with changes in tolerance to frost. However, the decrease in tolerance to frost (compared to the control cultivar) occurs in a mutant with BR perception disorders (BW312) and in a mutant with a severe BR deficit (BW084) caused by disturbances of biosynthesis at its early stage. Disruption of BR biosynthesis at a late stage (in mutant 522DK), associated in this case with some the limitation of BR production, did not affect plant frost tolerance. Interestingly, however, the level of frost tolerance of all tested mutants (though reduced in some of them) was, on average, at a level similar to the one found in the currently cultivating in Poland spring cultivar (Kucyk). All tested mutants unexpectedly showed higher tolerance to high temperatures of 38 and 45oC in comparison to the control cultivars from which they were obtained. It was expressed by limited injuries to whole leaves and smaller damage at the level of cell membranes. High temperature stress is usually accompanied by intensive evaporation of leaf water and increasing deficit of water in tissues. The dwarfness of mutants (meaning smaller surface of leaf evaporation) than cultivars, from which they were obtained, and more erected leaves (which also limits transpiration) may be the morphological basis for their better tolerance to high temperatures. The results obtained in the project may be useful for breeders if they are interested in using these semi-dwarf mutants to produce new cultivars of barley. On the other hand, in project these mutants were a convenient model for studies of the role playing by BR plants.
1. Sadura I., Janeczko A., 2018. Physiological and molecular mechanisms of brassinosteroid-induced tolerance to high and low temperature in plants. Biologia Plantarum 62:601-616.
2. Sadura I, Pociecha E, Dziurka M, Oklestkova J, Novak O, Gruszka D, Janeczko A. 2018. Mutations in the HvDWARF, HvCPD and HvBRI1 Genes-Involved in Brassinosteroid Biosynthesis/Signalling: Altered Photosynthetic Efficiency, Hormonal Homeostasis and Tolerance to High/Low Temperatures in Barley. Journal of Plant Growth Regulation. https://doi.org/10.1007/s00344-019-09914-z
3 next articles in preparation
Sadura I., Gruszka D., Maksymowicz A. & Janeczko A. Acclimation of brassinosteroid-deficient barley plants to low temperature. Changes in lipid composition and metabolic activity. XX ISBC Conference, International Society for Biological Calorimetry, 13-15.06. 2018, Cracow, Poland.
Sadura I., Libik–Konieczny M., Jurczyk B., Gruszka D. & Janeczko A. Acclimation of barley brassinosteroid mutants to high temperature. Expression of HSP genes. 11th International Conference Plant Functioning Under Environmental Stress, 12 – 15.09.2018, Cracow, Poland.
Sadura I., Dziurka M., Gruszka D. & Janeczko A. Changes in cytokinin and auxin contents in barley brassinosteroid mutants acclimated to low temperature. 11th International Conference Plant Functioning Under Environmental Stress, 12 – 15.09.2018, Cracow, Poland.
Sadura I., Libik-Konieczny M., Pociecha E., Gruszka D. & Janeczko A. Acclimation of brassinosteroid-deficient barley mutants to high and low temperature. Accumulation of membrane-bound proteins. 7th International Conference For Young Researchers. Multidirectional Research in Agriculture, Forestry and Technology; 16-17.04.2018, Krakow.
Sadura I., Pociecha E., Jurczyk B., Gruszka D., Janeczko A. Acclimation of brassinosteroid-deficient barley mutants to low and high temperature. 8th Conference of the Polish Society of Experimental Plant Biology, 12-15 September, Białystok, Poland.