Laboratory of Plant Genetics
Assoc. Prof. RNDr. Dana Holá, Ph.D.
Phone: +420 221 951 201
The Laboratory of Plant Genetics has been engaged in the study of the intraspecific variability in various biochemical, physiological, morphological, growth, developmental and yield characteristics of crop species for a long time (practically from its establishment more than 70 years ago). Particular attention has been paid to the analysis of the heterotic effect (the hybrid vigour) in various generations of plant hybrids. At the present time, this branch of our research is focused mostly on the dissection of the possible causes for different responses of plant genotypes to various environmental conditions, which is made on several levels (from the whole plant to cellular and sub-cellular level).
In the course of their life, plants are often exposed to an unfavourable environment which causes a stress response. Stress factors induce many complex and mutually-interconnected changes in a plant organism; some of these changes are specific for one type of stress, others can be caused by multiple stressors. The common factor of various stress responses of plants is usually the decrease in the efficiency of photosynthesis, the increase in the production of reactive oxygen species and the increased synthesis of various protective proteins and metabolites. The measurable parameters associated with these processes can advantageously be used as secondary biomarkers in the breeding and selection of genotypes tolerant to various stressors. The members of the Laboratory study these parameters mostly in connection with the plant response to drought, low temperatures or hypoxia associated with soil waterlogging. The research is made with agronomically important plant species and is based not only on the comparison of stress-tolerant and -sensitive genotypes per se but also on the analyses of larger genotype sets including various generations of hybrids. This enables us to find out whether the tolerance to a particular stress factor is heritable and also to ascertain the mechanisms participating in its transmission from parents to their progeny (Benešová et al., 2012, Holá et al., 2017).
However, plant response to unfavourable environmental conditions is a highly complex process. The final effect of any stress factor strongly depends on its intensity and duration and the plant developmental stage. Interactions between individual stressors during their joint action significantly influence the pattern of the plant stress response (leading to either a higher or lesser damage to the plant) compared to the effect each stress factor has when acting separately. Plants also use various biochemical and epigenetic mechanisms to “remember” previous exposure to some stressor and thus can be better prepared (“primed”) for a repetition of the same (or even different) stress. The Laboratory is interested in some of these mechanisms in order to ascertain their possible role in how rapidly and effectively the genotypes with different tolerance to a particular stress factor can respond after the stress is ended and during repeated stress exposures.
The third main research topic of the Laboratory is the function of various steroid compounds, mainly brassinosteroids (BRs) and ecdysteroids (ECs), in plant organisms. BRs are an important group of plant growth regulators participating in many processes that occur in plants. However, the exact changes BRs cause in plant cells/tissues are not yet fully explained. The members of the Laboratory study the effect of BRs on various components of photosynthetic apparatus (Holá, 2011, Rothová et al., 2014, Holá et al., 2022), examine the differences in the response of various plant genotypes to the exogenous application of these compounds, and are interested in the connection between BRs and plant stress response (Tůmová et al., 2018, Holá et al., 2019, Marková et al. 2023). BRs protect plants against many biotic and abiotic stressors and this protective function, together with the fact that these compounds are harmless both to humans and the general environment and that their effective concentrations are extremely low, make BRs ideal candidates for inclusion into modern agricultural technologies aimed at the improvement of plant stress tolerance.
In the case of plant analogues of insect hormones, ECs, it is still not clear what their role in plants is; they are mostly supposed to somehow protect plants against insects and similar biotic stressors. Our Laboratory, together with our colleagues from the Department of Biochemistry and Microbiology, Faculty of Food and Biochemical Technology, University of Chemistry and Technology in Prague, has recently for the first time shown that these compounds can also affect a plant photosynthetic apparatus in vivo. However, it seems that various plant species can differ in this respect and (interestingly) that ECs can functionally interact with BRs (Rothová et al., 2014, Kamlar et al. 2015, Holá et al., 2020).
Besides agronomically important crop species, the members of the Laboratory of Plant Genetics also studied the deciduous and evergreen trees of temperate forests. This research dealt mainly with the response of a tree photosynthetic apparatus to the elevated concentration of carbon dioxide in the air and with the intraspecific variability in selected populations of conifers in the Czech Republic. It is made in cooperation with the Laboratory of Ecophysiological Anatomy, Department of Experimental Plant Biology, Faculty of Science, Charles University in Prague and other institutions. In the course of this research, a method for the isolation of photochemically-active chloroplasts from conifer needles, which can be utilized for various conifer species and facilitates the measurement of different parts of photosynthetic electron-transport chain, has been designed (Holá et al., 2012). The possibility of the utilisation of non-destructively measurable photosynthetic parameters as suitable markers in the breeding of forest trees was examined together with the members of the Department of Genetics and Physiology of Forest Trees, Faculty of Forestry and Wood Sciences, Czech University of Life Sciences Prague (Čepl et al., 2016, Čepl et al., 2018).