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The characterisation of organ-specific phytohormone responses to nutrient deficiency and biotic stress
Kramná, Barbara ; Vaňková, Radomíra (advisor) ; Hronková, Marie (referee) ; Plíhalová, Lucie (referee)
Abiotic and biotic stresses lead to crop yield losses and ultimately negatively affect agriculture production. Elucidation of the mechanisms of plant stress responses and their regulation could help to understand plant defence and improve stress tolerance. Phytohormones stand behind both plant growth and developmental changes as well as stress signalling. This thesis summarises the results published in two articles focused on phytohormone dynamics in response to abiotic and biotic stresses, namely phosphate shortage and Plasmodiophora brassicae infection. A review article focuses in depth on strigolactones as master regulators of phosphate deficiency responses. The main emphasis is put on organ-specific reactions and exogenous phytohormone treatment with the potential to convey stress tolerance. In the case of phosphate shortage, the universal reaction in all organs was a decrease in active cytokinin trans-zeatin and gibberellin GA4 with a concurrent elevation of abscisic acid. Also, the high- affinity phosphate transporters (PHT1;4 and PHT1;7) exhibited increased gene expression within the whole plant. Shoot apical meristems showed numerous changes in gene expression and were the most affected organ during the lack of phosphate. Only in roots, we observed a substantial elevation of low active...
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The characterisation of organ-specific phytohormone responses to nutrient deficiency and biotic stress
Kramná, Barbara ; Vaňková, Radomíra (advisor) ; Hronková, Marie (referee) ; Plíhalová, Lucie (referee)
Abiotic and biotic stresses lead to crop yield losses and ultimately negatively affect agriculture production. Elucidation of the mechanisms of plant stress responses and their regulation could help to understand plant defence and improve stress tolerance. Phytohormones stand behind both plant growth and developmental changes as well as stress signalling. This thesis summarises the results published in two articles focused on phytohormone dynamics in response to abiotic and biotic stresses, namely phosphate shortage and Plasmodiophora brassicae infection. A review article focuses in depth on strigolactones as master regulators of phosphate deficiency responses. The main emphasis is put on organ-specific reactions and exogenous phytohormone treatment with the potential to convey stress tolerance. In the case of phosphate shortage, the universal reaction in all organs was a decrease in active cytokinin trans-zeatin and gibberellin GA4 with a concurrent elevation of abscisic acid. Also, the high- affinity phosphate transporters (PHT1;4 and PHT1;7) exhibited increased gene expression within the whole plant. Shoot apical meristems showed numerous changes in gene expression and were the most affected organ during the lack of phosphate. Only in roots, we observed a substantial elevation of low active...
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Imaging of fluorescence emission signals from healthy and infected leaf tissues
BENEDIKTYOVÁ, Zuzana
Auto-fluorescence emission of plant tissues can be a powerful reporter on plant biochemistry and physiology since it originates in substances inherent to primary or secondary metabolism. Plant bodies contain a plethora of intrinsic fluorescent compounds emitting practically all wavelengths of visible light. Moreover, the spectrum of fluorescent reporter signals was recently extended by a variety of fluorescent proteins that provide a new tool to mark whole cells or sub-cellular structures, study protein localization and monitor gene expression and molecule interactions. The imaging of such fluorescence signals reveals a possibility to acquire the information from as many as millions of points simultaneously, in vivo and in a non-invasive way thereby preserving integrity of cells and whole organisms. Imaging is particularly suited to visualize heterogeneity such as a localized immune response to invading pathogens. It can be applied both at macro- as well as micro-scales in two and three dimensions. The recent advancement in microscopy, the multi-photon microscopy, has made possible to monitor fluorescence signals, such as NAD(P)H fluorescence from intact leaf interior, that have been hidden to single-photon techniques.
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