Sirvi Autor "Yadlos, Oleksii" järgi

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Development of visual selection markers for plant transformation
(Tartu Ülikool, 2023) Yadlos, Oleksii; Wang, Yuh-Shuh, juhendaja
The generation of transgenic Arabidopsis thaliana plants relies heavily on the choice of selection markers. We investigated three potential visual seed-selection markers: the RUBY reporter, the amilCP chromoprotein, and the endogenous TTG1 gene. The RUBY reporter, which produces dark-red betalain pigment, successfully led to distinguishable seed color changes in Arabidopsis Col-0 and ttg1 mutant backgrounds. However, the use of the amilCP chromoprotein was limited by its low transformation efficiency and germination rate, likely due to its toxicity in plants. Attempts to use the TTG1 gene as an endogenous selection marker did not produce observable seed color changes in the first transgenic gen- eration, possibly due to insufficient TTG1 protein expression. Overall, this study demon- strates the potential of the RUBY reporter as an effective visual marker for seed selection and highlights the need to explore endogenous markers to improve the efficiency and con- venience of generating transgenic Arabidopsis plants.
Exploring the Role of the HT1-MPK12 Module in Guard Cell CO2 Sensing
(Tartu Ülikool, 2025) Yadlos, Oleksii; Wang, Yuh-Shuh, juhendaja; Kollist, Hannes, juhendaja; Tartu Ülikool. Loodus- ja täppisteaduste valdkond; Tartu Ülikool. Tehnoloogiainstituut
To optimise the balance between CO₂ uptake for photosynthesis and loss of water by transpiration, plant stomatal pores regulate their aperture in response to changes in CO₂ concentration. The HT1–MPK12/4 complexes have been implicated as key CO₂ sensors in stomatal guard cells, but the molecular basis of MPK12 and MPK4 function in CO₂ signalling, as well as the exact CO₂-sensing mechanism, remain unclear. MPK12 is specific to the guard cells, whereas MPK4 plays diverse roles in many cell types. Interestingly, MPK11, as a close homolog of MPK4 and MPK12, is not involved in stomatal regulation by CO₂. This thesis aimed to determine which regions of MPK12 are required for its CO₂-specific function and whether the HT1–MPK12 module can directly sense CO₂ via lysine carbamylation. We constructed MPK12/MPK11 chimeras and MPK12 truncation mutants and tested their ability to bind HT1 and restore normal CO₂-induced stomatal responses in plant lines in which native MPK12 was deleted. We also identified potential CO₂-binding lysines on MPK12 and HT1 and evaluated their functional importance in planta. Chimeric and truncation analyses revealed key features of MPK12 domains: the C-terminal lobe is essential for interaction with HT1, while the N-lobe is required for a wild-type CO₂ response. Several amino acids in the N-lobes of MPK12 and MPK4 were proposed to contribute to CO₂ signalling and HT1 inhibition, warranting further investigation. Preventing potential carbamylation on selected lysine residues in MPK12 and HT1 did not abolish stomatal CO₂ responses. These findings suggest that non covalent HCO₃⁻ binding, rather than lysine carbamylation, serves as the primary CO₂-sensing mechanism within the HT1–MPK12/4 module.