Characterization of MPK and HT1 kinases in CO2-induced stomatal movements
Date
2024-05-02
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Abstract
Taimed muudavad atmosfääri süsinikdioksiidi (CO2) fotosünteesi teel energiarikasteks orgaanilisteks ühenditeks ning selle protsessi käigus vabaneb hapnikku mis on vajalik inimestele ja teistele heterotroofsetele organismisele. Seetõttu on oluline mõista, kuidas taimed toimivad muutuvates keskkonnatingimustes.
Kaitserakud, mis moodustavad taimede lehtedes stomataalseid poore, reguleerivad taime gaasivahetust. Taimed peavad säilitama tasakaalu fotosünteesiks vajaliku CO2 omastamise ja veeauru väljutamise vahel läbi stomataalsete pooride. See tasakaal on taimede ellujäämiseks muutuvates keskkonnatingimustes ülioluline. Kõrgenenud CO2 vallandab stomati sulgemise ja see mõjutab lehtede temperatuuri, veekasutuse tõhusust, taimede kasvu ja saagikust. Molekulaarseid mehhanisme, mis määravad, kuidas taimed tunnetavad CO2 kaitserakkudes ja edastavad selle signaali stomataalse ava reguleerimiseks, ei mõistetud täielikult. Selles lõputöös pakkusime välja stomataalse CO2 tuvastamise mudeli. Näitasime, et interaktsioon mitogeen-aktiveeritud proteiinkinaaside (MPK) MPK4/12 ja HIGH LEAF TEMPERATURE 1 (HT1) vahel moodustab kaitserakkudes kaua otsitud primaarse stomataalse CO2/vesinikkarbonaadi anduri. Lisaks näitasime, et CO2 tundlikkuse mehhanism ei sõltu MPK12 kinaasi aktiivsusest. Käesolevas lõputöös esitatud järeldusi saab edasi kasutada moduleeritud veekasutuse efektiivsusega põllukultuuride kavandamiseks tõusvas atmosfääri CO2 keskkonnas.
Plants are converting atmospheric carbon dioxide (CO2) into energy rich organic compounds by photosynthesis and this process releases oxygen for human beings and other heterotrophs. Therefore, understanding how plants work in the changing environmental conditions is important. Guard cells, which form stomatal pores in plant leaves, regulate plant gas exchange. Plants need to maintain a balance between CO2 uptake for photosynthesis and releasing water vapor through the stomatal pores. This balance is crucial for plant survival in changing environmental conditions. Elevated CO2 triggers stomatal closure and this affects leaf temperature, water-use efficiency, plant growth and crop yield. The molecular mechanisms defining how plants sense CO2 in guard cells and transmit this signal to regulate stomatal aperture were not fully understood. In this thesis, we proposed a model for stomatal CO2-sensing. We demonstrated that interaction between mitogen-activated protein kinases (MPKs) MPK4/12 and HIGH LEAF TEMPERATURE 1(HT1) form the long-sought primary stomatal CO2/bicarbonate sensor in guard cells. Furthermore, we demonstrated that the CO2-sensing mechanism is independent of the MPK12 kinase activity. The findings presented in this thesis can be further used to design crops with modulated water use efficiency in the rising atmospheric CO2 environment.
Plants are converting atmospheric carbon dioxide (CO2) into energy rich organic compounds by photosynthesis and this process releases oxygen for human beings and other heterotrophs. Therefore, understanding how plants work in the changing environmental conditions is important. Guard cells, which form stomatal pores in plant leaves, regulate plant gas exchange. Plants need to maintain a balance between CO2 uptake for photosynthesis and releasing water vapor through the stomatal pores. This balance is crucial for plant survival in changing environmental conditions. Elevated CO2 triggers stomatal closure and this affects leaf temperature, water-use efficiency, plant growth and crop yield. The molecular mechanisms defining how plants sense CO2 in guard cells and transmit this signal to regulate stomatal aperture were not fully understood. In this thesis, we proposed a model for stomatal CO2-sensing. We demonstrated that interaction between mitogen-activated protein kinases (MPKs) MPK4/12 and HIGH LEAF TEMPERATURE 1(HT1) form the long-sought primary stomatal CO2/bicarbonate sensor in guard cells. Furthermore, we demonstrated that the CO2-sensing mechanism is independent of the MPK12 kinase activity. The findings presented in this thesis can be further used to design crops with modulated water use efficiency in the rising atmospheric CO2 environment.
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