Sirvi Märksõna "ABA" järgi

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Search for missing components in high VPD-induced stomatal closure pathway
(Tartu Ülikool, 2024) Morozova, Daana; Merilo,Ebe, juhendaja; Tartu Ülikool. Loodus- ja täppisteaduste valdkond; Tartu Ülikool. Tehnoloogiainstituut
Climate warming is associated with rising atmospheric Vapour Pressure Deficit (VPD), which affects plant physiology and production. Some proteins in the high VPD-induced stomatal closure pathway are known (e.g., protein kinase OST1), but there are still missing components. To address this knowledge gap, the study aimed to investigate Arabidopsis mutants defective in selected genes in order to reveal new elements that might be involved in VPD-induced stomata closure. Mutants were selected based on Wang et al. (2020) table of OST1 putative substrates and the expression levels of these genes in guard cells versus mesophyll cells. Experiments were conducted using a gas exchange measurement device to study plants’ stomatal conductance in response to high VPD and a plant stress hormone - abscisic acid (ABA). The study results showed no statistically significant differences in the steady-state stomata conductance and closure responses among mutants and wild-type, suggesting that these genes are not involved in VPD-induced stomata closure. Therefore, more studies are needed to reveal the missing components in the stomatal high VPD-induced closure pathway above OST1. Current results still add knowledge about stomatal behavior in future climatic conditions.
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Stomatal Conductance Depends on Abscisic Acid Production in Both Guard Cells and in Phloem Companion Cells
(Tartu Ülikool, 2017-06-10) Parik, Helen; PhD, Dmitry Yarmolinsky, supervisor; Prof. Hannes Kollist , supervisor; Tartu Ülikool. Loodus- ja täppisteaduste valdkond; Tartu Ülikool. Molekulaar- ja rakubioloogia instituut
The question how plants use water is important as water availability is often a limiting factor for plant growth. Stomata are mainly responsible for water loss from plant tissues and, therefore, regulatory mechanisms controlling stomatal apertures are in the research focus of plant water management. Abscisic acid (ABA) has an important role in reducing stomatal conductance, however, importance of ABA biosynthesis in guard cells and in phloem is not fully studied. To address this question, we generated transgenic plants with restored ABA biosynthesis either in guard cells or in phloem by using tissue-specific promoters. Our study shows that both guard cells and phloem companion cells can produce ABA in quantities which are enough to regulate plant development and stomatal conductance on the level of wildtype plants.
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The function of ABA transporters during low humidity-induced stomatal closure in Arabidopsis thaliana.
(2021) Hasanov, Turgay
Plants are important for our nature and for all living things. These organisms can produce food, energy and several natural products from carbon dioxide and solar energy. Plants take up CO2 from the air in exchange for water via small pores called stomata on the leaf surface. These stomata are formed by pairs of cells, called guard cells. As plants are sessile organisms, they cannot move and need to adapt their physiology to the imposed environmental conditions. Drought is one of the major problems caused by climate change and guard cell physiology plays an important role in regulating stomatal apertures and the plant water content. For stomatal aperture regulation under limiting water conditions, the plant hormone abscisic acid (ABA) plays a major role. To understand guard cell physiology and the role of ABA in the plant response to low air humidity, defined as the Vapor Pressure Deficit (VPD) between plants and the atmosphere, we performed gas exchange analyses using Arabidopsis thaliana wild type plants and mutants in which ABA transporter genes were disrupted. Among the tested mutants, we observed a slower VPD response in a mutant in which the ABCG22 gene was disrupted. However, we did not observe clearly altered high VPD responses of abcg25, abcg31, abcg40, npf4.6 and npf5.2 ABA transporter mutants. This may be due to a high functional overlap between several ABA transporter genes. We also performed gene expression analyses of ABA transporter genes using the Genevestigator tool. This allowed us to propose the testing of additional ABA transporter genes that might be relevant for the high VPD response in Arabidopsis.
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Tundmatu geeni (PUSA) ja CYP707A3 toime iseloomustamine hariliku müürlooga (Arabidopsis thaliana) taimedes
(Tartu Ülikool, 2025) Veigel, Madli Johanna; Tulva, Ingmar, juhendaja; Tartu Ülikool. Loodus- ja täppisteaduste valdkond; Tartu Ülikool. Molekulaar- ja rakubioloogia instituut
Taimedel on gaasivahetuseks lehtede pinnal õhulõhed, mida on võimalik liigse veekaotuse kontrollimiseks sulgeda. Õhulõhede sulgumiseks on oluline taimehormoon abstsiishape (ABA). Käesolevas töös uuriti abstsiishappe lagundamiseks vajalikku CYP707A3 geeni ja tundmatu, mutantsel fenotüübil põhineva esmase nimetusega PUSA geeni toimet hariliku müürlooga (Arabidopsis thaliana) taimedes. Tundmatu PUSA geen avastati ja eraldati varasemalt ühest häirunud CYP707A3 geeni sisaldavast taimeliinist (SALK_078173), millel oli silmapaistev fenotüüp, mistõttu sooviti teada saada, kumma geeni häirumisest on põhjustatud SALK_078173 fenotüüp. Saadi teada, et CYP707A3 geeni toime oli uuritud taimeliinides madal ning tundmatu PUSA geen on oluline taimede kasvamiseks. Samuti selgus, et SALK_078173 fenotüüpi põhjustas tundmatu PUSA geeni häirumine.