Comparative studies of lipid metabolism in drought-tolerant and drought-sensitive plants and deep understanding of the resurrection grass Oropetium thomaeum
Comparative studies of lipid metabolism in drought-tolerant and drought-sensitive plants and deep understanding of the resurrection grass Oropetium thomaeum
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DissertationPrüfungsdatum
14.06.2024Datum der Veröffentlichung
12.08.2024Erstgutachter
Bartels, DorotheaZweitgutachter
Dörmann, PeterMetadaten
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1. Increasing water scarcity is known as a crucial challenge to sustainable development of the planet. Water scarcity will impact 40% of the world’s population at risk of drought by 2030. Most higher plants are unable to survive desiccation to an air-dried state, however, a small group of vascular plants termed “resurrection plants” can revive from a severe cellular water loss. Oropetium thomaeum is a compact resurrection plant that has the smallest known genome among the grasses and could survive the extreme water stress such as loss of >95% of cellular water. Oropetium thomaeum belongs to the Chloridoideae subfamily of Poaceae and 75% of the genome is located in conserved syntenic regions of grass genomes. A proportion (24% of genes) of tandem duplicated genes similar to other grasses are present in Oropetium thomaeum.
2. The stomata in Oropetium thomaeum leaves are a four-celled structure, a typical character of a C4 plant. The stomata contain more lipids than other surrounding organelles, possibly to help stomatal movement and then support tolerance of the plants during dehydration. Comparative cellular analyses of desiccated and fully hydrated leaves revealed the accumulation of oil bodies in leaf tissues during desiccation by Nile red staining, which is similar to morphological and expression patterns in desiccated seeds.
3. Drought stress triggers the activities of oil body-related degrading enzymes (CLO: Caleosin) in Oropetium thomaeum, OtCLO3, OtCLO4, and OtCLO6 transcript expression levels showed a significant increase during desiccation treatment in leaf tissues, indicating that during drought stress oil bodies are activated by a degradation process, to help organelles get energy to maintain or enhance the ability to tolerate abiotic stress. However, at the same time, oil bodies accumulated during drought stress in leaf tissues of Oropetium thomaeum with similar morphological and expression patterns to desiccated seeds. These changes suggest that the generation rate of oil bodies is higher than the degradation rate in Oropetium thomaeum.
4. SDP1 (SUGAR-DEPENDENT 1, encodes a triacylglycerol lipase) is involved in oil body degradation in plants. The transcript level of OtSDP1 showed a low abundance in leaf tissues of Oropetium thomaeum during dehydration and rehydration. In this study, a large accumulation of oil bodies was found in leaf tissues with drought stress, which rapidly decreased after rehydration, indicating that the activity of the degrading enzymes was not positively correlated with transcript levels of Oropetium thomaeum. This result suggests that OtSDP1 may also functioning during post-transcription.
5. DGAT2 plays a key role in TAG synthesis in leaf tissues of Oropetium thomaeum while DGAT1 is the main enzyme for TAG synthesis in seeds of Arabidopsis thaliana. Comparison of DGAT2 expression level in other resurrection plants such as Craterostigma plantagineum and Lindernia brevidens, also showed a significant increase under drought stress. These results suggest that DGAT2 is likely to have an important role in TAG synthesis in desiccation tolerant plants.
6. Sterol acyltransferases were identified as acyl-CoA: sterol acyltransferases (ASAT) and phospholipid: sterol acyltransferases (PSAT) in plants. PSAT1 is not the key enzyme to limit the sterol metabolic rate in tomato (Solanum lycopersicum), and SlPSAT1 and SlASAT1 show overlapping but largely complementary models of expression during tomato fruit growth. This statement is consistent with the results in this study. PSAT1 and ASAT also increased or decreased simultaneously in Arabidopsis thaliana and Oropetium thomaeum, under drought conditions. These results could be a proof that PSAT1 and ASAT1 functions are likely overlapping in a complementary way in Arabidopsis thaliana and Oropetium thomaeum leaf tissues.
2. The stomata in Oropetium thomaeum leaves are a four-celled structure, a typical character of a C4 plant. The stomata contain more lipids than other surrounding organelles, possibly to help stomatal movement and then support tolerance of the plants during dehydration. Comparative cellular analyses of desiccated and fully hydrated leaves revealed the accumulation of oil bodies in leaf tissues during desiccation by Nile red staining, which is similar to morphological and expression patterns in desiccated seeds.
3. Drought stress triggers the activities of oil body-related degrading enzymes (CLO: Caleosin) in Oropetium thomaeum, OtCLO3, OtCLO4, and OtCLO6 transcript expression levels showed a significant increase during desiccation treatment in leaf tissues, indicating that during drought stress oil bodies are activated by a degradation process, to help organelles get energy to maintain or enhance the ability to tolerate abiotic stress. However, at the same time, oil bodies accumulated during drought stress in leaf tissues of Oropetium thomaeum with similar morphological and expression patterns to desiccated seeds. These changes suggest that the generation rate of oil bodies is higher than the degradation rate in Oropetium thomaeum.
4. SDP1 (SUGAR-DEPENDENT 1, encodes a triacylglycerol lipase) is involved in oil body degradation in plants. The transcript level of OtSDP1 showed a low abundance in leaf tissues of Oropetium thomaeum during dehydration and rehydration. In this study, a large accumulation of oil bodies was found in leaf tissues with drought stress, which rapidly decreased after rehydration, indicating that the activity of the degrading enzymes was not positively correlated with transcript levels of Oropetium thomaeum. This result suggests that OtSDP1 may also functioning during post-transcription.
5. DGAT2 plays a key role in TAG synthesis in leaf tissues of Oropetium thomaeum while DGAT1 is the main enzyme for TAG synthesis in seeds of Arabidopsis thaliana. Comparison of DGAT2 expression level in other resurrection plants such as Craterostigma plantagineum and Lindernia brevidens, also showed a significant increase under drought stress. These results suggest that DGAT2 is likely to have an important role in TAG synthesis in desiccation tolerant plants.
6. Sterol acyltransferases were identified as acyl-CoA: sterol acyltransferases (ASAT) and phospholipid: sterol acyltransferases (PSAT) in plants. PSAT1 is not the key enzyme to limit the sterol metabolic rate in tomato (Solanum lycopersicum), and SlPSAT1 and SlASAT1 show overlapping but largely complementary models of expression during tomato fruit growth. This statement is consistent with the results in this study. PSAT1 and ASAT also increased or decreased simultaneously in Arabidopsis thaliana and Oropetium thomaeum, under drought conditions. These results could be a proof that PSAT1 and ASAT1 functions are likely overlapping in a complementary way in Arabidopsis thaliana and Oropetium thomaeum leaf tissues.
Klassifikation (DDC)
570 Biowissenschaften, BiologieSong, Xiaomin: Comparative studies of lipid metabolism in drought-tolerant and drought-sensitive plants and deep understanding of the resurrection grass Oropetium thomaeum. - Bonn, 2024. - Dissertation, Rheinische Friedrich-Wilhelms-Universität Bonn.
Online-Ausgabe in bonndoc: https://nbn-resolving.org/urn:nbn:de:hbz:5-77678
Online-Ausgabe in bonndoc: https://nbn-resolving.org/urn:nbn:de:hbz:5-77678
@phdthesis{handle:20.500.11811/11815,
urn: https://nbn-resolving.org/urn:nbn:de:hbz:5-77678,
author = {{Xiaomin Song}},
title = {Comparative studies of lipid metabolism in drought-tolerant and drought-sensitive plants and deep understanding of the resurrection grass Oropetium thomaeum},
school = {Rheinische Friedrich-Wilhelms-Universität Bonn},
year = 2024,
month = aug,
note = {1. Increasing water scarcity is known as a crucial challenge to sustainable development of the planet. Water scarcity will impact 40% of the world’s population at risk of drought by 2030. Most higher plants are unable to survive desiccation to an air-dried state, however, a small group of vascular plants termed “resurrection plants” can revive from a severe cellular water loss. Oropetium thomaeum is a compact resurrection plant that has the smallest known genome among the grasses and could survive the extreme water stress such as loss of >95% of cellular water. Oropetium thomaeum belongs to the Chloridoideae subfamily of Poaceae and 75% of the genome is located in conserved syntenic regions of grass genomes. A proportion (24% of genes) of tandem duplicated genes similar to other grasses are present in Oropetium thomaeum.
2. The stomata in Oropetium thomaeum leaves are a four-celled structure, a typical character of a C4 plant. The stomata contain more lipids than other surrounding organelles, possibly to help stomatal movement and then support tolerance of the plants during dehydration. Comparative cellular analyses of desiccated and fully hydrated leaves revealed the accumulation of oil bodies in leaf tissues during desiccation by Nile red staining, which is similar to morphological and expression patterns in desiccated seeds.
3. Drought stress triggers the activities of oil body-related degrading enzymes (CLO: Caleosin) in Oropetium thomaeum, OtCLO3, OtCLO4, and OtCLO6 transcript expression levels showed a significant increase during desiccation treatment in leaf tissues, indicating that during drought stress oil bodies are activated by a degradation process, to help organelles get energy to maintain or enhance the ability to tolerate abiotic stress. However, at the same time, oil bodies accumulated during drought stress in leaf tissues of Oropetium thomaeum with similar morphological and expression patterns to desiccated seeds. These changes suggest that the generation rate of oil bodies is higher than the degradation rate in Oropetium thomaeum.
4. SDP1 (SUGAR-DEPENDENT 1, encodes a triacylglycerol lipase) is involved in oil body degradation in plants. The transcript level of OtSDP1 showed a low abundance in leaf tissues of Oropetium thomaeum during dehydration and rehydration. In this study, a large accumulation of oil bodies was found in leaf tissues with drought stress, which rapidly decreased after rehydration, indicating that the activity of the degrading enzymes was not positively correlated with transcript levels of Oropetium thomaeum. This result suggests that OtSDP1 may also functioning during post-transcription.
5. DGAT2 plays a key role in TAG synthesis in leaf tissues of Oropetium thomaeum while DGAT1 is the main enzyme for TAG synthesis in seeds of Arabidopsis thaliana. Comparison of DGAT2 expression level in other resurrection plants such as Craterostigma plantagineum and Lindernia brevidens, also showed a significant increase under drought stress. These results suggest that DGAT2 is likely to have an important role in TAG synthesis in desiccation tolerant plants.
6. Sterol acyltransferases were identified as acyl-CoA: sterol acyltransferases (ASAT) and phospholipid: sterol acyltransferases (PSAT) in plants. PSAT1 is not the key enzyme to limit the sterol metabolic rate in tomato (Solanum lycopersicum), and SlPSAT1 and SlASAT1 show overlapping but largely complementary models of expression during tomato fruit growth. This statement is consistent with the results in this study. PSAT1 and ASAT also increased or decreased simultaneously in Arabidopsis thaliana and Oropetium thomaeum, under drought conditions. These results could be a proof that PSAT1 and ASAT1 functions are likely overlapping in a complementary way in Arabidopsis thaliana and Oropetium thomaeum leaf tissues.},
url = {https://hdl.handle.net/20.500.11811/11815}
}
urn: https://nbn-resolving.org/urn:nbn:de:hbz:5-77678,
author = {{Xiaomin Song}},
title = {Comparative studies of lipid metabolism in drought-tolerant and drought-sensitive plants and deep understanding of the resurrection grass Oropetium thomaeum},
school = {Rheinische Friedrich-Wilhelms-Universität Bonn},
year = 2024,
month = aug,
note = {1. Increasing water scarcity is known as a crucial challenge to sustainable development of the planet. Water scarcity will impact 40% of the world’s population at risk of drought by 2030. Most higher plants are unable to survive desiccation to an air-dried state, however, a small group of vascular plants termed “resurrection plants” can revive from a severe cellular water loss. Oropetium thomaeum is a compact resurrection plant that has the smallest known genome among the grasses and could survive the extreme water stress such as loss of >95% of cellular water. Oropetium thomaeum belongs to the Chloridoideae subfamily of Poaceae and 75% of the genome is located in conserved syntenic regions of grass genomes. A proportion (24% of genes) of tandem duplicated genes similar to other grasses are present in Oropetium thomaeum.
2. The stomata in Oropetium thomaeum leaves are a four-celled structure, a typical character of a C4 plant. The stomata contain more lipids than other surrounding organelles, possibly to help stomatal movement and then support tolerance of the plants during dehydration. Comparative cellular analyses of desiccated and fully hydrated leaves revealed the accumulation of oil bodies in leaf tissues during desiccation by Nile red staining, which is similar to morphological and expression patterns in desiccated seeds.
3. Drought stress triggers the activities of oil body-related degrading enzymes (CLO: Caleosin) in Oropetium thomaeum, OtCLO3, OtCLO4, and OtCLO6 transcript expression levels showed a significant increase during desiccation treatment in leaf tissues, indicating that during drought stress oil bodies are activated by a degradation process, to help organelles get energy to maintain or enhance the ability to tolerate abiotic stress. However, at the same time, oil bodies accumulated during drought stress in leaf tissues of Oropetium thomaeum with similar morphological and expression patterns to desiccated seeds. These changes suggest that the generation rate of oil bodies is higher than the degradation rate in Oropetium thomaeum.
4. SDP1 (SUGAR-DEPENDENT 1, encodes a triacylglycerol lipase) is involved in oil body degradation in plants. The transcript level of OtSDP1 showed a low abundance in leaf tissues of Oropetium thomaeum during dehydration and rehydration. In this study, a large accumulation of oil bodies was found in leaf tissues with drought stress, which rapidly decreased after rehydration, indicating that the activity of the degrading enzymes was not positively correlated with transcript levels of Oropetium thomaeum. This result suggests that OtSDP1 may also functioning during post-transcription.
5. DGAT2 plays a key role in TAG synthesis in leaf tissues of Oropetium thomaeum while DGAT1 is the main enzyme for TAG synthesis in seeds of Arabidopsis thaliana. Comparison of DGAT2 expression level in other resurrection plants such as Craterostigma plantagineum and Lindernia brevidens, also showed a significant increase under drought stress. These results suggest that DGAT2 is likely to have an important role in TAG synthesis in desiccation tolerant plants.
6. Sterol acyltransferases were identified as acyl-CoA: sterol acyltransferases (ASAT) and phospholipid: sterol acyltransferases (PSAT) in plants. PSAT1 is not the key enzyme to limit the sterol metabolic rate in tomato (Solanum lycopersicum), and SlPSAT1 and SlASAT1 show overlapping but largely complementary models of expression during tomato fruit growth. This statement is consistent with the results in this study. PSAT1 and ASAT also increased or decreased simultaneously in Arabidopsis thaliana and Oropetium thomaeum, under drought conditions. These results could be a proof that PSAT1 and ASAT1 functions are likely overlapping in a complementary way in Arabidopsis thaliana and Oropetium thomaeum leaf tissues.},
url = {https://hdl.handle.net/20.500.11811/11815}
}
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