Caracterização fisiológica do mutante gun4 de Arabidopsis thaliana sob estresse luminoso
Autor(a) principal: | |
---|---|
Data de Publicação: | 2009 |
Tipo de documento: | Dissertação |
Idioma: | por |
Título da fonte: | LOCUS Repositório Institucional da UFV |
Texto Completo: | http://locus.ufv.br/handle/123456789/4312 |
Resumo: | Mutations in GUN (Genome UNcoupled) genes have helped to understand the pathways of the chloroplast signal transduction that control the expression of nuclear photosynthetic genes. In this context, the gun4 genotype has been characterized in biochemical and molecular aspects. However, little is known whether this mutant produces a phenotype physiological aspects. In order to complement the phenotypic characterization of gun4 genotype, the aim of this study was evaluate the photosynthetic responses of gun4 plants of Arabidopsis thaliana under different levels of light and under light stress. The gun4 plants, in the absence of light stress showed reduced levels of chlorophyll a and b, minimal (Fo) and maximal (Fm) fluorescence in dark-adapted leaves, and quantum yield of unregulated energy dissipation of photosystem II (ΦNO) in 20%, 26%, 18% e 32%, respectively. Also, the effective quantum yield of the FSII (ΦFSII) and photochemical quenching (qL) were 11% and 20% higher, respectively. Higher values of ETR (electrons transport rate), ΦFSII and qL were also found in gun4 under different light intensities, showing that gun4 can maximize the transfer of light energy absorbed in the light harvest complex of FSII for the photosynthetic process. The rate of net carbon assimilation (A) and stomatal conductance (gs) were 43% and 61% lower in gun4 respectively, despite no difference in the flow of absorption of 14CO2 was observed, suggesting that the lower magnitude of photosynthesis is due to resistance to influx of CO2. After 14 hours of light stress, there was no difference in A, and the values of the electron transport rate (ETR) and ΦFSII were reduced by 35% and 50% respectively, both in gun4 and wild type (WT) plants. However, the quantum yield potential of FSII (Fv/Fm) decreased significantly only in WT, suggesting that gun4 may have a greater ability to minimize photoinhibitory effects. These results provide additional evidences for the higher non-photochemical quenching (qN) and quantum yield of regulated energy dissipation of the gun4 FSII (ΦNPQ). Together, the photochemical phenotypes of gun4 may explain the increase (48%) in the photochemical global network connectance after 28 hours of stress, demonstrating the greater ability of this genotype to adjust its photosynthetic apparatus in response to light stress. Finally, the results found in this study demonstrated that gun4 transfers and dissipates more efficiently the excess of light energy absorbed under light stress condition, despite a strong reduction in chlorophyll content. The results suggest the existence of a mechanism for the adjustment of the photosystem in order to offset the reduction of light absorption, indicating the importance of this mutant to explore the mechanisms that control the plasticity of the photochemical protein complex. |
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Daloso, Danilo de Menezeshttp://lattes.cnpq.br/0306680503261422Damatta, Fábio Murilohttp://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4784185Y9Ribeiro, Dimas Mendeshttp://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4778644J9Loureiro, Marcelo Ehlershttp://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4780851Y3Martins, Gilberto Sachettohttp://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4785612D0Ribas, Rogério Ferreirahttp://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4777511A8Kuki, Kacilda Naomihttp://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4784674P62015-03-26T13:36:40Z2011-03-232015-03-26T13:36:40Z2009-02-18DALOSO, Danilo de Menezes. Physiological characterization of gun4 mutant of Arabidopsis thaliana under light stress. 2009. 54 f. Dissertação (Mestrado em Controle da maturação e senescência em órgãos perecíveis; Fisiologia molecular de plantas superiores) - Universidade Federal de Viçosa, Viçosa, 2009.http://locus.ufv.br/handle/123456789/4312Mutations in GUN (Genome UNcoupled) genes have helped to understand the pathways of the chloroplast signal transduction that control the expression of nuclear photosynthetic genes. In this context, the gun4 genotype has been characterized in biochemical and molecular aspects. However, little is known whether this mutant produces a phenotype physiological aspects. In order to complement the phenotypic characterization of gun4 genotype, the aim of this study was evaluate the photosynthetic responses of gun4 plants of Arabidopsis thaliana under different levels of light and under light stress. The gun4 plants, in the absence of light stress showed reduced levels of chlorophyll a and b, minimal (Fo) and maximal (Fm) fluorescence in dark-adapted leaves, and quantum yield of unregulated energy dissipation of photosystem II (ΦNO) in 20%, 26%, 18% e 32%, respectively. Also, the effective quantum yield of the FSII (ΦFSII) and photochemical quenching (qL) were 11% and 20% higher, respectively. Higher values of ETR (electrons transport rate), ΦFSII and qL were also found in gun4 under different light intensities, showing that gun4 can maximize the transfer of light energy absorbed in the light harvest complex of FSII for the photosynthetic process. The rate of net carbon assimilation (A) and stomatal conductance (gs) were 43% and 61% lower in gun4 respectively, despite no difference in the flow of absorption of 14CO2 was observed, suggesting that the lower magnitude of photosynthesis is due to resistance to influx of CO2. After 14 hours of light stress, there was no difference in A, and the values of the electron transport rate (ETR) and ΦFSII were reduced by 35% and 50% respectively, both in gun4 and wild type (WT) plants. However, the quantum yield potential of FSII (Fv/Fm) decreased significantly only in WT, suggesting that gun4 may have a greater ability to minimize photoinhibitory effects. These results provide additional evidences for the higher non-photochemical quenching (qN) and quantum yield of regulated energy dissipation of the gun4 FSII (ΦNPQ). Together, the photochemical phenotypes of gun4 may explain the increase (48%) in the photochemical global network connectance after 28 hours of stress, demonstrating the greater ability of this genotype to adjust its photosynthetic apparatus in response to light stress. Finally, the results found in this study demonstrated that gun4 transfers and dissipates more efficiently the excess of light energy absorbed under light stress condition, despite a strong reduction in chlorophyll content. The results suggest the existence of a mechanism for the adjustment of the photosystem in order to offset the reduction of light absorption, indicating the importance of this mutant to explore the mechanisms that control the plasticity of the photochemical protein complex.Mutações em genes denominados GUN (Genome UNcoupled) têm auxiliado na compreensão das rotas de transdução de sinais do cloroplasto que controlam a expressão de genes fotossintéticos nucleares. Nesse sentido, o genótipo gun4 tem sido caracterizado em aspectos bioquímicos e moleculares, no entanto pouco se sabe sobre aspectos fisiológicos desse mutante. Diante disso, de forma a complementar essa caracterização fenotípica, o objetivo desse trabalho foi avaliar as respostas fotossintéticas do mutante gun4 de Arabidopsis thaliana sob diferentes níveis de luz. Plantas gun4, na ausência de estresse luminoso, apresentaram níveis de clorofila a e b, fluorescências mínima (Fo) e máxima (Fm) de folhas adaptadas ao escuro e rendimento quântico de dissipação não regulada de energia do fotossistema II (ΦNO) reduzidos em 20%, 26%, 18% e 32%, respectivamente, enquanto que o rendimento quântico efetivo do FSII (ΦFSII) e o coeficiente de extinção fotoquímico (qL) foram 11% e 20% maiores, respectivamente. Valores maiores de ETR (taxa de transporte de elétrons), ΦFSII e qL também foram observados em gun4 sob diferentes intensidades luminosas, demonstrando que este fenótipo transfere de forma mais eficiente a energia luminosa absorvida no complexo coletor de luz do FSII para o processo fotossintético. A taxa de assimilação líquida de carbono (A) e a condutância estomática (gs) foram 43% e 61% menores em gun4, respectivamente. Porém, não houve diferença no fluxo de absorção de 14CO2, sugerindo que a menor magnitude de A seja devido a uma restrição difusional ao influxo de CO2. Após 14 h de estresse, não houve diferença em A e os valores da taxa de transporte de elétrons (ETR) e ΦFSII foram reduzidos em 35% e 50%, respectivamente, tanto nas plantas gun4 como no tipo selvagem (WT). Entretanto, o rendimento quântico potencial do FSII (Fv/Fm) decresceu significativamente apenas em WT, sugerindo que gun4 possa minimizar, mais eficientemente, efeitos fotoinibitórios. Isto se evidencia, adicionalmente, nos maiores valores de coeficiente de extinção não fotoquímico (qN) e rendimento quântico de dissipação regulada de energia do FSII (ΦNPQ). Em conjunto, esses fenótipos fotoquímicos de gun4 podem explicar o maior aumento (48%) na conectância global da rede fotoquímica após 28 h de estresse, demonstrando a maior capacidade deste genótipo em ajustar seu aparato fotossintético em resposta ao estresse luminoso. Por fim, os resultados encontrados neste trabalho demonstraram a alta capacidade do genótipo gun4 em dissipar o excesso de energia luminosa absorvida sob estresse e, apesar da forte redução no teor de clorofila, transferir esta mais eficientemente. Isso sugere a existência de um mecanismo de adaptação dos fotossistemas de forma a compensar a redução na absorção de luz, indicando um valor importante deste mutante para explorar os mecanismos que controlam a plasticidade dos complexos protéicos fotoquímicos.Coordenação de Aperfeiçoamento de Pessoal de Nível Superiorapplication/pdfporUniversidade Federal de ViçosaMestrado em Fisiologia VegetalUFVBRControle da maturação e senescência em órgãos perecíveis; Fisiologia molecular de plantas superioresArabidopsis thalianagun4Estresse luminosoComplexo coletor de luzRedes fotossintéticasArabidopsis thalianagun4Light stressComplex light collectorNetworks photosyntheticCNPQ::CIENCIAS AGRARIAS::AGRONOMIA::FITOTECNIA::FISIOLOGIA DE PLANTAS CULTIVADASCaracterização fisiológica do mutante gun4 de Arabidopsis thaliana sob estresse luminosoPhysiological characterization of gun4 mutant of Arabidopsis thaliana under light stressinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/masterThesisinfo:eu-repo/semantics/openAccessreponame:LOCUS Repositório Institucional da UFVinstname:Universidade Federal de Viçosa (UFV)instacron:UFVORIGINALtexto completo.pdfapplication/pdf450533https://locus.ufv.br//bitstream/123456789/4312/1/texto%20completo.pdfd14de51f177a16c047cb046fafb1e533MD51TEXTtexto completo.pdf.txttexto completo.pdf.txtExtracted texttext/plain80869https://locus.ufv.br//bitstream/123456789/4312/2/texto%20completo.pdf.txtcad923159aa6d58083b938ac8f750fa3MD52THUMBNAILtexto completo.pdf.jpgtexto completo.pdf.jpgIM Thumbnailimage/jpeg3600https://locus.ufv.br//bitstream/123456789/4312/3/texto%20completo.pdf.jpg75d498639bcab6204084ae46fb07f6ddMD53123456789/43122016-04-10 23:06:37.81oai:locus.ufv.br:123456789/4312Repositório InstitucionalPUBhttps://www.locus.ufv.br/oai/requestfabiojreis@ufv.bropendoar:21452016-04-11T02:06:37LOCUS Repositório Institucional da UFV - Universidade Federal de Viçosa (UFV)false |
dc.title.por.fl_str_mv |
Caracterização fisiológica do mutante gun4 de Arabidopsis thaliana sob estresse luminoso |
dc.title.alternative.eng.fl_str_mv |
Physiological characterization of gun4 mutant of Arabidopsis thaliana under light stress |
title |
Caracterização fisiológica do mutante gun4 de Arabidopsis thaliana sob estresse luminoso |
spellingShingle |
Caracterização fisiológica do mutante gun4 de Arabidopsis thaliana sob estresse luminoso Daloso, Danilo de Menezes Arabidopsis thaliana gun4 Estresse luminoso Complexo coletor de luz Redes fotossintéticas Arabidopsis thaliana gun4 Light stress Complex light collector Networks photosynthetic CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::FITOTECNIA::FISIOLOGIA DE PLANTAS CULTIVADAS |
title_short |
Caracterização fisiológica do mutante gun4 de Arabidopsis thaliana sob estresse luminoso |
title_full |
Caracterização fisiológica do mutante gun4 de Arabidopsis thaliana sob estresse luminoso |
title_fullStr |
Caracterização fisiológica do mutante gun4 de Arabidopsis thaliana sob estresse luminoso |
title_full_unstemmed |
Caracterização fisiológica do mutante gun4 de Arabidopsis thaliana sob estresse luminoso |
title_sort |
Caracterização fisiológica do mutante gun4 de Arabidopsis thaliana sob estresse luminoso |
author |
Daloso, Danilo de Menezes |
author_facet |
Daloso, Danilo de Menezes |
author_role |
author |
dc.contributor.authorLattes.por.fl_str_mv |
http://lattes.cnpq.br/0306680503261422 |
dc.contributor.author.fl_str_mv |
Daloso, Danilo de Menezes |
dc.contributor.advisor-co1.fl_str_mv |
Damatta, Fábio Murilo |
dc.contributor.advisor-co1Lattes.fl_str_mv |
http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4784185Y9 |
dc.contributor.advisor-co2.fl_str_mv |
Ribeiro, Dimas Mendes |
dc.contributor.advisor-co2Lattes.fl_str_mv |
http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4778644J9 |
dc.contributor.advisor1.fl_str_mv |
Loureiro, Marcelo Ehlers |
dc.contributor.advisor1Lattes.fl_str_mv |
http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4780851Y3 |
dc.contributor.referee1.fl_str_mv |
Martins, Gilberto Sachetto |
dc.contributor.referee1Lattes.fl_str_mv |
http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4785612D0 |
dc.contributor.referee2.fl_str_mv |
Ribas, Rogério Ferreira |
dc.contributor.referee2Lattes.fl_str_mv |
http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4777511A8 |
dc.contributor.referee3.fl_str_mv |
Kuki, Kacilda Naomi |
dc.contributor.referee3Lattes.fl_str_mv |
http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4784674P6 |
contributor_str_mv |
Damatta, Fábio Murilo Ribeiro, Dimas Mendes Loureiro, Marcelo Ehlers Martins, Gilberto Sachetto Ribas, Rogério Ferreira Kuki, Kacilda Naomi |
dc.subject.por.fl_str_mv |
Arabidopsis thaliana gun4 Estresse luminoso Complexo coletor de luz Redes fotossintéticas |
topic |
Arabidopsis thaliana gun4 Estresse luminoso Complexo coletor de luz Redes fotossintéticas Arabidopsis thaliana gun4 Light stress Complex light collector Networks photosynthetic CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::FITOTECNIA::FISIOLOGIA DE PLANTAS CULTIVADAS |
dc.subject.eng.fl_str_mv |
Arabidopsis thaliana gun4 Light stress Complex light collector Networks photosynthetic |
dc.subject.cnpq.fl_str_mv |
CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::FITOTECNIA::FISIOLOGIA DE PLANTAS CULTIVADAS |
description |
Mutations in GUN (Genome UNcoupled) genes have helped to understand the pathways of the chloroplast signal transduction that control the expression of nuclear photosynthetic genes. In this context, the gun4 genotype has been characterized in biochemical and molecular aspects. However, little is known whether this mutant produces a phenotype physiological aspects. In order to complement the phenotypic characterization of gun4 genotype, the aim of this study was evaluate the photosynthetic responses of gun4 plants of Arabidopsis thaliana under different levels of light and under light stress. The gun4 plants, in the absence of light stress showed reduced levels of chlorophyll a and b, minimal (Fo) and maximal (Fm) fluorescence in dark-adapted leaves, and quantum yield of unregulated energy dissipation of photosystem II (ΦNO) in 20%, 26%, 18% e 32%, respectively. Also, the effective quantum yield of the FSII (ΦFSII) and photochemical quenching (qL) were 11% and 20% higher, respectively. Higher values of ETR (electrons transport rate), ΦFSII and qL were also found in gun4 under different light intensities, showing that gun4 can maximize the transfer of light energy absorbed in the light harvest complex of FSII for the photosynthetic process. The rate of net carbon assimilation (A) and stomatal conductance (gs) were 43% and 61% lower in gun4 respectively, despite no difference in the flow of absorption of 14CO2 was observed, suggesting that the lower magnitude of photosynthesis is due to resistance to influx of CO2. After 14 hours of light stress, there was no difference in A, and the values of the electron transport rate (ETR) and ΦFSII were reduced by 35% and 50% respectively, both in gun4 and wild type (WT) plants. However, the quantum yield potential of FSII (Fv/Fm) decreased significantly only in WT, suggesting that gun4 may have a greater ability to minimize photoinhibitory effects. These results provide additional evidences for the higher non-photochemical quenching (qN) and quantum yield of regulated energy dissipation of the gun4 FSII (ΦNPQ). Together, the photochemical phenotypes of gun4 may explain the increase (48%) in the photochemical global network connectance after 28 hours of stress, demonstrating the greater ability of this genotype to adjust its photosynthetic apparatus in response to light stress. Finally, the results found in this study demonstrated that gun4 transfers and dissipates more efficiently the excess of light energy absorbed under light stress condition, despite a strong reduction in chlorophyll content. The results suggest the existence of a mechanism for the adjustment of the photosystem in order to offset the reduction of light absorption, indicating the importance of this mutant to explore the mechanisms that control the plasticity of the photochemical protein complex. |
publishDate |
2009 |
dc.date.issued.fl_str_mv |
2009-02-18 |
dc.date.available.fl_str_mv |
2011-03-23 2015-03-26T13:36:40Z |
dc.date.accessioned.fl_str_mv |
2015-03-26T13:36:40Z |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/masterThesis |
format |
masterThesis |
status_str |
publishedVersion |
dc.identifier.citation.fl_str_mv |
DALOSO, Danilo de Menezes. Physiological characterization of gun4 mutant of Arabidopsis thaliana under light stress. 2009. 54 f. Dissertação (Mestrado em Controle da maturação e senescência em órgãos perecíveis; Fisiologia molecular de plantas superiores) - Universidade Federal de Viçosa, Viçosa, 2009. |
dc.identifier.uri.fl_str_mv |
http://locus.ufv.br/handle/123456789/4312 |
identifier_str_mv |
DALOSO, Danilo de Menezes. Physiological characterization of gun4 mutant of Arabidopsis thaliana under light stress. 2009. 54 f. Dissertação (Mestrado em Controle da maturação e senescência em órgãos perecíveis; Fisiologia molecular de plantas superiores) - Universidade Federal de Viçosa, Viçosa, 2009. |
url |
http://locus.ufv.br/handle/123456789/4312 |
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por |
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info:eu-repo/semantics/openAccess |
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Universidade Federal de Viçosa |
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Mestrado em Fisiologia Vegetal |
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UFV |
dc.publisher.country.fl_str_mv |
BR |
dc.publisher.department.fl_str_mv |
Controle da maturação e senescência em órgãos perecíveis; Fisiologia molecular de plantas superiores |
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Universidade Federal de Viçosa |
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