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Registro Completo |
Biblioteca(s): |
Embrapa Cerrados; Embrapa Soja. |
Data corrente: |
23/02/2000 |
Data da última atualização: |
23/02/2000 |
Autoria: |
NEPOMUCENO, A. L. |
Título: |
Physiological and molecular responses of plants to water deficit. |
Ano de publicação: |
1998 |
Fonte/Imprenta: |
[S.l.]: University of Arkansas, 1998. |
Páginas: |
269p. |
Idioma: |
Inglês |
Notas: |
PhD. Thesis. |
Conteúdo: |
Tolerance to drought in plants results from networks of mechanisms working isolated or in combination. Genotypes that differ in tolerance to water-deficit stress should have qualitative and/or quantitative differences in gene expression. Therefore, to identify and isolate genes, which may differ among four cotton genotypes with diverse responses to water deprivaton, Differential Display (DDRT-PCR) was used. These genotypes were first physiologically characterized in growth chamber and greenhouse experiments. Water and osmotic potential of roots and leaves, photosynthetic rate and relative water content were some of the physiological parameters used to measure plant responses during and after the water defficit applied. Cultivar Siokra L-23 and the wild type T-1521, two drought tolerant genotypes, showed a significant ability of osmotic adjust during water deficit. Photosynthetic rate and relative water content were maintained near control values in the two tolerant genotypes. However, cultivar CS 50 and Stoneville 506, showed significant sensitivity to the water deficit applied, confirming previous observations. These results guided subsequent work with DDRT-PCR using mRNA samples colected during these experiments. Fifty-two cDNA fragments differentially expressed during water deficit were identified using DD. The differentially displayed fragments were isolated from the polyacrylamide gels and cloned in pGEM-T vectors. After cloning they were sequenced using thermocycling dideoxynucleotide chain termination protocols. Search of gene banks revealed 17 clones with high homology to known genes, and 20 clones with low homology, while 15 clones had no homologous entries. Among the sequences that showed high homology was a heat shock protein that binds to calmodulin. This gene was expressed only in the water-deficit tolerant genotypes (Siokra L-23 and T-1521) during the stress. Another gene identified by homology was trehalose-6-phosphate synthase. This enzyme is part of the metabolic pathway for production of trehalose, a sugar known to osmoprotect cell membranes during desiccation. The differentially expressed gene sequences could have use in screening germplasm banks for similar genotypes, in plant physiology studies, and in molecular mapping of plant responses to water deficit. MenosTolerance to drought in plants results from networks of mechanisms working isolated or in combination. Genotypes that differ in tolerance to water-deficit stress should have qualitative and/or quantitative differences in gene expression. Therefore, to identify and isolate genes, which may differ among four cotton genotypes with diverse responses to water deprivaton, Differential Display (DDRT-PCR) was used. These genotypes were first physiologically characterized in growth chamber and greenhouse experiments. Water and osmotic potential of roots and leaves, photosynthetic rate and relative water content were some of the physiological parameters used to measure plant responses during and after the water defficit applied. Cultivar Siokra L-23 and the wild type T-1521, two drought tolerant genotypes, showed a significant ability of osmotic adjust during water deficit. Photosynthetic rate and relative water content were maintained near control values in the two tolerant genotypes. However, cultivar CS 50 and Stoneville 506, showed significant sensitivity to the water deficit applied, confirming previous observations. These results guided subsequent work with DDRT-PCR using mRNA samples colected during these experiments. Fifty-two cDNA fragments differentially expressed during water deficit were identified using DD. The differentially displayed fragments were isolated from the polyacrylamide gels and cloned in pGEM-T vectors. After cloning they were sequenced using thermocycling d... Mostrar Tudo |
Palavras-Chave: |
Drought resistance; Genotypes; Plant pohysiology; Plant water relation; Plante response. |
Thesagro: |
Água; Algodão; Deficiência Hídrica; Fisiologia; Genética Molecular; Genótipo; Gossypium Hirsutum; Planta; Relação Água-Planta; Resistência a Seca; Stress. |
Thesaurus Nal: |
cotton; molecular genetics; water deprivation. |
Categoria do assunto: |
-- |
Marc: |
LEADER 03263nam a2200361 a 4500 001 1559664 005 2000-02-23 008 1998 bl uuuu m 00u1 u #d 100 1 $aNEPOMUCENO, A. L. 245 $aPhysiological and molecular responses of plants to water deficit. 260 $a[S.l.]: University of Arkansas$c1998 300 $a269p. 500 $aPhD. Thesis. 520 $aTolerance to drought in plants results from networks of mechanisms working isolated or in combination. Genotypes that differ in tolerance to water-deficit stress should have qualitative and/or quantitative differences in gene expression. Therefore, to identify and isolate genes, which may differ among four cotton genotypes with diverse responses to water deprivaton, Differential Display (DDRT-PCR) was used. These genotypes were first physiologically characterized in growth chamber and greenhouse experiments. Water and osmotic potential of roots and leaves, photosynthetic rate and relative water content were some of the physiological parameters used to measure plant responses during and after the water defficit applied. Cultivar Siokra L-23 and the wild type T-1521, two drought tolerant genotypes, showed a significant ability of osmotic adjust during water deficit. Photosynthetic rate and relative water content were maintained near control values in the two tolerant genotypes. However, cultivar CS 50 and Stoneville 506, showed significant sensitivity to the water deficit applied, confirming previous observations. These results guided subsequent work with DDRT-PCR using mRNA samples colected during these experiments. Fifty-two cDNA fragments differentially expressed during water deficit were identified using DD. The differentially displayed fragments were isolated from the polyacrylamide gels and cloned in pGEM-T vectors. After cloning they were sequenced using thermocycling dideoxynucleotide chain termination protocols. Search of gene banks revealed 17 clones with high homology to known genes, and 20 clones with low homology, while 15 clones had no homologous entries. Among the sequences that showed high homology was a heat shock protein that binds to calmodulin. This gene was expressed only in the water-deficit tolerant genotypes (Siokra L-23 and T-1521) during the stress. Another gene identified by homology was trehalose-6-phosphate synthase. This enzyme is part of the metabolic pathway for production of trehalose, a sugar known to osmoprotect cell membranes during desiccation. The differentially expressed gene sequences could have use in screening germplasm banks for similar genotypes, in plant physiology studies, and in molecular mapping of plant responses to water deficit. 650 $acotton 650 $amolecular genetics 650 $awater deprivation 650 $aÁgua 650 $aAlgodão 650 $aDeficiência Hídrica 650 $aFisiologia 650 $aGenética Molecular 650 $aGenótipo 650 $aGossypium Hirsutum 650 $aPlanta 650 $aRelação Água-Planta 650 $aResistência a Seca 650 $aStress 653 $aDrought resistance 653 $aGenotypes 653 $aPlant pohysiology 653 $aPlant water relation 653 $aPlante response
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