Effectiveness of Ascorbic Acid and Zinc as drought antagonists in bread wheat plants monitored by different DNA markers
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2018-01-23
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O trigo mole é um cereal economicamente importante a nível mundial e devido às alterações climáticas, a seca é frequente afetando o rendimento e a qualidade desta cultura. O Ácido Ascórbico (AsA) e o Zinco (Zn) podem atuar como antagonistas da seca minimizando os efeitos negativos deste stresse abiótico. A seca e outros stresses abióticos geram instabilidade genómica nas plantas que pode ser monitorizada por marcadores moleculares. “Conserved DNA Domain Polymorphism” (CDDP) e “Start Codon Targeted” (SCoT) são “gene-targeted” markers capazes de detetar variação em regiões genómicas funcionais; marcadores baseados em retrotransposões (RTNs) podem monitorizar a atividade dos RTNs e os marcadores “Random Amplified Polymorphic DNA” (RAPD) podem detetar instabilidade genómica ao longo do genoma. Neste trabalho, pretendeu-se testar a eficiência de “priming” de sementes e/ou a aplicação foliar com AsA ou sulfato de Zn heptahidratado (ZnSO4.7H2O) para mitigação da seca em plantas de trigo mole da cv. Jordão através da avaliação da instabilidade genómica em plantas tratadas relativamente às plantas controlo ambas em dois regimes hídricos (rega e seca) usando marcadores CDDP, SCoT, “Inter-Retrotransposon Amplified Polymorphism” (IRAP), “Retrotransposon-Microsatellite Amplified Polymorphism” (REMAP), “interPriming Binding Site” (iPBS), “Inter-Simple Sequence Repeat” (ISSR) e RAPDs. A instabilidade genómica foi refletida pelo aparecimento de novas bandas e pela perda de bandas nas plantas tratadas relativamente às plantas controlo. Assim, com base nas percentagens de polimorfismo obtidas com os diferentes marcadores de DNA em todos os tratamentos e em ambos os regimes hídricos, extrapolou-se o antagonista da seca mais adequado ao trigo mole. Os polimorfismos gerados poderão ter sido devidos a alterações na sequência do DNA quer dos locais de hibridação dos primers quer na região genómica entre eles. Ambos os marcadores “gene-targeted”, SCoT e CDDP permitiram uma análise da variação do DNA ao longo do genoma e foram adequados à deteção de instabilidade genómica em plantas de trigo mole em stresse abiótico. Contudo, consideraram-se osresultados CDDP mais fiáveis uma vez que foram produzidos com base em primers especifícos para genes de resposta ao stresse hídrico previamente isolados em trigo mole. As técnicas IRAP e REMAP evidenciaram as taxas de polimorfismo mais elevadas, corroborando a elevada actividade insercional e transcripcional dos RTNs em plantas sob stresse abiótico como a seca, a qual pode ser detetada por marcadores baseados em RTNs. Os marcadores RAPD demonstraram ser úteis para uma análise genómica relatiavmente à deteção de instabilidade genómica em plantas de trigo mole sob stresse abiótico. Em suma, integrando todos os dados moleculares e estatísticos obtidos neste trabalho, o “priming” de sementes com Zn (Zn priming) parece ser o tratamento mais adequado para plantas de trigo mole sob seca.
Bread wheat is economical important worldwide and due to the climate changes drought is frequent and it is affecting the yield and quality of this crop. Ascorbic Acid (AsA) and Zinc (Zn) can act as drought antagonists minimizing the negative effects of this abiotic stress. Drought and other abiotic stresses generate genomic instability in plants that can be monitored by molecular markers. Conserved DNA Domain Polymorphism (CDDP) and Start Codon Targeted (SCoT) are gene-targeted markers that are able to assess variation in functional genomic regions; retrotransposons (RTNs)-based markers may moniter the RTNs activity and Random Amplified Polymorphic DNA (RAPD) are able to screen genomic instabilities throughout the genome. In this study, we intend to test the effectiveness of seed priming and/or foliar application with Ascorbic Acid (AsA) or Zinc sulphate heptahydrate (ZnSO4.7H2O) for drought mitigation in bread wheat plants of cv. „Jordão‟ by evaluating the genomic instability in treated plants relative to control plants both under two water regimes (watering and drought) using CDDPs, SCoTs, Inter-Retrotransposon Amplified Polymorphism (IRAP), Retrotransposon-Microsatellite Amplified Polymorphism (REMAP), inter-Priming Binding Site (iPBS), Inter-Simple Sequence Repeats (ISSRs) and RAPDs. The genomic instability was reflected by the appearance of new bands and loss of bands in treated plants relative to control. Therefore, based on the percentage of these polymorphic bands achieved with the different DNA markers in all treatments of both water regimes, it was extrapolated the most suited drought antagonist for bread wheat. The polymorphisms were generated due to alterations in the DNA sequence that may affect both priming binding sites and the genomic region between them. Both SCoT and CDDP gene-targeted markers allowed a genome-wide DNA variation analysis being suitable for detection of genomic instability in bread wheat plants under abiotic stress. However, we considered more reliable the CDDP results since their production was based on primers specific to water stress responsive genes previously isolated in bread wheat. The IRAP and REMAP techniques evidenced higher percentages of polymorphism, corroborating the assumption that plants under abiotic stress such as drought have higher RTNs insertional and transcriptional activities that could be detectable by RTNs-based markers. RAPD assays demonstrated to be a useful tool in order to do a genome wide analysis for the detection of genomic instabilities in bread wheat plants under abiotic stress. Overall, integrating all the molecular and statistical results achieved in this work, seed priming with Zn (Zn priming) appeared to be the most suitable treatment for bread wheat plants under drought.
Bread wheat is economical important worldwide and due to the climate changes drought is frequent and it is affecting the yield and quality of this crop. Ascorbic Acid (AsA) and Zinc (Zn) can act as drought antagonists minimizing the negative effects of this abiotic stress. Drought and other abiotic stresses generate genomic instability in plants that can be monitored by molecular markers. Conserved DNA Domain Polymorphism (CDDP) and Start Codon Targeted (SCoT) are gene-targeted markers that are able to assess variation in functional genomic regions; retrotransposons (RTNs)-based markers may moniter the RTNs activity and Random Amplified Polymorphic DNA (RAPD) are able to screen genomic instabilities throughout the genome. In this study, we intend to test the effectiveness of seed priming and/or foliar application with Ascorbic Acid (AsA) or Zinc sulphate heptahydrate (ZnSO4.7H2O) for drought mitigation in bread wheat plants of cv. „Jordão‟ by evaluating the genomic instability in treated plants relative to control plants both under two water regimes (watering and drought) using CDDPs, SCoTs, Inter-Retrotransposon Amplified Polymorphism (IRAP), Retrotransposon-Microsatellite Amplified Polymorphism (REMAP), inter-Priming Binding Site (iPBS), Inter-Simple Sequence Repeats (ISSRs) and RAPDs. The genomic instability was reflected by the appearance of new bands and loss of bands in treated plants relative to control. Therefore, based on the percentage of these polymorphic bands achieved with the different DNA markers in all treatments of both water regimes, it was extrapolated the most suited drought antagonist for bread wheat. The polymorphisms were generated due to alterations in the DNA sequence that may affect both priming binding sites and the genomic region between them. Both SCoT and CDDP gene-targeted markers allowed a genome-wide DNA variation analysis being suitable for detection of genomic instability in bread wheat plants under abiotic stress. However, we considered more reliable the CDDP results since their production was based on primers specific to water stress responsive genes previously isolated in bread wheat. The IRAP and REMAP techniques evidenced higher percentages of polymorphism, corroborating the assumption that plants under abiotic stress such as drought have higher RTNs insertional and transcriptional activities that could be detectable by RTNs-based markers. RAPD assays demonstrated to be a useful tool in order to do a genome wide analysis for the detection of genomic instabilities in bread wheat plants under abiotic stress. Overall, integrating all the molecular and statistical results achieved in this work, seed priming with Zn (Zn priming) appeared to be the most suitable treatment for bread wheat plants under drought.
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Antagonistas da seca , marcadores moleculares , remodelação genómica , stresse abiótico , Triticum aestivum L. em. Thell