Características fisiológicas e moleculares de uma cultivar de cana-de-açúcar tolerante à seca e submetida ao déficit hídrico prolongado
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Data
2016-08-26
Autores
Telles, Bruna Robiati [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
A cana-de-açúcar é uma cultura fortemente influenciada pela seca, o que é um fator limitante para a produção sucroenergética. No Brasil, esta cultura está se expandindo para regiões com deficiência hídrica bastante acentuada, e uma das formas de contornar este problema é utilizar cultivares que sejam mais adaptadas a este tipo de estresse. Por isso, o objetivo deste trabalho foi analisar o comportamento fisiológico e molecular de plantas de cana-de-açúcar submetidas a distintos períodos de deficiência hídrica, a fim de contribuir com novos conhecimentos na área e auxiliar no desenvolvimento e cultivo de plantas mais bem adaptadas a essa condição. Neste trabalho, foram utilizadas duas cultivares de cana-de-açúcar contrastantes à seca (SP81-3250 e RB855453), tolerante e sensível, respectivamente. As plantas foram cultivadas em casa de vegetação e submetidas a três controlados potenciais hídricos do solo (controle, déficit hídrico moderado e déficit hídrico severo) a partir de 60 dias após o plantio. Essas plantas foram avaliadas molecular e fisiologicamente em três épocas distintas: 30, 60 e 90 dias após a aplicação dos tratamentos, sendo este um dos poucos trabalhos disponíveis até o momento sobre a resposta de plantas de cana-de-açúcar sob déficit hídrico prolongado. A tecnologia de RNA-Seq foi utilizada para obtenção dos transcriptomas de folhas dos dois genótipos de cana. A montagem de novo desses transcriptomas foi realizada, o que permitiu identificar os genes exclusivos de ambas as cultivares e analisar os exclusivos da cultivar tolerante envolvidos na resposta de defesa ao déficit hídrico prolongado. Os parâmetros fisiológicos avaliados mostraram alterações significativas em resposta ao déficit hídrico. A montagem de novo resultou em 161.295 isoformas, sendo 86.087 genes distintos. Para anotação, os transcritos foram alinhados contra sequências de Sorghum bicolor, Arabidopsis thaliana, bem como sequências de cana-de-açúcar disponíveis em bancos de dados públicos. Através da análise de genes diferencialmente expressos, foram identificados 5.236 genes exclusivos. Destes, 2.635 genes são da cultivar SP81-3250 e 2.601 genes da cultivar RB855453. Entre os genes exclusivos da cultivar tolerante, alguns foram anotados como proteases, fatores de transcrição, enzimas antioxidantes, proteínas da via de sinalização do etileno e proteínas da via de sinalização do ácido salicílico, todos envolvidos na resposta de defesa ao déficit hídrico, o que permitiu levantar novas hipóteses sobre o mecanismo de tolerância à seca prolongada.
The sugarcane culture is strongly influenced by drought, which is a limiting factor for sugar and energy production. In Brazil, this culture is expanding to regions with very severe water stress and one way to workaround this issue is to use cultivars that are more adapted to this form of stress. Therefore, the objective of this study has been to analyze the physiological and molecular behavior of sugarcane plants submitted to different periods of water stress in order to contribute to new knowledge in the area and assist in the development and cultivation of better-adapted plants to this condition. In this study, we have employed two cultivars of sugarcane that are contrasting to drought (SP81-3250 and RB855453), tolerant and sensitive, respectively. Plants have been cultivated in a greenhouse and submitted to three controlled potential soil hydric (control, moderate drought and severe water deficit) from 60 days after planting.These plants have been evaluated molecular and physiologically in three different periods: 30, 60 and 90 days after treatment application, which is one of the few studies available to date on the response of sugarcane plants under prolonged drought. RNA-Seq technology has been used to obtain the transcriptomes leaves of the two genotypes of sugarcane.The de novo assembly has been performed which has allowed identifying exclusive genes of both cultivars and analyzing the exclusive tolerant cultivar involved in defense response to prolonged drought. The physiological parameters evaluated have shown significant changes in response to water stress.The de novo assembly resulted in 161,295 isoforms, with 86,087 different genes. To record, the transcripts have been were aligned against sequences of Sorghum bicolor, Arabidopsis thaliana, and sugarcane sequences available in public databases. Through the analysis of differentially expressed genes have been identified 5,236 exclusive genes. Out of those, 2,635 genes come from cultivar SP81-3250 and 2,601 genes come from cultivar RB855453. Among exclusive genes of tolerant cultivar, some have been listed as the proteases, transcription factors, antioxidant enzymes, proteins of the ethylene signaling pathway and proteins of salicylic acid signaling pathway, all involved in the defense response to drought, which have allowed to raise new hypotheses about the mechanism of tolerance the prolonged drought
The sugarcane culture is strongly influenced by drought, which is a limiting factor for sugar and energy production. In Brazil, this culture is expanding to regions with very severe water stress and one way to workaround this issue is to use cultivars that are more adapted to this form of stress. Therefore, the objective of this study has been to analyze the physiological and molecular behavior of sugarcane plants submitted to different periods of water stress in order to contribute to new knowledge in the area and assist in the development and cultivation of better-adapted plants to this condition. In this study, we have employed two cultivars of sugarcane that are contrasting to drought (SP81-3250 and RB855453), tolerant and sensitive, respectively. Plants have been cultivated in a greenhouse and submitted to three controlled potential soil hydric (control, moderate drought and severe water deficit) from 60 days after planting.These plants have been evaluated molecular and physiologically in three different periods: 30, 60 and 90 days after treatment application, which is one of the few studies available to date on the response of sugarcane plants under prolonged drought. RNA-Seq technology has been used to obtain the transcriptomes leaves of the two genotypes of sugarcane.The de novo assembly has been performed which has allowed identifying exclusive genes of both cultivars and analyzing the exclusive tolerant cultivar involved in defense response to prolonged drought. The physiological parameters evaluated have shown significant changes in response to water stress.The de novo assembly resulted in 161,295 isoforms, with 86,087 different genes. To record, the transcripts have been were aligned against sequences of Sorghum bicolor, Arabidopsis thaliana, and sugarcane sequences available in public databases. Through the analysis of differentially expressed genes have been identified 5,236 exclusive genes. Out of those, 2,635 genes come from cultivar SP81-3250 and 2,601 genes come from cultivar RB855453. Among exclusive genes of tolerant cultivar, some have been listed as the proteases, transcription factors, antioxidant enzymes, proteins of the ethylene signaling pathway and proteins of salicylic acid signaling pathway, all involved in the defense response to drought, which have allowed to raise new hypotheses about the mechanism of tolerance the prolonged drought
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Palavras-chave
Déficit hídrico prolongado, Expressão gênica, Genes de tolerância, Montagem de novo, RNA-seq, Saccharum spp, Prolonged water deficit, Gene expression, Tolerance genes, De novo assembly