Drought tolerance conferred to sugarcane by association with Gluconacetobacter diazotrophicus: a transcriptomic view of hormone pathways

Sugarcane interacts with particular types of beneficial nitrogen-fixing bacteria that provide fixed-nitrogen and plant growth hormones to host plants, promoting an increase in plant biomass. Other benefits, as enhanced tolerance to abiotic stresses have been reported to some diazotrophs. Here we aim to study the effects of the association between the diazotroph Gluconacetobacter diazotrophicus PAL5 and sugarcane cv. SP70-1143 during water depletion by characterizing differential transcriptome profiles of sugarcane. RNA-seq libraries were generated from roots and shoots of sugarcane plants free of endophytes that were inoculated with G. diazotrophicus and subjected to water depletion for 3 days. A sugarcane reference transcriptome was constructed and used for the identification of differentially expressed transcripts. The differential profile of non-inoculated SP70-1143 suggests that it responds to water deficit stress by the activation of drought-responsive markers and hormone pathways, as ABA and Ethylene. qRT-PCR revealed that root samples had higher levels of G. diazotrophicus 3 days after water deficit, compared to roots of inoculated plants watered normally. With prolonged drought only inoculated plants survived, indicating that SP70-1143 plants colonized with G. diazotrophicus become more tolerant to drought stress than non-inoculated plants. Strengthening this hypothesis, several gene expression responses to drought were inactivated or regulated in an opposite manner, especially in roots, when plants were colonized by the bacteria. The data suggests that colonized roots would not be suffering from stress in the same way as non-inoculated plants. On the other hand, shoots specifically activate ABA-dependent signaling genes, which could act as key elements in the drought resistance conferred by G. diazotrophicus to SP70-1143. This work reports for the first time the involvement of G. diazotrophicus in the promotion of drought-tolerance to sugarcane cv. SP70-1143, and it describes the initial molecular events that may trigger the increased drought tolerance in the host plant

Dengue: transmissão, aspectos clínicos, diagnóstico e tratamento

A dengue é uma arbovirose transmitida principalmente pela picada do mosquito Aedes aegypti. Pode ser assintomática ou apresentar amplo espectro clínico, variando de doença febril autolimitada até formas graves, que podem evoluir com choque circulatório e óbito. Para evitar esse desfecho, a precocidade no diagnóstico da doença e na detecção de sinais de alarme, que indicam evolução desfavorável; assim como a instituição de tratamento adequado, são fundamentais. Não há tratamento específico, ele é apenas sintomático e de suporte. Até o momento, não existe vacina disponível para prevenção da doença, sendo o controle do vetor a medida mais efetiva.  Dengue is an arbovirus transmitted mainly by the bite of the mosquito Aedes aegypti.It can be asymptomatic or present a wide clinical spectrum, ranging from self-limited febrile illness to severe forms that could evolve with circulatory shock and death. In order to avoid this outcome, early diagnosis of disease and the detection of warning signs that indicate unfavorable, as well as adequate treatment are essential, There is no specific treatment, it is only symptomatic and supportive. Up to now, there is no vaccine available for prevention of disease, vector control the most effective measure.  

Ferulic acid: a key component in grass lignocellulose recalcitrance to hydrolysis

In the near future, grasses must provide most of the biomass for the production of renewable fuels. However, grass cell walls are characterized by a large quantity of hydroxycinnamic acids such as ferulic and p-coumaric acids, which are thought to reduce the biomass saccharification. Ferulic acid (FA) binds to lignin, polysaccharides and structural proteins of grass cell walls cross-linking these components. A controlled reduction of FA level or of FA cross-linkages in plants of industrial interest can improve the production of cellulosic ethanol. Here, we review the biosynthesis and roles of FA in cell wall architecture and in grass biomass recalcitrance to enzyme hydrolysis