Cladonia verticillaris (lichen) indicates negative impacts derived from the combustion of biodiesel blends: an alert for the environmental management for biofuels use.

The use of biodiesel blends with petroleum diesel in vehicular engines demands the evaluation of the possible impacts and effects of the gases emitted from their combustion on the environment. Among studies on these questions, biomonitoring using lichens is a viable alternative, given their interactions with the elements dispersed in the atmosphere, as well as its sensitivity and capacity to retain contaminants. In this study, we analyzed the effects of gas emissions from the combustion of biodiesel mixture with petroleum diesel on Cladonia verticillaris thalli. Samples of the lichen (10 g) were exposed to the gases emitted by the exhaust of the generator engine during the combustion process of biodiesel mixtures to petroleum diesel (7% (B7), 10% (B10), 40% (B40), 50% (B50), and 70% (B70)). At 90 days after exposure, samples were analyzed for n-alkane profiles, thallus morphology, photosynthetic pigment contents, and secondary lichen metabolites (protocetraric and fumarprotocetraric acids). Sets B7 and B10 showed better resistance of the lichen to pollutants. Set B40 showed a high stress evidenced by the chain elongation of n-alkanes structure and high chlorophyll production, presenting high morphological damages when compared to the control sets, B7 and B10. The results showed significant reductions of n-alkanes profiles for mixtures with high concentrations of biodiesel (B50 and B70), as well as decreases in the chlorophyll content. These groups showed an increase in the synthesis of secondary metabolites, corroborating the hypothesis that high concentrations of biodiesel in the mixture with petroleum diesel have greater impacts on the lichen. Schematic model for demonstration of using the lichen Cladonia verticillaris as biomonitor of effects from gas emissions from the combustion of biodiesel blends with petroleum diesel by a stationary engine.

Differential expression of SofDIR16 and SofCAD genes in smut resistant and susceptible sugarcane cultivars in response to Sporisorium scitamineum.

Proteomic profiling of the stalk of a smut resistant and a susceptible sugarcane cultivars revealed the presence of dirigent and dirigent-like proteins in abundance in the pool of high molecular mass (HMMG) and mid-molecular mass (MMMG) glycoproteins, produced as part of the defensive response to the fungal smut pathogen. Quantitative RT-PCR analysis showed that expression levels of SofDIR16 (sugarcane dirigent16) and SofCAD (sugarcane cinnamyl alcohol dehydrogenase) were higher in the smut resistant My 55-14 cultivar than in the sensitive B 42231 cultivar prior to infection. Inoculation with fungal sporidia or water decreased the level of SofCAD transcripts in My 55-14, indicating that regulation of SofCAD expression does not take part of the specific response to smut infection. In contrast, SofDIR16 expression was almost nullified in My 55-14 after inoculation with fungal sporidia, but not after water injection. It is proposed that the decreased expression of dirigent proteins induces the formation of lignans, which are involved in the defense response of the smut resistant My 55-14 cultivar.