Resumo Problemas fitossanitários atingem drasticamente a cultura do maracujazeiro em todo o mundo. Entre elas, a verrugose, doença fúngica que ataca a parte aérea das plantas, principalmente as folhas mais jovens, prejudica o desenvolvimento e reduz a produtividade das plantas. O objetivo deste trabalho foi avaliar o efeito de uma glicoproteína de parede celular fúngica chamada pGM de peptidogalactomanana, no controle da infecção por Cladosporum hebarum, causadora da verrugose. Parâmetros morfológicos e de desenvolvimento da planta foram avaliados em dois genótipos de maracujá, ‘H09-110/111’ e ‘FB300’, sob condições de casa de vegetação. O tratamento com pGM foi capaz de mitigar os danos causados ao desenvolvimento das plantas em parâmetros como: altura, número de folhas, diâmetro do caule, área foliar e biomassa no genótipo ‘H09-110/111’; quando comparado com o controle. Porém, no genótipo ‘FB300’, não foram observadas diferenças significativas em relação ao controle. A incidência e a severidade da doença também foram reduzidas pelo tratamento com pGM. Portanto, este estudo sugere que o uso da pGM pode levar ao controle e à atenuação dos danos causados por este fungo nas fases iniciais do maracujá ‘H09-110/111’, quando as plantas são mais suscetíveis a estresses bióticos.

Abstract Phytosanitary problems drastically affect passion fruit cultivation around the world. Scab, a fungal disease that attacks the aerial part of plants, especially the younger leaves, impairs development and reduces plant productivity. The objective of this work was to evaluate the effect of treatment with a fungal cell wall glycoprotein, named pGM from peptidogalactomanann, in the control scab caused by Cladosporium hebarum infection. Under greenhouse conditions, morphological parameters or plant development were evaluated in two passion fruit genotypes, ‘H09-110/111’ and ‘FB300’. pGM treatment was able to mitigate the damage caused to plant development in parameters such as height, the number of leaves, stem diameter, leaf area and biomass in the ‘H09-110/111’ genotype compared to the control. However, in the genotype ‘FB300’, no significant differences were observed concerning the control. Passion fruit scab disease incidence and severity were also reduced by pGM treatment. Therefore, this study suggests that the use of pGM can lead to control and attenuation of the damage caused by this fungus in the early stages of passion fruit plants ‘H09-110/111’ when the plants are more susceptible to biotic stresses.

Brown, red and green algae from the Southeastern coast of Brazil were successively extracted with chloroform/methanol 2:1 and 1:2 (v/v). The crude lipid extract was partitioned according to Folch and the lower phase enriched in glycolipids was fractionated on a silica gel column chromatography eluted with chloroform, acetone and methanol. Three major orcinol-reactive bands present in the acetone and methanol fractions were detected by thin-layer chromatography with chromatographic mobilities corresponding to sulfoglycolipids and glycosyldiacylglycerols. These fractions exhibited potent antiviral activity against HSV-1-ACVs and HSV-1-ACVr and present low toxicity for cell cultures. Purification and identification of these bioactive glycolipids will be necessary in order to elucidate their primary structures and mechanism of action.

Monohexosilceramidas (CMHs, cerebrosídios) são glicoesfingolipídios compostos de uma ceramida hidrofóbica ligada a uma unidade de açúcar. Em células fúngicas, CMHs são moléculas muito bem conservadas, consistindo de uma porção ceramida contendo 9-metil-4,8-esfingadienina ligada através de uma ligação amida aos ácidos 2-hidroxioctadecanoico ou 2-hidroxihexadecanoico e uma porção carboidrato constituída de uma unidade de glucose ou galactose. Ceramidas contendo 9-metil-4,8-esfingadienina são normalmente glicosiladas formando os cerebrosídios fúngicos; no entanto uma descrição recente de uma dihexosilceramida (CDH) em Magnaporthe grisea, apresentando fitoesfingosina sugere a existência de vias alternativas para a glicosilação de ceramidas nas células fúngicas. Além de suas particularidades estruturais, os CMHs de fungos apresentam uma distribuição celular incomum e funções biológicas características. Monohexosilceramidas estão aparententemente envolvidas nas transições morfológicas ou no crescimento dos fungos Pseudallescheria boydii, Candida albicans, Cryptococcus neoformans, Aspergillus nidulans, A. fumigatus e Schizophylum commune. A elucidação dos aspectos estruturais e funcionais dos cerebrosídios fúngicos pode contribuir para a descoberta de novos agentes antifúngicos que inibam o crescimento ou a diferenciação de espécies patogênicas.

Ceramide monohexosides (CMHs, cerebrosides) are glycosphingolipids composed of a hydrophobic ceramide linked to one sugar unit. In fungal cells, CMHs are very conserved molecules consisting of a ceramide moiety containing 9-methyl-4,8-sphingadienine in amidic linkage to 2-hydroxyoctadecanoic or 2-hydroxyhexadecanoic acids, and a carbohydrate portion consisting of one residue of glucose or galactose. 9-Methyl 4,8-sphingadienine-containing ceramides are usually glycosylated to form fungal cerebrosides, but the recent description of a ceramide dihexoside (CDH) presenting phytosphingosine in Magnaporthe grisea suggests the existence of alternative pathways of ceramide glycosylation in fungal cells. Along with their unique structural characteristics, fungal CMHs have a peculiar subcellular distribution and striking biological properties. In Pseudallescheria boydii, Candida albicans, Cryptococcus neoformans, Aspergillus nidulans, A. fumigatus, and Schizophyllum commune, CMHs are apparently involved in morphological transitions and fungal growth. The elucidation of structural and functional aspects of fungal cerebrosides may therefore contribute to the design of new antifungal agents inhibiting growth and differentiation of pathogenic species.