Efficacy of Argentinean propolis extracts on control of potato soft rot caused by Erwinia carotovora subsp.

Background: Erwinia carotovora subsp. cause the potato soft rot, which is a major disease in agriculture. Antibacterial agents currently applied on potato soft rot often offer a restricted control and have several disadvantages.

Antifungal metabolites from Schinopsis balansae Engl (Anacardiaceae): isolation, identification and evidences of their mode of action on Fusarium graminearum Schwabe.

An antifungal activity-directed fractionation of leaf constituents from Schinopsis balansae on Fusarium graminearum yielded a fraction mainly made of a mixture of four 3-n-heptadec(en)ylcatechols (PALK). The PALK fraction showed on macroconidia germination a MIC value of 500 μg/mL which was twofold higher than that required for prothioconazole (MIC = 250 μg/mL). Sublethal concentrations of PALK modify the morphogenesis in germinating macroconidia, and decreased fungal production of HO and deoxynivalenol biosynthesis at early fungal growth.

Plant growth inhibitors isolated from sugarcane (Saccharum officinarum) straw.

Several compounds related with plant defense and pharmacological activities have been isolated from sugarcane. Straw phytotoxins and their possible mechanisms of growth inhibition are largely unknown. A bioassay-guided fractionation of the phytotoxic constituents leachated from a sugarcane straw led to the isolation of trans-ferulic (trans-FA), cis-ferulic (cis-FA), vanillic (VA) and syringic (SA) acids.

Inhibition of hydrolytic enzyme activities and plant pathogen growth by invertase inhibitors.

The invertase inhibitory protein isolated from Cyphomandra betacea Sendt and Solanum tuberosum inhibited the invertase activity from different species, genera and even plant family. Furthermore, proteinaceous inhibitors are not invertase specific; fungal, bacterial and higher plant enzymes including polygalacturonase, pectinase, pectin lyase, alpha-L-arabinofuranosidase and beta-glucosidase are also shown to be inhibited. Both inhibitors exhibited an in vitro antibacterial action against phytopathogenics strains of Xanthomonas campestris pvar vesicatoria CECT 792, Pseudomonas solanacearum CECT 125, Pseudomonas corrugata CECT 124, Pseudomonas syringae and Erwinia carotovora var carotovora.