Antifungal activity screening of fractions from Annona cherimola Mill. leaf extract against Fusarium oxysporum.

The antifungal effect of ethanolic extract fractions of Annona cherimola leaves against the mycelial growth of Fusarium oxysporum was studied. The ethanolic crude extract was solvent partitioned and the ethyl acetate phase was fractionated by column or preparative thin-layer chromatography. All fractions were developed on TLC and analyzed for acetogenins (ACG) with Kedde reagent. The antifungal effect assays were carried out in vitro by the diffusion method on PDA plates. The ethanolic extract of A. cherimola leaves was highly active against F. oxysporum growth; subfractions obtained from the antifungal screening had a significant effect (p < 0.05) on the F. oxysporum growth parameters. The screening showed that as the purification steps progressed, the inhibition of mycelial growth increased. Six bioactive ACG (Annomolon-B, 34-epi annomolon B, almunequin, cherimoline 1, cherimoline 2, and isocherimoline 1) were identified by LC-QTOF-MS/MS. These findings suggested that bioactive ACG from A. cherimola leaves could be an alternative resource of a promising botanical fungicide to control plant diseases caused by F. oxysporum.

Osmo- and cryotherapy of sugarcane (Saccharum spp. L.) shoot-tips infected with sugarcane mosaic virus (SCMV).

In this work, we investigated the effect of different osmoprotective treatments and of cryopreservation using a droplet-vitrification (D-V) protocol to eliminate sugarcane mosaic virus (SCMV) of shoot-tips excised from in vitro propagated infected plantlets. Shoot-tips of sugarcane (Saccharum spp. L.) were precultured on semisolid MS medium supplemented with 0.3 M sucrose for 1 day, loaded in solution with 0.4 M sucrose and 2 M glycerol for 30 min and exposed to plant vitrification solution 2 for 15 min at room temperature prior to ultra-rapid cooling in liquid nitrogen. Virus indexing was performed by the DAS-ELISA immunoenzymatic test. The presence of SCMV was confirmed in the donor-plantlets derived of infected field material. No virus was detected in the regenerated plantlets from shoot-tips subjected to cryopreservation protocol. The progressive decrease in absorbances occurred from the first preculture treatment and no significant differences (P ≤ 0.05) were found with respect to following steps of D-V protocol. These results indicate that the osmotic dehydration treatments (osmotherapy) and cryopreservation (cryotherapy) may be potentially effective strategies to remove the SCMV from infected plants.