Pullusurfactans A-E, new biosurfactants produced by Aureobasidium pullulans A11211-4-57 from a fleabane, Erigeron annus (L.) pers.

Yeast biosurfactants have potent applications in medical, cosmeceutical, and food industries due to their specific modes of action, low toxicity, and applicability. In this study, biosurfactant-producing yeasts were screened for various industrial applications. Among them, Aureobasidium pullulans strain A11211-4-57 with potent surfactant activity from fleabane flower, Erigeron annus (L.) pers., was selected. From culture supernatant of strain A11211-4-57, five new low-surface-tension chemicals designated as pullusurfactans A-E were identified through consecutive chromatography steps, involving ODS, silica gel, Sephadex LH-20, and ODS Sep-pak cartridge columns. Based on mass and NMR measurements, structures of pullusurfactans A-E were determined as myo-inositol lipids with molecular formulae of C20H35O9, C18H32O8, C20H35O9, C24H42O9, and C18H32O8, respectively. These compounds exhibited potent biosurfactant activities (22.90, 22.40, 32.28, 25.28, and 22.44 mN/m, respectively). These results suggest that these novel biosurfactants have potential use as biosurfactants in industrial aspect.

A novel subgroup 16SrVII-D phytoplasma identified in association with Erigeron witches' broom.

Erigeron sp. plants showing symptoms of witches' broom and stunting were found near orchards of passion fruit in São Paulo state, Brazil. These symptoms were indicative of infection by phytoplasmas. Thus, the aim of this study was to detect and identify possible phytoplasmas associated with diseased plants. Total DNA was extracted from symptomatic and asymptomatic plants and used in nested PCR conducted with the primer pairs P1/Tint and R16F2n/16R2. Amplification of genomic fragments of 1.2 kb from the 16S rRNA gene confirmed the presence of phytoplasma in all symptomatic samples. The sequence identity scores between the 16S rRNA gene of the phytoplasma strain identified in the current study and those of previously reported 'Candidatus Phytoplasma fraxini'-related strains ranged from 98% to 99% indicating the phytoplasma to be a strain affiliated with 'Candidatus Phytoplasma fraxini'. The results from a phylogenetic analysis and virtual RFLP analysis of the 16S rRNA gene sequence with 17 restriction enzymes revealed that the phytoplasma strain belongs to the ash yellows phytoplasma group (16SrVII); the similarity coefficient of RFLP patterns further suggested that the phytoplasma represents a novel subgroup, designated 16SrVII-D. The representative of this new subgroup was named EboWB phytoplasma (Erigeron bonariensis Witches' Broom).

Growth promotion of Xanthium italicum by application of rhizobacterial isolates of Bacillus aryabhattai in microcosm soil.

This study was conducted using rhizobacteria, which are able to exert beneficial effects upon plant growth in the infertile soil collected from barren lakeside areas. Four strains of plant growth promoting bacteria were isolated from the rhizosphere of a common wild plant, Erigeron canadensis. Isolated strains LS9, LS11, LS12, and LS15 were identified as Bacillus aryabhattai by 16S rDNA sequence analysis. B. aryabhattai LS9, LS11, LS12, and LS15 could solubilize 577.9, 676.8, 623.6, and 581.3 mg/L of 0.5% insoluble calcium phosphate within 2 days of incubation. Production of indole acetic acid, a typical growth promoting phytohormone auxin, by strain LS15 was 471.3 mg/L in 2 days with the addition of auxin precursor L-tryptophan. All the strains also produced other phytohormones such as indole butyric acid, gibberellins, and abscisic acid, and strain LS15 showed the highest production rate of gibberellin (GA(3)), 119.0 µg/mg protein. Isolated bacteria were used in a microcosm test for growth of wild plant Xanthium italicum, which can be utilized as a pioneer plant in barren lands. Seed germination was facilitated, and the lengths of roots, and shoots and the dry weights of germinated seedlings after 16 days were higher than those of the uninoculated control plants. Root lengths of seedlings of X. italicum increased by 121.1% in LS11-treated samples after 16 days. This plant growth-promoting capability of B. aryabhattai strains may be utilized as an environmentally friendly means of revegetating barren lands, especially sensitive areas such as lakeside lands.