Irpexine, an Isoindolinone Alkaloid Produced by Coculture of Endophytic Fungi, Irpex lacteus and Phaeosphaeria oryzae.

A new isoindolinone alkaloid, irpexine (1), was isolated as a racemate, along with a known green pigment, hypoxyxylerone (2), from the coculture of two endophytic fungi, Irpex lacteus and Phaeosphaeria oryzae. Compound 1 was found to be a newly produced metabolite of I. lacteus in the coculture with P. oryzae. Although 2 was produced in a monoculture of I. lacteus, its production was markedly enhanced by the coculture.

Multilocus phylogeny of Acrospermaceae: New epibiotic species and placement of Gonatophragmium, Pseudovirgaria, and Phaeodactylium anamorphs.

Acrospermum is a poorly known genus of epibiotic and saprophytic species with a subcosmopolitan distribution. Here, we investigate the intriguing relationship between Acrospermum and its host plants in the fern family Polypodiaceae, where it occurs upon approximately 45 neotropical species. We conducted phylogenetic analyses using an eight-marker comprehensive ascomycete data set comprising 719 species representing all major lineages along with 23 new Acrospermum specimens sampled from ferns. We ask whether fern-dwelling Acrospermum are monophyletic, whether epibiotic Acrospermum have evolved independently from saprophytic ancestors, and identify anamorphic phases by incorporating sequences for all suspected taxa. Our results corroborate the placement of Acrospermales within the Dothideomycetes with strong support. However, the order remains incertae sedis due to weak support along the branches subtending the clade that includes the Acrospermales plus Dyfrolomycetales. Our results show a strong phylogenetic pattern in lifestyles but do not clearly identify an ancestral life history state. The first divergence in Acrospermaceae splits fungicolous taxa from taxa that inhabit plants; saprophytes and anamorphic phases found on angiosperms occur in both clades. Fungicolous species are monophyletic, whereas species with an epibiotic or necrotic life history upon plants are nonmonophyletic due to the position of the saprophyte A. longisporium. Previously, all Acrospermum collected from ferns were identified as A. maxonii. Our results indicate that this is not monophyletic due to the inclusion of Gonatophragmium triuniae. Two species are described herein as A. gorditum, sp. nov., and A. leucocephalum, sp. nov. We find no instances of co-cladogenesis; however, our ability to detect this is limited by the lack of resolution in the A. maxonii clade. Rather, we see that that the distribution of epibiotic Acrospermum is explained by the overlap between the ecological niche of the Acrospermum species and its host.

Aureimonas flava sp. nov., a novel endophytic bacterium isolated from leaf of Acrostichum aureum.

A Gram-negative, aerobic, coccus-shaped, non-spore-forming bacterium, designated M2BS4Y-1T, was isolated from a surface-sterilized leaf of Acrostichum aureum collected from Guangxi Zhuang Autonomous Region, China and investigated by a polyphasic approach to determine its taxonomic position. Strain M2BS4Y-1T grew optimally with 1 % (w/v) NaCl, at 30 °C and at pH 7.0-8.0. Substrate mycelia and aerial mycelia were not formed, and no diffusible pigments were observed on the media tested. Phylogenetic analysis based on its 16S rRNA gene sequence showed that strain M2BS4Y-1T was most closely related to species of the genus Aureimonas, and shared the highest 16S rRNA gene sequence similarity of 97.79 % to Aureimonas phyllosphaerae DSM 25026T. The average nucleotide identity (ANI) and in silico DNA-DNA hybridization (DDH) values between strain M2BS4Y-1T and A.phyllosphaerae DSM 25026T were 83.7 % and 26.5 %, respectively. The ANI and DDH values were below the recommended thresholds. The DNA G+C content of strain M2BS4Y-1T was 70.0 mol%. The cell-wall peptidoglycan contained meso-diaminobutyric acid and ubiquinone Q-10 was the respiratory lipoquinone. The polar lipids comprised diphosphatidylglycerol, phosphatidylglycerol, phosphatidylcholine, phosphatidylmonomethylethanolamine, phosphatidylethanolamine, sulfoquinovosyldiacylglycerol, two unknown aminolipids, an unidentified phospholipid and four unidentified lipids, while the major fatty acids were C18 : 1ω7c and C16 : 0. On the basis of phylogenetic, chemotaxonomic and phenotyptic data, strain M2BS4Y-1T can be characterized to represent a novel species of the genus Aureimonas, for which the name Aureimonas flava sp. nov. is proposed. The type strain is M2BS4Y-1T (=KCTC 62837T=CGMCC 1.13747T).

Arbuscular mycorrhizal colonization in field-collected terrestrial cordate gametophytes of pre-polypod leptosporangiate ferns (Osmundaceae, Gleicheniaceae, Plagiogyriaceae, Cyatheaceae).

To determine the mycorrhizal status of pteridophyte gametophytes in diverse taxa, the mycorrhizal colonization of wild gametophytes was investigated in terrestrial cordate gametophytes of pre-polypod leptosporangiate ferns, i.e., one species of Osmundaceae (Osmunda banksiifolia), two species of Gleicheniaceae (Diplopterygium glaucum, Dicranopteris linearis), and four species of Cyatheales including tree ferns (Plagiogyriaceae: Plagiogyria japonica, Plagiogyria euphlebia; Cyatheaceae: Cyathea podophylla, Cyathea lepifera). Microscopic observations revealed that 58 to 97% of gametophytes in all species were colonized with arbuscular mycorrhizal (AM) fungi. Fungal colonization was limited to the multilayered midrib (cushion) tissue in all gametophytes examined. Molecular identification using fungal SSU rDNA sequences indicated that the AM fungi in gametophytes primarily belonged to the Glomeraceae, but also included the Claroideoglomeraceae, Gigasporaceae, Acaulosporaceae, and Archaeosporales. This study provides the first evidence for AM fungal colonization of wild gametophytes in the Plagiogyriaceae and Cyatheaceae. Taxonomically divergent photosynthetic gametophytes are similarly colonized by AM fungi, suggesting that mycorrhizal associations with AM fungi could widely occur in terrestrial pteridophyte gametophytes.

Xylactam B, A New Isobenzofuranone from an Endophytic Xylaria sp.

A new nitrogen containing compound named xylactam B (2), along with a further eight known compounds, ceramide 2a, cerebroside B, cyclo(prolyl,valyl), marmesin, 5-methoxycarbonylmellein, 5-methylmellein, polypropylene glycol and p-hydroxybenzoic acid, were isolated from an endophytic Xylaria sp. The structure elucidation of the new compound and the other isolates was carried out with the help of spectroscopic analyses and databases.

Colonización y estructura de la comunidad de hongos micorrízicos arbusculares en Alsophila firma (Cyatheaceae) en bosque mesófilo de montaña en Veracruz, México / Colonization and structure of arbuscular mycorrhizal fungi community in Alsophila firma (Cyatheales: Cyatheaceae) from a tropical montane cloud forest in Veracruz, México

Alsophila firma is a tree fern that is distributed mainly in tropical montane cloud forest (TMCF) and is considered as a threatened species. Arbuscular mycorrrhizal fungi (AMF) have been proposed as an alternative in rescue programs of endangered species. However, our knowledge about diversity of AMF and mycorrhizal status of the species of TMCF is limited. In Mexico TMCF shows different degrees of conservation because of fragmentation and land use change. In this study, we evaluated the level of colonization, richness and abundances of spores of AMF in three fragments with different conservation status: conserved (100 years), secondary vegetation (17 years) and disturbed. For this, soil samples and roots were collected from five individuals of A. firma per site, with at least 100m away from each other; a total of 100cm of roots were analysed per site. Root samples showed AMF and occasionally dark septate fungi (DSF) colonizations. For the overall study, 19 species of AMF were recorded: Gigaspora (7), Acaulospora (4), Glomus (4), Funneliformis (2), Sclerocystis (1) and Scutellospora (1). The dominant species in the three sites were Funneliformis geosporum and Acaulospora scrobiculata. The highest diversity (H’) and evenness (J’) (p<0.05) were found in the conserved site (H’=1.7, J’=0.66), when compared to the secondary vegetation (H’=1.5, J’=0.61), and the disturbed site (H’=0.74, J’=0.41). Statistical analysis showed that the AMF degree of colonization was significantly higher (p<0.05) in the conserved site; although, the disturbed site showed low richness and abundances of AMF, the degree of root colonization did not differ statistically (p<0.05) with the secondary vegetation site. Chao2 (Richness estimation model) showed that the number of analysed samples were sufficient to represent the structure of the AMF communities with values >90%. The present study confirmed that A. firma is a mycorrhizal species that exhibits high levels of colonization even in disturbed sites. We suggest that F. geosporum and A. scrobiculata may have the potential to inoculate the gametophyte and young sporophyte of A. firma, to support restoration programs, because of their abundances and high tolerance to disturbed sites.

Alsophila firma es un helecho arborescente que crece principalmente en bosque mesófilo de montaña (BMM) y se encuentra en la categoría de riesgo. Los hongos mico- rrízicos arbusculares (HMA) se han propuesto como una alternativa para programas de recuperación de especies nativas en peligro. Sin embargo, sabemos poco sobre la diversidad de HMA y del estatus micorrízico de las espe- cies vegetales del BMM. En México el BMM presenta diferentes grados de conservación debido a la fragmentación y el cambio de uso de suelo. Se evaluó el grado de colonización, riqueza y abundancia de esporas de los HMA presentes en fragmentos de BMM con diferente historia de manejo: conservado (100 años), en recuperación (17 años) y alterado. Se estudiaron muestras de suelo y raíces toma- das de 5 individuos de A. firma por cada sitio, con al menos 100m de distancia entre individuos. Se analizaron en total 100cm de raíz por cada sitio. Las muestras de raíz presentaron colonización principalmente de HMA y ocasionalmente por hongos septados oscuros (HSO). Se encontraron 19 especies: Gigaspora (7), Acaulospora (4), Glomus (4), Funneliformis (2), Sclerocystis (1) y Scutellospora (1). Las especies dominantes en los tres sitios fueron Funneliformis geosporum y Acaulospora scrobiculata. La mayor diversidad (H’) y equitatividad (J’) (p<0.05) se presentaron en el sitio conservado (H’=1.7; J’ 0.66) con respecto al sitio en recuperación (H’=1.5, J’ 0.61) y alterado (H’=0.74, J’=0.41). Los niveles de colonización micorrízica total de raíz fueron estadísticamente mayores (p<0.05) en el sitio conservado. Aunque el sitio alterado presenta una baja riqueza y abundancia de HMA la colonización micorrízica total de raíz no fue estadísticamente diferente (p<0.05) respecto al sitio en recuperación. El estimador Chao2 indica que las muestras analizadas reflejan la estructura general de la comunidad de HMA con valores superiores al 93%. El presente estudio confirma que A. firma es una especie micorrízica con altos niveles de colonización incluso en sitios alterados. Se sugiere que las especies F. geosporum y A. scrobiculata por su alta tolerancia a sitios alterados pueden tener potencial para inocular gametofitos y esporofitos de A. firma para incrementar la supervivencia en programas de restauración.

Ultrastructure and composition of cell wall appositions in the roots of Asplenium (Polypodiales).

Cell wall appositions (CWAs), formed by the deposition of extra wall material at the contact site with microbial organisms, are an integral part of the response of plants to microbial challenge. Detailed histological studies of CWAs in fern roots do not exist. Using light and electron microscopy we examined the (ultra)structure of CWAs in the outer layers of roots of Asplenium species. All cell walls studded with CWAs were impregnated with yellow-brown pigments. CWAs had different shapes, ranging from warts to elongated branched structures, as observed with scanning and transmission electron microscopy. Ultrastructural study further showed that infecting fungi grow intramurally and that they are immobilized by CWAs when attempting to penetrate intracellularly. Immunolabelling experiments using monoclonal antibodies indicated pectic homogalacturonan, xyloglucan, mannan and cellulose in the CWAs, but tests for lignins and callose were negative. We conclude that these appositions are defense-related structures made of a non-lignified polysaccharide matrix on which phenolic compounds are deposited in order to create a barrier protecting the root against infections.