Biodiversity and dairy traits of lactic acid bacteria from foliage of aromatic plants before and after dehydration process monitored by a smart sensors system.

The main hypothesis of this work was to evaluate the presence of lactic acid bacteria (LAB) intrinsically resistant to plant essential oils in sage (Salvia officinalis L.) and laurel (Laurus nobilis), for future applications in functional cheese production by addition of aromatic herbs. The effect of the drying process on the viability of LAB was evaluated with three biomass densities (3, 4 and 5 kg/m2). The drying densities did not affect weight loss, but influenced the levels of LAB of sage and laurel. A total of 10 different strains of Enterococcus faecium, Enterococcus mundtii, Enterococcus raffinosus and Leuconostoc mesenteroides were identified from laurel, while sage did not host any LAB species. In particular, L. mesenteroides was the only species sensitive to the heat treatment. Only five strains, all enterococci, were resistant to at least one antibiotic, even though no strain showed gelatinase or haemolytic activity. The investigation on the technological traits useful in cheese making demonstrated that all LAB can be considered non starter LAB, because they were characterized by a slow acidification capacity (the pH was still above 6.00 after 3 d) and a very limited autolysis (the maximum decrease of the optical density at 599 nm was barely 0.2).

Antifungal potential of Lauraceae rhizobacteria from a tropical montane cloud forest against Fusarium spp.

The occurrence of pests and diseases can affect plant health and productivity in ecosystems that are already at risk, such as tropical montane cloud forests. The use of naturally occurring microorganisms is a promising alternative to mitigate forest tree fungal pathogens. The objectives of this study were to isolate rhizobacteria associated with five Lauraceae species from a Mexican tropical montane cloud forest and to evaluate their antifungal activity against Fusarium solani and F. oxysporum. Fifty-six rhizobacterial isolates were assessed for mycelial growth inhibition of Fusarium spp. through dual culture assays. Thirty-three isolates significantly reduced the growth of F. solani, while 21 isolates inhibited that of F. oxysporum. The nine bacterial isolates that inhibited fungal growth by more than 20% were identified through 16S rDNA gene sequence analysis; they belonged to the genera Streptomyces, Arthrobacter, Pseudomonas, and Staphylococcus. The volatile organic compounds (VOC) produced by these nine isolates were evaluated for antifungal activity. Six isolates (Streptomyces sp., Arthrobacter sp., Pseudomonas sp., and Staphylococcus spp.) successfully inhibited F. solani mycelial growth by up to 37% through VOC emission, while only the isolate INECOL-21 (Pseudomonas sp.) inhibited F. oxysporum. This work provides information on the microbiota of Mexican Lauraceae and is one of the few studies identifying forest tree-associated microbes with inhibitory activity against tree pathogens.

Genomic comparisons of the laurel wilt pathogen, Raffaelea lauricola, and related tree pathogens highlight an arsenal of pathogenicity related genes.

Raffaelea lauricola is an invasive fungal pathogen and symbiont of the redbay ambrosia beetle (Xyleborus glabratus) that has caused widespread mortality to redbay (Persea borbonia) and other Lauraceae species in the southeastern USA. We compare two genomes of R. lauricola (C2646 and RL570) to seven other related Ophiostomatales species including R. aguacate (nonpathogenic close relative of R. lauricola), R. quercus-mongolicae (associated with mortality of oaks in Korea), R. quercivora (associated with mortality of oaks in Japan), Grosmannia clavigera (cause of blue stain in conifers), Ophiostoma novo-ulmi (extremely virulent causal agent of Dutch elm disease), O. ulmi (moderately virulent pathogen that cause of Dutch elm disease), and O. piceae (blue-stain saprophyte of conifer logs and lumber). Structural and functional annotations were performed to determine genes that are potentially associated with disease development. Raffaelea lauricola and R. aguacate had the largest genomes, along with the largest number of protein-coding genes, genes encoding secreted proteins, small-secreted proteins, ABC transporters, cytochrome P450 enzymes, CAZYmes, and proteases. Our results indicate that this large genome size was not related to pathogenicity but was likely lineage specific, as the other pathogens in Raffaelea (R. quercus-mongolicae and R. quercivora) had similar genome characteristics to the Ophiostoma species. A diverse repertoire of wood-decaying enzymes were identified in each of the genomes, likely used for toxin neutralization rather than wood degradation. Lastly, a larger number of species-specific, secondary metabolite, synthesis clusters were identified in R. lauricola suggesting that it is well equipped as a pathogen, which could explain its success as a pathogen of a wide range of lauraceous hosts.

Xylaria karyophthora: a new seed-inhabiting fungus of Greenheart from Guyana.

In 2010-2011, a Xylaria sp. was documented growing from seeds of both Chlorocardium rodiei and Chlorocardium venenosum, a commercially valuable timber in Guyana. We conducted extensive surveys in 2015-2016, where this Xylaria sp. was observed fruiting from ca. 80% of dispersed seeds in both natural and logged forests in the Upper Demerara-Berbice, Potaro-Siparuni, and the Cuyuni-Mazaruni districts of central Guyana. Species of Xylaria are ascomycetous fungi generally characterized by black, carbonaceous, multiperitheciate ascoma commonly found growing on dead wood. Combined teleomorphic and molecular data indicate that the fungus represents a novel species, described here as Xylaria karyophthora.

Identification of two new species of Meliolinites associated with Lauraceae leaves from the middle Miocene of Fujian, China.

Several studies have investigated both the paleoclimate and the well-preserved fossil remains from the middle Miocene found in China's Fujian Province. This study describes two new species of Meliolinites, including their fungal hyphae, reproductive structures, and spores. The distribution of modern Meliolaceae indicates that they live in warm, humid, subtropical to tropical climates. Moreover, the fossil leaves and the epiphyllous fungal remains, indicate the prevalence of a warm, humid, subtropical to tropical climate in this area during the middle Miocene. In addition, it was observed that the surrounding cells of the fungi found on the uninfected host leaves were normal, whereas the infected host leaves themselves were abnormally dim. These features are a reflection of self-protection, and it can, therefore, be inferred that the host leaves were alive when they were infected. The present study used fossil angiosperm leaves with cuticles obtained from the Fotan sediments from Fujian to investigate not only the taxonomy of the fossils but also to interpret the paleoclimate and paleoecology.

The Fungus Raffaelea lauricola Modifies Behavior of Its Symbiont and Vector, the Redbay Ambrosia Beetle (Xyleborus Glabratus), by Altering Host Plant Volatile Production.

The redbay ambrosia beetle Xyleborus glabratus is the vector of the symbiotic fungus, Raffaelea lauricola that causes laurel wilt, a highly lethal disease to members of the Lauraceae family. Pioneer X. glabratus beetles infect live trees with R. lauricola, and only when tree health starts declining more X. glabratus are attracted to the infected tree. Until now this sequence of events was not well understood. In this study, we investigated the temporal patterns of host volatiles and phytohormone production and vector attraction in relation to laurel wilt symptomology. Following inoculations with R. lauricola, volatile collections and behavioral tests were performed at different time points. Three days after infection (DAI), we found significant repellency of X. glabratus by leaf odors of infected swamp bay Persea palustris as compared with controls. However, at 10 and 20 DAI, X. glabratus were more attracted to leaf odors from infected than non-infected host plants. GC-MS analysis revealed an increase in methyl salicylate (MeSA) 3 DAI, whereas an increase of sesquiterpenes and leaf aldehydes was observed 10 and 20 DAI in leaf volatiles. MeSA was the only behaviorally active repellent of X. glabratus in laboratory bioassays. In contrast, X. glabratus did not prefer infected wood over healthy wood, and there was no associated significant difference in their volatile profiles. Analyses of phytohormone profiles revealed an initial increase in the amount of salicylic acid (SA) in leaf tissues following fungal infection, suggesting that the SA pathway was activated by R. lauricola infection, and this activation caused increased release of MeSA. Overall, our findings provide a better understanding of X. glabratus ecology and underline chemical interactions with its symbiotic fungus. Our work also demonstrates how the laurel wilt pathosystem alters host defenses to impact vector behavior and suggests manipulation of host odor by the fungus that attract more vectors.

Chemotyping the temporal volatile organic compounds of an invasive fungus to the United States, Raffaelea lauricola.

Volatile organic compounds (VOCs) in the headspace of the fungus Raffaelea lauricola have been monitored and identified over a twenty-eight day growth period. R. lauricola is an invasive and phytopathogenic fungus that was first identified in the United States in the mid-2000s. It is believed to be spread by a host beetle, Xyleborus glabratus, and is detrimental both to wild members of the Lauraceae family and to commercial avocado groves particularly in the Southeastern region of the country. The fungus causes the fatal laurel wilt disease, a result of the host tree shutting down its vascular system in order to halt the spread of the fungus. The current study identified the VOCs present in the headspace of R. lauricola over the initial growth stage using headspace solid phase microextracion-gas chromatography-mass spectrometry (HS-SPME-GC-MS). Results revealed the VOC dynamics of the fungus in culture, indicating that the initial growth period of the fungus may coincide with potential responses from the host trees that may recognize and respond to the pathogen when the fungal VOCs are produced as a result of primary metabolic processes. As fungal growth progresses past initial growth phases, the predominant compounds seen in the odor profile are hydrocarbons and terpenes, produced from secondary metabolic processes. The odor profile pattern for the twenty-eight day growth period did change with the stages of growth. Based on the information learned from this pilot study, a discussion is presented of possible host tree reactions to R. lauricola and implications for future experiments.

Antifungal Long-Chain Alkenyl Sulphates Isolated from Culture Broths of the Fungus Chaetopsina sp.

During a high-throughput screening program focused on the discovery and characterization of new antifungal compounds, a total of 8320 extracts from Fundacion MEDINA's collection were screened against a panel of 6 fungal parasitic strains, namely Candida glabrata, Candida krusei, Candida parapsilosis, Candida tropicalis, Candida albicans, and Aspergillus fumigatus. A total of 127 extracts displayed antifungal properties and, after LC/MS dereplication, 10 were selected for further fractionation. Bioassay-guided fractionation from a 1-L fermentation of one of these extracts, belonging to the fungus Chaetopsina sp., led to the isolation of linoleyl sulphate (1), linolenyl sulphate (2), and oleyl sulphate (3) as the compounds responsible for the antifungal activity. These molecules were previously described as synthetic products with the ability to produce the allosteric inhibition of soybean lipoxygenase and human lipoxygenase.

Search for antifungal compounds from the wood of durable tropical trees.

Research on antifungal compounds from the durable wood from French Guiana Amazonian forest trees highlights the correlation between the activity of their extracts against wood-rotting fungi and human pathogens. The fractionation of an ethyl acetate extract of Sextonia rubra wood led to the isolation of rubrenolide (1) and rubrynolide (2). The potential of compounds 1 and 2 is described through the evaluation of their activity against 16 pathogenic fungi and their cytotoxicity toward NIH-3T3 mammalian fibroblast cells.

Theissenia rogersii sp. nov. and phylogenetic position of Theissenia.

Theissenia rogersii deviates from known Theissenia species primarily in having large ascospores with a thick wall layer and a unique configuration of two stromatal tissue types, one carbonaceous and the other fibrous. The carbonaceous tissue forms palisades on and beneath the perithecial layer as well as encasing individual perithecia, whereas the fibrous tissue fills the spaces between columns of the palisades as well as between encased perithecia. Phylogenetic analyses based on DNA sequences of beta-tubulin and alpha-actin genes placed Theissenia in the subfamily Hypoxyloideae among the genera that are characterized by having bipartite stromata (i.e. with the stromata differentiated into an outer dehiscing layer and an inner perithecium-bearing layer).

Diversity and distribution of saprobic microfungi in leaf litter of an Australian tropical rainforest.

The diversity and distribution of microfungal assemblages in leaf litter of a tropical Australian forest was assessed using two methods: (1) cultures were isolated using a particle filtration protocol (wet season 2001), and (2) fruit bodies were observed directly on leaf surfaces following incubation in humid chambers (wet and dry season of 2002). Four tree species were studied using both methods, namely Cryptocarya mackinnoniana (Lauraceae), Elaeocarpus angustifolius (Elaeocarpaceae), Ficus pleurocarpa (Moraceae), and Opisthiolepis heterophylla (Proteaceae). An additional two species, Darlingia ferruginea (Proteaceae) and Ficus destruens (Moraceae), were studied using direct observations. In total, fruiting bodies of 185 microfungal species were recorded on leaf surfaces (31-81 species per tree species), and 419 morphotypes were detected among isolates obtained by particle filtration (111-203 morphotypes per tree species). Although the observed microfungal diversity was higher with the particle filtration protocol, both methods concurred with respect to microfungal distributions. The overlap of microfungal species in pair wise comparisons of tree species was low (14-30%), and only 2 and 3% of microfungal species were observed in leaves of all tree species by particle filtration and by direct observations respectively. Multivariate analysis of data from direct observations confirmed the hypothesis that microfungal assemblages are strongly influenced by host phylogeny and are also affected by seasonal and site factors. The importance of host species in shaping microfungal distributions was also supported by the particle filtration data. Several taxa new to science, as well as some widespread saprotrophs, were detected on only one host. The underlying reasons for this affinity remain unclear, but we hypothesise that a number of factors may be involved such as fungal adaptation to plant secondary metabolites or the presence of a biotrophic phase in the fungus' life cycle.

Estimation of microfungal diversity in tropical rainforest leaf litter using particle filtration: the effects of leaf storage and surface treatment.

Fungal species richness and abundance were assessed in leaf litter of the Australian rainforest tree Neolitsea dealbata (Lauraceae) using particle filtration. Results were comparable to the species richness and abundance reported in previous studies of tropical leaf litter microfungi. Eight leaf samples yielded 1365 strains. In an assessment of the effect of surface treatments, 736 strains in 112 morphotaxa were isolated, while 639 strains in 141 morphotaxa were recovered to assess the effect of surface treatment. Isolation rates in airdried leaves stored at room temperature for four weeks declined linearly, while the number of morphotaxa remained essentially constant for the first three weeks. Isolates of common morphotaxa were lost preferentially over those of rarer taxa. Such losses of isolates may be acceptable if only presence/absence data are collected. If frequency data are vital for community analysis, only fresh material should be utilised. Two surface sterilisation treatments were applied to N. dealbata leaves. An ethanol/sodium hypochlorite treatment was considered unsuitable because it significantly reduced the number of morphotaxa derived from the leaf lamina. A sodium hypochlorite treatment reduced the number of detectable propagules in the wash water without changing the number of morphotaxa derived from leaf particles in comparison with those of the control group.

A mitogen-activated protein kinase kinase required for induction of cytokinesis and appressorium formation by host signals in the conidia of Colletotrichum gloeosporioides.

Differentiation of fungal conidia of phytopathogens into the infection structure, appressorium, requires contact with a hard surface and host signals. The molecular signaling involved in the induction of this differentiation is poorly understood. We report the cloning of a mitogen-activated protein kinase kinase (MEK), CgMEK, from Colletotrichum gloeosporioides and its role in the induction of these developmental processes involved in pathogenesis. Disruption of CgMEK1 resulted in the loss of its ability to form appressoria in response to the host's signals and a loss of virulence. Results of confocal microscopic examination of germinating conidia of the gene-disrupted mutants were similar to those for wild-type conidia treated with an MEK inhibitor, suggesting that CgMEK1 is involved in two developmental processes in the differentiation into appressorium: (1) polarized cell division, with the preferential increase in F-actin in one of the daughter nuclei after nuclear division and the formation of septum; and (2) differentiation of the germ tube into an appressorium. CgMEK1 is required for the differentiation.

pH regulation of pectate lyase secretion modulates the attack of Colletotrichum gloeosporioides on avocado fruits.

Growth of Colletotrichum gloeosporioides in pectolytic enzyme-inducing medium (PEIM) increased the pH of the medium from 3. 8 to 6.5. Pectate lyase (PL) secretion was detected when the pH reached 5.8, and the level of secretion increased up to pH 6.5. PL gene (pel) transcript production began at pH 5.0 and increased up to pH 5.7. PL secretion was never detected when the pH of the inducing medium was lower than 5.8 or when C. gloeosporioides hyphae were transferred from PL-secreting conditions at pH 6.5 to pH 3.8. This behavior differed from that of polygalacturonase (PG), where pg transcripts and protein secretion were detected at pH 5.0 and continued up to 5.7. Under in vivo conditions, the pH of unripe pericarp of freshly harvested avocado (Persea americana cv. Fuerte) fruits, resistant to C. gloeosporioides attack, was 5.2, whereas in ripe fruits, when decay symptoms were expressed, the pericarp pH had increased to 6.3. Two avocado cultivars, Ardit and Ettinger, which are resistant to C. gloeosporioides attack, had pericarp pHs of less than 5.5, which did not increase during ripening. The present results suggest that host pH regulates the secretion of PL and may affect C. gloeosporioides pathogenicity. The mechanism found in avocado may have equivalents in other post-harvest pathosystems and suggests new approaches for breeding against and controlling post-harvest diseases.

Pudrición negra en raicillas de palto (persea americana mill) por cylindrocarpon destructans: patogenecidad y aspectos epidemiológicos / Black root rot in avocado plants (persea americana mill) by cylindrocarpon destructans: pathogenicity and epidemiological

En un vivero comercial de Quillota (V región, Chile)), durante los años 1994 y 1995 se produjo en plantas de palto (persea americana mill.) un súbito decaimiento de éstas, caracterizádo por síntomas iniciales de marchitez, pérdida de turgor de las hojas, asociada a clorisis y necrosis marginal y al mismo tiempo, a nivel de las raíces, se observó una pudrición severa de color café oscuro a negro. Sólo por concepto de estos problemas, se destruyeron 22.000 plantas en dos años. A partir de la zona de avance de las lesiones radiculares, se aisló en forma consistente colonias de cylindrocarpon destructans, no detectándose representantes del género phytophthora. Con el propósito de determinar la posible fuente de inóculo, se efectuaron aislamientos desde el sustrato empleado, sus diferentes componentes y de semillas, recuperándose este patógeno sólo desde la arena de río y suelo de tranque. De acuerdo con los resultados obtenidos a partir de los diferentes aislamientos, las pruebas de patogenecidad y los síntomas observados, se considera a c. destructans como el agente causal de una nueva enfermedad que afecta a plantas de palto en vivero

Morphological variability of Colletotrichum gloesporiodes isolates from avocado trees from northeastern Brazil

Isolados de Colletotrichum gloeosporioides de abacateiros cultivados no Nordeste do Brasil foram estudados em culturas monoconidiais. A maioria dos isolados produziram massas de conídios distribuidas em anéis concêntricos na superfície do BDA em resposta a alternância de luz. Algumas culturas monoconidiais formaram peritécios, porém baixa produçäo de conídios, enquanto que outras produziram conídios em abundância, mas näo formaram peritécios. Em geral, houve produçäo de esclerócios escuros, pequenos e de formato esférico. Os conídios foram produzidos em sucessäo na extremidade de conidióforos fialídicos ou no ápice de setas. Estas, apresentaram-se retas, septadas, escuras, com ápice mais claro e, em alguns casos, férteis. Todos os isolados monoconidiais dentro de uma mesma érea geográfica ou entre elas mostraram variaçäo em relaçäo a tamanho de conídios e apressóriois. A diferença

Appressoria of Brazilian isolates of Colletotrichum gloeosporioides (penz.) sacc. causal agent of anthracnoses diseases

Foram estudados alguns aspectos morfológicos funcionais de apressórios de Colletotrichum gloeosporioides de diferentes fontes e localidades do Nordeste do Brasil. De cada isolado, foram feitas 15 culturas monoconidiais, sendo utilizada a técnica de microcultura para os estudos morfológicos dos apressórios havendo variaçäo no tamanho, forma e quantidade produzida entre os isolados. Um mesmo isolado mostrou apressórios levemente lobados e näo lobados, os quais variaram de castanho escuro a claro, ocasionalmente apresentando um septo, com um poro germinativo a cada célula. Em alguns casos, os apressórios germinaram e formaram apressórios secundários isolados ou em cadeias. Algumas vezes, eles formaram um tubo germinativo que deu origem a conídios de um modo fialídico. Estes resultados sugerem que a importância dos apressórios na natureza, näo é somente a sua capacidade de penetrar diretamente na superfície do hospedeiro, mas também, a sua