RESUMEN
IMPORTANCE: In addition to being considered a biocontrol agent, the fungus Trichoderma atroviride is a relevant model for studying mechanisms of response to injury conserved in plants and animals that opens a new landscape in relation to regeneration and cell differentiation mechanisms. Here, we reveal the co-functionality of a lipoxygenase and a patatin-like phospholipase co-expressed in response to wounding in fungi. This pair of enzymes produces oxidized lipids that can function as signaling molecules or oxidative stress signals that, in ascomycetes, induce asexual development. Furthermore, we determined that both genes participate in the regulation of the synthesis of 13-HODE and the establishment of the physiological responses necessary for the formation of reproductive aerial mycelium ultimately leading to asexual development. Our results suggest an injury-induced pathway to produce oxylipins and uncovered physiological mechanisms regulated by LOX1 and PLP1 to induce conidiation, opening new hypotheses for the novo regeneration mechanisms of filamentous fungi.
Asunto(s)
Trichoderma , Animales , Trichoderma/genética , Transducción de Señal , Micelio , Reproducción , Estrés Oxidativo , Regulación Fúngica de la Expresión Génica , Esporas Fúngicas/metabolismoRESUMEN
A Gram-positive bacterium, designated CMU-AB225T, was isolated from rhizosphere soil of an oil palm (Elaeis guineensis). The strain exhibited a blue aerial spore mass and a light cream to moderate yellow substrate mycelium and formed chains of spiny spores. Whole-cell hydrolysates consisted of ll-diaminopimelic acid, glucose, ribose, mannose and galactose. The predominant menaquinones were MK-9(H6), MK-9(H8) and MK-9(H4). The polar lipids profile contained diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol, phosphatidylinositol-mannoside, four unidentified lipids, two unidentified aminolipids and an unidentified glycolipid. The major cellular fatty acids (>10â%) were iso-C16â:â0, C16â:â0, anteiso-C15â:â0 and iso-C15â:â0. The G+C content of genomic DNA was 69.7 mol%. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain CMU-AB225T was a member of the genus Streptomyces and formed a distinct phyletic line which was most closely related to Streptomyces koyangensis JCM 14915T, Streptomyces misionensis JCM 4497T and Streptomyces aurantiogriseus JCM 4346T. Multilocus sequence analysis (MLSA) using five housekeeping genes (atpD, gyrB, recA, rpoB and trpB) showed that the MLSA distances of strain CMU-AB225T to phylogenetically related species were greater than the 0.007 threshold. Moreover, the low values of DNA-DNA relatedness and phenotypic differences, especially a blue aerial mycelium, enabled strain CMU-AB225T to be distinguished from its closely related species. It is thus proposed that strain CMU-AB225T represents a novel species, namely Streptomyces venetus sp. nov. The type strain is CMU-AB225T (=JCM 31290T=TBRC 2001T).
Asunto(s)
Arecaceae/microbiología , Filogenia , Rizosfera , Microbiología del Suelo , Streptomyces/clasificación , Técnicas de Tipificación Bacteriana , Composición de Base , ADN Bacteriano/genética , Ácido Diaminopimélico/química , Ácidos Grasos/química , Genes Bacterianos , Glucolípidos/química , Fosfolípidos/química , Pigmentación , ARN Ribosómico 16S/genética , Análisis de Secuencia de ADN , Streptomyces/genética , Streptomyces/aislamiento & purificación , Tailandia , Vitamina K 2/análogos & derivados , Vitamina K 2/químicaRESUMEN
The role of the aerial mycelium of the fungus Fusarium solani in the biodegradation of n-pentane was evaluated in a continuous fungal bioreactor (FB) to determine the contribution of the aerial (hyphae) and non-aerial (monolayer) fungal biomass. The experimental results showed that although the aerial biomass fraction represented only 25.9(±3)% on a dry weight basis, it was responsible for 71.6(±4)% of n-pentane removal. The FB attained a maximum elimination capacity (ECmax) of 680(±30) g m(-3) h(-1) in the presence of fungal hyphae (which supported an interfacial area of 5.5(±1.5) × 10(6) m(2) m(-3)). In addition, a mathematical model capable of describing n-pentane biodegradation by the filamentous fungus was also developed and validated against the experimental data. This model successfully predicted the influence of the aerial biomass fraction and its partition coefficient on the n-pentane removal, with EC decreasing from 680(±30) g m(-3) h(-1) to values of 200(±14) g m(-3) h(-1) when the dimensionless partition coefficient increased from 0.21(±0.09) with aerial biomass to 0.88(±0.06) without aerial biomass.
Asunto(s)
Reactores Biológicos/microbiología , Fusarium/crecimiento & desarrollo , Modelos Teóricos , Micelio/crecimiento & desarrollo , Pentanos/análisis , Compuestos Orgánicos Volátiles/análisis , Biodegradación Ambiental , Biomasa , Fusarium/metabolismo , Interacciones Hidrofóbicas e Hidrofílicas , Micelio/metabolismoRESUMEN
Actinomycetes produce a number of useful secondary metabolites with antibiotic, insecticidal and herbicidal activities. Actinomycetes are prokaryotes, but the morphology of their mycelia is similar to that of fungi. Our research into the regulators of aerial mycelium-differentiation and spore germination and the surrounding research is discussed.
RESUMEN
1997 Fred Griffith Review Lecture(Delivered at the 138th Meeting of the Society for General Microbiology, 2 September 1977).