Growth of Schizolobium parahyba var. amazonicum seedlings by strains of Trichoderma spp. under boron rates

Brazil has many important native species, which includes Schizolobium parahyba var. amazonicum (Huber ex Ducke) Barneby, however, the growth of this species is inhibited in soils with low boron contents, or excess boron, which causes phytotoxicity. Applications of strains of Trichoderma spp. increase the plants' tolerance to abiotic stresses, including tolerance to low or excess levels of nutrients such as boron (B). Thus, the objective of this work was to evaluate plant development and the effect of strains of Trichoderma spp. in Schizolobium parahyba var. amazonicum seedlings grown under different boron rates. A randomized block experimental design was used, with a 4×5 factorial scheme, consisting of 4 strains of Trichoderma spp. and 5 B rates (0, 0.5, 1.0, 1.5, and 2.0 mg dm-3), with seven replications, in greenhouse. Plant height, stem diameter, fresh and dry mass, leaf, stem and total were evaluated at 120 days after emergence. The stains of Trichoderma spp. and B rates presented significant interaction for all evaluated variables, decreasing phytotoxicity. The strain IBLF006WP (T. harzianum) showed a higher capacity of increasing the plants' tolerance to boron, followed by URM5911 (T. asperellum). However, the beneficial effect of increasing this tolerance with the application of these strains is only feasible for soils with high contents of this micronutrient in the soil.

Antagonistic microorganisms and nitrogen fertilization in control of tomato southern blight

The present study assessed the efficacy of formulated biocontrol agents and nitrogen fertilization on southern blight control. Antagonism test in vitro was performed to assess the inhibitory activity of Bacillus methylotrophicus and Trichoderma asperellum against the growth of Sclerotium rolfsii. Tomato seedlings were transplanted into the substrate added with ammonium nitrate doses and inoculated with the formulated biocontrol agents Ônix (B. methylotrophicus) or Quality (T. asperellum). Subsequently, seedlings were inoculated with S. rolfsii. Plant mortality, shoot and root weight were assessed 11 days after the last inoculation. Agents had effective inhibitory activity against S. rolfsii; thus, they could reduce southern blight severity when combined with ammonium nitrate. However, plant mortality was not reduced by them.(AU)

Antagonistic activity of volatile metabolites from Trichoderma asperellum / 生物工程学报

Trichoderma spp. is a kind of filamentous fungi with important biocontrol value. Twelve strains of Trichoderma spp. were isolated from the soils of different types of crops in Shaoxing, Zhejiang and Foshan, Guangdong. The antagonistic resistance to Fusarium oxysporum was compared by plate confrontation test. The further analysis of volatile secondary metabolites for two strains were carried out using HS-SPME-GC-MS analysis. The results showed that T. asperellum ZJSX5003 and GDFS1009 had fast growth ability, and the inhibition effects on F. oxysporum were 73% and 74% respectively. Six identical volatile metabolites were detected as follows 2-Methyl-1-propanol, 3-Methyl-1-butanol, 3-Methyl-3-buten-1-ol, Acetyl methyl carbinol, Butane-2,3-diol and 6-n-pentyl-2H-pyran-2-one (6-PAP). Among them, 6-PAP was validated to have a higher inhibitory effect on F. oxysporum in vitro. This study will provide basis for the development of biocontrol agents with metabolites of Trichoderma, such as 6-PAP.

Biocontrol potential of saline- or alkaline-tolerant Trichoderma asperellum mutants against three pathogenic fungi under saline or alkaline stress conditions

ABSTRACT Salinity and alkalinity are major abiotic stresses that limit growth and development of poplar. We investigated biocontrol potential of saline- and alkaline-tolerant mutants of Trichoderma asperellum to mediate the effects of salinity or alkalinity stresses on Populus davidiana × P. alba var. pyramidalis (PdPap poplar) seedlings. A T-DNA insertion mutant library of T. asperellum was constructed using an Agrobacterium tumefaciens mediated transformation system; this process yielded sixty five positive transformants (T1-T65). The salinity tolerant mutant, T59, grew in Potato Dextrose Agar (PDA) containing up to 10% (1709.40 mM) NaCl. Under NaCl-rich conditions, T59 was most effective in inhibiting Alternaria alternata (52.00%). The alkalinity tolerant mutants, T3 and T5, grew in PDA containing up to 0.4% (47.62 mM) NaHCO3. The ability of the T3 and T5 mutants to inhibit Fusarium oxysporum declined as NaHCO3 concentrations increased. NaHCO3 tolerance of the PdPap seedlings improved following treatment with the spores of the WT, T3, and T5 strains. The salinity tolerant mutant (T59) and two alkalinity tolerant mutants (T3 and T5) generated in this study can be applied to decrease the incidence of pathogenic fungi infection under saline or alkaline stress.

Biocontrol potential of saline- or alkaline-tolerant Trichoderma asperellum mutants against three pathogenic fungi under saline or alkaline stress conditions

ABSTRACT Salinity and alkalinity are major abiotic stresses that limit growth and development of poplar. We investigated biocontrol potential of saline- and alkaline-tolerant mutants of Trichoderma asperellum to mediate the effects of salinity or alkalinity stresses on Populus davidiana × P. alba var. pyramidalis (PdPap poplar) seedlings. A T-DNA insertion mutant library of T. asperellum was constructed using an Agrobacterium tumefaciens mediated transformation system; this process yielded sixty five positive transformants (T1T65). The salinity tolerant mutant, T59, grew in Potato Dextrose Agar (PDA) containing up to 10% (1709.40 mM) NaCl. Under NaCl-rich conditions, T59 was most effective in inhibiting Alternaria alternata (52.00%). The alkalinity tolerant mutants, T3 and T5, grew in PDA containing up to 0.4% (47.62 mM) NaHCO3. The ability of the T3 and T5 mutants to inhibit Fusarium oxysporum declined as NaHCO3 concentrations increased. NaHCO3 tolerance of the PdPap seedlings improved following treatment with the spores of the WT, T3, and T5 strains. The salinity tolerant mutant (T59) and two alkalinity tolerant mutants (T3 and T5) generated in this study can be applied to decrease the incidence of pathogenic fungi infection under saline or alkaline stress.

Non-Aspergillus fungal rhinosinusitis at a tertiary care hospital and the first report of human infection by Trichoderma asperellum

We describe 27 cases of fungal rhinosinusitis, which were caused by agents other than Aspergillus, diagnosed at our institution during a 24-year period. Particular focus was on defining the causal fungi and the predisposing factors. Fungal cultures were obtained from 20 cases and there was no growth in seven cases. Classification of mycotic disease of the nose and paranasal sinuses as invasive and noninvasive is based on clinical, radiological, and histopathological factors. The most common pathogens were Histoplasma capsulatum (n=4), Scedosporium apiospermum (n=2), Alternaria alternata (n=2), Schizophyllum commune (n=2), Pseudallescheria boydii (n=1), Penicillium sp. (n=1), Lichtheimia (Absidia) corymbifera (n=1), Xylaria enteroleuca (n=1), Trichoderma asperellum (n=1), T. harzianum (n=1), T. viride (n=1), Fusarium solani (n=1), Cladosporium sp. (n=1), and Cryptococcus neoformans (n=1). From the ones that revealed no growth, four were classified as hyalohyphomycosis and three were mucormycosis by the histopathological findings. In addition, we describe the first welldocumented case of rhinosinusitis and human infection by T. asperellum.

A novel putative non-ligninolytic dehalogenase activity for 3-chloropropionic acid (3CP) utilization by Trichoderma asperellum strain SD1

Aims: Trichoderma asperellum strain SD1 grows on 3-chloropropionic acid (3CP), a β-haloalkanoic acid, and produces a putative extracellular dehalogenase that can degrade this acid. Here we further characterized the fungal enzyme system responsible for biodegradation of 3CP. Methodology and results: The primary qualification of the ligninolytic potential in T. asperellum strain SD1 was performed using guaiacol oxidation. When strain SD1 was grown in liquid minimal medium with the presence of 3CP as the sole carbon source, no lignin peroxidase, manganese peroxidase, or laccase activity was detected. The ligninolytic condition was achieved only in the presence of glucose or when guaiacol was present as an inducer. Under nonligninolytic conditions, 3CP was utilized by strain SD1. Therefore, 3CP was utilized under ligninolytic conditions as well as under non-ligninolytic conditions, suggesting that extracellular peroxidases and laccase are not involved in the degradation of 3CP by T. asperellum strain SD1. Conclusion, significance, and Impact of study: Very few studies have explained the degradation of β-chloro– substituted haloalkanoic acids such as 3CP by dehalogenases. This is the first report to identify a novel putative β- haloacid dehalogenase that degrades 3CP under ligninolytic and non-ligninolytic conditions. T. asperellum strain SD1, thus has the potential in the development of dehalogenating enzymes for industrial biocatalytic processes, in future.

Importancia del aislamiento y del rango de concentración de conidias en el efecto de Trichoderma asperellum sobre el crecimiento de plántulas de Solanum lycopersicum L / Importance of strain and concentration range of conidia in the effect of Trichoderma asperellum on the growth of tomato seedlings Solanum lycopersicum L

El crecimiento longitudinal de tallos y raíces fue investigado en plántulas de tomate (Solanum lycopersicum L), luego de la aplicación de cuatro aislamientos de Trichoderma asperellum: T25, T46, T84 y T109. Sólo la aplicación del aislamiento T109 causó un incremento significativo (p ≤ 0,05) del crecimiento longitudinal de tallos y raíces. El peso seco de las plántulas también fue estimulado desde la primera semana luego de la aplicación de T109. El crecimiento fue estimulado significativamente (p ≤ 0,05) por la aplicación de 105 y 106 conidias/ml, pero no lo fue por la aplicación de 104, 107 y 108 conidias/ml. Estos resultados indican que el estímulo del crecimiento producido por T. asperellum en plántulas de tomate, sólo ocurre con aislamientos particulares y un rangos de concentración específicos.

Longitudinal growth of shoot and roots was investigated in tomato seedlings (Solanum lycopersicum L) after application of four isolates of T. asperellum (T25, T46, T84 y T109). Only the isolate T109 caused a significant (p ≤ 0.05) increase of longitudinal growth of roots and shoots, and dry weight of seedlings was also stimulated from the first week after T109 application. The growth was significantly (p ≤ 0.05) stimulated by 105 and 106 conidia/ml, but it was not by 104, 107 and 108 conidia/ml. These results indicate that growth stimulus caused by T. asperellum in tomato seedlings, occurs only with specific isolates and at a specific concentration ranges.

Trichoderma asperellum Chi42 Genes Encode Chitinase

Four Trichoderma strains (CH2, SH16, PQ34, and TN42) were isolated from soil samples collected from Quang Tri and Thua Thien Hue provinces in Vietnam. The strains exhibited high chitinolytic secretion. Strain PQ34 formed the largest zone of chitinase-mediated clearance (> 4 cm in diameter) in agar containing 1% (w/v) colloidal chitin. Analysis of the internal transcribed spacer regions of these strains indicated that they were Trichoderma asperellum. The molecular weights of the chitinases were approximately 42 kDa. Chitinase genes (chi42) of T. asperellum strains TN42, CH2, SH16, and PQ34 were 98~99% homologous to the ech42 gene of T. harzianum CB-Pin-01 (accession No. DQ166036). The deduced amino acid sequences of both T. asperellum strains SH16 and TN42 shared 100% similarity.