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Braz. j. microbiol ; 49(supl.1): 236-245, 2018. graf
Article in English | LILACS | ID: biblio-974331


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.

Plant Diseases/microbiology , Trichoderma/physiology , Sodium Chloride/metabolism , Populus/growth & development , Alkalies/metabolism , Alternaria/physiology , Antibiosis , Plant Diseases/prevention & control , Stress, Physiological , Trichoderma/genetics , Populus/microbiology , Seedlings/growth & development , Seedlings/microbiology
Braz. j. microbiol ; 45(4): 1263-1270, Oct.-Dec. 2014. ilus, tab
Article in English | LILACS | ID: lil-741276


Trichoderma spp is the cause of the green mold disease in mushroom cultivation production. Many disinfection treatments are commonly applied to lignocellulose substrates to prevent contamination. Mushroom growers are usually worried about the contaminations that may occur after these treatments during handling or spawning. The aim of this paper is to estimate the growth of the green mold Trichoderma sp on lignocellulose substrates after different disinfection treatments to know which of them is more effective to avoid contamination during spawning phase. Three different treatments were assayed: sterilization (121 ºC), immersion in hot water (60 and 80 ºC), and immersion in alkalinized water. Wheat straw, wheat seeds and Eucalyptus or Populus sawdust were used separately as substrates. After the disinfection treatments, bagged substrates were sprayed with 3 mL of suspension of conidia of Trichoderma sp (10(5) conidia/mL) and then separately spawned with Pleurotus ostreatus or Gymnopilus pampeanus. The growth of Trichoderma sp was evaluated based on a qualitative scale. Trichoderma sp could not grow on non-sterilized substrates. Immersions in hot water treatments and immersion in alkalinized water were also unfavorable treatments for its growth. Co- cultivation with mushrooms favored Trichoderma sp growth. Mushroom cultivation disinfection treatments of lignocellulose substrates influence on the growth of Trichoderma sp when contaminations occur during spawning phase. The immersion in hot water at 60 ºC for 30 min or in alkalinized water for 36 h, are treatments which better reduced the contaminations with Trichoderma sp during spawning phase for the cultivation of lignicolous species.

Agaricales/growth & development , Disinfection/methods , Trichoderma/growth & development , Alkalies/metabolism , Anti-Infective Agents/metabolism , Eucalyptus/microbiology , Hot Temperature , Populus/microbiology , Temperature , Trichoderma/drug effects , Trichoderma/radiation effects , Triticum/microbiology
Bol. micol ; 20: 57-61, dic. 2005. ilus
Article in Spanish | LILACS | ID: lil-476865


Entre septiembre a diciembre del 2004 el Instituto Forestal y el Servicio Agrícola y Ganadero, en investigaciones conjuntas de estrategias de control biológico para Tremex fuscicornis Fabr. (Hym. Siricidae), se profundizó en el conocimiento de la asociación simbiótica que presenta esta avispa xilófaga con un hongo. T. fuscicornis, es una avispa taladradora del álamo que presenta en sus glándulas micangiales el micelio y esporas de un hongo asociado, el cual inyectado al árbol en el momento de la oviposición, causa su posterior decaimiento y biodegradación. Desde hembras adultas se obtuvieron los micangios que contenían micelio y artrosporas del hongo, estos fueron macerados y posteriormente sembrados en agar papa dextrosa, desarrollándose colonias fúngicas que formaron artrosporas. El micelio de estas colonias fue inoculado en varios tipos de sustratos vegetales esterillizados, en especial en trozas de álamo, donde se desarrollaron basidiocarpos, los que taxonómicamente correspondieron a Cerrena unicolor (Bull.) Murr., primer reporte para Chile de este basidiomicete.

Since september to december 2004,Instituto Forestal and Servicio Agrícola y Ganadero, while investigating together the strategies for the biological control of Tremex fuscicornis Fabr. (Hym.Siricidae), acquired thorough knowledge about the symbiotic association existing between this xylophagus wasp with a fungus. T. fuscicornis is a horntail wasp attacking poplar trees and which has in its mycangial glands the mycelium and spores of an associated fungus that once injected in the tree at the oviposition stage, causes its further decayand rottenness. Mycangia containing mycelium and arthrospores of this fungi were obtained from adult females. They were macerated and then cultivated inpotato dextrose agar (PDA) what resulted in fungal colonies that further formed arthrospores. The myceliumof these colonies was inoculated into different kinds of sterilized vegetal substrates, mainly in pieces of poplartrees, where basidiocarpes were developed, taxonomically corresponding to Cerrena unicolor (Bull.) Murr., thisbeing the first report on this basidiomycete in Chile.

Fungi/isolation & purification , Fungi/classification , Insect Vectors , Insecta , Populus/microbiology , Chile