Morphogenesis in Trichoderma: Action spectrum of photoinduced sporulation

Summary An action spectrum for photoinduced sporulation (conidia formation) in Trichoderma viride is presented. The detectable quantum efficiency was between 350 and 550 nm with peaks near 380 and 440 nm with a minimum at about 400 nm. Essentially no sporulation occurred at 254 nm or from 525 to 1100 nm. The half maximum response is reached with 6.6·10^-10 Einstein/cm² at 447 nm.     

Changes in the lipid composition during the photo-induced conidiation ofTrichoderma viride

The sporulating and nonsporulating mycelium ofTrichoderma viride exhibited significant differences in the levels of triacylglycerols, sterol esters, fatty acids, gangliosides, phosphatidylethanolamine and sphingomyelin. Quantitative changes in the contents of polar and nonpolar lipids were observed also during the analyses of one-, two-, and three-day-old sporulation zones in colonies subjected to repeated photo-induction. These findings are similar to the changes observed during the differentiation of other species of fungi.     

Growth and conidiation ofTrichoderma viride are affected by non-steroidal antiinflammatory agents

Nonsteroid antiinflammatory agents (NSAIA's) (inhibitors of cyclooxygenase and lipoxygenase) of several structural series inhibited growth ofTrichoderma viride. The most potent growth inhibitors were indomethacin and its derivative repanidal which inhibited in the range of 0.1 mmol/L. The weakest inhibitors were acetylosalicylic acid and lysine salicylate which exerted only a weak effect at concentrations above 1 mmol/L. The inhibition of growth was accompanied by a stimulation of conidiation in the dark. A light pulse increased the efficiency of these drugs to stimulate the conidiation.Saccharomyces cerevisiae was as sensitive to NSAIA's asT. viride whileBotrytis cinerea was less sensitive. The results indicate that arachidonate metabolism may play a role in the growth of fungi and may participate also in the process of conidiation.     

Photoinduced conidiation inTrichoderma viride: A study with inhibitors

The influence of a number of inhibitors affecting respiration, oxidative phosphorylation, cAMP-phosphodiesterase and of the antioxidant 1,4-dithiothreitol on growth and photoinduced conidiation ofTrichoderma viride were investigated. In all cases, growth and conidiation were influenced to a different extent. Among the first group of compounds, antimycin A was the most potent inhibitor of conidiation while it influenced growth much less. A similar effect was obtained with 2,4-dinitrophenol and 1,4-dithiothreitol. On the other hand, 3-isobutyl-1-methylxanthine (inhibitor of phosphodiesterase) greatly stimulated the conidiation induced by light without affecting growth. It is concluded that the redox reactions represent a vital component of the differentiation pathway and that cAMP may play a regulatory role in this process.     

The effect of volatile and gaseous metabolites of swelling seeds on germination of fungal spores

Effects of volatile and gaseous metabolites of swelling seeds of pea, bean, wheat, corn, cucumber, tomato, lentil, carrot, red pepper and lettuce on germination of spores of five genera of fungi were found to depend rather on the fungal than on the plant genus. Germination of spores ofBotrytis cinerea, Mucor racemosus andTrichoderma viride was most severely inhibited. Spores ofVerticillium dahliae were less sensitive and germination of spores ofFusarium oxysporum was inhibited only in two cases. On the other hand, exudates of pea and bean stimulated germination of spores ofFusarium oxysporum. Also spores ofTrichoderma viride germinated better in an atmosphere enriched with exuded metabolites of swelling lettuce seeds. When carbon dioxide produced by the swelling seeds was absorbed in potassium hydroxide, spores ofTrichoderma viride andVerticillium dahliae did not germinate at all, the inhibitory effects of volatile and gaseous exudates on germination of spores ofMucor racemosus were accentuated, and also the percentage of germinated spores ofFusarium oxysporum decreased. Germination of spores ofBotrytis cinerea was not influenced. Absorption of volatile and gaseous metabolites in a solution of potassium permanganate decreased in most cases their inhibitory effects, particularly inBotrytis cinerea.     

Chloroplast activities of dark-imbibed and photoinduced spores of the fernOnoclea sensibilis

Summary Chloroplast activities of dark-imbibed (non-germinating) and photoinduced (germinating) spores of the sensitive fern,Onoclea sensibilis were compared to gain insight into the germination process. There were no changes in the number of chloroplasts or in the chlorophyll contents of the spore during dark-imbibition and during the early phase of germination. Levels of increase in the Chloroplast DNA content of dark-imbibed and photoinduced spores were nearly the same and were associated with autoradiographic incorporation of [³H]thymidine into the cytoplasm. However, incorporation of the label into the nucleus occurred only during photoinduction of spores. Analysis of Chloroplast and nuclear DNA contents by dot-blot hybridization with labeled gene-specific probes has confirmed that chloroplast DNA content of the spore increases during dark-imbibition and photoinduction, while increase in nuclear DNA occurs only in photoinduced spores. Chloroplasts isolated from dark-imbibed and photoinduced spores incorporated [³H]TTP into an acid-insoluble fraction identified as DNA. The results show that physiological activities of chloroplasts of dark-imbibed and photoinduced spores ofO. sensibilis are similar and support an exclusive role for nuclear DNA synthesis in spore germination.     

An action spectrum for photoinduced sporulation in the fungus Trichoderma viride

When a dark grown colony of Trichoderma viride is exposed towhite light for a short time, sporulation occurs only in thenarrow region of mycelia produced just prior to illumination.The action spectrum of this light effect was obtained for wavelengthsbelow 520 mµ using monochromatic irradiation of knownintensity having a band width of 10 mµ. The action spectrumshows 4 distinct peaks at 320, 380, 430 and 480 mµ. Thewavelengths at 320 and 380 mµ are most effective in photoinducedsporulation. The longer wavelengths, 430 and 480 mµ, areconsiderably less effective. The possibility that a carotenoid or a flavin compound may bea photoreceptor in this photoinduced sporulation is discussed. (Received January 4, 1969; )     

Trichoderma viride as a mycoparasite ofAspergillus spp.

Summary Trichoderma viride was found to be parasitic on three species of Aspergillus. The mycoparasitism was characterized by frequent coiling, penetration and hyphal growth of the parasite inside the conidiophores of Aspergillus. The volatile and non-volatile metabolites ofT. viride, more or less, inhibited radial growth of all the testAspergillus spp.     

Production of humic acids from oil palm empty fruit bunch by submerged fermentation with Trichoderma viride: Cellulosic substrates and nitrogen sources

The novelty of this study was to produce humic acids by submerged fermentation of empty fruit bunch (EFB) with Trichoderma viride and to investigate the effects of the cellulosic substrates and the organic sources of nitrogen on the biotechnological production of these acids. The results obtained indicate the potential application of EFB, a waste of oil palm processing, for humic acids production. Because EFB contains cellulose, hemicellulose and lignin, fermentations were also performed using these polymers as carbon sources, separately or in combination. After 120 h of fermentation, significant production of humic acids was observed only in cultures containing either EFB or a mixture of the three polymers. Use of either potato peptone or yeast extract as a nitrogen source yielded nearly identical patterns of fungal growth and production of humic acids. The data obtained from microscopic imaging of T. viride growth and sporulation in EFB, coupled with the determined rates of production of humic acids indicated that the production of these acids is related to T. viride sporulation. © 2013 American Institute of Chemical Engineers Biotechnol. Prog., 29:631–637, 2013     

Biocontrol potential of Trichoderma species against mango malformation pathogens

Malformation disease of Mango (Mangifera indica L.) caused by Fusarium moniliforme var. subglutinans is one of the most destructive diseases, which is a major production constraint in the mango-growing regions of India. In this study, The bioagents Trichoderma viride (Tr1), Trichoderma virens (Tr2) and Trichoderma harzianum (Tr3) were evaluated in culture with the pathogens to monitor the antagonistic effect and their volatile compound and culture filtrates (non-volatile compound). It was found that all the three isolates of bioagents significantly checked the growth of F. moniliforme var. subglutinans. In dual culture, the best result was obtained with T. harzianum followed by T. virens and T. viride. A similar result was also observed in the case of culture filtrates ofTrichoderma spp. The results clearly showed that inhibition of the growth of the fusaria isolates by T. harzianum was significantly superior to T. viride andT.virens. In case of antifungal activity of volatile compounds released by Trichoderma isolates, it was also observed that T. virens was more superior to T.harzianum and T. viride.     

Effect of volatile substances fromOriganum majorana andOcimum basilicum on spore respiration and germination of some soil fungi

Oxygen uptake by the spores ofFusarium moniliforme, F. oxysporum, F. semitectum, F. solani, Mucor racemosus andTrichoderma viride was increased in the presence of volatile substances extracted, fromOriganum majorana andOcimum basilicum. This increase was greater in the presence of volatile substances fromO. basilicum thanO. majorana, except in the case ofF. semitectum where the reverse was true. A drop in the RQ of all the germinating spores was observed in the presence of these substances. Volatile substances fromO. majorana reduced the spore germination ofM. racemosus whereas the spores ofT. viride were stimulated to germinate. Volatile substances fromO. basilicum stimulated the spore germination ofM. racemosus whereasT. viride spores were not affected.     

Cellulase activity of higher fungi

The method of liquefaction of gel from cross-linked cellulose was used for monitoring the cellulolytic activity of 114 cultures of higher fungi, 47 of which belonged toPleurotus ostreatus. All cultures ofP. ostreatus had a low activity. The highest cellulase activity, manifested byPiptoporus betulinus, was comparable with that ofTrichoderma viride QM6a.     

Effects of antibiotics on the life cycle ofNeurospora crassa

Some antibiotics and synthetic inhibitors affect, in several ways, the life cycle ofNeurospora crassa (germination of conidia → myceliar growth → formation of conidia). Bikaverin, cyanein, scopathrioin and phenethyl alcohol retard the germination of conidia, without inhibiting it completely. 5-Fluorouracil, ramihyphin A and zygosporin A (cytoohalasin D) do not inhibit the germination. Bikaverin brings about a thickening of the hyphae of growing mycelium. Ramihyphin A, cyanein, scopathricin and zygosporin A stimulate the ramification of hyphae while 5-fluorouracil and phenethyl alcohol do not affect the myceliar morphology apart from their inhibitory effect on growth. Actinomycin D, 5-fluorouracil, cycloheximide, ramihyphin A and partially also sodium iodoacetate inhibit to a different degree the photoinduced formation of conidia. The inhibition by 5-fluorouracil is very conspicuous when the agent is present during the photoinduction but considerably weaker when it is applied 2 h after the photoinduction.     

Inhibition of photo-inducedTrichoderma viride conidiation by inhibitors of RNA synthesis

The photo-induced conidiation ofTrichoderma viride is suppressed by ethidium bromide, acriflavin, lomofungin and 8-quinolinol at concentrations which do not inhibit the colony growth of this deuteromycete.     

Biological control of a soil-borne pythium infection by seed inoculation

Summary 1. A three-fold effect was produced on white mustard seedlings grown in soil infected withPythium sp. Seed germination, the number of healthy plants which survived and the fresh weight of the shoots were reduced.2. Disease symptoms were controlled to some extent by dusting the seeds with spores of some common soil saprophytes includingTrichoderma viride, Penicillium nigricans, P. jrequentans andP. godlewskii.3. Of three strains ofTrichoderma viride which were tested for antagonism toPythium sp., a gliotoxin-producing strain was more effective in controlling the disease than a viridin-producing strain and an antibiotically inactive strain gave least protection to the seedlings.4. The disease symptoms were less severe in soil treated with acid or calcium hydroxide. Inoculation of the seeds withT. viride gave further control of the disease in soil treated with calcium hydroxide but not in acidified soils. These results are discussed in relation to the production of gliotoxin byT. viride.     

Laboratory-scale biosynthesis ofTrichoderma mycolytic enzymes for protoplast release fromCochliobolus lunatus

Summary Microorganism useful for the induction of enzymes lytic towards walls of filamentous fungusCochliobolus lunatus were studies. Production of specificTrichoderma viride mycolytic enzymes was studied in a laboratory fermentor. The product with high chitinase and relatively low protease activity gave better yields ofC. lunatus protoplasts than commercial Novozym 234.     

Effect of nitrogen source on aroma production by Trichoderma viride

Summary The effect of nitrogen source on the aroma production of a strain of Trichoderma viride was investigated. The compound giving the culture its characteristic coconut-like aroma was identified as 6-pentyl--pyrone. Variation of the nitrogen source affected the quantity of the lactone produced but did not cause a significant difference in the aroma of the culture. The lactone formation was also affected by the method of cultivation, and sporulation was not essential for its formation.     

SCP production by Chaetomium cellulolyticum,a new thermotolerant cellulolytic fungus

Chaetomium cellulolyticum, a newly isolated cellulolytic fungus, showed 50–100% faster growth rates and over 80% more final biomass-protein formation than Trichoderma viride, a well-known high cellulase-producing cellulolytic organism, when cultivated on Solka-floc (a purified, predominantly amorphorous form of cellulose) or partially delignified sawdust (consisting of a mixture of hardwoods) as the sole-carbon source in the fermentation media. However, in both cases, T. viride produced much higher quantities of free cellulases at faster rates and also degraded more substrate than C. cellulolyticum. It is concluded that the synthesis mechanisms and/or the nature of the cellulase complexes of the two types of organisms are quite different such that C. cellulolyticum is more optimal for single-cell protein (SCP) production, while T. viride is more optimal for the production of extracellular cellulases. It was also found that the amino acid composition of C. cellulolyticum is generally better than that of T. viride and compares favorably with those of the FAO reference protein, alfalfa, and soya meal. In addition, preliminary feeding trials on rats have shown no adverse effects of the SCP produced by C. cellulolyticum fermentations.     

Effect of rhizosphere fungi on seed germination

Summary The effect of culture filtrates of some common rhizosphere fungi on the seed germination ofDichanthium annulatum, Bothriochloa pertusa andSetaria glauca was studied. Surface sterilized seeds were soaked in the fungal culture filtrates for 24 hours and after several washings in distilled water transferred to moist filter paper in Petri dishes and the percentage germination recorded. No significant inhibition or stimulation of germination was noticed in any of the treatments. The only exception wasTrichoderma viride which inhibited the germination ofD. annulatum seeds to some extent.     

产褪黑素绿色木霉工程菌的构建及生理特性分析

【背景】褪黑素(melatonin)是动植物内广泛存在的一种小分子生物胺类物质,在促进生物生长和提高环境耐受性等方面发挥重要作用。木霉(Trichoderma)既是重要的生防菌株也是高效的工业产品生产菌株,能够合成丰富的代谢产物。【目的】针对目前木霉菌株中还未发现褪黑素合成的问题,构建具有褪黑素合成能力的绿色木霉(Trichoderma viride)工程菌,并对其生理特性进行研究。【方法】在绿色木霉Tv-1511中异源表达了来源于人基因组的芳烷基胺N-乙酰转移酶(aralkylamineN-acetyltransferase,AANAT)编码基因hAANAT和乙酰复合胺-O-甲基转移酶(acetylserotonin-O-methyltransferase,ASMT)编码基因hASMT,高效液相色谱法(highperformance liquid chromatography, HPLC)检测了木霉工程菌合成褪黑素的产量,并利用生化方法检测了工程菌的生长、抗逆及对植物的促生抗病能力。【结果】获得了具有褪黑素合成能力的绿色木霉工程菌,此株工程菌具有更好的生长和产孢特性、更强的逆境胁迫耐...