Light-independent conidiation in Trichoderma spp.: a novel approach to microcycle conidiation

Khurana, Nitika; Saxena, Rajendra Kumar; Gupta, Rani; Kuhad, Ramesh Chander

doi:10.1007/bf00383079

Cited by 8 publications

(6 citation statements)

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“…The entomopathogenic fungi B. bassiana and M. acridum have been developed as control agents against insects [13, 14, 15, 30]. In addition, several Trichoderma spp.…”

Section: Biological Significance and Application Of MCmentioning

confidence: 99%

Microcyle Conidiation in Filamentous Fungi

2014

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The typical life cycle of filamentous fungi commonly involves asexual sporulation after vegetative growth in response to environmental factors. The production of asexual spores is critical in the life cycle of most filamentous fungi. Normally, conidia are produced from vegetative hyphae (termed mycelia). However, fungal species subjected to stress conditions exhibit an extremely simplified asexual life cycle, in which the conidia that germinate directly generate further conidia, without forming mycelia. This phenomenon has been termed as microcycle conidiation, and to date has been reported in more than 100 fungal species. In this review, first, we present the morphological properties of fungi during microcycle conidiation, and divide microcycle conidiation into four simple categories, even though fungal species exhibit a wide variety of morphological differences during microcycle conidiogenesis. Second, we describe the factors that influence microcycle conidiation in various fungal species, and present recent genetic studies that have identified the genes responsible for this process. Finally, we discuss the biological meaning and application of microcycle conidiation.

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“…The entomopathogenic fungi B. bassiana and M. acridum have been developed as control agents against insects [13, 14, 15, 30]. In addition, several Trichoderma spp.…”

Section: Biological Significance and Application Of MCmentioning

confidence: 99%

Microcyle Conidiation in Filamentous Fungi

2014

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“…(Saxena et al ., 1992) and under light-independent conditions in Trichoderma spp. (Khurana et al ., 1993). Although some work has been done on the induction and on the ultrastructure, the internal events regulating microcycle differentiation are still not fully understood (Maheshwari, 1991).…”

Section: Introductionmentioning

confidence: 99%

Polyamines as Modulators of Microcycle Conidiation in Aspergillus Flavus

et al. 1996

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Since polyamines (PAS) play a potential role in the regulation of growth and developmental processes in a wide variety of organisms, we have examined the influence of the PAS putrescine (Put) and spermidine (Spd) and the PA biosynthetic inhibitors a-difluoromethylornithine (DFMO), adif luoromethylarginine (DFMA), methylglyoxal bis-(guanylhydrazone) (MGBG) and cyclohexylamine (CHA), singly and in combinations on microcycle conidiation (MC) in Aspergillus flaws. The exogenous application of the diamine Put (concentrations ranging from 01 to 5 mM) caused a sharp decline of MC in a dose-dependent fashion, but induced vegetative growth. However, the triamine Spd (01-5 mM) had a minimal effect on M C and induced a shift from M C to normal conidiation. PA inhibitors, especially DFMO, MGBG and CHA, produced greater inhibition of MC and complete inhibition of M C was observed at 5 mM of these inhibitors. DFMA even at 5 mM had only a weak inhibitory effect on MC. DFMO also inhibited conidial germination and germ tube growth. MGBG and CHA, while having an inhibitory effect on MC, induced vegetative growth. The inhibitory effect of PA inhibitors was partially reversed by exogenous Put or Spd, with Spd being more effective than Put. The analysis of free PA levels during various phases of M C revealed that undifferentiated spores contained a high Put/Spd ratio and there was a dramatic decrease in Put/Spd ratio before and during microcycle conidiophore maturity. The change in spermine titres could not be detected. These observations imply that Put is essential for vegetative growth, while S p d is involved in MC, and that a low Put/Spd ratio seems to be important for spore differentiation to MC.

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“…The developmental patterns differ from those predicted by simple cooption of a preexisting mode of environmental induction for rapid conidiation. Most ascomycete fungi under stressful physical and/or chemical conditions largely or completely eliminate hyphal growth and undergo microcycle conidiation producing many conidia 22 . In contrast, our derived populations show both rapid hyphal growth and rapid conidiation.…”

Section: Discussionmentioning

confidence: 99%

Developmental evolution facilitates rapid adaptation

Lin

Kazlauskas

Travisano

2017

Sci Rep

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Developmental evolution has frequently been identified as a mode for rapid adaptation, but direct observations of the selective benefits and associated mechanisms of developmental evolution are necessarily challenging to obtain. Here we show rapid evolution of greatly increased rates of dispersal by developmental changes when populations experience stringent selection. Replicate populations of the filamentous fungus Trichoderma citrinoviride underwent 85 serial transfers, under conditions initially favoring growth but not dispersal. T. citrinoviride populations shifted away from multicellular growth toward increased dispersal by producing one thousand times more single-celled asexual conidial spores, three times sooner than the ancestral genotype. Conidia of selected lines also germinated fifty percent faster. Gene expression changed substantially between the ancestral and selected fungi, especially for spore production and growth, demonstrating rapid evolution of tight regulatory control for down-regulation of growth and up-regulation of conidia production between 18 and 24 hours of growth. These changes involved both developmentally fixed and plastic changes in gene expression, showing that complex developmental changes can serve as a mechanism for rapid adaptation.

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Light-independent conidiation in Trichoderma spp.: a novel approach to microcycle conidiation

Cited by 8 publications

References 8 publications

Microcyle Conidiation in Filamentous Fungi

Microcyle Conidiation in Filamentous Fungi

Polyamines as Modulators of Microcycle Conidiation in Aspergillus Flavus

Developmental evolution facilitates rapid adaptation

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