Benomyl-tolerant microfungi associated with mycorrhizae of black spruce

1988 ◽  
Vol 66 (3) ◽  
pp. 553-557 ◽  
Author(s):  
Richard C. Summerbell

The population of microfungi associated with mycorrhizal root tips of Picea mariana was sampled to determine which species were able to grow on isolation medium amended with the selective fungicide benomyl. Benomyl significantly favoured the isolation of soil Zygomycetes, including members of the genera Mortierella and Micromucor, but inhibited the growth of most soil fungi of ascomycetous affinities. Since some of the inhibited taxa, e.g., Trichoderma spp., are potential inhibitors of mycorrhiza formation in vivo, these results may explain instances where the application of benomyl has been shown to increase mycorrhiza formation in the field.

2016 ◽  
Vol 46 (5) ◽  
pp. 666-673 ◽  
Author(s):  
Philippe St. Martin ◽  
Azim U. Mallik

Naturally regenerating and planted black spruce (Picea mariana (Mill.) B.S.P.) in post-fire landscapes in eastern Canada often exhibit stunted growth in the presence of ericaceous shrubs such as Kalmia angustifolia L. After a period of stunted growth, some seedlings experience a growth release, exhibiting growth rates closer to normally growing seedlings. We hypothesized that an increase in colonization of root tips by ectomycorrhizal (ECM) fungi is responsible for this release and that the percentage of root tips colonized by ECM fungi would be higher on seedlings that had a released or normally growing neighbour within close proximity. We quantified ECM fungi diversity and abundance from 255 soil cores from stunted, released, and normally growing black spruce seedlings sampled in two Kalmia-dominated sites in Newfoundland. Growth and microsite characteristics around each seedling were also measured. We found that normal and released seedlings had significantly higher proportions of ECM fungi root tips than stunted seedlings, supporting our final hypothesis; however, there was no significant difference in distance between neighbours. Soil chemical properties are thought to inhibit the vegetative spread of ECM fungi species in this particular system and are identified as an important topic for further research.


2020 ◽  
Vol 55 (1) ◽  
pp. 27-34
Author(s):  
G. Zadehdabagh ◽  
K. Karimi ◽  
M. Rezabaigi ◽  
F. Ajamgard

The northern of Khuzestan province in Iran is mainly considered as one of the major areas of miniature rose production. Blossom blight caused by Botrytis cinerea has recently become a serious limiting factor in rose production in pre and post-harvest. In current study, an attempt was made to evaluate the inhibitory potential of some local Trichoderma spp. strains against B. cinerea under in vitro and in vivo conditions. The in vitro results showed that all Trichoderma spp. strains were significantly able to reduce the mycelial growth of the pathogen in dual culture, volatile and non-volatile compounds tests compared with control, with superiority of T. atroviride Tsafi than others. Under in vivo condition, the selected strain of T. atroviride Tsafi had much better performance than T. harzianum IRAN 523C in reduction of disease severity compared with the untreated control. Overall, the findings of this study showed that the application of Trichoderma-based biocontrol agents such as T. atroviride Tsafi can be effective to protect cut rose flowers against blossom blight.


Botany ◽  
2011 ◽  
Vol 89 (2) ◽  
pp. 133-140 ◽  
Author(s):  
Marios Viktora ◽  
Rodney A. Savidge ◽  
Om P. Rajora

Black spruce (Picea mariana) reproduces sexually from seeds and asexually by layering. There is a prevalent concept that clonal reproduction maintains populations of this species in the subarctic and arctic regions. We used microsatellite DNA markers of the nuclear genome to investigate the genetic structure of montane and subalpine black spruce populations from the Western Yukon Plateau in relation to this concept. Sixty individual trees at a minimum distance of 4 m from each other were sampled from each of four populations and individual trees were genotyped for eight microsatellite loci. Each of the 60 individuals from three montane pure black spruce populations growing on flat terrain at relatively low elevations had unique multilocus genotypes, indicating an absence of clonal structure in those populations. However, in an anthropologically undisturbed climax white spruce-dominated subalpine black spruce population on a northwest slope near Mount Nansen, the majority of the sampled individuals belonged to eight genetically distinct clones (genets). Clone size differed by altitude, the dominant genet being nearest the timberline–tundra ecotone. The results indicate that black spruce reproduction is variable and adaptive, being primarily sexual in flat-terrain montane populations previously subjected to fire disturbance, but mixed vegetative–sexual in the anthropogenically undisturbed subalpine population. This study is the first to employ molecular markers a priori to examine the mode of reproduction in natural black spruce populations.


2014 ◽  
Vol 40 (2) ◽  
pp. 141-146 ◽  
Author(s):  
Zayame Vegette Pinto ◽  
Matheus Aparecido Pereira Cipriano ◽  
Amaury da Silva dos Santos ◽  
Ludwig Heinrich Pfenning ◽  
Flávia Rodrigues Alves Patrício

Bottom rot, caused by Rhizoctonia solani AG 1-IB, is an important disease affecting lettuce in Brazil, where its biological control with Trichoderma was not developed yet. The present study was carried out with the aim of selecting Trichoderma isolates to be used in the control of lettuce bottom rot. Forty-six Trichoderma isolates, obtained with baits containing mycelia of the pathogen, were evaluated in experiments carried out in vitro and in vivo in a greenhouse in two steps. In the laboratory, the isolates were evaluated for their capabilities of parasitizing and producing toxic metabolic substances that could inhibit the pathogen mycelial growth. In the first step of the in vivo experiments, the number and the dry weight of lettuce seedlings of the cultivar White Boston were evaluated. In the second step, 12 isolates that were efficient in the first step and showed rapid growth and abundant sporulation in the laboratory were tested for their capability of controlling bottom rot in two repeated experiments, and had their species identified. The majority of the isolates of Trichoderma spp. (76%) showed high capacity for parasitism and 50% of them produced toxic metabolites capable of inhibiting 60-100% of R. solani AG1-IB mycelial growth. Twenty-four isolates increased the number and 23 isolates increased the dry weight of lettuce seedlings inoculated with the pathogen in the first step of the in vivo experiments.In both experiments of the second step, two isolates of T. virens, IBLF 04 and IBLF 50, reduced the severity of bottom rot and increased the number and the dry weight of lettuce seedlings inoculated with R. solani AG1-IB. These isolates had shown a high capacity for parasitism and production of toxic metabolic substances, indicating that the in vitro and in vivo steps employed in the present study were efficient in selecting antagonists to be used for the control of lettuce bottom rot.


2017 ◽  
Vol 52 (12) ◽  
pp. 1140-1148 ◽  
Author(s):  
Patrícia Elias Haddad ◽  
Luis Garrigós Leite ◽  
Cleusa Maria Mantovanello Lucon ◽  
Ricardo Harakava

Abstract: The objective of this work was to evaluate, in vitro and in vivo, the potential of Trichoderma spp. strains to control Sclerotinia sclerotiorum in soybeans (Glycine max) and to perform the molecular identification of the best perfoming strains. The effect of 120 strains of Trichoderma spp. on the viability of S. sclerotiorum sclerotia was evaluated in vitro through immersion in suspension of conidia from the antagonists and plating in culture medium. The best performing strains were evaluated in vivo, in a greenhouse, for control of the pathogen inoculated on 'Pintado' soybean seeds and plants. Of the 120 strains tested in vitro, 22 strains of Trichoderma spp. caused 100% inhibition of sclerotia germination. In the greenhouse, five strains inhibited the negative effect of the pathogen on seed germination and two strains increased in up to 67% plant dry matter. The best performing strains were identified as T. koningiopsis (3 strains), T. asperelloides (3), T. atroviride (2), and T. virens (1). Trichoderma strains are able to protect soybean plants from the harmful effect of S. sclerotiorum and, at the same time, they can promote the growth of the aerial part in greenhouse conditions.


1978 ◽  
Vol 54 (6) ◽  
pp. 296-297 ◽  
Author(s):  
Douglas A. Mead

Height growth of eastern larch (Larix laricina (Du Roi) K. Koch) and black spruce (Picea mariana (Mill.) B.S.P.) was determined using standard stem analysis methods on trees from two sites in northwestern Ontario. The data were obtained from mixed larch-spruce stands which were relatively undisturbed. The larch exhibited substantially better height growth than the spruce through age 65.


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