scholarly journals Rye Snow Mold-Associated Microdochium nivale Strains Inhabiting a Common Area: Variability in Genetics, Morphotype, Extracellular Enzymatic Activities, and Virulence

2020 ◽  
Vol 6 (4) ◽  
pp. 335
Author(s):  
Vladimir Gorshkov ◽  
Elena Osipova ◽  
Mira Ponomareva ◽  
Sergey Ponomarev ◽  
Natalia Gogoleva ◽  
...  

Snow mold is a severe plant disease caused by psychrophilic or psychrotolerant fungi, of which Microdochium species are the most harmful. A clear understanding of Microdochium biology has many gaps; the pathocomplex and its dynamic are poorly characterized, virulence factors are unknown, genome sequences are not available, and the criteria of plant snow mold resistance are not elucidated. Our study aimed to identify comprehensive characteristics of a local community of snow mold-causing Microdochium species colonizing a particular crop culture. By using the next-generation sequencing (NGS) technique, we characterized fungal and bacterial communities of pink snow mold-affected winter rye (Secale cereale) plants within a given geographical location shortly after snowmelt. Twenty-one strains of M. nivale were isolated, classified on the basis of internal transcribed spacer 2 (ITS2) region, and characterized by morphology, synthesis of extracellular enzymes, and virulence. Several types of extracellular enzymatic activities, the level of which had no correlations with the degree of virulence, were revealed for Microdochium species for the first time. Our study shows that genetically and phenotypically diverse M. nivale strains simultaneously colonize winter rye plants within a common area, and each strain is likely to utilize its own, unique strategy to cause the disease using “a personal” pattern of extracellular enzymes.

2021 ◽  
Vol 13 (7) ◽  
pp. 3768
Author(s):  
Zhiyuan Hu ◽  
Jiating Li ◽  
Kangwei Shi ◽  
Guangqian Ren ◽  
Zhicong Dai ◽  
...  

The rapid expansion of Canada goldenrod (Solidago canadensis L.) in China has drawn considerable attention as it may not only decrease vegetation diversity but also alter soil nutrient cycling in the affected ecosystems. Soil extracellular enzymes mediate nutrient cycling by catalyzing the organic matter decomposition; however, the mechanisms by which alien plant invasion may affect soil extracellular enzymes remain unclear. The objective of this study was to investigate the responses of soil extracellular enzyme activities and ecoenzymatic stoichiometry to S. canadensis invasion. Several extracellular enzymatic activities related to carbon, nitrogen, and phosphorus cycling were measured using a fluorometric method. Ecoenzymatic stoichiometry was used as a proxy of soil microbial metabolic limitations. S. canadensis invasion appeared to be associated with decreased activities of enzymes and with substantial conversions of microbial metabolic carbon and nitrogen limitations. The changes in the activities of extracellular enzymes and the limitations of microbial metabolism were correlated with the alterations in the nutrient availability and resource stoichiometry in the soil. These findings reveal that the alterations in soil available nutrients associated with S. canadensis invasion may regulate extracellular enzymatic activities and cause microbial metabolic limitations, suggesting that S. canadensis invasion considerably affects biogeochemical cycling processes.


2021 ◽  
Vol 13 (4) ◽  
pp. 2121 ◽  
Author(s):  
Ingrid Vigna ◽  
Angelo Besana ◽  
Elena Comino ◽  
Alessandro Pezzoli

Although increasing concern about climate change has raised awareness of the fundamental role of forest ecosystems, forests are threatened by human-induced impacts worldwide. Among them, wildfire risk is clearly the result of the interaction between human activities, ecological domains, and climate. However, a clear understanding of these interactions is still needed both at the global and local levels. Numerous studies have proven the validity of the socioecological system (SES) approach in addressing this kind of interdisciplinary issue. Therefore, a systematic review of the existing literature on the application of SES frameworks to forest ecosystems is carried out, with a specific focus on wildfire risk management. The results demonstrate the existence of different methodological approaches that can be grouped into seven main categories, which range from qualitative analysis to quantitative spatially explicit investigations. The strengths and limitations of the approaches are discussed, with a specific reference to the geographical setting of the works. The research suggests the importance of local community involvement and local knowledge consideration in wildfire risk management. This review provides a starting point for future research on forest SES and a supporting tool for the development of a sustainable wildfire risk adaptation and mitigation strategy.


1985 ◽  
Vol 92 (1) ◽  
pp. 19-22 ◽  
Author(s):  
Ma. A. Calvo ◽  
T. Bruguera ◽  
F. J. Caba�es ◽  
R. Ma. Calvo ◽  
J. Trape ◽  
...  

2005 ◽  
Vol 56 (2) ◽  
pp. 173 ◽  
Author(s):  
G. Caruso ◽  
L. Monticelli ◽  
F. Azzaro ◽  
M. Azzaro ◽  
F. Decembrini ◽  
...  

Three microbial extracellular enzymes, leucine aminopeptidase (LAP), β-glucosidase (β-glu) and alkaline phosphatase (AP), were studied in six small Mediterranean littoral ponds, to evaluate the diversity of microbial activities relative to prevailing environmental conditions. The marked diversification of the trophic states, ranging from oligotrophy to eutrophy, in the ponds was reflected in a range of enzyme patterns at different spatial and temporal scales. There were higher levels and greater variability of microbial activity in the oldest and most ‘confined’ ponds (ranges: 0.55–4360.00 nm h−1, 0.15–76.44 nm h−1, 1.29–1600.00 nm h−1 for LAP, β-glu and AP respectively) compared with the youngest and most seaward ponds (ranges: 22.64–612.0 nm h−1, 0.06–48.89 nm h−1, 0.32–744.0 nm h−1 for LAP, β-glu and AP respectively). The close relationship of the degradative potential with chlorophyll-a and particulate organic carbon could be a consequence of the stimulating effect of phytoplankton-released polymeric compounds (organic matter) and/or a response of the microbial community to warm temperatures, which were recorded from July to September. Within an area less than 1 km2, different aquatic ecosystems coexist and maintain their distinctive properties in terms of microbial biogeochemical processes.


2002 ◽  
Vol 31 (1-2) ◽  
pp. 44-52 ◽  
Author(s):  
Karine Le Gorrec ◽  
Cristelle Connes ◽  
Alain Guibert ◽  
Jean-Louis Uribelarrea ◽  
Didier Combes

1987 ◽  
Vol 65 (6) ◽  
pp. 1152-1156 ◽  
Author(s):  
D. A. Gaudet ◽  
T. H. H. Chen

The development of resistance in winter-wheat seedlings to the cottony snow mold pathogen, Coprinus psychromorbidus Redhead et Traquair, was studied under controlled-environment conditions. Resistance was measured by the percentage of inoculated plants surviving after incubation at −3 °C for 8–12 weeks. The number of weeks of prehardening growth prior to inoculation, fresh weight, LT50, and tiller number were positively correlated with resistance to C. psychromorbidus. Prehardening temperatures of 7 and 15 °C favored development of snow mold resistance compared with 2 °C, but the LT50 (50% killing temperature) values of uninoculated plants were not significantly different. After 1 and 2.5 weeks growth at 20 °C, plants hardened at 2 °C and 12-h day length gradually increased in resistance to snow mold from 1 to 15 weeks of hardening. Development of resistance to C. psychromorbidus in winter wheat was most influenced by the amount of prehardening growth, and the development of freezing resistance played a minor role in disease resistance development. This form of resistance, which develops with increasing plant age, appeared to reduce the rate of infection and disease development by C. psychromorbidus.


2001 ◽  
Vol 81 (3) ◽  
pp. 541-550 ◽  
Author(s):  
D. A. Gaudet ◽  
A. Laroche ◽  
B. Puchalski

Resistance to snow molds in winter wheat increases with plant age, and older plants express higher levels of resistance than young plants. Experiments were conducted to study the effect of plant age on percent crown water content (%CWC) and dry weights in fall rye and winter wheat cultivars grown under controlled environments and in the field at Lethbridge, AB. Under controlled environments, the oldest (6 wk of pre-hardening growth at 20°C) treatments accumulated the greatest dry weights following exposure of plants to 1 to 6 wk hardening conditions at 2°C, compared with younger (1 to 4 wk pre-hardening growth) treatments. Exposure of plants to hardening temperatures had the greatest effect on %CWC values, which decreased, gradually, from 82–89% (4.95–8.67 g H2O g–1 DW) in unhardened treatments to 67–72% (2.05–2.65 g H2O g–1 DW) in plants receiving the 6 wk pre-hardening and 6 wk hardening growth. However, the oldest treatments (4 to 6 wk pre-hardening growth) always exhibited the lowest %CWC values among all hardening treatments. The %CWC in the oldest (6 wk) unhardened plants was also lower ([Formula: see text] = 80.8% or 4.24 g H2O g–1 DW) than in the youngest (1wk) unhardened plants ([Formula: see text] = 91.2% or 11.31 g H2O g–1 DW ), demonstrating that water loss occurs in older plants in the absence of low hardening temperatures. In a field study at Lethbridge during the autumn, winter, and early spring of 1997–1998 and 1998–1999, different seeding dates were employed to obtain plants differing in age and developmental state. The %CWC in early-seeded treatments was lower during the autumn, and remained lower in early spring, compared with later seeded cultivars. The %CWC in crowns was negatively associated with the snow mold resistance rating of a fall rye and five winter wheat cultivars under controlled environment conditions, and among a fall rye and 13 winter wheat cultivars in the field; the highest correlation values in the field were observed from mid-November to mid-March during 1997–1998 (r = –0.84), and 1998–1999 (r = – 0.76). These results indicate that the type of snow mold resistance that increases with plant age is related to the accumulation of crown dry matter and the ability of wheat and rye plants to lose crown water in response to both extended growth at warm temperatures and hardening at low, above freezing temperatures. Key words: Carbohydrates, fructans, low temperature basidiomycete, Coprinus psychromorbidus


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