scholarly journals Pathogen and Endophyte Assemblages Co-vary With Beech Bark Disease Progression, Tree Decline, and Regional Climate

2021 ◽  
Vol 4 ◽  
Author(s):  
Eric W. Morrison ◽  
Matt T. Kasson ◽  
Jeremy J. Heath ◽  
Jeff R. Garnas
Keyword(s):  
Disease Progression ◽  
Fungal Pathogens ◽  
Regional Climate ◽  
Fungal Endophytes ◽  
Positive Association ◽  
Scale Insect ◽  
Tree Decline ◽  
Beech Bark Disease ◽  
Clonostachys Rosea ◽  
Community Interactions

Plant–pathogen interactions are often considered in a pairwise manner with minimal consideration of the impacts of the broader endophytic community on disease progression and/or outcomes for disease agents and hosts. Community interactions may be especially relevant in the context of disease complexes (i.e., interacting or functionally redundant causal agents) and decline diseases (where saprobes and weak pathogens synergize the effects of primary infections and hasten host mortality). Here we describe the bark endophyte communities associated with a widespread decline disease of American beech, beech bark disease (BBD), caused by an invasive scale insect (Cryptococcus fagisuga) and two fungal pathogens, Neonectria faginata and N. ditissima. We show that the two primary fungal disease agents co-occur more broadly than previously understood (35.5% of infected trees), including within the same 1-cm diameter phloem samples. The two species appear to have contrasting associations with climate and stages of tree decline, wherein N. faginata was associated with warmer and N. ditissima with cooler temperatures. Neonectria ditissima showed a positive association with tree crown dieback – no such association was observed for N. faginata. Further, we identify fungal endophytes that may modulate disease progression as entomopathogens, mycoparasites, saprotrophs, and/or additional pathogens, including Clonostachys rosea and Fusarium babinda. These fungi may alter the trajectory of disease via feedbacks with the primary disease agents or by altering symptom expression or rates of tree decline across the range of BBD.

scholarly journals Pathogen and endophyte assemblages co-vary with beech bark disease progression, tree decline, and regional climate

2021 ◽  
Author(s):  
Eric W. Morrison ◽  
Matt T. Kasson ◽  
Jeremy J. Heath ◽  
Jeff R. Garnas
Keyword(s):  
Disease Progression ◽  
Fungal Pathogens ◽  
Regional Climate ◽  
Fungal Endophytes ◽  
Positive Association ◽  
Scale Insect ◽  
Tree Decline ◽  
Beech Bark Disease ◽  
Clonostachys Rosea ◽  
Community Interactions

AbstractPlant-pathogen interactions are often considered in a pairwise manner with minimal consideration of the impacts of the broader endophytic community on disease progression and/or outcomes for disease agents and hosts. Community interactions may be especially relevant in the context of disease complexes (i.e, interacting or functionally redundant causal agents) and decline diseases (where saprobes and weak pathogens synergize the effects of primary infections and hasten host mortality). Here we describe the bark endophyte communities associated with a widespread decline disease of American beech, beech bark disease (BBD), caused by an invasive scale insect (Cryptococcus fagisuga) and two fungal pathogens, Neonectria faginata and N. ditissima. We show that the two primary fungal disease agents co-occur more broadly than previously understood (35.5% of infected trees), including within the same 1-cm diameter phloem samples. The two species appear to have contrasting associations with climate and stages of tree decline, wherein N. faginata was associated with warmer and N. ditissima with cooler temperatures. Neonectria ditissima showed a positive association with tree crown dieback – no such association was observed for N. faginata. Further, we identify fungal endophytes that may modulate disease progression as entomopathogens, mycoparasites, saprotrophs and/or additional pathogens, including Clonostachys rosea and Fusarium babinda. These fungi may alter the trajectory of disease via feedbacks with the primary disease agents or by altering symptom expression or rates of tree decline across the range of BBD.

Use of fungal endophytes to increase cucurbit plant performance by conferring abiotic and biotic stress tolerance

2014 ◽  
Author(s):  
Stanley Freeman ◽  
Russell Rodriguez ◽  
Adel Al-Abed ◽  
Roni Cohen ◽  
David Ezra ◽  
...  
Keyword(s):  
Stress Tolerance ◽  
Fungal Pathogens ◽  
Systems Approach ◽  
Crop Yields ◽  
Fungal Endophytes ◽  
Limited Resource ◽  
Pathogenic Fungi ◽  
Plant Performance ◽  
Crop Species ◽  
Desert Areas

Major threats to agricultural sustainability in the 21st century are drought, increasing temperatures, soil salinity and soilborne pathogens, all of which are being exacerbated by climate change and pesticide abolition and are burning issues related to agriculture in the Middle East. We have found that Class 2 fungal endophytes adapt native plants to environmental stresses (drought, heat and salt) in a habitat-specific manner, and that these endophytes can confer stress tolerance to genetically distant monocot and eudicot hosts. In the past, we generated a uv non-pathogenic endophytic mutant of Colletotrichum magna (path-1) that colonized cucurbits, induced drought tolerance and enhanced growth, and protected 85% - 100% against disease caused by certain pathogenic fungi. We propose: 1) utilizing path-1 and additional endophtyic microorganisms to be isolated from stress-tolerant local, wild cucurbit watermelon, Citrulluscolocynthis, growing in the Dead Sea and Arava desert areas, 2) generate abiotic and biotic tolerant melon crop plants, colonized by the isolated endophytes, to increase crop yields under extreme environmental conditions such as salinity, heat and drought stress, 3) manage soilborne fungal pathogens affecting curubit crop species growing in the desert areas. This is a unique and novel "systems" approach that has the potential to utilize natural plant adaptation for agricultural development. We envisage that endophyte-colonized melons will eventually be used to overcome damages caused by soilborne diseases and also for cultivation of this crop, under stress conditions, utilizing treated waste water, thus dealing with the limited resource of fresh water.

scholarly journals Evaluation of Resistance to the Beech Scale Insect (Cryptococcus fagisuga) and Propagation of American Beech (Fagus grandifolia) by Grafting

2007 ◽  
Vol 56 (1-6) ◽  
pp. 163-169 ◽  
Author(s):  
M. Ramirez ◽  
J. Loo ◽  
M. J. Krasowski
Keyword(s):  
Developmental Stages ◽  
Scale Insect ◽  
Fagus Grandifolia ◽  
Life Stages ◽  
Total Resistance ◽  
Beech Bark Disease ◽  
American Beech ◽  
Insect Colonies ◽  
Cryptococcus Fagisuga

Abstract Scions collected from diseased trees and from those without symptoms of beech bark disease (BBD) were cleft-grafted in 2003 and 2004 onto rootstock of unknown resistance to BBD. Grafting success varied among genotypes and year (30% in 2003 and 12% in 2004), and improved with increasing rootstock diameter. Successful grafts were used to test resistance to the beech scale insect, Cryptococcus fagisuga (the initiating agent of BBD) by introducing eggs onto the bark of scions and allowing time for the emergence of all developmental stages of the insects. Significantly fewer insects colonized scions collected from putatively resistant trees than those collected from diseased trees. In some cases, where egg placement overlapped a portion of the rootstock, insect colonies developed on the rootstock but not on the scion collected from resistant trees. Occasionally, scions from putatively resistant trees were colonized, whereas some of those from diseased trees were not. When scions from putatively resistant trees were heavily colonized, only adult insects were present and no eggs or other life stages of the insect were found. The findings indicate that the extent of resistance to the scale insect (hence to BBD) ranges from partial to total resistance.

scholarly journals Deciphering bacterial and fungal endophyte communities in leaves of two maple trees with green islands

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Franziska Wemheuer ◽  
Bernd Wemheuer ◽  
Rolf Daniel ◽  
Stefan Vidal
Keyword(s):  
Fungal Pathogens ◽  
Fungal Endophytes ◽  
Fungal Endophyte ◽  
Fungal Community Composition ◽  
Senescent Leaf ◽  
Acer Campestre ◽  
Main Driver ◽  
Leaf Tissues ◽  
Species Specific ◽  
Green Island

Abstract Green islands (the re-greening of senescent leaf tissues) are particularly evident on leaves infected with fungal pathogens. To date, there is only a limited number of studies investigating foliar endophytic microorganisms in phytopathogen-infected leaves. Here, we analysed bacterial and fungal endophyte communities in leaves without green islands (control leaves; CL), within green island areas (GLA) and the surrounding yellow leaf areas (YLA) of leaves with green islands of Acer campestre and A. platanoides. GLA samples of A. campestre and A. platanoides were dominated by Sawadaea polyfida and S. bicornis, respectively, suggesting that these fungi might be responsible for the green islands. We detected a higher fungal richness and diversity in CL compared to GLA samples of A. campestre. Leaf status (CL, GLA, YLA) significantly altered the composition of fungal communities of A. campestre. This was related to differences in fungal community composition between YLA and GLA samples. Site was the main driver of bacterial communities, suggesting that bacterial and fungal endophytes are shaped by different factors. Overall, we observed Acer species-specific responses of endophyte communities towards the presence of green islands and/or leaf type, which might be attributed to several fungi and bacteria specifically associated with one Acer species.

scholarly journals Occurrence of Foliar Pathogens of Watermelon on Commercial Farms in South Carolina Estimated with Stratified Cluster Sampling

Plant Disease ◽  
2018 ◽  
Vol 102 (11) ◽  
pp. 2285-2295 ◽  
Author(s):  
Gabriel Rennberger ◽  
Patrick Gerard ◽  
Anthony P. Keinath
Keyword(s):  
South Carolina ◽  
Fungal Pathogens ◽  
Positive Association ◽  
Cluster Sampling ◽  
Corynespora Cassiicola ◽  
Two Stage ◽  
Common Pathogen ◽  
Commercial Farms ◽  
Pathogen Occurrence ◽  
Foliar Pathogens

A survey of foliar pathogens of watermelon based on two-stage cluster sampling was conducted on commercial farms in South Carolina in spring 2015, spring and fall 2016, and fall 2017. In total, 60 fields from 27 different growers in seven counties representing the main watermelon-producing areas in the state were sampled, using a stratified two-stage cluster sampling approach. In the sampling design, counties corresponded to strata, growers to first-stage clusters, and fields to second-stage clusters. In each field, 100 symptomatic leaves were collected at five equidistant sampling points along four transects encompassing a square shape of 2,500 m2. After collection, pathogens were identified based on reproductive structures formed on leaves during >12 h incubation. Estimates were obtained for the statewide probability of pathogen occurrence and associations between pathogen pairs. Six fungal pathogens, Stagonosporopsis spp., Podosphaera xanthii, Cercospora citrullina, Colletotrichum orbiculare, Myrothecium sensu lato (s.l.), and Corynespora cassiicola; the oomycete Pseudoperonospora cubensis; and three viral pathogens were identified on the examined leaves. With the exception of fall 2017, Stagonosporopsis spp. was the most prevalent pathogen in every season, followed by P. xanthii. The highest occurrence of P. cubensis was in spring 2015; it did not occur in 2016. The highest occurrence of C. orbiculare was in spring 2016; it did not occur in spring 2015. Myrothecium s.l. was the most common pathogen in fall 2017 and the second most common pathogen occurring by itself in fall 2016. The third most common pathogen in fall 2017, Corynespora cassiicola, was not observed in any other season. Eight of the 80 isolates of Stagonosporopsis spp. collected were identified as S. caricae, the rest as S. citrulli. All isolates of S. caricae were found in spring 2015 and originated from two fields in different counties. A total of three positive and five negative associations were found between pathogen pairs co-occurring on the same leaf. A positive association between Stagonosporopsis spp. and C. citrullina was the only significant association between pathogens found in two seasons, spring 2015 and spring 2016. Based on estimates of probability of pathogen occurrence across seasons, Stagonosporopsis spp. and P. xanthii are the most common pathogens on watermelons in South Carolina. This is the first report of C. cassiicola, S. caricae, and Myrothecium s.l. on watermelon in South Carolina.

scholarly journals Biological Control of Pathogens Causing Root Rot Complex in Field Pea Using Clonostachys rosea Strain ACM941

2003 ◽  
Vol 93 (3) ◽  
pp. 329-335 ◽  
Author(s):  
Allen G. Xue
Keyword(s):  
Root Rot ◽  
Seed Treatment ◽  
Fungal Pathogens ◽  
Seedling Emergence ◽  
Field Pea ◽  
Mycosphaerella Pinodes ◽  
Limiting Factor ◽  
Aphanomyces Euteiches ◽  
Clonostachys Rosea

Pea root rot complex (PRRC), caused by Alternaria alternata, Aphanomyces euteiches, Fusarium oxysporum f. sp. pisi, F. solani f. sp. pisi, Mycosphaerella pinodes, Pythium spp., Rhizoctonia solani, and Sclerotinia sclerotiorum, is a major yield-limiting factor for field pea production in Canada. A strain of Clonostachys rosea (syn. Gliocladium roseum), ACM941 (ATCC 74447), was identified as a mycoparasite against these pathogens. When grown near the pathogen, ACM941 often was stimulated to produce lateral branches that grew directly toward the pathogen mycelium, typically entwining around the pathogen mycelium. When applied to the seed, ACM941 propagated in the rhizosphere and colonized the seed coat, hypocotyl, and roots as the plant developed and grew. ACM941 significantly reduced the recovery of all fungal pathogens from infected seed, increased in vitro seed germination by 44% and seedling emergence by 22%, and reduced root rot severity by 76%. The effects were similar to those of thiram fungicide, which increased germination and emergence by 33 and 29%, respectively, and reduced root rot severity by 65%. When soil was inoculated with selected PRRC pathogens in a controlled environment, seed treatment with ACM941 significantly increased emergence by 26, 38, 28, 13, and 21% for F. oxysporum f. sp. pisi, F. solani f. sp. pisi, M. pinodes, R. solani, and S. sclerotiorum, respectively. Under field conditions from 1995 to 1997, ACM941 increased emergence by 17, 23, 22, 13, and 18% and yield by 15, 6, 28, 6, and 19% for the five respective pathogens. The seed treatment effects of ACM941 on these PRRC pathogens were greater or statistically equivalent to those achieved with thiram. Results of this study suggest that ACM941 is an effective bioagent in controlling PRRC and is an alternative to existing chemical products.

Fungal endophytes nearly double minimum leaf conductance in seedlings of a neotropical tree species

2007 ◽  
Vol 23 (3) ◽  
pp. 369-372 ◽  
Author(s):  
A. Elizabeth Arnold ◽  
Bettina M. J. Engelbrecht
Keyword(s):  
Tropical Forests ◽  
Water Uptake ◽  
Mycorrhizal Fungi ◽  
Fungal Pathogens ◽  
Vascular Tissue ◽  
Water Status ◽  
Fungal Endophytes ◽  
Arbuscular Mycorrhizal ◽  
Plant Performance ◽  
Neotropical Tree

Drought strongly influences plant phenology, growth and mortality in tropical forests, thereby shaping plant performance, population dynamics and community structure (Bunker & Carson 2005, Condit et al. 1995). Microbial symbionts of plants profoundly influence host water relations (Lösch & Gansert 2002), but are rarely considered in studies of tropical plant physiology. In particular, plant–fungus associations, which are ubiquitous in plant communities and especially common in tropical forests, play important and varied roles in plant water status. Fungal pathogens associated with roots, vascular tissue and foliage may interfere with water uptake and transport, increase rates of foliar transpiration, and induce xylem embolism and tissue death (Agrios 1997). In contrast, rhizosphere mutualists such as ecto- and arbuscular mycorrhizal fungi may benefit hosts by increasing surface area for water uptake, enhancing stomatal regulation of water loss, and increasing root hydraulic conductivity (Auge 2001, Lösch & Gansert 2002).

Fungal endophytes in Peperomia obtusifolia and their potential as inhibitors of chickpea fungal pathogens

2021 ◽  
Vol 37 (1) ◽  
Author(s):  
Nathalie Ruiz Mostacero ◽  
María Victoria Castelli ◽  
Melisa Isabel Barolo ◽  
Susana Lucrecia Amigot ◽  
Cecilia Luisa Fulgueira ◽  
...  
Keyword(s):  
Fungal Pathogens ◽  
Fungal Endophytes

Glucose- The X Factor for the survival of human fungal pathogens and disease progression in the host

2021 ◽  
pp. 126725
Author(s):  
Hafsa Qadri ◽  
Munazah Fazal Qureshi ◽  
Manzoor Ahmad Mir ◽  
Abdul Haseeb Shah
Keyword(s):  
Disease Progression ◽  
Fungal Pathogens

scholarly journals Impact of Visceral Fat On The Prognosis of Coronavirus Disease 2019: An Observational Cohort Study

2021 ◽  
Author(s):  
Hiroaki Ogata ◽  
Masahiro Mori ◽  
Yujiro Jingushi ◽  
Hiroshi Matsuzaki ◽  
Katsuyuki Katahira ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Disease Progression ◽  
Cox Regression ◽  
Characteristic Curve ◽  
Predictive Ability ◽  
Positive Association ◽  
Abdominal Fat ◽  
Prediction Ability ◽  
Cox Regression Analysis ◽  
The Right

Abstract Background Clarification of the risk factors for coronavirus disease 2019 (COVID-19) severity is strongly warranted for global health. Recent studies have indicated that elevated body mass index (BMI) is associated with unfavorable progression of COVID-19. This is assumed to be due to excessive deposition of visceral adipose tissue (VAT); however, the evidence investigating the association between intra-abdominal fat and COVID-19 prognosis is sparse. We therefore investigated whether measuring the amount of intra-abdominal fat is useful to predict the prognosis of COVID-19. Methods The present study enrolled 53 consecutive cases of COVID-19 patients aged ≥ 20 years with chest computed tomography (CT) scans. The VAT area, total adipose tissue (TAT) area, and VAT/TAT ratio were estimated using axial CT images at the level of the upper pole of the right kidney. Severe COVID-19 was defined as death or acute respiratory failure demanding oxygen at ≥ 6 liters per minute, a high-flow nasal cannula, or mechanical ventilation. The association of VAT/TAT with the incidence of progression to a severe state was estimated as a hazard ratio (HR) using Cox regression analysis. To compare the prediction ability for COVID-19 disease progression between BMI and VAT/TAT, the area under the receiver operating characteristic curve (AUC) of each was assessed. Results A total of 15 cases (28.3% of the whole study subjects) progressed to severe stages. The incidence of developing severe COVID-19 increased significantly with VAT/TAT (HR per 1% increase = 1.040 (95% CI 1.008–1.074), P = 0.01). After adjustment for potential confounders, the positive association of VAT/TAT with COVID-19 aggravation remained significant (multivariable-adjusted HR = 1.055 (95% CI 1.000–1.112) per 1% increase, P = 0.049). The predictive ability of VAT/TAT for COVID-19 becoming severe was significantly better than that of BMI (AUC of 0.73 for VAT/TAT and 0.50 for BMI; P = 0.0495 for the difference). Conclusions A higher ratio of VAT/TAT was an independent risk factor for disease progression among COVID-19 patients. VAT/TAT was superior to BMI in predicting COVID-19 morbidity. COVID-19 patients with high VAT/TAT levels should be carefully observed as high-risk individuals for morbidity and mortality.

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