scholarly journals Future Climate Alters Pathogens-Microbiome Co-occurrence Networks in Wheat Straw Residues during Decomposition

Proceedings ◽  
2021 ◽  
Vol 66 (1) ◽  
pp. 22
Author(s):  
Sara Fareed Mohamed Wahdan ◽  
François Buscot ◽  
Witoon Purahong

The return of plant residues to the ground is used to promote soil carbon sequestration, improve soil structure, reduce evaporation, and help to fix additional carbon dioxide in the soil. The microbial communities with diverse ecological functions that colonize plant residues during decomposition are expected to be highly dynamic. We aimed to characterize microbial communities colonizing wheat straw residues and their ecological functions during the early phase of straw decomposition. The experiment, run in Central Germany, was conducted in a conventional farming system under both ambient conditions and a future climate scenario expected in 50–70 years from now. We used MiSeq illumina sequencing and network analysis of bacterial 16S rRNA and fungal ITS genes. Our results show that future climate alters the dynamics of bacterial and fungal communities during decomposition. We detected various microbial ecological functions within wheat straw residues such as plant growth-promoting bacteria, N-fixing bacteria, saprotrophs, and plant pathogenic fungi. Interestingly, plant pathogenic fungi dominated (~87% of the total sequences) within the wheat residue mycobiome under both ambient and future climate conditions. Therefore, we applied co-occurrence network analysis to predict the potential impacts of climate change on the interaction between pathogenic community and other bacterial and fungal microbiomes. The network under ambient climate consisted of 91 nodes and 129 correlations (edges). The highest numbers of connections were detected for the pathogens Mycosphaerella tassiana and Neosetophoma rosigena. The network under future climate consisted of 100 nodes and 170 correlations. The highest numbers of connections were detected for the pathogens Pseudopithomyces rosae and Gibellulopsis piscis. We conclude that the future climate significantly changes the interactions between plant pathogenic fungi and other microorganisms during the early phrase of decomposition.

2020 ◽  
Vol 8 (6) ◽  
pp. 908
Author(s):  
Sara Fareed Mohamed Wahdan ◽  
Shakhawat Hossen ◽  
Benjawan Tanunchai ◽  
Martin Schädler ◽  
François Buscot ◽  
...  

Returning wheat residues to the soil is a common practice in modern agricultural systems and is considered to be a sustainable practice. However, the negative contribution of these residues in the form of “residue-borne pathogens” is recognized. Here, we aimed to investigate the structure and ecological functions of fungal communities colonizing wheat residues during the early phase of decomposition in a conventional farming system. The experiment was conducted under both ambient conditions and a future climate scenario expected in 50–70 years from now. Using MiSeq Illumina sequencing of the fungal internal transcribed spacer 2 (ITS2), we found that plant pathogenic fungi dominated (~87% of the total sequences) within the wheat residue mycobiome. Destructive wheat fungal pathogens such as Fusarium graminearum, Fusarium tricinctum, and Zymoseptoria tritci were detected under ambient and future climates. Moreover, future climate enhanced the appearance of new plant pathogenic fungi in the plant residues. Our results based on the bromodeoxyuridine (BrdU) immunocapture technique demonstrated that almost all detected pathogens are active at the early stage of decomposition under both climate scenarios. In addition, future climate significantly changed both the richness patterns and the community dynamics of the total, plant pathogenic and saprotrophic fungi in wheat residues as compared with the current ambient climate. We conclude that the return of wheat residues can increase the pathogen load, and therefore have negative consequences for wheat production in the future.


2021 ◽  
Author(s):  
Luiz Henrique Rosa ◽  
Otávio Henrique Bezerra Pinto ◽  
Lívia Costa Coelho ◽  
Peter Convey ◽  
Micheline Carvalho-Silva ◽  
...  

Abstract We evaluated fungal and bacterial diversity in an established moss carpet on King George Island, Antarctica, affected by ‘fairy ring’ disease using metabarcoding. These microbial communities were assessed through the main stages of the disease. A total of 127 fungal and 706 bacterial taxa were assigned. The phylum Ascomycota dominated the fungal assemblages, followed by Basidiomycota, Rozellomycota, Chytridiomycota, Mortierellomycota and Monoblepharomycota. The fungal community displayed high indices of diversity, richness and dominance, which increased from healthy through infected to dead moss samples. Bacterial diversity and richness were greatest in healthy moss and least within the infected fairy ring. Chalara sp. 1, Alpinaria sp., Helotiaceae sp. 2, Chaetothyriales sp. 1, Ascomycota sp. 1, Rozellomycota sp. and Fungi sp. were most abundant within the fairy ring samples. A range of fungal taxa were more abundant in dead rather than healthy or fairy ring moss samples. The dominant prokaryotic phyla were Actinobacteriota, Proteobacteria, Bacteroidota and Cyanobacteria. The taxon Cyanobacteriia sp., whilst consistently dominant, were less abundant in fairy ring samples. Microbacteriaceae sp. and Chloroflexi sp. were the most abundant taxa within the fairy rings. Our data confirmed the presence and abundance of a range of plant pathogenic fungi, supporting the hypothesis that the disease is linked with multiple fungal taxas. Further studies are required to characterise the interactions between plant pathogenic fungi and their host Antarctic mosses. Monitoring the dynamics of mutualist, phytopathogenic and decomposer microorganisms associated with moss carpets may provide bioindicators of moss health.


2021 ◽  
Vol 9 (1) ◽  
pp. 168
Author(s):  
Fabienne Hilgers ◽  
Samer S. Habash ◽  
Anita Loeschcke ◽  
Yannic Sebastian Ackermann ◽  
Stefan Neumann ◽  
...  

Terpenoids constitute one of the largest and most diverse groups within the class of secondary metabolites, comprising over 80,000 compounds. They not only exhibit important functions in plant physiology but also have commercial potential in the biotechnological, pharmaceutical, and agricultural sectors due to their promising properties, including various bioactivities against pathogens, inflammations, and cancer. In this work, we therefore aimed to implement the plant sesquiterpenoid pathway leading to β-caryophyllene in the heterologous host Rhodobacter capsulatus and achieved a maximum production of 139 ± 31 mg L−1 culture. As this sesquiterpene offers various beneficial anti-phytopathogenic activities, we evaluated the bioactivity of β-caryophyllene and its oxygenated derivative β-caryophyllene oxide against different phytopathogenic fungi. Here, both compounds significantly inhibited the growth of Sclerotinia sclerotiorum and Fusarium oxysporum by up to 40%, while growth of Alternaria brassicicola was only slightly affected, and Phoma lingam and Rhizoctonia solani were unaffected. At the same time, the compounds showed a promising low inhibitory profile for a variety of plant growth-promoting bacteria at suitable compound concentrations. Our observations thus give a first indication that β-caryophyllene and β-caryophyllene oxide are promising natural agents, which might be applicable for the management of certain plant pathogenic fungi in agricultural crop production.


2012 ◽  
Vol 78 (23) ◽  
pp. 8191-8201 ◽  
Author(s):  
Timo P. Sipilä ◽  
Kim Yrjälä ◽  
Laura Alakukku ◽  
Ansa Palojärvi

ABSTRACTThe exploitation of soil ecosystem services by agricultural management strategies requires knowledge of microbial communities in different management regimes. Crop cover by no-till management protects the soil surface, reducing the risk of erosion and nutrient leaching, but might increase straw residue-borne and soilborne plant-pathogenic fungi. A cross-site study of soil microbial communities andFusariumfungistasis was conducted on six long-term agricultural fields with no-till and moldboard-plowed treatments. Microbial communities were studied at the topsoil surface (0 to 5 cm) and bottom (10 to 20 cm) by general bacterial and actinobacterial terminal restriction fragment length polymorphism (T-RFLP) and phospholipid fatty acid (PLFA) analyses.Fusarium culmorumsoil fungistasis describing soil receptivity to plant-pathogenic fungi was explored by using the surface layer method. Soil depth had a significant impact on general bacterial as well as actinobacterial communities and PLFA profiles in no-till treatment, with a clear spatial distinction of communities (P< 0.05), whereas the depth-related separation of microbial communities was not observed in plowed fields. The fungal biomass was higher in no-till surface soil than in plowed soil (P< 0.07). Soil total microbial biomass and fungal biomass correlated with fungistasis (P< 0.02 for the sum of PLFAs;P< 0.001 for PLFA 18:2ω6). Our cross-site study demonstrated that agricultural management strategies can have a major impact on soil microbial community structures, indicating that it is possible to influence the soil processes with management decisions. The interactions between plant-pathogenic fungi and soil microbial communities are multifaceted, and a high level of fungistasis could be linked to the high microbial biomass in soil but not to the specific management strategy.


2018 ◽  
Vol 25 (2) ◽  
pp. 268-286 ◽  
Author(s):  
Maurizio Vurro ◽  
Angela Boari ◽  
Francesca Casella ◽  
Maria Chiara Zonno

Fungal phytotoxins are natural secondary metabolites produced by plant pathogenic fungi during host–pathogen interactions. They have received considerable particular attention for elucidating disease etiology, and consequently to design strategies for disease control. Due to wide differences in their chemical structures, these toxic metabolites have different ecological and environmental roles and mechanisms of action. This review aims at summarizing the studies on the possible use of these metabolites as tools in biological and integrated weed management, e.g. as: novel and environmentally friendly herbicides; lead for novel compounds; sources of novel mechanisms of action. Moreover, the limiting factors for utilizing those metabolites in practice will also be briefly discussed.


2016 ◽  
Vol 5 (08) ◽  
pp. 4744
Author(s):  
Zahra Ibrahim El-Gali

This study was carried out to identify the unknown different symptoms and their causes as plant pathogenic fungi from Al-Jabal Al-Akhdar District. Plant materials with fungal signs and symptoms were collected and examined. The main fungi consistently isolated from symptomatic leaves and twigs were Pestalotiopsis spp. Morphology, colony characteristics, and pathogenicity of the isolates were examined. My report the occurrence of Pestalotiopsis spp. on leaves of mastic (Pistacia lentiscus) for the first time in Libya.


2014 ◽  
Vol 92 (1) ◽  
pp. 10-27 ◽  
Author(s):  
Bilal Ökmen ◽  
Jérôme Collemare ◽  
Scott Griffiths ◽  
Ate van der Burgt ◽  
Russell Cox ◽  
...  

Soil Research ◽  
2000 ◽  
Vol 38 (3) ◽  
pp. 699 ◽  
Author(s):  
Yothin Konboon ◽  
Graeme Blair ◽  
Rod Lefroy ◽  
Anthony Whitbread

Matching plant residue mineralisation rate to plant nutrient demand is one way of increasing the efficiency of nutrient cycling. A glasshouse experiment was conducted in a Soloth soil with a C4d13 C signature using drained pots to examine the effect on the yield of Japanese millet (Echinochloa frumentocea) and the fate of 15 N, 35 S, and C (using d 13 C shift) from the C 3 plants Flemingia macrophylla, Medicago truncatula hay, and wheat (Triticum aestivum) straw applied at 3 t/ha in the presence of N and NPKS fertiliser. The yield of Japanese millet at 91 days was highest where medic hay had been added (13.7 g/pot) and lowest where wheat straw was used (11.5 g/pot). Recovery of 35 S by the millet was highest in the wheat straw and medic hay treatments (mean 11.5%), whilst recovery of 15 N was highest from medic hay (15.8%). Leaching losses of 35 S were highest in the Flemingia and medic treatments (mean 8.1%), and 15 N loss in leachate was highest in the medic hay treatment (6.6%). A maximum of 1.5% of the C added in residues was recovered in the leachate of the medic hay treatment.


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