Adaptability of Sphaerodes mycoparasitica on anamorph and teleomorph related to its mycoparasitic-polyphagous lifestyle

Non-Peer Reviewe

Endophytes modulate drought tolerance in pulses by scavenging reactive oxygen species in plant cells under drought stress

Non-Peer Reviewe

Endophytic hyphal compartmentalization is required for successful mycobiont-wheat interaction as revealed by confocal laser microscopy

Non-Peer ReviewedRoot endophytic fungi are seen as promising alternatives to replace chemical fertilizers and pesticides in sustainable and organic agriculture systems. Fungal endophytes structure formations play key roles in symbiotic intracellular association with plant-roots. To compare the morphologies of Ascomycete endophytic fungi in wheat, we analyzed growth morphologies during endophytic development of hyphae within the cortex of living vs dead root cells. Confocal laser scanning microscopy (CLSM) was used to characterize fungal cell morphology within lactofuchsin-stained roots. Cell form regularity Ireg and cell growth direction Idir, indexes were used to quantify changes in fungal morphology. Endophyte fungi in living roots had a variable Ireg and Idir values, low colonization abundance and patchy colonization patterns, whereas the same endophyte species in dead (γ-irradiated) roots had consistent form of cells and mostly grew parallel to the root axis. Knot, coil and vesicle structures dominated in living roots, as putative symbiotic functional organs. Finally, an increased hypha septation in living roots might indicate local specialization within endophytic Ascomycota. Our results suggested that the applied method could be expanded to other septate fungal symbionts

Quantification of a novel biotrophic mycoparasitic fungus using genus specific real-time PCR for biocontrol of phytopathogenic Fusarium graminearum in wheat root under controlled conditions

Non-Peer ReviewedFusarium species are well-known causal agents of Fusarium root-rot, Fusarium head blight (FHB), and Fusarium damaged kernels (FDK) diseases in Saskatchewan and other provinces of Canada. Our goal is to develop quantitative real-time PCR techniques to determine and evaluate interactions between Fusarium-associated biotrophic mycoparasitic fungus SMCD 2220 and 3-acetyldeoxynivalenol (3-ADON) producing Fusarium graminearum Schwabe – in and surrounding wheat roots. ITS1F/ITS4 (internal transcribed spacer) sequences from SMCD 2220 biotrophic mycoparasitic fungal isolate and 20 different Fusarium strains were aligned, and consensus sequences were verified. Four candidate primer sets from ITS regions were designed based on the non-conserved regions of the consensus sequences. Using the primer set SmyITSF/R, the biotrophic mycoparasite genomic DNAs were amplified from SMCD 2220. This primer set was developed for assessing and quantifying the interactions between SMCD 2220 biotrophic mycoparasite and F. graminearum. Well-known necrotrophic T. harzianum T-22, was used as the positive control. During in vitro studies, only SMCD 2220 was observed to improve wheat seed germination, whereas T-22 induced post-emergence damping-off symptoms. Under controlled phytotron conditions, both SMCD 2220 and T. harzianum strains were able to reduce the quantity of F. graminearum in spring wheat root, as well as improving the survival and growth of the spring wheat seedlings. However, amount of SMCD 2220 DNA detected was no significantly difference between wheat inoculated with F. graminearum and without Fusarium. In contrary, the amount of T. harzianum DNA monitored in the treatment inoculated with F. graminearum was observed to reduce significantly, as compared to non-Fusarium treatment

Première mention du Marssonina salicicola sur des saules pleureurs au Québec

Au cours des printemps 1996 et 1997, des prélèvements ont été réalisés sur cinq sites à Montréal (Québec) pour établir l'étiologie de l'anthracnose des saules pleureurs (Salix alba Tristis' et S. babylonica). Sur les 25 arbres examinés, 21 étaient affectés par une maladie fongique due au Marssonina salicicola qui constitue le stade conidien du Drepanopeziza sphaeroides. Cette détection est la première mention de la présence du champignon au Canada, à l’est des Rocheuses.During spring 1996 and 1997, five sites on the Island of Montreal, Quebec, were examined to study the occurrence of anthracnose on weeping willows (Salix alba Tristis' and S. babylonica). On 21 trees of 25 surveyed, the pathogenic fungus Marssonina salicicola, the conidial state of Drepanopeziza sphaeroides, was found. This report is the first mention of the presence of this fungus in Canada, east of the Rocky Mountains

Fungicide effects on N2-fixing bacteria and N2-fixation in chickpea

Non-Peer ReviewedFungicide application in field crops have unexpected non-target effects on the agroecosystem. Molecular methods (polymerase chain reaction – denaturing gradient gel electrophoresis and cloning technology) were used to test the effects of four fungicide application programs targeting Ascochyta blight (Ascochyta rabiei) on the N2-fixing bacterial communities associated with two chickpea cultivars, and on chickpea nodulation. Treatments were replicated four times in complete blocks in the field, in 2008 and 2009. Results showed the richness of the N2-fixing bacterial communities did not change significantly (P > 0.05, data didn’t shown) with fungicide application, but different intensities of fungicide application selected different dominant N2-fixing taxa, as revealed by Correspondence Analysis (CA) of DNA sequences. Genotypes of chickpea cultivars significantly affected both the richness and composition of the N2-fixing bacterial communities, as revealed by results of CA. Both fungicide and crop genotype affected nodulation scores of chickpea based on ANOVA results (P < 0.001 for nodulation scores test and P = 0.04 for fixed N test), reflecting impacts on nitrogen fixation. Redundancy analysis (RDA) also revealed significant relationships (P = 0.014) among fixed nitrogen, nodulation scores and identified rhizosphere N2-fixing bacteria. Based on these results, we conclude that both the foliar fungicide applications and chickpea genotype can affect the composition and function of N2-fixing bacterial community in chickpea field

Pulse-wheat rotation: pulse crops effects on wheat endophytic bacteria, and feedback on wheat yield

Non-Peer ReviewedCrop rotation is a common cultivation strategy and the legacy of a previous crop on biotic soil properties could feedback on the productivity of the following crop due to the mutual influence existing between plants and their biological environment. Polymerase chain reaction and 454 GS FLX pyrosequencing of amplicons were used in this study to determine the effects of genotype and termination time of previous pulse crops on the productivity and endophytic bacterial community colonizing the roots of durum wheat. In 2008-09, when chickpea plants (late maturing plant) were terminated as early as yellow pea (In July), all three genotypes of chickpea passed a sol biota to durum wheat that formed endophytic bacterial community which was similar to that formed following yellow pea, an early maturing plant. These four endophytic bacterial communities were different from those formed in wheat roots following late-terminated chickpea crops. Additionally, late terminated pulse crops (September) led to the formation of endophytic bacterial communities highly dominated by Firmicutes. These communities were less diverse than those formed after early-terminated pulse crops, which were dominated by Actinobacteria. High durum wheat yield was associated with the production of fewer heads m-2 and with the abundance of endophytic Actinobacteria and Acidobacteria. In contrast, low grain yield was associated with the abundance of endophytic Firmicutes. The effect of termination time was weak in 2009-2010, which was probably overridden by the extremely high amount of precipitation received during this period. The results demonstrate an important biotic legacy of crop termination time in agro-ecosystems, by influencing the endophytic bacterial colonization on the following crop. Environmental conditions appear as a key factor for the expression of this effect of crop termination time in agroecosystems

A study of fungal biodiversity in the root of durum wheat, chickpea, and pea in agro-ecosystems of Saskatchewan

Non-Peer Reviewe

Fungal surface measurements: water contact angles

Non-Peer ReviewedFungal surface properties have been implicated as one of the main factors affecting fungal colonization and adhesion to plant surfaces. Characterization of fungal surfaces through hydrophobic measurements is important for understanding its function. Water contact angles are a direct and simple approach for characterization of fungal surface hydrophobicity. The objective of this study was to evaluate if utilization of undisturbed fungal cultures coupled with versatile image analysis allow for more accurate contact angle measurements. Fungal cultures were grown on agar slide media and contact angles were measured utilizing a modified microscope and digital camera setup, with Low Bond Axisymmetric Drop Shape Analysis Model (LB_ADSA) for contact angle determination. Fungal strains were categorized into hydrophobic, hydrophilic and a newly defined hydroamphiphilic class containing fungi taxa with changing hydrophobicity