Characterization of Novel Trichoderma asperellum Isolates to Select Effective Biocontrol Agents Against Tomato Fusarium Wilt

El_Komy, Mahmoud H.,Saleh, Amgad A.,Eranthodi, Anas,Molan, Younes Y. The Korean Society of Plant Pathology 2015 Plant Pathology Journal Vol.31 No.1

The use of novel isolates of Trichoderma with efficient antagonistic capacity against Fusarium oxysporum f. sp. lycopersici (FOL) is a promising alternative strategy to pesticides for tomato wilt management. We evaluated the antagonistic activity of 30 isolates of T. asperellum against 4 different isolates of FOL. The production of extracellular cell wall degrading enzymes of the antagonistic isolates was also measured. The random amplified polymorphic DNA (RAPD) method was applied to assess the genetic variability among the T. asperellum isolates. All of the T. asperellum isolates significantly reduced the mycelial growth of FOL isolates but the amount of growth reduction varied significantly as well. There was a correlation between the antagonistic capacity of T. asperellum isolates towards FOL and their lytic enzyme production. Isolates showing high levels of chitinase and ${\beta}$-1,3-glucanase activities strongly inhibited the growth of FOL isolates. RAPD analysis showed a high level of genetic variation among T. asperellum isolates. The UPGMA dendrogram revealed that T. asperellum isolates could not be grouped by their antagonistic behavior or lytic enzymes production. Six isolates of T. asperellum were highly antagonistic towards FOL and potentially could be used in commercial agriculture to control tomato wilt. Our results are consistent with the conclusion that understanding the genetic variation within Trichoderma isolates and their biochemical capabilities are required for the selection of effective indigenous fungal strains for the use as biocontrol agents.

Comparative Analysis of Defense Responses in Chocolate Spot-Resistant and -Susceptible Faba Bean (Vicia faba) Cultivars Following Infection by the Necrotrophic Fungus Botrytis fabae

El-Komy, Mahmoud H. The Korean Society of Plant Pathology 2014 Plant Pathology Journal Vol.30 No.4

In this study, resistance responses were investigated during the interaction of Botrytis fabae with two faba bean cultivars expressing different levels of resistance against this pathogen, Nubaria (resistant) and Giza 40 (susceptible). Disease severity was assessed on leaves using a rating scale from 1 to 9. Accumulation levels of reactive oxygen species (ROS), lipid peroxidation and antioxidant enzymes (superoxide dismutase, catalase and ascorbate peroxidase) were measured in leaf tissues at different times of infection. The expression profiles of two pathogenesis-related proteins (PRPs) encoded by the genes PR-1 and ${\beta}$-1,3-glucanase were also investigated using reverse transcription RT-PCR analysis. The accumulation of these defense responses was induced significantly in both cultivars upon infection with B. fabae compared with un-inoculated controls. The resistant cultivar showed weaker necrotic symptom expression, less ROS accumulation, a lower rate of lipid peroxidation and higher activity of the enzymatic ROS scavenging system compared with susceptible cultivar. Interestingly, ROS accumulated rapidly in the resistant leaf tissues and peaked during the early stages of infection, whereas accumulation was stronger and more intense in the susceptible tissues in later stages. Moreover, the response of the resistant cultivar to infection was earlier and stronger, exhibiting high transcript accumulation of the PR genes. These results indicated that the induction of oxidant/antioxidant responses and the accumulation of PRPs are part of the faba bean defense mechanism against the necrotrophic fungus B. fabae with a different intensity and timing of induction, depending on the resistance levels.

Higher Expression of Toll-like Receptors 3, 7, 8, and 9 in Pityriasis Rosea

Mostafa Abou El-Ela,Rania Abdel Hay,Mohamed El-Komy,Rehab Hegazy,Amin Sharobim,Laila Rashed,Khalda Amr 대한병리학회 2017 Journal of Pathology and Translational Medicine Vol.51 No.2

Background: Pityriasis rosea (PR) is a common papulosquamous skin disease in which an infective agent may be implicated. Toll-like receptors (TLRs) play an important role in immune responses and in the pathophysiology of inflammatory skin diseases. Our aim was to determine the possible roles of TLRs 3, 7, 8, and 9 in the pathogenesis of PR. Methods: Twenty-four PR patients and 24 healthy individuals (as controls) were included in this case control study. All recruits were subjected to routine laboratory investigations. Biopsies were obtained from one active PR lesion and from healthy skin of controls for the detection of TLR 3, 7, 8, and 9 gene expression using real-time polymerase chain reaction. Results: This study included 24 patients (8 females and 16 males) with active PR lesions, with a mean age of 28.62 years. Twenty four healthy age- and sex-matched individuals were included as controls (8 females and 16 males, with a mean age of 30.83 years). The results of the routine laboratory tests revealed no significant differences between both groups. Significantly elevated expression of all studied TLRs were detected in PR patients relative to healthy controls (p < .001). Conclusions: TLRs 3, 7, 8, and 9 might be involved in the pathogenesis of PR.

Comparative Analysis of Defense Responses in Chocolate Spot-Resistant and -Susceptible Faba Bean (Vicia faba) Cultivars Following Infection by the Necrotrophic Fungus Botrytis fabae

Mahmoud H. El-Komy 한국식물병리학회 2014 Plant Pathology Journal Vol.30 No.4

In this study, resistance responses were investigatedduring the interaction of Botrytis fabae with two fababean cultivars expressing different levels of resistanceagainst this pathogen, Nubaria (resistant) and Giza 40(susceptible). Disease severity was assessed on leavesusing a rating scale from 1 to 9. Accumulation levels ofreactive oxygen species (ROS), lipid peroxidation andantioxidant enzymes (superoxide dismutase, catalaseand ascorbate peroxidase) were measured in leaf tissuesat different times of infection. The expression profilesof two pathogenesis-related proteins (PRPs) encodedby the genes PR-1 and β-1,3-glucanase were also investigatedusing reverse transcription RT-PCR analysis. The accumulation of these defense responses was inducedsignificantly in both cultivars upon infection withB. fabae compared with un-inoculated controls. Theresistant cultivar showed weaker necrotic symptomexpression, less ROS accumulation, a lower rate of lipidperoxidation and higher activity of the enzymatic ROSscavenging system compared with susceptible cultivar. Interestingly, ROS accumulated rapidly in the resistantleaf tissues and peaked during the early stages of infection,whereas accumulation was stronger and moreintense in the susceptible tissues in later stages. Moreover,the response of the resistant cultivar to infectionwas earlier and stronger, exhibiting high transcriptaccumulation of the PR genes. These results indicatedthat the induction of oxidant/antioxidant responses andthe accumulation of PRPs are part of the faba beandefense mechanism against the necrotrophic fungus B. fabae with a different intensity and timing of induction,depending on the resistance levels.

Characterization of Novel Trichoderma asperellum Isolates to Select Effective Biocontrol Agents Against Tomato Fusarium Wilt

Mahmoud H. El_Komy,Amgad A. Saleh,Anas Eranthodi,Younes Y. Molan 한국식물병리학회 2015 Plant Pathology Journal Vol.31 No.1

The use of novel isolates of Trichoderma with efficient antagonistic capacity against Fusarium oxysporum f. sp. lycopersici (FOL) is a promising alternative strategy to pesticides for tomato wilt management. We evaluated the antagonistic activity of 30 isolates of T. asperellum against 4 different isolates of FOL. The production of extracellular cell wall degrading enzymes of the antagonistic isolates was also measured. The random amplified polymorphic DNA (RAPD) method was applied to assess the genetic variability among the T. asperellum isolates. All of the T. asperellum isolates significantly reduced the mycelial growth of FOL isolates but the amount of growth reduction varied significantly as well. There was a correlation between the antagonistic capacity of T. asperellum isolates towards FOL and their lytic enzyme production. Isolates showing high levels of chitinase and β-1,3-glucanase activities strongly inhibited the growth of FOL isolates. RAPD analysis showed a high level of genetic variation among T. asperellum isolates. The UPGMA dendrogram revealed that T. asperellum isolates could not be grouped by their antagonistic behavior or lytic enzymes production. Six isolates of T. asperellum were highly antagonistic towards FOL and potentially could be used in commercial agriculture to control tomato wilt. Our results are consistent with the conclusion that understanding the genetic variation within Trichoderma isolates and their biochemical capabilities are required for the selection of effective indigenous fungal strains for the use as biocontrol agents.

Microstructure and dielectric study of pure BST and doped BSTF ceramic materials by broadband dielectric spectroscopy

H.M. Abomostafa,G.M. El-Komy,G.M. Turky 한국물리학회 2020 Current Applied Physics Vol.20 No.5

Pure BST and doped BSTF (with BSTF2: Fe2O3 2 wt % and BSTF4: Fe2O3 4 wt %) ceramics were prepared by solid state reaction. XRD pattern showed the different phases were formed depend on the weight percent of Fe2O3. The crystal size and lattice parameters increased while the lattice strain decreased. The topography of the sintered samples shows increase of the grain size with increasing Fe2O3 ratio and hence enhances the compaction of ceramics. Broadband dielectric spectroscopy was employed to investigate the effect of magnetite nanoparticle on the dielectric properties of the pure BST ceramic. The interfacial polarization and the conductivity contribution reflect the high values of permittivity and its gradual increase as frequency decreases. The two BSTF samples show relaxation peak dynamic originated from presence of immobile species/electrons at low temperatures and defects/vacancies results from the formation of oxygen vacancies originates from the spontaneous change in oxidation states of Fe ions (Fe 3+/Fe2+) at high temperatures. The relaxation rate obeys Arrhenius law at high temperatures in case of BST sample with activation energy 225 kJ/mol. This high value of activation energy at higher temperatures reflects and confirms the slowed down of the dynamics at the interphase and the decoupling nature of the OH-dynamic and the interfacial polarization.