In vitro control of Alternaria citri using antifungal potentials of Trichoderma species

The antifungal potential of five species of Trichoderma viz., Trichoderma viride, Trichoderma aureoviride,  Trichoderma reesei, Trichoderma koningii and Trichoderma harzianum was investigated in vitro against  Alternaria citri, the causal agent of the black rot disease on a broad range of citrus cultivars. Cultural filtrates of Trichoderma species were obtained by growing them on different media. The effect of different filtrate  concentrations revealed that aqueous extracts of all Trichoderma species significantly reduced the fungal  biomass of the target fungal pathogen. Generally, 100% culture filtrate of the test Trichoderma species  significantly reduced the growth of fungus. On each medium, a different response was observed. Culture filtrate of T. harzianum was found highly effective in suppressing growth (up to 93%) of the test fungal species  grown on malt extract medium. T. harzianum and malt extract medium were therefore selected for fraction  analysis. There was 68% reduction in growth of the A. citri due to 1% concentration of ethyl acetate fraction of cultural filtrate of T. harzianum when grown in malt extract broth.Key words: Citrus, Alternaria citri, ethyl acetate fraction, Trichoderma harzianum, viride, aureoviride, reesei, koningii

Effect of leaf rust infection on mycorrhizal colonization of weeds

Abstract The present study reports the effect of leaf rusts Puccinia punctiformis (Str.) Röhl., Melampsora euphorbiae (Schub.) Cast. and Uromyces rumicis (Schum.) Winter, on arbuscular mycorrhizal (AM) colonization of host weeds namely Cirsium arvense (L.) Scop., Euphorbia helioscopia L. and Rumex dentatus L., respectively. Healthy, moderately infected and severely infected plants of these test species were collected at flowering stage. Mycelial colonization was recorded in terms of percentage on the bases of presence and absence of these structures. Arbuscular and vesicular colonization were quantified by counting these structures per centimeter of root length on an average. Mycelial colonization was not significantly affected by disease in any of the three test species. There was very heavy colonization ranging from 90-100% in different healthy and diseased root samples. Response of arbuscular colonization to rust infection was variable with respect to host species. In both C. arvense and E. helioscopia effect of moderate rust infection was insignificant. Heavy disease infection significantly suppressed the number of arbuscules in C. ravens and increased in E. helioscopia. Conversely, in R. dentatus moderate rust infection significantly enhanced the number of arbuscules while heavy infection completely arrested the formation of these structures. Vesicular colonization was significantly enhanced by heavy infection in C. arvense while in E. helioscopia both moderate and heavy infections significantly reduced the number of arbuscules. In R. dentatus vesicular colonization was entirely lacking

14+ MILLION TOP 1% MOST CITED SCIENTIST 12.2% AUTHORS AND EDITORS FROM TOP 500 UNIVERSITIES Biological Control Potential of Parthenium Hysterophorus Against Fusarium Solani -A Cause of Fusarium Wilt in Potato

Abstract Fusarium wilt, caused by Fusarium solani, is potential disease of potato in Pakistan. Recent studies have shown that fungal plant pathogens can be controlled by plant products as the plant materials are biodegradable, display structural diversity and complexity. Presently the pathogenic potential and biological control of Fusarium solani was studied by inoculating potato plants with three strains of F. solani, to screen the most virulent isolate among F. solani FCBP-016, F. solani FCBP-434 and F. solani FCBP-470. It was found through pathogenicity test that F. solani FCBP-434 was the most pathogenic among three F. solani strains with variation in genetic level. This disparity in genetic constitution might be a cause of its high pathogenicity. Further, antifungal bioassays were conducted to confirm mycotoxic potential of different plant parts i.e., root, shoot and leaf of P. hysterophorus against F. solani FCBP-434 using 1, 2, 3, and 4% concentrations of the aqueous, methanol and n-hexane extracts. Bioassays revealed that among the three solvents of P. hysterophorus, the growth of F. solani FCBP-434 was greatly inhibited at 1 & 2% conc. of aqueous and methanol extracts of leaf and stem while in case of n-hexane extract 3 & 4% conc. were proved more effective. Among root extracts, the higher concentrations of aqueous and n-hexane exhibited more promising results by causing reduction of 85 & 74%, respectively, whereas in methanol extract again lower conc. were more inhibitory

Mutation of <i style="">Alternaria tenuissima </i>FCBP-252 for hyper-active <img src='/image/spc_char/alpha.gif'> -amylase

591-596 Production of extracellular α-amylase enzyme by a filamentous fungus, Alternaria tenuissima was studied in solid-state fermentation (SSF) as well as submerged fermentation (SmF). The potential strain was successfully mutated by UV and ethyl methanesulfonate (EMS). High-level of -amylase activity was obtained by the mutant At-Ch-5.6 (76.75 Units mL-1) after chemical treatment followed by UV mutant At-UV-2.8 (63.12 Units mL-1) which was significantly higher than parental A. tenuissima FCBP-252 (32 Units mL-1). These mutants with high levels of activity were genetically characterized using RAPD-PCR. Expression pattern of mutants exhibited that the mutants were isogenic variants of parent strain and out-performance of the mutants could be attributed to change in genetic make up. This work represented the first report of strain improvement in Alternaria for hyper activity of –amylase enzyme and suggested that this fungus could be used to extract purified enzyme. </smarttagtype

Fungitoxicity of aqueous and organic solvent extracts of Datura metel against Ascochyta rabiei

Abstract In vitro efficacy of aqueous and methanolic extracts of Datura metel was evaluated against Ascochyta rabiei, (the causal agent of chickpea blight) and the sensitivity of colony growth was studied in terms of inhibition zone. The inhibitory potential of all the extracts was greatest at lower concentration. The aqueous and methanol extracts of shoot of Datura metel caused 21-34% and 20-40% reduction in growth of Ascochyta rabiei whereas the root extracts proved less effective as they caused 15-25% and 11-29% reduction in growth of A. rabiei, respectively