Systemic Resistance in Chickpea (Cicer arietinum L.) Elicited by Some Biotic Inducers Against Root Diseases

The effect of seed treatment of chickpea (Cicer arietinum L.) with biotic inducers such as Trichoderma viride, Trichoderma harzianum, Pseudomonas fluorescens and Bacillus subtilis in contrast to the fungicide Rizolex-T, were evaluated in the greenhouse and under field conditions during the 2017/2018 season to control the plant disease caused by Fusarium oxysporum, Rhizoctonia solani, or Sclerotinia sclerotiorum, at Giza Agriculture Research Station, Agricultural Research Center, Giza Governorate, Egypt. The tested strains significantly inhibit the mycelial growth of the three tested fungi for pathogenic growth. Compared to the untreated control under greenhouse and field conditions, all the biotic inducer treatments tested significantly decreased the percentages of damping-off, root rot, stem rot and/or wilt diseases. It was noticed that Rizolex-T and (Trichoderma viride + Trichoderma harzianum) have reached the highest percentage of surviving plants followed by (Pseudomonas fluorescens + Bacillus subtilis), Trichoderma viride, Trichoderma harzianum, Bacillus subtilis, Pseudomonas fluorescens and Serratia marcescens, respectively. As well as all the treatments of the checked biocontrol agents increased the growth and yield parameters of chickpea significantly, i.e., plant hight, branches number per plant, pods number per plant, seeds number per plant, seeds weight per plant, 100 seeds weight, and chickpea yield ton/fed. In the presence of the three studied pathogens, defense-related enzyme activities (β-1,3 glucanase, peroxidase, and polyphenoloxidase) have also been determined in all chickpea plants treated with tested biotic inducers compared to untreated infested and non-infested control. The treatment of (Trichoderma harzianum + Trichoderma viride) showed the highest increase in phenol content and the activities of defense-related enzymes

Evaluation of Antimicrobial bioactive compounds from Endophytic Fungi Isolated from Moringa oleifera

Endophytic fungi are microorganisms that inhabit the living tissues of their host plants without causing any host loss. They are considered as a continuous natural source of novel bioactive secondary metabolites with potential application in medicine, which are almost same to their host plant. In this study a total of nine endophytic fungal isolates were collected from leaves and stems of Moringa oleifera. Based on the colonization frequency (CF) results, the highest number of isolates was obtained from plant stem, while the least was from leaves. The nine isolates were identified by keeping track of morphological and microscopic observations. Identification of the two antimicrobial potent strains was confirmed by 18S rDNA-based molecular analysis. The nine isolates were found belonging to Chaetomium, Alternaria, Fusarium, Aspergillus, Mycelia, Penicillium and Nigrospora taxa. Among them, Chaetomium taxon was included the highest CF) 40% (. Evaluation of antimicrobial activity documented ethyl acetate fungal extract as the highest effective inhibitor against Gram-negative and Gram-positive bacteria, and Aspergillus fumigatus. Minimum inhibitory concentration (MIC) was examined for the two most potent antimicrobial effective extracts, from Chaetomium laterale and Chaetomium interruptum; it was ranged from 12.5 to 0.39 mg/ml

Evaluation of the Native Killer Yeasts against the Postharvest Phytopathogenic mould of Balady Orange Fruits

Yeasts are some of the most important postharvest biocontrol agents (BCAs). Postharvest oranges frequently deteriorate due to green and blue moulds, leading to significant economic losses. The purposes of the present study were to isolate blue and green moulds from infected orange fruits, to assess the ability of killer yeasts isolated from healthy orange fruits and leaves from orange orchards to control blue and green moulds and to evaluate the additive effect of BCAs in combination with 2% sodium bicarbonate (SBC), 2%, sodium benzoate (SB), 2% calcium chloride, 0.2% salicylic acid (SA) or 0.5% chitosan. Among eight fungi isolated from orange fruits showing symptoms of green and blue mulds infection, two were identified as P. digitatum and P. italicum and selected for in vitro assays. Twenty eight yeast isolates were obtained from orange leaves and from the surface of fruits. All yeasts exhibited high killer activity. Twelve yeasts reduced 22.5 –70% of P. digitatum growth while seven isolates reduced 21.1- 68.5% of P. italicum growth. The most potent yeast isolates were identified as Candida pseudotropicalis, Candida salmanticensis, Candida membranifaciens and Pichia guilliermondii. Combination of the BCAs, C. pseudotropicalis, C. salmanticensis and P. guilliermondii with SBC, CaCl2 or chitosan increased their effectiveness against P. digitatum. While combination of C. pseudotropicalis, C. membranifaciens and P. guilliermondii with these natural compounds decreased their effectiveness against P. italicum. Combination of C. membranifaciens with SA increased its effectiveness against P. digitatum. Sodium benzoate has additive effect on C. pseudotropicalis against P. digitatum and C. pseudotropicalis and P. guilliermondii against P. italicum

Rock phosphate solubilization by Aspergillus species grown on olive-cake waste and its application in plant growth improvement

Egyptian Journal of Biology Vol.3 2001: 89-9

Optimization and molecular identification of novel cellulose degrading bacteria isolated from Egyptian environment

Cellulase producing bacteria were isolated from both soil and ward poultry, using CMC (carboxymethylcellulose) agar medium and screened by iodine method. Cellulase activity of the isolated bacteria was determined by DNS (dinitrosalicylic) acid method. The highly cellulolytic isolates (BTN7A, BTN7B, BMS4 and SA5) were identified on the basis of Gram staining, morphological cultural characteristics, and biochemical tests. They were also identified with 16S rDNA analysis. The phylogenetic analysis of their 16S rDNA sequence data showed that BTN7B has 99% similarity with Anoxybacillus flavithermus, BMS4 has 99% similarity with Bacillus megaterium, SA5 has 99% homology with Bacillus amyloliquefaciens and BTN7A was 99% similar with Bacillus subtilis. Cellulase production by these strains was optimized by controlling different environmental and nutritional factors such as pH, temperature, incubation period, different volumes of media, aeration rate and carbon source. The cellulase specific activity was calculated in each case. In conclusion four highly cellulolytic bacterial strains were isolated and identified and the optimum conditions for each one for cellulase production were determined. These strains could be used for converting plant waste to more useful compounds