Aims and Scope
Isolation, Identification and In Vitro Test for the Biocontrol Potential of Trichoderma viride on Fusarium oxysporum f. sp. LycopersiciTsegaye Mekuria Ayele, Guesh Desta Gebremariam, Subban Patharajan
Tomato production in Ethiopia is challenged by many pests and diseases. Fusarium wilt is one of the most important diseases of tomato affecting its productivity.
Tomato tissue and soil samples were collected from tomato farmlands around Aksum town to isolate and identify pathogenic Fusarium species and Trichoderma species with biocontrol efficacy. Samples were processed in the Aksum University Biotechnology laboratory following standard procedures.
Results and Discussion:
Eight Fusarium and five Trichoderma isolates were obtained. Six of the Fusarium isolates were identified as Fusarium oxysporum, whereas the remaining two were Fusarium equiseti and Fusarium circinatum. Detached leaf bioassay of the F. oxysporum on tomato leaves showed leaf lesion on the tomato variety, Melka oda. The isolated Trichoderma strains were screened for biocontrol potential against virulent F. oxysporum in vitro. The Trichoderma isolate showing the highest biocontrol efficacy against the virulent Fusarium was morphologically identified as Trichoderma viride. in vitro F. oxysporum-T. viride dual culture assay demonstrated that T. viride inhibits the growth of F. oxysporum f.sp. lycopersici with 76.94% growth inhibition.
Fusarium oxysporum is prevalent in tomato growing farmlands covered in this study. T. viride identified in this study is an effective biocontrol agent for the identified F. oxysporum fsp. lycopersici in vitro.
February 22, 2021
Isolation and Characterization of Phosphate Solubilizing Bacteria from Phosphate Solid Sludge of the Moroccan Phosphate MinesFatima Z. Aliyat, Mohamed Maldani, Mohammed El Guilli, Laila Nassiri, Jamal Ibijbijen
Although phosphorus (P) reserves in the soil are important, orthophosphate ions are the only forms of P that can be used by plants. The specificity of phosphate solubilizing bacteria (PSB) to convert insoluble forms of P to an available form Pi is an important trait to reactivate immobilized phosphorus. Therefore, the use of PSB as inoculants increases the P uptake by plants.
The present study aims at isolating and selecting the phosphate solubilizing bacteria from Phosphate Solid Sludge (PSS) in order to improve the agronomic efficacy of P fertilizers.
Materials and Method:
The strains isolated from 7 samples of phosphate sludge were tested for their ability to solubilize phosphate in NBRIP medium with Tricalcium Phosphate (TCP) as the sole source of phosphorus, strains with a high solubility index (PSI) were selected. The isolates obtained have been studied for their ability to solubilize TCP quantitatively, and their phosphate solubilizing activity was estimated by the vanadate-molybdate method. The production of Indol-1-Acetic Acid (IAA), Siderophore, and Hydrogen Cyanide (HCN) by the isolates was tested. The best strains have been identified based on 16S rRNA gene sequence comparisons.
27 strains were isolated on selective medium NBRIP from Phosphate solid sludge. They all showed significant different abilities to solubilize P. CB19 was the most efficient strain in NBRIP agar with SI= 4.79; BM11 was the most efficient strain in NBRIP liquid medium releasing 174.33μg/ml soluble P. Based on 16S rRNA gene sequence comparisons, four genera were identified: Pseudomonas, Serratia, Pantoea and Enterobacter.
The PSB isolates varied in their Phosphate solubilizing efficiency, IAA production, Siderophore, and HCN.
March 20, 2020
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