Growth vigour of some Egyptian cotton variety seedlings in relation to selected rhizospheric microflora antagonistic toRhizoctonia solani Kuhn

Summary Growth responses of Ashmouni and Karnak cotton variety seedlings toRhizoctonia solani, the damping-off fungus, or toBacillus subtilis (two different strains),Aspergillus terreus andAspergillus flavus isolated from the rhizosphere of cotton, and all antagonistic to the pathogen, were expressed in terms of growth-vigour criteria.The presence ofR. solani in the soil inhibited the growth vigour of both cotton variety seedlings. However, Karnak seedlings were more sensitive to the pathogen than Ashmouni seedlings. One of the strains ofB. subtilis andA. terreus generally increased the vigour of both cotton variety seedlings.A. flavus lowered most of the growth criteria of Karnak or Ashmouni cotton seedlings.

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Zusammenfassung Rhizoctonia solani, der Parasiet von Baumwolle-Keimlingen, wurde isoliert.Sowohl Bacillus subtilis als auchAspergillus terreus und Aspergillus flavus wurden von der Rhizosphere der Baumwolle-Pflanzen isoliert. Diese Organismen wurden als antagonistisch gegenRhizoctonia solani erkannt. Die Wirkung dieser Organismen auf das Wachstum von Keimlingen der Baumwolle sorten Ashmouni und Karnak wurde untersucht. R. solani hemmt das Wachstum der Keimlinge beider Baumwolle-Sorten. Es wurde festgestellt, dass Karnak empfindlicher ist als Ashmouni. Einer der Stämme vonB. subtilis undA. terreus erwiesen sich als Wachstum förderend bei beiden Baumwolle-Sorten.A. flavus dagegen vermindert das Wachstum von Karnak und Ashmouni.

     

Antagonism between Rhizoctonia solani causing damping — off and selected rhizospheric microflora of some egyptian cotton varieties

Summary Seven bacterial isolates and many species of fungi have been isolated from the rhizospheres of Ashmouni and Karnak cotton variety seedlings. Two strains ofBacillus subtilis and two fungi, namelyAspergillus terreus andAspergillus flavus proved to be antagonistic toRhizoctonia solani on glucose — peptone agar. Other antagonistic bacterial isolates were slow growers on the agar medium, and hence were not chosen for further studies. Similarly, most of the other rhizospheric fungi of cotton were of the compatible type and were, therefore, rejected.     

Targeting ERK/COX-2 signaling pathway in permethrin-induced testicular toxicity: a possible modulating effect of matrine

Molecular Biology Reports - Permethrin (PER), the prevalent synthetic pyrethroid, was reported to have genotoxic effects along with male reproductive organs impairment. Matrine, the Chinese herb...     

Variations in the cultural characteristics of Rhizoctonia solani,and its antagonists: Aspergillus terreus and Aspergillus flavus occurring in the rhizosphere of cotton

Summary Cultural studies onRhizoctonia solani, the causal agent of damping-off of cotton, as well as on two fungi of its antagonistic rhizospheric microflora, namelyAspergillus terreus andAspergillus flavus have shown coincidence of some of their cultural characteristics. However,R. solani produced mycelial growth far ahead both antagonists except at 37° C and at pH 4, at its optimum temperature. It is expected that for a successful biological control ofR. solani in the soil,A. terreus is applied at a soil-temperatured above 35° C in an acid medium.     

Bacterial and fungal metabolites of rhizospheric microflora of cotton antagonistic to Rhizoctonia solani Kühn

Summary Growth response ofRhizoctonia solani Kühn, the damping-off fungus, to metabolites of selected antagonistic rhizospheric bacteria and fungi of some Egyptian cotton varieties, namely, two strains ofBacillus subtilis Cohn,Aspergillus terreus Thom, andAspergillus flavus Link produced in culture media containing nitrate- or ammonium-nitrogen sources, proved the potency ofB. subtilis metabolites in inhibitingR. solani mycelial growth whether from nitrate- or ammonium-nitrogen culture media. Metabolite filtrates ofB. subtilis (II) are more potent than those ofB. subtilis (I). Increasing concentration of bacterial metabolite filtrates resulted in a decreased mycelial dry weight ofR. solani. The bacterial inhibitory factor forR. solani mycelial growth is partially affected by heat. Metabolite filtrates ofA. terreus from nitrate-nitrogen are slightly more potent than from ammonium-nitrogen culture media while an opposite relation is evident withA. flavus metabolites. Growth responses ofR. solani to different experimental dilutions of metabolite filtrates ofA. terreus andA. flavus proved the intervention of the nutritive factor in witholding growth of the damping-off fungus.