Year: 2022 | Month: March | Volume 15 | Issue 1
Plant Growth Promoting Activity and Biocontrol Potential of Soil Yeast
Among soil microorganisms, yeasts have received little attention as bioonoculant and biocontrol agents in comparison to bacterial, actinomycetes, and filamentous fungal antagonists. The ability of certain taxa of yeasts to multiply rapidly, to produce antibiotics and cell wall-degrading enzymes, to induce resistance of host tissues, and to produce plant growth regulators indicates the potential to exploit them as biocontrol agents and plant growth promoters. We investigated the ability of the soil yeast Rhodotorula sp. and Candida tropicalis to stimulate plant growth promoting characters and biocontrol potential. In vitro culture experiments found that Rhodotorula sp. SY3 (623.14 ug/ml with tryptophan: 150.12 ug/ml without tryptophan) and Candida tropicalis SY5 (580.25 ug/ml - with tryptophan: 120.24 ug/ml - without tryptophan) produces large quantities of indole acetic acid (IAA), but grows rapidly on aminocyclopropane-1-carboxylate (ACC) as a sole source of nitrogen, indicative of high ACC deaminase activity. The strain also tested positive for hydrogen cyanide production, solubilisation of phosphorus and zinc. The yeast isolates significantly inhibited the Alternaria sp. and Colletotrichum sp. pathogen with Per cent inhibition of mycelial growth over control ranging between 32% and 55%. The application of the yeast crude extract could suppress population of M. javanica under laboratory conditions. In conclusion, our data confirm that soil yeast strains can promote plant growth and control pathogens, it could be considered for the development of biological fertiliser treatments.
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