Evaluation of Plant Growth-Promoting Yeasts and Their Effect on Chickpea Plant Growth

Yeasts play a significant role in a wide range of fields, and the fascination they arouse stems from their incredible diversity in natural habitats. Among these habitats we focused on the soil of a unique biotope (oasis) in the Algerian Sahara, where yeasts have received little attention. For the first time, the distribution of yeasts, was determined depending on the plant and seasons. Their metabolic activity represented in the PGP effects, benefits the studied plant (chickpea) at the soil level involving the production of NH3, IAAs, the solubilization of inorganic phosphorus and zinc oxide, and even the micro-symbionts by the stimulation of nodulation. The isolated yeasts were also shown to possess PGP properties that largely exceed those of the reference strain Saccharomyces cerevisiae, with the strain RSZ1 of Kodamaea ohmeri having the best solubilization and production indices. When compared to the non-infected control and those inoculated with the reference strain S. cerevisiae, these characteristics enhanced the dry biomass yield of the examined plant by three to four or even six times. Another effect was nodulation, in which the number of nodules significantly increased compared to the control. Yeasts have a high-temperature tolerance limit of 43°C, posing a significant challenge in this biotope. This little-known role of yeasts, particularly in Algeria, is interesting, and can be used with other microorganisms as an alternative to hazardous chemical fertilizers and as bio-inputs in the improvement of healthy agricultural production, revegetation of degraded sites, and the establishment of life in these biotopes.