Make it grow: Pseudozyma aphidis extract promotes plant growth

Feeding the increasing global population requires higher agricultural yields while avoiding the use of harmful products. Beneficial micro-organisms provide an eco-friendly alternative to synthetic fertilizers and pesticides. We isolated a unique Pseudozyma aphidis strain demonstrating significant plant-protecting and growth-promoting activity on plants treated with live cultures. Here, we extracted and screened the most active plant growth-promoting fraction from P. aphidis and calibrated the dosage and application method. The fraction secreted by P. aphidis was applied to seeds and plants, thus eliminating the dependency on live colonies on the plants and leading to more consistent treatments with known extract concentration and repeatable results. We determined that the optimal application of the P. aphidis extract is seed coating combined with bi-weekly spraying at a concentration of 3 mg/mL. Tomato, corn, and melon plants treated with P. aphidis extract exhibited significantly enhanced germination rates shoot length, and biomass of treated tomato and melon plants. Plants treated with P. aphidis extract flowered 1 to 2 weeks earlier than the control and had increased yield. The treated tomato plants' fruit matured earlier, producing over 60% more ripe fruit than the control. The fruit also exhibited unexpectedly higher quality; it was firmer and had better flavor. We found that P. aphidis uses plant growth promotion mechanisms that include auxin-like molecules, siderophores and volatile molecule secretion. Our results highlight the potential of P. aphidis extract as an eco-friendly plant growth and crop-enhancing agent, reducing reliance on harmful agricultural inputs.