Paz Soto Elgueta

The common pea (Pisum sativum L.) is widely cultivated due to its nutritional value and adaptability, though climate change and increasing food demand require improved agricultural strategies. The genus Metarhizium, an entomopathogenic fungus, has shown potential to enhance plant growth and physiology. This study aims to evaluate the effect of naturalized Metarhizium spp. isolates on agronomic parameters and root architecture of Pisum sativum seedlings under greenhouse conditions. Fungi were isolated from rhizosphere soils using Tenebrio molitor larvae. Six Metarhizium strains and a control (sterile distilled water) were tested, with eight replicates per treatment. After 36 days, growth parameters and chlorophyll content were measured at ambient temperatures between 12.1 ± 1.5 and 42.4 ± 2.4 °C. Significant differences were analyzed using Tukey’s HSD post hoc test (p < 0.05). Significant increases in shoot length were observed in strains MM23B and MM26B (13.2 ± 0.6 and 13.0 ± 1.1 cm). Stem diameter was higher in MM23B, G9C, and MM30D (3.1–3.2 mm). Chlorophyll content increased moderately, with MM29C reaching 296.7 ± 35.9 compared to 242.5 ± 22.8 µmol m⁻² in the control. Shoot biomass was highest in G9C, MM23B, and MM26B (0.27–0.29 g) with higher shoot/root ratios in MM23B and MM26B (2.41 and 2.58). Root biomass showed no significant differences. However, root system architecture was modified, particularly in MM26B, which significantly increased root length (239.08 ± 34.22 cm) and area (20.70 ± 2.13 cm²), without changes in volume or diameter. Finally, naturalized Metarhizium spp. isolates demonstrated potential as plant growth-promoting fungi, improving physiological and morphological parameters in early P. sativum development.