Studies on the Phosphorus-Solubilizing Ability of Isaria cateinannulata and Its Influence on the Growth of Fagopyrum tataricum Plants

I. cateinannulatahas been shown to promote the growth ofF. tataricum. However, whether its growth-promoting capacity is related to its ability to solubilize phosphorus has not been reported. Therefore, in this study, we sought to assess the phosphorus-solubilizing ability of 18 strains ofI. cateinannulataby analyzing their growth in an inorganic phosphorus culture medium. The effects ofF. tataricumon growth and effective phosphorus content were analyzed through field experiments. The results showed that all 18 strains ofI. cateinannulatahad a phosphorus release capacity, with phosphorus solubilization ranging from 5.14 ± 0.37 mg/L to 6.21 ± 0.01 mg/L, and strain 9 exhibited the best phosphorus solubilization effect. Additionally, the field results demonstrated thatI. cateinannulatapositively influenced the growth, root length, and yield ofF. tataricumby increasing the chlorophyll and soluble phosphorus content. This study will provide a material basis and theoretical support for investigating the interaction mechanism betweenI. cateinannulataandF. tataricum.