*2.6. Experimental Design*

The Agricultural Research Center in Giza, Egypt, provided three-week-old pepper seedlings. The consolidated seedlings were transplanted into 40 × 40 cm plastic pots, each treatment containing 6 seedlings. The pots in the green plastic house had a 1:3 mixture of sand and clay, totaling 7 kg. The pots were kept in the greenhouse at a temperature of 22 ◦C during the daylight hours and 18 ◦C at the nighttime, with a relative humidity of 70–85%. Except for the healthy control pot, the pathogenic fungus *F. oxysporum* (10<sup>7</sup> spores mL) was introduced into the soil after planting. For five days, the plants were irrigated routinely. Then, before and after flowering, a one-handed pressure sprayer was used to spray microalgae suspensions to the leaves of the plants three times (20 mL per plant once every week) at a concentration of1gL<sup>−</sup>1. Roots were soaked in 1 g of dried algae extract per kg of soil. All plants were irrigated every 72 h for the period of the experiment. The pots were arranged in three duplicates in a completely randomized design: T1-healthy control (sowing pepper seedlings in sterilized soil), T2-infected control (sowing the pepper seedlings in sterilized soil inoculated with *F. oxysporum*), T3-infected plants treated with *Desmonostoc muscorum* through the soil, T4-infected plants treated with *Anabaena oryzae* through the soil, T5-infected plants treated with *Arthrospira platensis* through the soil, T6-infected plants

treated with *Desmonostoc muscorum* through the foliar spray, T7-infected plants treated with *Anabaena oryzae* through the foliar spray and T8-infected plants treated with *Arthrospira platensis* through foliar application. For plant resistance evaluation, morphological and biochemical signals from plant samples were analyzed 45 days after sowing, and the disease was assayed.
