*3.2. Invertebrate Collection*

The sponge, *Acanthella cavernosa*, was collected by a ROV H800 (ECA, Lannion, France) on the upper mesophotic reef of Eilat at Dekel Beach at 51 m depth in the Gulf of Aqaba, Israel (2 April 2017, 29◦32- 12.48"N; 34◦56- 55.656"E). The sponge was identified by Dr. Nicole J. de Voogd from Naturalis, Biodiversity Research Center, Leiden, the Netherlands. Collection of animals complied with a permit issued by the Israel Nature and National Parks Protection Authority.

#### *3.3. Strain Isolation and Identification*

*Chrysosporium lobatum* TM-237-S5 was isolated from a 1 cm<sup>3</sup> sample of *Acanthella cavernosa*. The invertebrate was immediately stored after collection and conserved at −20 ◦C until lab work processing. Part of the invertebrate (1 cm3) was ground in sterile sea water and heated at 50 ◦C for 1 h. The suspension was serially diluted, plated on selective isolation media, and incubated at 28 ◦C for at least 6 weeks. The strain was isolated from marine agar medium. The colony was purified on PDA and MA media and preserved in 10% glycerol solution.

Genomic DNA of the strain TM237-S5 was isolated using a DNeasy Plant Mini Kit (Qiagen), according to the manufacturer's instructions. The ITS region was amplified with primers ITS1F (5- -CTTGGTCATTTAGAGGAAGTAA -3- ) and ITS4 (5- -TCCTCCGCTTATTGATATGC) using described polymerase chain reaction (PCR) conditions [36]. Amplicons were sequenced by Sanger sequencing (GATC, Eurofins genomics), and the sequences were aligned against the non-redundant database of the NCBI using the BLASTn program. Then, phylogeny inference was performed on the Phylogeny.fr platform and comprised the following steps [37]: Sequences from TM237-S5 and representative *Chrysosporium* and *Chrysosporium*-related sequences described by Gurung et al. (2018) were aligned with MUSCLE (v3.8.31) [38]. After alignment, ambiguous regions were removed with Gblocks (v0.91b) [39]. The phylogenetic tree was reconstructed using the maximum likelihood method implemented in the PhyML program (v3.0 aLRT) [40], and reliability for internal branch was assessed using the aLRT test [41]. Graphical representation and edition of the phylogenetic tree were performed with TreeDyn (v198.3) [42]. The strain *Chrysosporium lobatum* TM237-S5 was assigned the GenBank number MN080876.

#### *3.4. Microbial Cultivation*

*Chrysosporium lobatum* TM-237-S5 spores were conserved at −20 ◦C in 10% glycerol. Before cultivation, the strain was revived for 5 days on a 15 cm petri plate containing potato dextrose agar (PDA). Sterile water (4 × 10 mL) was poured on the plate surface, and the spores were recovered from the plates by gentle scratching of the surface with a scalpel. Three plates offer 100 mL of concentrated spore suspension. Ten bottles were filled with 30 g of XAD Resin (AMBERLITE™ XAD™16HP N) and sterilized. 10 mL of Water and 10 mL of spore suspension were introduced in each resin containing bottle. The mixture was stirred, poured on a 25 × 25 cm petri plate containing PDA medium, homogeneously spread on the surface of the plate, and incubated at 27 ◦C. Preparative cultures were engaged on 10 25 × 25 cm petri plates.
