Arthropod Pathogen Microarray design and synthesis

Design principles used for APM oligonucleotides (70 nt) were based on previous pan-viral microarrays using ArrayOligoSelector (AOS) [54]. Briefly, array oligonucleotides were selected for uniqueness against an insect nucleic acid background, for ∼50% GC content to maintain high complexity, and for cross-reactivity of highly-conserved nucleic acid features with evolutionarily related targets (<−50 kcal/mol predicted binding energy). Arthropod pathogen oligonucleotides (GEO GPL11490) were synthesized by Invitrogen, suspended at 40 pmol/µL in 3× SSC and 0.4 pmol/µL control oligo and printed on poly-L-lysine slides (Thermo) with silicon pins as previously described [100]. Each oligonucleotide and its reverse complement were printed twice for redundancy. Arrays were allowed to air-dry and stored and room temperature. Prior to use, oligonucelotides were cross-linked to slides via UV exposure (600 mJ), washed with 3× SSC/0.2% SDS and blocked using a methylpyrrolidone solution (335 mL 1-methyl-2-pyrrolidinone, 5.5 grams succinic anhydride, 15 mL 1 M sodium borate).