Genome-wide analysis of the spider Pardosa pseudoannulata revealed the function of spliceosome components in cold adaptation

Organisms adapt to cold stress in winter with various molecular mechanisms. Alternative splicing (AS) is one of the most extensive mechanisms in response to cold stress in plants, but has been rarely reported in animals. Arthropods are widely distributed on earth, and overwintering poses a challenge for the population growth. Here, we investigated the role of AS in response to cold stress in arthropods using the spider Pardosa pseudoannulata as a model. We found that about 48.7 % of multi-exon genes underwent AS events in overwintering spiders collected from fields, and ∼35.3 % were alternatively spliced in cold-acclimated spiders in laboratory, showing a gradual increase as temperature decreases. Spliceosome components were concurrently regulated by cold stress in both transcription and AS aspects. Knockdown of SMB/B' and SMFa during cold acclimation impaired the regulation on AS of cold-responsive genes and led to reduced cold stress tolerance. SMB/B' and SMFa improved cold adaptation probably through regulating AS events of genes from 4 enriched pathways (spliceosome, circadian rhythm, circadian rhythm-fly, and RNA degradation), which have been reported important in tolerance to cold stress. Taken together, spliceosome components contribute to cold acclimation by ensuring the adequate splicing patterns of cold-responsive genes in the spider, and enhanced its tolerance to cold stress.