Comparison between the Gametophyte and the Sporophyte Transcriptomes of the Endangered Fern Vandenboschia speciosa

Abstract

Genomic resources are essential to understanding the evolution and functional biology of organisms. Nevertheless, generating genomic resources from endangered species may be challenging due to the scarcity of available specimens and sampling difficulties. In this study, we compare the transcriptomes of the sporophyte and the gametophyte of the endangered fern Vandenboschia speciosa. After Illumina sequencing and de novo transcriptome assembly of the gametophyte, annotation proved the existence of cross-species contamination in the gametophyte sample. Thus, we developed an in silico decontamination step for the gametophyte sequences. Once the quality check of the decontaminated reads passed, we produced a de novo assembly with the decontaminated gametophyte reads (with 43,139 contigs) and another combining the sporophyte and in silico decontaminated gametophyte reads (with 42,918 contigs). A comparison of the enriched GO terms from the top 1000 most expressed transcripts from both tissues showed that the gametophyte GO term set was enriched in sequences involved in development, response to stress, and plastid organization, while the sporophyte GO term set had a larger representation of more general metabolic functions. This study complements the available genomic resources on the life cycle of the endangered fern Vandenboschia speciosa.