4. Conclusions
The comprehensive study on Riccia fluitans utilizing nanopore
direct RNA sequencing has unveiled critical insights into the plant’s
transcriptomic adjustments in response to environmental transitions
between terrestrial and aquatic habitats. Analysis of native mRNA
sequences revealed variations in poly(A) tail lengths, m6A
modifications, and differential expression profiling, which collectively
underscore the complex regulatory mechanisms Riccia fluitansemploys to adapt to changing environments. The identification of
specific transcripts with altered poly(A) tail lengths and m6A
modifications suggests a fine-tuned post-transcriptional regulatory
layer that responds to environmental cues. The differential poly(A) tail
length, particularly in transcripts involved in stress responses and
metabolic processes, indicates a strategic modulation of mRNA stability
and translational efficiency as an adaptation strategy. Similarly, the
variability in m6A modifications, especially in transcripts coding for
ribosomal proteins and enzymes, hints at a sophisticated mechanism to
adjust mRNA processing, translation, and decay in response to aquatic
versus terrestrial conditions. The differential expression analysis
further complements these findings by highlighting genes that are
upregulated or downregulated depending on the environment. The
downregulation of specific genes in terrestrial conditions and
upregulation in aquatic conditions reflects a robust transcriptional
response to environmental stresses and challenges. This differential
expression not only pertains to coding RNAs but also to long non-coding
RNAs and other RNA types, suggesting a broad and integrated gene
regulatory network that encompasses various RNA molecules.