P1155A Global View of Expression Dynamics across Vegetative and Reproductive Stages in Marchantia polymorpha by Deep Sequencing
Marchantia polymorpha is a dioecious liverwort representing the most basal lineage of embryophytes and thus occupies a critical position in land plant evolution. Hence, M. polymorpha lends itself as a great model to study the missing pieces of sex determination evolution. Unfortunately, the accessibility of sequence information in this liverwort is still scarce. Therefore, we employed RNA-Seq to report a comprehensive gametophyte transcriptome profile of M. polymorpha at six distinct developmental stages: vegetative male (VM) and female (VF) thalli, immature reproductive male (IMM) and female (IMF) and mature reproductive male (MM) and female (MF) reproductive structures. Around 80 million short reads were obtained and assembled into a non-redundant set of 46,533 transcripts. Expression analysis reported 6.4% genes were specifically expressed in one of the six stages indicating presence of different molecular mechanisms carrying maleness and femaleness in morphologically identical male and female thallus of the plant. In-silico data was further validated by Real-time PCR for selected transcripts which showed significant difference between developmental stages or between male and female tissues. Comparative genomic analysis between algae, liverwort, mosses and higher plants revealed that 24 Transcription Factors families out of 85 analysed, originated as Marchantia evolved and 6 of them play roles in plant sexual reproduction. Our study primarily presents an extensive and abundant amount of novel sequence information for M. polymorpha. This information will serve as a valuable genomics resource for further molecular evolutionary studies and for functional characterization of genes involved in sex differentiation and sexual reproduction of this liverwort.