Proteome plasticity during Physcomitrium patens spore germination – from desiccation tolerance to heterotrophic growth and reconstitution of photoautotrophy

ABSTRACT: The establishment of seeds is considered a milestone in plant evolution. A major proportion of the protein networks underpinning desiccation tolerance, the accumulation of storage compounds, and the regulation of dormancy have probably evolved much earlier, however. The same is likely to be the case for the molecular program that drives the transition from heterotrophic offspring to the autotrophic plant. We hypothesized that a comparison with a bryophyte representing a distinct evolutionary lineage to seed plants may reveal the origin of components of the “seed program”. Therefore, we investigated the proteome of five timepoints of moss (P. patens) spore germination as well as protonemata and gametophores, and compared it to Arabidopsis proteome data during seedling establishment. This quantitative comparison showed that not only spores are functionally related to seeds but also the functional similarity of germinating spores and young seedlings. We observed remarkable similarities with regard to desiccation tolerance, lipid droplet proteome composition, control of dormancy, and the metabolic pathways that transform fatty acids into sugars. However, there were also striking differences. For example, the spores of P. patens did not harbor any obvious storage proteins. Furthermore, we did not detect homologs to the main triacylglycerol lipase in Arabidopsis, SUGAR DEPENDENT1. Instead, we discovered a triacylglycerol lipase of the oil body lipase family and a lipoxygenase as being the overall most abundant proteins in spores. This finding indicates an alternative pathway for triacylglycerol degradation via oxylipin intermediates in the moss.

INSTRUMENT(S): Q Exactive HF

ORGANISM(S): Physcomitrella Patens Subsp. Patens (moss)

TISSUE(S): Spore, Protonema, Gametophore

SUBMITTER: Till Ischebeck  

LAB HEAD: Till Ischebeck

PROVIDER: PXD043767 | Pride | 2023-12-15

REPOSITORIES: Pride