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ABSTRACT A complete picture of how signaling pathways lead to multicellularity is largely unknown. Previously, we generated mutations in a protein prenylation enzyme, GGB, and showed that it is essential for maintaining multicellularity in the moss Physcomitrium patens. Here, we show that ROP GTPases act as downstream factors that are prenylated by GGB and themselves play an important role in the multicellularity of P. patens. We also show that the loss of multicellularity caused by the suppression of GGB or ROP GTPases is due to uncoordinated cell expansion, defects in cell wall integrity and the disturbance of the directional control of cell plate orientation. Expressing prenylatable ROP in the ggb mutant not only rescues multicellularity in protonemata but also results in development of gametophores. Although the prenylation of ROP is important for multicellularity, a higher threshold of active ROP is required for gametophore development. Thus, our results suggest that ROP activation via prenylation by GGB is a key process at both cell and tissue levels, facilitating the developmental transition from one dimension to two dimensions and to three dimensions in P. patens.
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This content will become publicly available on November 7, 2026
Evidence for Early Evolution of Sulfated Peptide Signaling in Plant Development
Abstract In plants, the cell wall fixes the position of each cell; therefore, during development, plants rely on cellular proliferation and expansion for tissue patterning and organ formation. How plant cells communicate with neighboring cells to coordinate expansion for properly patterned tissues and organs is not well understood. In seed plants, organ growth is known to be modulated by sulfotyrosyl peptide signaling. Here, we report that the activity of TYROSYL PROTEIN SULFOTRANSFERASE (TPST), which is responsible for the post-translational modification of sulfotyrosyl peptides, is essential for expansion during development in the non-vascular plant,Physcomitrium patens. Plants that harbor a null mutation in the gene encoding TPST (Δtpst) were smaller, formed fewer caulonemal filaments, and were unable to form expanded gametophores. In Δtpstmultiple aspects of gametophore development were affected, including the first division of the gametophore initial, as well as reduced rates of cell division and expansion. Mutational analysis ofP. patensTPST identified the residue Histidine 124, a candidate catalytic residue, as essential for TPST function. Notably, addition of the sulfated signaling peptide, PSY1 from eitherP. patensorArabidopsis thaliana, rescued all Δtpstdevelopmental deficits. Taken together, these data suggest that TPST functions to sulfate PSY, and this activity is necessary for plant growth and development. Furthermore, since addition of AtPSY fully rescues Δtpstand PpPSY promotes root elongation in Arabidopsis and rice, these findings suggest that PSY signaling is evolutionarily conserved.
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- Award ID(s):
- 2436798
- PAR ID:
- 10688418
- Publisher / Repository:
- bioRxiv
- Date Published:
- Format(s):
- Medium: X
- Institution:
- bioRxiv
- Sponsoring Org:
- National Science Foundation
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