The role of auxin-mediated gene activation in the bryophyte, Physcomitrium patens.

Perception and response to the hormone auxin is critical to plant growth and development. Expression of auxin-response genes is tightly regulated via known mechanisms of both activation and repression. Across the plant lineage, auxin-response gene induction is performed by AUXIN-REPSONSE FACTOR (ARF) activating transcription factors.

Clade-D auxin response factors regulate auxin signaling and development in the moss Physcomitrium patens.

Auxin response factors (ARFs) are a family of transcription factors that are responsible for regulating gene expression in response to changes in auxin level. The analysis of ARF sequence and activity indicates that there are 2 major groups: activators and repressors. One clade of ARFs, clade-D, is sister to clade-A activating ARFs, but are unique in that they lack a DNA-binding domain.

Heterologous expression of a lycophyte protein enhances angiosperm seedling vigor.

Seedling vigor is a key agronomic trait that determines juvenile plant performance. Angiosperm seeds develop inside fruits and are connected to the mother plant through vascular tissues. Their formation requires plant-specific genes, such as BREVIS RADIX (BRX) in Arabidopsis thaliana roots.

Plant PIEZO homologs modulate vacuole morphology during tip growth.

In animals, PIEZOs are plasma membrane-localized cation channels involved in diverse mechanosensory processes. We investigated PIEZO function in tip-growing cells in the moss and the flowering plant PIEZO1 and PIEZO2 redundantly contribute to the normal growth, size, and cytoplasmic calcium oscillations of caulonemal cells. Both PIEZO1 and PIEZO2 localized to vacuolar membranes.

Systematic survey of the function of ROP regulators and effectors during tip growth in the moss Physcomitrella patens.

Rho/Rac of plants (ROP) GTPases are plant-specific small GTPases that regulate cell morphology. ROP activity is controlled by several families of regulatory proteins. However, how these diverse regulators contribute to polarized growth remains understudied.

SECONDARY WALL ASSOCIATED MYB1 is a positive regulator of secondary cell wall thickening in Brachypodium distachyon and is not found in the Brassicaceae.

Grass biomass is comprised chiefly of secondary walls that surround fiber and xylem cells. A regulatory network of interacting transcription factors in part regulates cell wall thickening. We identified Brachypodium distachyon SECONDARY WALL ASSOCIATED MYB1 (SWAM1) as a potential regulator of secondary cell wall biosynthesis based on gene expression, phylogeny, and transgenic plant phenotypes.

Simultaneous imaging and functional studies reveal a tight correlation between calcium and actin networks.

Tip-growing cells elongate in a highly polarized manner via focused secretion of flexible cell-wall material. Calcium has been implicated as a vital factor in regulating the deposition of cell-wall material. However, deciphering the molecular and mechanistic calcium targets in vivo has remained challenging.

Interplay between Ions, the Cytoskeleton, and Cell Wall Properties during Tip Growth.

Tip growth is a focused and tightly regulated apical explosion that depends on the interconnected activities of ions, the cytoskeleton, and the cell wall.

Long-Term Growth of Moss in Microfluidic Devices Enables Subcellular Studies in Development.

Key developmental processes that occur on the subcellular and cellular level or occur in occluded tissues are difficult to access, let alone image and analyze. Recently, culturing living samples within polydimethylsiloxane (PDMS) microfluidic devices has facilitated the study of hard-to-reach developmental events. Here, we show that an early diverging land plant, Physcomitrella patens, can be continuously cultured within PDMS microfluidic chambers.