Biology subjects

Procko, C.

Publications and source records attributed to Procko, C..

3 recordsLinked to original sources

bioRxiv2022

Leaf hydraulic maze; Differential effect of ABA on vascular bundle-sheath, palisade, and spongy mesophyll controlling hydraulic conductance

Leaf hydraulic conductance (Kleaf) facilitates the movement of water for transpiration, enabling continual CO2 uptake while the plant maintains its water status. We hypothesized that bundle-sheath and mesophyll cells play key roles in regulating the radial flow of water out of the xylem under optimal and stress conditions. To examine that hypothesis, we generated transgenic Arabidopsis plants that were insensitive to abscisic acid (ABA) in their bundle sheath (BSabi) or mesophyll (MCabi) cells. Both BSabi and MCabi plants showed greater Kleaf and transpiration under optimal conditions. Yet, the stomatal apertures, stomatal indices and vein densities of the BSabi plants were similar to those of WT plants. MCabi plants had larger stomatal apertures, a higher stomatal index and greater vascular diameter and biomass, relative to the WT and BSabi. In response to xylem-fed ABA, both transgenic and WT plants reduced their Kleaf and transpiration. However, leaf water potential was reduced only in the WT. The membrane osmotic water permeability (Pf) of the WTs spongy mesophyll was higher than that of its palisade mesophyll. Moreover, only the spongy cells reduced their Pf in response to ABA. ABA-insensitive spongy mesophyll cells had a low Pf; whereas ABA-insensitive bundle-sheath cells had a higher Pf. Palisade cells maintained a low Pf at all ABA levels. ABA increased the symplastic water pathway, but its contribution to Kleaf was negligible. We suggest that the bundle sheath-spongy mesophyll pathway may control Kleaf to maintain steady-state conditions in the palisade cells and optimal whole-leaf water-use efficiency.

plant biology↗

bioRxiv2020

Stretch-activated ion channels identified in the touch-sensitive structures of carnivorous Droseraceae plants

In response to touch, some carnivorous plants such as the Venus flytrap have evolved spectacular movements to capture animals for nutrient acquisition. However, the molecules that confer this sensitivity remain unknown. We used comparative transcriptomics to show that expression of three genes encoding homologs of the MscS-Like (MSL) and OSCA/TMEM63 family of mechanosensitive ion channels are localized to touch-sensitive trigger hairs of Venus flytrap. We focus here on the candidate with the most enriched expression in trigger hairs, the MSL homolog FLYCATCHER1 (FLYC1). We show that FLYC1 transcripts are localized to mechanosensory cells within the trigger hair, transfecting FLYC1 induces chloride-permeable stretch-activated currents in naive cells, and transcripts coding for FLYC1 homologs are expressed in touch-sensing cells of Cape sundew, a related carnivorous plant of the Droseraceae family. Our data suggest that the mechanism of prey recognition in carnivorous Droseraceae evolved by co-opting ancestral mechanosensitive ion channels to sense touch.

plant biology↗

bioRxiv2020

C. elegans REMO-1, a glial GPCR, regulates stress-induced nervous system remodeling and behavior

Animal nervous systems remodel following stress. Although global stress-dependent changes are well documented, contributions of individual neuron remodeling events to animal behavior modification are challenging to study. In response to environmental insults, C. elegans become stress-resistant dauers. Dauer entry induces amphid sensory-organ remodeling, in which bilateral AMsh glial cells expand and fuse, allowing embedded AWC chemosensory neurons to extend sensory receptive endings. We show that amphid remodeling accelerates dauer exit upon exposure to favorable conditions, and identify a G protein-coupled receptor, REMO-1, driving AMsh glia fusion, AWC neuron remodeling, and dauer exit. REMO-1 is expressed in and localizes to AMsh glia tips, is dispensable for other remodeling events, and promotes stress-induced expression of the remodeling receptor tyrosine kinase VER-1. Our results demonstrate how single-neuron structural changes affect animal behavior, identify key glial roles in stress-induced nervous system shape changes, and demonstrate that remodeling primes animals to respond to favorable conditions.

neuroscience↗