Live Imaging of Phosphate Levels in Arabidopsis Root Cells Expressing a FRET-Based Phosphate Sensor.

Phosphorous (P) is an essential macronutrient in all organisms serving various fundamental biological processes, and is one of the least available plant nutrients in the soil. The application of inorganic phosphate (Pi) fertilizers is frequent, but it has a high environmental and financial cost. Breeding crops for improved Pi use-efficiency is a promising plant-based solution to pursue a reduction of fertilizer dependency.

Evidence for multiple receptors mediating RALF-triggered Ca signaling and proton pump inhibition.

Acidification of the apoplastic space facilitates cell wall loosening and is therefore a key step in cell expansion. PSY1 is a growth-promoting secreted tyrosine-sulfated glycopeptide whose receptor directly phosphorylates and activates the plasma membrane H -ATPase, which results in acidification and initiates cellular expansion. Although the mechanism is not clear, the Rapid Alkalinization Factor (RALF) family of small, secreted peptides inhibits the plasma membrane H -ATPase, leading to alkalinization of the apoplastic space and reduced growth.

Tenuazonic acid from Stemphylium loti inhibits the plant plasma membrane H -ATPase by a mechanism involving the C-terminal regulatory domain.

Pathogenic fungi often target the plant plasma membrane (PM) H -ATPase during infection. To identify pathogenic compounds targeting plant H -ATPases, we screened extracts from 10 Stemphylium species for their effect on H -ATPase activity. We identified Stemphylium loti extracts as potential H -ATPase inhibitors, and through chemical separation and analysis, tenuazonic acid (TeA) as a potent H -ATPase inhibitor.

Perspectives for using genetically encoded fluorescent biosensors in plants.

Genetically encoded fluorescent biosensors have long proven to be excellent tools for quantitative live imaging, but sensor applications in plants have been lacking behind those in mammalian systems with respect to the variety of sensors and tissue types used. How can this be improved, and what can be expected for the use of genetically encoded fluorescent biosensors in plants in the future? In this review, we present a table of successful physiological experiments in plant tissue using fluorescent biosensors, and draw some conclusions about the specific challenges plant cell biologists are faced with and some of the ways they have been overcome so far.

Do 14-3-3 proteins and plasma membrane H+-AtPases interact in the barley epidermis in response to the barley powdery mildew fungus?

14-3-3 proteins form a family of highly conserved proteins with central roles in many eukaryotic signalling networks. In plants, they bind to and activate the plasma membrane H+-ATPase, creating a binding site for the phytotoxin fusicoccin. Barley 14-3-3 transcripts accumulate in the epidermis upon inoculation with the powdery mildew fungus.