Entries by Kathleen Farquharson

Small Talk: Protons Help Calcium Get the Message Across

Calcium (Ca2+) is a versatile second messenger that controls a range of cellular processes—from pollen tube growth to stress responses—by regulating the activity of various proteins. Although Ca2+ is present at millimolar concentrations in the cell wall and vacuole, a set of channels, pumps, and buffers keeps the cytosolic free Ca2+ concentration ([Ca2+]cyt) low (in […]

In Brief: Loss of a Silencing Cascade Contributed to Indica Rice Domestication

Thousands of years of artificial selection have produced rice plants (Oryza sativa) that are vastly different from their wild progenitor species in terms of architecture, yield, and resilience. Most of the genetic changes linked to rice domestication involved genes encoding transcription factors. However, gain and loss of microRNAs (miRNAs), the class of small RNAs (21–24 […]

Microtubules Direct Lignin and Xylan Deposition in a Cellulose-Independent Manner

Although secondary cell walls represent the bulk of plant biomass, the mechanism by which cellulose, hemicellulose, and lignin assemble into a functional three-dimensional matrix is unknown. Cortical microtubules are thought to guide cellulose deposition in the plasma membrane by defining the trajectories of the cellulose synthase complex (CSC; Paradez et al., 2006), whereas hemicelluloses and […]

A Lipid Droplet-Associated Degradation System in Plants

Once viewed merely as inert packets of metabolic energy that are mobilized during postgerminative growth, lipid droplets (LDs) have emerged as dynamic organelles with important roles in processes ranging from stress responses to hormone signaling (Pyc et al., 2017). LDs consist of a core of neutral lipids surrounded by a phospholipid monolayer harboring specific structural […]

Life of PPi: Soluble PPases and H+-PPase act cooperatively to keep pyrophosphate levels in check

Inorganic phosphate (PPi) is a byproduct of many metabolic reactions, including those involved in sucrose, sugar nucleotide, and cellulose biosynthesis. Although PPi is an important phosphate donor and source of cellular energy, high levels of cytosolic PPi are toxic, disrupting the metabolic reactions that produce it. Thus, maintaining low cytosolic PPi levels, through PPi hydrolysis, […]

The Trojan Horse Approach to Protein Jockeying

In the decades since Agrobacterium tumefaciens was first used as a vector to deliver genetic material into plants (Zambryski et al., 1983), this powerful tool has provided important insights into the biological functions of countless gene products. However, this approach has its shortcomings; in addition to being time consuming, unpredictable position effects influence the expression […]

The Shifting Transcriptional Response of Corn Smut Fungus

As a biotrophic fungus, Ustilago maydis (corn smut fungus) relies on living plant tissues for sustenance. Once U. maydis cells of compatible mating types fuse on a leaf surface, they produce a dikaryotic filament with a specialized infection structure—the appressorium—that penetrates epidermal cells. Initially totally encased by the plant’s plasma membrane, the fungus then grows […]

A Novel Class of Histone Readers

Polycomb-group (PcG) proteins are part of an epigenetic memory system that regulates global gene expression throughout development in multicellular eukaryotes (Butenko and Ohad, 2011). Sophisticated mechanisms recruit high molecular weight complexes of PcG proteins to specific targets in the genome. Two major PcG complexes present in eukaryotes—POLYCOMB RESPRESSIVE COMPLEX1 (PRC1) and PRC2—each consist of four […]

A Phloem Protein Contributes to Aphid Resistance and Heat Stress Tolerance

Aphids are highly destructive insect pests—in addition to robbing plants of sugar-rich phloem sap, they carry viruses that can be deadly to the plant. To reach the phloem sap, aphids must penetrate the plasma membrane of sieve elements. Mature sieve elements, which are virtually empty, translocate carbohydrates and signaling molecules, such as RNAs and soluble […]