Entries by Philip Carella

Resistance on Tap: PDR Transporters Direct Antimicrobial Metabolites Towards Invading Pathogens

In Arabidopsis thaliana and related species within the Mustard family (Brassicaceae), the tryptophan (trp)-derived antimicrobial metabolite camalexin (3-thiazol-2-yl-indole) plays a central role in defense against bacterial, fungal, and oomycete pathogens. Upon pathogen attack, cytochrome P450 monooxygenases involved in camalexin biosynthesis (CYP71A13 and PAD3) are upregulated via the WRKY33 transcription factor, which itself is activated by […]

The EDS1-SAG101 complex regulates TNL-based immunity in Solanaceous plants (Plant Cell)

Microbial pathogens secrete virulence effector proteins into host cells to suppress basal plant defenses. Plant resistance (R) receptors induce robust immune signaling after directly or indirectly detect such effector-mediated host manipulation. In Arabidopsis, immunity transduced through many TNL (TIR-NBS-LRR) class R receptors requires heterodimeric complexes consisting of the lipase-like EDS1 (Enhanced Disease Resistance1) and sequence-related […]

ALOG transcription factors influence the morphological diversity of plant lateral organs (bioRxiv)

Land plants evolved from freshwater streptophytic algae over 450 million years ago and have since separated into morphologically diverse lineages. A key feature in the transition from aquatic to terrestrial life was the development of 3D body plans with lateral organs. In a new preprint, Naramoto and colleagues describe the identification of an evolutionarily conserved […]

PEN3 and PDR12 secrete camalexin to the apoplast to limit pathogen growth in Arabidopsis (Plant Cell)

Phytoalexins are important antimicrobial compounds that plants synthesize to fend off invading pathogens. In the Brassica family, the tryptophan (trp)-derived phytoalexin ‘camalexin’ provides broad-spectrum resistance against bacterial, fungal, and oomycete pathogens. The regulation of camalexin biosynthesis during pathogen attack is well described, however a mechanistic understanding of its transport towards invading pathogens was previously unresolved. […]

Pipecolic contributes to systemic acquired resistance in barley ($) (MPMI)

Systemic acquired resistance (SAR) is a robust long-distance immune response mediated by a diverse contingent of candidate phloem-mobile signals that prime distal uninfected tissues for enhanced resistance to future infections. The lysine-derived catabolite pipecolic acid (Pip) has emerged as a key mediator of SAR in dicot model species like Arabidopsis, however comparatively less is known […]

A simple arsenic detoxification strategy in the fern Pteris vittata ($) (Curr Biol)

Arsenic contamination is a growing human health threat. The fern Pteris vittata demonstrates a remarkable capacity to accumulate and sequester high levels of the toxic heavy metal arsenic from contaminated environments. Cai et al. used an ‘omics’-guided approach to identify and characterize the molecular mechanisms that afford arsenic tolerance in Pteris. De novo transcriptome analysis […]

The macroevolutionary history of light signaling ($) (Mol Plant)

The ability to sense and respond to light is a fundamental feature of photosynthetic organisms like plants. Much has been learned about the molecular genetic mechanisms controlling light perception and downstream signaling processes in evolutionarily young land plant lineages like angiosperms, with comparatively less knowledge in early divergent plants (bryophytes, lycophytes) or their algal predecessors. […]

Land plants recruited an ancestral bHLH for tip-growing surface cell development ($) (New Phytol)

Land plants (embryophytes) evolved from freshwater charophycean algae over 450 million years ago. The transition from aquatic to terrestrial environments likely required the evolution and expansion of genetic programs controlling three dimensional growth and the formation of tip-growing surface cells (rhizoids/root hairs) from the plant body. Bonnot et al. investigated the function and evolutionary history […]

Antagonistic responses to ‘symbiotic’ AM fungi in the non-host Arabidopsis thaliana ($) (New Phytol)

A strikingly vast array of phylogenetically distant plants are able to form intimate interactions with symbiotic arbuscular mycorrhizal (AM) fungi for the mutually beneficial exchange of nutrients. Several years of intensive research have revealed the complex regulatory networks and genetic ‘toolkits’ that enable these interactions, yet comparatively less attention is paid to understanding interactions between […]