Entries by Philip Carella

Selaginella moellendorffii expression atlas provides insight into the origin and evolution of plant vasculature (bioRxiv)

Land plants (embryophytes) evolved from freshwater algal predecessors over 450 million years ago and have since separated into the morphologically diverse lineages observed today. A key feature in the expansion of plant life on land was the development of the plant vasculature and complex rooting systems. In a new preprint, Ferrari and colleagues present a […]

The QKY-SYP121 complex controls long-distance florigen movement ($) (Plant Cell)

In Arabidopsis thaliana, changes in day-length (photoperiod) activate the expression and transport of phloem-mobile florigen (FT, FLOWERING LOCUS T) to the shoot apical meristem to trigger the transition to flowering. While the role of FT as a long-distance signal is well-established, the underlying mechanisms controlling its movement from phloem companion cells (CCs) to sieve elements (SEs) […]

Some Things Never Change: Conserved MYC-family bHLH Transcription Factors Mediate dinor-OPDA Signaling in Liverworts

The lipidic phytohormone jasmonyl-isoleucine (JA-Ile) is a key mediator of stress-versus-growth signaling in vascular plants. Upon it’s accumulation, JA-Ile is detected by the F box receptor protein COI1 (CORONATINE INSENSITIVE1), which in turn leads to the ubiquitination and proteasomal degradation of JAZ (JASMONATE ZIM-DOMAIN) repressor proteins that would otherwise bind to and inhibit MYC-family bHLH […]

Die Another Way: An EDS1-SAG101 Complex Mediates TNL Immunity in Solanaceous Plants

Disease resistance (R) receptors detect pathogen effector-mediated host manipulation and induce effector-triggered immunity (ETI) that is often associated with programmed cell death. R proteins are generally conserved across plants, consisting of nucleotide-binding site and leucine rich repeat (NBS-LRR) domains alongside a variable N-terminal coiled-coil (CC) or Toll-like Interleukin receptor (TIR) domain; referred to as CNL […]

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 […]