Entries by Philip Carella

Close Encounters of the ARF Kind: Proximity-based ARF1 GTPase Activity Regulates Vesicle Trafficking

ADP-RIBOSYLATION FACTOR (ARF) proteins play essential roles in vesicle trafficking by regulating the formation of membrane vesicles that move cargo throughout the cell. Their activity is controlled by specific guanine exchange factors (ARF-GEFs) that activate ARFs by catalyzing a GDP to GTP exchange that ultimately recruits vesicle coat proteins, and by ARF-GAPs (GTPase ACTIVATING PROTEINs) […]

Stop the FUSS: BPCs restrict FUSCA3 transcription to promote ovule and seed development

Tightly controlled genetic programs regulate developmental phase transitions within distinct tissues and cells. This is especially true for the vegetative-to-reproductive and reproductive-to-seed developmental phase changes that ensure the production of gametes capable of generating viable seed upon fertilization. The LAFL transcription factors LEC2 (LEAFY COTYLEDON2), ABI3 (ABA INSENSITIVE3), FUS3 (FUSCA3), and LEC1 (LEAFY COTYLEDON1) have […]

Good Fats, Bad Fats: Phosphoinositide Species Differentially Localize to Plant-Pathogen Interfaces and Influence Disease Progression

Many filamentous pathogens invade living plant cells with specialized intracellular infection structures (haustoria) that promote microbial growth. Cytological studies demonstrate that the haustoria of fungal and oomycete pathogens are separated from host cell cytoplasm by a highly differentiated and de novo-formed extra-haustorial membrane (EHM). The differentiated EHM that surrounds invading haustoria, or the differentiated membrane […]

Xylem-mobile Oxylipins are Critical Regulators of Induced Systemic Resistance in Maize

In addition to promoting plant growth and development, the colonization of roots by beneficial microorganisms often provides aboveground tissues with enhanced resistance to pathogen attack. This form of resistance, referred to as ‘induced systemic resistance’ (ISR), relies on the long-distance movement of root-derived signals that travel through the vasculature to access and prime defenses in […]

Mellowed Yellow: WHITE PETAL1 Regulates Carotenoid Accumulation in Medicago Petals

Carotenoids are tetraterpenoid (C40) lipophilic compounds that are widely distributed in nature and play key roles in pigmentation, photosynthesis, and development (Nisar et al., 2015). Detailed biochemical and genetic analyses have uncovered the carotenoid biosynthetic pathway, which generates a diverse array of molecules that are either colorless or impart red (lycopene), orange (carotene), or yellow […]

Moving on Up: An MCTP-SNARE Complex Mediates Long-distance Florigen Transport

Flowering plants integrate endogenous and external cues to accurately time the transition from vegetative to reproductive growth (Cho et al., 2017). Many plants, including Arabidopsis thaliana, sense changes in day length (photoperiod) to transition to flowering as the season changes. Decades of careful molecular genetic dissections have uncovered the photoperiod-induced flowering pathway of Arabidopsis, which […]

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 […]