Entries by Arif Ashraf

Cytoskeleton dynamics necessary for early events of lateral root initiation (Curr. Biol.)

Symmetric cell division leads to proliferation, and asymmetric cell division establishes differential growth. Formation of lateral roots (LRs) depends on asymmetric division of initially symmetric founder cells. Barro et al. studied the mechanism of asymmetric radial expansion by analyzing cytoskeleton dynamics using mutants, pharmacological drugs, and tissue-specific perturbation. They expressed MAP4 (MICROTUBULE-ASSOCIATED PROTEIN4) specifically in […]

Cytokinin functions as an asymmetric and anti-gravitropic signal in lateral roots (Nature Comms)

Lateral roots help plants to explore the soil and environmental conditions. Waidmann et al. took advantage of natural variants to understand lateral growth angle by analyzing gravitropic set point angle (GSA). Using Col-0 as a reference, lines that over- or under-respond (steeper or shallower root angle) were identified. From their genome-wide association study, the authors […]

TRANSPORTER OF IBA1 links auxin and cytokinin to influence root architecture ($) (Devel. Cell)

Indole-3-butyric acid (IBA) is the precursor of the hormone auxin and it controls the formation of lateral roots. Evidence suggests that IBA is converted to IAA, endogenous active auxin. The major study material to distinguish between IBA and IAA was highlighted by the IBA-specific efflux carrier ABCG36/PDR8/PEN3, and abcg36 mutant hyperaccumulates IBA in the root. […]

A mechanistic framework for auxin dependent Arabidopsis root hair elongation to low external phosphate (Nature Comms)

Plants respond to a low phosphate environment through increased elongation of root hairs. Bhosale et al. showed that low external P increases levels of the auxin (IAA) in Arabidopsis roots through the TAA1 (TRYPTOPHAN AMINO TRANSFERASE 1)-mediated auxin biosynthesis pathway. At the same time, the auxin influx carrier AUX1 facilitates shootward auxin transport in low-P […]

Cytokinin modulates context-dependent chromatin accessibility through the type-B response regulators ($) (Nature Plants)

The cytokinin-based response is assumed to be achieved through context-dependent transcriptional regulatory mechanisms. Potter et al. analyzed cytokinin-induced alterations in chromatin accessibility using ATAC-seq (Assay for Transposase-Accessible Chromatin using Sequencing) and combined these results with RNA-seq and  chromatin immunoprecipitation (ChIP)-seq datasets. Their results suggest that differentially accessible regions are adjacent to cytokinin-regulated genes and mostly […]

CONSTITUTIVE TRIPLE RESPONSE 1 and PIN2 coordinately regulate indeterminate root growth (Plant Sci)

Méndez-Bravo et al. explored the mechanism for the dramatic phenotype of the ctr1 mutant (CONSTITUTIVE TRIPLE RESPONSE 1), which inhibits both cell division and elongation. In the ctr1-1 mutant background, auxin response is induced at the root tip and an increase in expression of the auxin transporter PIN2 is observed. The authors also found a […]

PID/WAG-mediated phosphorylation of PIN3 mediates polarity switches during gravitropism (Sci Reports)

Auxin distribution depends on the polar localization of PIN-FORMED or PIN proteins. Based on different development and environmental stimuli, PIN proteins switch polarity to redirect the auxin flux. Additionally, phosphorylation of PIN is required for its function. For instance, PIN3 phosphorylation is required for PIN3 polarization and hypocotyl gravitropic response. Grones et al. showed that […]

A Golgi-released subpopulation of the trans-Golgi network mediates protein secretion in Arabidopsis ($)

The plant trans-Golgi network (TGN) plays the role of early endosomes and acts as hub for the both secretory and vacuolar trafficking pathways. Two types of TGN, GA-TGN (Golgi-associated TGN) and GI-TGN (Golgi-released independent TGN), have been observed in plants. Here, Uemura et al. explore the cellular and physiological roles of GI-TGN. They show that […]

A regulatory module controlling stress-induced cell cycle arrest in Arabidopsis (bioRxiv)

Progression of the cell cycle central to growth, but during stress conditions plants arrest cell cycle progression to enable the organism to survive. SUPPRESSOR OF GAMMA RESPONSE 1 (SOG1), a plant-specific NAC-type transcription factor, regulates the expression of almost all genes induced by double-strand breaks (DSBs) and consequently arrests the cell cycle in G2. Takahashi […]