Entries by Arif Ashraf

Plant Science Research Weekly: October 11

This week’s Plant Science Research Weekly is guest edited by Arif Ashraf. He is a postdoc at Facette lab in the University of Massachusetts Amherst and his research focus is deciphering the asymmetric cell division during stomatal development. He is working as an ASPB ambassador, Plantae Fellow, Co-founder of Plant Postdoc Slack and science writer […]

BZU2/ZmMUTE controls symmetrical division of guard mother cell and specifies neighbor cell fate in maize (OA) (PLOS Genetics)

Stomatal development has been studied thoroughly in the dicot model plant Arabidopsis thaliana, but stomatal development fundamentally differs between dicot and monocot for the subsidiary cells, a pair of dumbbell-shaped cells adjacent to the guard cell, formation. In this study, Wang et al., identified an EMS mutation, bzu2-1, in maize which lacks subsidiary cells and […]

Nuclear-cytoplasmic partitioning of ARF proteins controls auxin responses ($) (Mol Cell)

ARF (Auxin Response Factor) transcription factor proteins contain three domains: an N-terminal DNA-binding domain, a variable middle region, and a C-terminal PB1 domain. Powers et al. found that ARF7 and ARF19 accumulate as large-order assemblies in the cytoplasmic region of mature root cells, but the cytoplasmic signal disappears in the actively dividing cells. They showed […]

Evolution of fast root gravitropism in seed plants (Nature Comms)

Plants’ invasion of land was accompanied by the evolution of a root system which in seed plants includes a fast gravitropic response. Gravitropism occurs through three distinct steps – (1) gravity perception by dense starch-filled amyloplasts, (2) transmission of gravitropic signal by auxin through auxin influx (AUX1/LAX) and efflux (PIN) carriers, (3) gravity-stimulated root growth […]

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 […]