Recent Posts

Deep evolutionary roots for the plant hormone auxin (eLIFE)

Auxin is an endogenous plant hormone that orchestrates complex tissue development across diverse green plant lineages. In a recent article, Mutte et al. performed a deep phylogenomics analysis of known and predicted auxin signalling mechanisms present in green plants and their algal predecessors. This…

Polyamines regulate strawberry fruit ripening by abscisic acid, auxin, and ethylene (Plant Physiol)

Polyamines, which include putrescine [NH2(CH2)4NH2], spermidine [NH2(CH2)4NH(CH2)3NH2], and  spermine [NH2(CH2)3NH(CH2)4NH(CH2)3NH2], are widespread in nature. Although their mechanisms of action remain largely unresolved, they have demonstrated roles in plants ranging from abiotic stress tolerance…

Diffusible repression of cytokinin signaling produces endodermal symmetry and passage cells (Nature)

Passage cells are a subset of interspersed root endodermal cells that are unsuberized, which is thought to aid in transport because suberin inhibits transcellular transport. In Arabidopsis, suberization follows a stereotypic pattern which responds to many stress conditions, partly mediated by abscisic…

Letters: Auxin and vesicle traffic (Plant Physiol)

Three letters to Plant Physiology address the role of vesicles in auxin transport, discussing the evidence and conclusions from a recently published paper from three perspectives. Does auxin accumulate in endocytic vesicles? If so, how, and why? The Letters address both the methods used and the intrepetation…

Membrane protein MHZ3 stabilizes OsEIN2 in rice by interacting with its Nramp-like domain (PNAS)

Much of the ethylene biosynthesis and signaling pathway has been characterized from study of  the dicot Arabidopsis. In this study, Ma et al. have characterized the ethylene insensitive mutant mhz3 from rice. MHZ3 is a membrane protein localized to the endoplasmic reticulum that interacts with OsEIN2…

Regulation of Arabidopsis Brassinosteroid receptor BRI1 endocytosis and ubiquitination ($) (PNAS)

BRI1 (BRASSINOSTEROID INSENSITIVE1) is a plasma-membrane localized brassinosteroid (BR) receptor that is endocytosed to internal membranes following BR binding. In this study, Zhou, Liu et al. provide a mechanistic model of BRI1 endocytosis through ubiquitination. They identified two E3 ubiquitin ligases,…

The auxin-regulated CrRLK1L kinase ERULUS controls cell wall composition during root hair tip growth ($) (Curr Biol)

Root hair outgrowth requires the plant hormone auxin and polarized tip growth and cell wall deposition. Schoenaers et al. showed that the plasma membrane-localized receptor-like kinase ERULUS (ERU) regulates tip growth in root hairs. ERU is regulated by auxin via ARF7 and ARF19 transcription factors,…

Brassinosteroids and Hydrotropism

Soil water availability is a major constraint for crop growth throughout the world. Hydrotropism, the bending of roots in response to moisture gradients, enables plants to take better advantage of available soil water. In contrast to gravitropism and phototropism which have been studied extensively,…

Fresh as an Exitron: A Flower-specific Splice Variant of AUXIN RESPONSE FACTOR8 Helps Shape the Stamen

Eukaryotic genes contain protein-coding exons interspersed with non-coding introns. While introns are usually spliced out of mRNA (often in conjunction with various exons), intron retention usually causes mRNA to remain in the nucleus instead of being exported to the cytoplasm for translation. This process…