Entries by Alecia Biel

Antagonistic action of ABA and cytokinin signaling mediates drought stress response in Arabidopsis ($) (Mol Plant)

Drought stress results in a conglomeration of hormone pathways that interact to coordinate plant growth and stress response. ABA and cytokinin signaling are known to be antagonistic but it is unclear how these two pathways are connected. Huang et al. identified roles for several ARR proteins, negative regulators in cytokinin signaling, in the ABA pathway. […]

HRB2-BBX21 interaction regulates stomatal aperture

Stomata must maintain a balance between opening for carbon uptake and closing to prevent dehydration and pathogen invasion during times of stress. Kang et al. investigate this relationship, utilizing light and ABA signaling to modulate stomatal dynamics. HBR2 was identified as a chromatin-remodeling factor, corresponding to the gene PKL. The mutant hrb2 has defects in […]

Guard cells in fern stomata are connected by plasmodesmata, but control cytosolic Ca2+ levels autonomously (New Phytol)

Potassium (K+) and calcium (Ca2+) ions are important for stomatal function in seed plants,  however little is known about the contributions of these ions in the stomata of bryophytes and early-branching vascular plants. Voss et al. focus on how fern stomata regulate ion transport. Injection of K+ into guard cells (GC) activated outward ion channels, […]

RH8-PP2CA interaction in ABA signaling ($)

It is well understood that abscisic acid (ABA) inhibits PPC2A phosphatase activity, which subsequently relieves phosphate-induced inhibition of a kinase interacting partner. This pathway composes the ‘core’ ABA signaling pathway, activating process involved in the ABA response such as stomatal closure to preserve water loss. Baek et al. identified an additional player in this core […]

The ADAPTOR PROTEIN-3 complex mediates pollen tube growth by coordinating vacuolar targeting and organization (Plant Physiol)

Adaptor proteins (AP) are involved in sorting proteins and are able to recognize cargo and coat proteins during vesicle formation. AP-3 specifically targets protein cargoes to vacuoles. Feng et al. investigate the role of AP-3 in plant reproduction. ap-3 mutants have reduced seed set that is characterized by unfertilized ovules predominately at the bottom of […]

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 acid (ABA). Anderson et al. investigate the mechanism behind this patterning and the […]

Tip-localized Ca2+-permeable channels control pollen tube growth via kinase-dependent R- and S-type anion channel regulation (New Phytol.)

Calcium plays a major role in regulating pollen tube (PT) growth. Calcium levels are oscillatory in nature at the PT tip, along with anion efflux.  Calcium has been shown to regulate anion channels in guard cells through calcium protein kinase (CPK) activation. Gutermuth et al. provide evidence for a similar mechanism in PTs. They developed […]

Review. Great moments in evolution: the conquest of land by plants ($) (Curr Opin Plant Biol)

Plant occupation of land was a crucial step in evolution, without which life as we know it today would not exist. Stefan Rensing takes us on an evolutionary journey, discussing the advent of photosynthesis in cyanobacteria and eukaryotic algae, which led to atmospheric oxygen, to plant terrestrialization, which required complex processes such as the development […]

A functional study of AUXILIN-LIKE1 and 2, two putative clathrin uncoating factors in Arabidopsis (Plant Cell)

Trafficking within a cell can occur through clathrin-mediated endocytosis (CME). CME depends upon coating plasma membrane vesicles with clathrin and adaptor proteins but the mechanism is unclear in plants. Adamowski et al. establish a means with which to study this process in order to further elucidate the machinery involved in plant endocytosis. Proteins involved in […]