Arabidopsis abi3 mutants are altered in various aspects of seed development and germination that reflect a decreased responsiveness to the hormone abscisic acid. The ABI3 gene has been isolated by positional cloning. A detailed restriction fragment length polymorphism (RFLP) map region was constructed. An RFLP marker closely linked locus identified, analyzing an overlapping set cosmid clones containing this marker, localized within 35-kb region. 11-kb subfragment then shown complement mutant...

While few publications have documented the uptake of nanoparticles in plants, this is first study describing and distribution ultrasmall anatase TiO2 plant model system Arabidopsis. We modified nanoparticle surface with Alizarin red S sucrose demonstrated that nanoconjugates traversed cell walls, entered into cells, accumulated specific subcellular locations. Optical X-ray fluorescence microscopy coregistered vacuoles nuclei.

Smallubiquitin-like modifier (SUMO) is a member of the superfamily ubiquitin-like polypeptides that become covalently attached to various intracellular target proteins as way alter their function, location, and/or half-life. Here we show SUMO conjugation system operates in plants through characterization the<i>Arabidopsis</i> pathway. An eight-gene family encoding tag was discovered were genes enzymes required for processing, ligation, and release. A diverse array conjugates could be...

Ubiquitination of various intracellular proteins by ubiquitin-protein ligases (or E3s) plays an essential role in eukaryotic cell regulation primarily through its ability to selectively target for degradation the 26S proteasome. Skp1, Cullin, F-box (SCF) complexes are one influential E3 class that use deliver targets a core ligase activity provided and Rbx1 subunits. Almost 700 can be found Arabidopsis, indicating SCF E3s likely play pervasive plant physiology development. Here, we describe...

Ethylene inhibits hypocotyl elongation in etiolated Arabidopsis seedlings. However, when was grown the light presence of ethylene or its precursor 1-aminocyclopropane-1-carboxylic acid (ACC), a marked induction occurred. This resulted from an increase cell expansion rather than division. The effects and ACC were antagonized by action inhibitor Ag + . response absent weakened set ethylene-insensitive mutants ( etr1-3 , ein2-1 ein3-1 ein4 ain1-10 ein7 ). With exception degree inhibition...

The 26S proteasome is an essential protease complex responsible for removing most short-lived intracellular proteins, especially those modified with polyubiquitin chains. We show here that Arabidopsis mutant expressing altered RPN10 subunit exhibited a pleiotropic phenotype consistent specific changes in function. rpn10-1 plants displayed reduced seed germination, growth rate, stamen number, genetic transmission through the male gamete, and hormone-induced cell division, which can be...

The 26S proteasome is an ATP-dependent eukaryotic protease responsible for degrading many important cell regulators, especially those conjugated with multiple ubiquitins. Bound on both ends of the 20S core a multisubunit regulatory particle that plays crucial role in substrate selection by as yet unknown mechanism(s). Here, we show RPN12 subunit Arabidopsis involved cytokinin responses. A T-DNA insertion mutant affects RPN12a has decreased rate leaf formation, reduced root elongation,...

The 26S proteasome (26SP) is a multi-subunit, multi-catalytic protease that responsible for most of the cytosolic and nuclear protein turnover. 26SP composed two sub-particles, 19S regulatory particle (RP) binds unfolds targets, 20S core (20SP) degrades proteins into small peptides. Most targets are conjugated to poly-ubiquitin (Ub) chain serves as degradation signal. However, some such oxidized proteins, do not require poly-Ub tag proteasomal degradation, recent studies have shown main in...

Abstract The dynamic instability of cortical microtubules (MTs) (i.e., their ability to rapidly alternate between phases growth and shrinkage) plays an essential role in plant development. In addition, recent studies have revealed a pivotal for the response salt stress conditions. includes rapid depolymerization MTs followed by formation new MT network that is believed be better suited surviving high salinity. Although this initial adaptation stress, underlying molecular mechanism has...

In spite of the mounting concerns, current understanding extent and mechanisms phytotoxicity manufactured nanomaterials remains limited. Here we show that in Arabidopsis thaliana, ultra-small anatase TiO(2) nanoparticles cause reorganization elimination microtubules followed by accelerated 26S proteasome-dependent degradation tubulin monomers. Similar to other microtubule-disrupting agents, induce isotropic growth root cells. Because are essential for normal function all eukaryotic cells,...

Pentatricopeptide repeat (PPR) proteins belong to a family of approximately 450 members in Arabidopsis, which few have been characterized. We identified loss function alleles SLO2, defective PPR protein belonging the E+ subclass P-L-S subfamily. slo2 mutants are characterized by retarded leaf emergence, restricted root growth, and late flowering. This phenotype is enhanced absence sucrose, suggesting defect energy metabolism. The growth retardation phenotypes largely suppressed supplying...

Abstract Morphological responses of plants to shading have long been studied as a function light quality, in particular the ratio red far that affects phytochrome activity. However, changes quantity are also expected be important for response because adapt reduction overall energy input. Here, we present data on involvement auxin and ethylene low intensities. Decreased intensities coincided with increased production Arabidopsis rosettes. This was rapid reacted within minutes. In addition,...

Summary Recent genetic analyses of longevity in animals have revealed that long‐lived strains are more tolerant to environmental stresses. To investigate whether extended Arabidopsis also correlates with an increase stress tolerance, the response was tested 11 late‐flowering mutants superoxide radical‐generating herbicide paraquat. A tight correlation between flowering time and paraquat tolerance found when plants were exposed low doses herbicide. Furthermore, mutant gigantea ( gi‐3 )...

The 26 S proteasome is a multisubunit protease complex responsible for degrading wide range of intracelular proteins in eukaryotes, especially those modified with polyubiquitin chains. It composed self-compartmentalized core (CP) that houses the peptidase active sites appended on either or both ends by regulatory particle (RP) identifies appropriate substrates and translocates them into lumen CP breakdown. Here, we describe molecular biochemical properties from plant Arabidopsis thaliana....

The past decade has witnessed a tremendous increase in our understanding of the role ethylene plant development. Genes encoding enzymes biosynthesis pathway have been isolated, allowing manipulation endogenous levels intact plants. In parallel, collection mutants was obtained by using simple response assay. This resulted identification several genes involved signal transduction. data these new tools allowed long‐standing hypotheses to be tested, while gaining novel insight into function...

Abstract Although the final size of plant organs is influenced by environmental cues, it generally accepted that primary determinants are intrinsic factors regulate and coordinate cell proliferation expansion. Here, we show optimal proteasome function required to maintain shoot organ in Arabidopsis (Arabidopsis thaliana). Loss subunit regulatory particle AAA ATPase (RPT2a) causes a weak defect 26S activity leads an enlargement leaves, stems, flowers, fruits, seeds, embryos. These increases...

Abstract The hormones auxin and cytokinin are essential for plant growth development. Because of the central importance root shoot apical meristems in growth, auxin/cytokinin interactions have been predominantly analyzed relation to meristem formation function. In contrast, during organ remained largely unexplored. Here, we show that a specific interaction between operates both where it serves as an additional determinant We found at low concentrations limits action cytokinin. An increase...

The chloroplast is the main organelle for stress-induced production of reactive oxygen species (ROS). However, how chloroplastic ROS homeostasis maintained under salt stress largely unknown. We show that EGY3, a gene encoding chloroplast-localized protein, induced by and oxidative stresses. loss EGY3 function causes hypersensitivity while overexpression increases tolerance to both interacts with Cu/Zn-SOD2 (CSD2) promotes CSD2 stability conditions. In egy3-1 mutant plants, degradation limits...

The 26S proteasome is an essential multicatalytic protease complex that degrades a wide range of intracellular proteins, especially those modified with ubiquitin. Arabidopsis thaliana and other plants use pairs genes to encode most the core subunits, both isoforms often incorporated into mature complex. Here, we show gene pair encoding regulatory particle non-ATPase subunit (RPN5) has unique role in function development. Homozygous rpn5a rpn5b mutants could not be generated due defect male...