We have isolated a dominant, auxin-insensitive mutant of Arabidopsis thaliana, massugu2 (msg2), that displays neither hypocotyl gravitropism nor phototropism, fails to maintain an apical hook as etiolated seedling, and is defective in lateral root formation. Yet other aspects growth development msg2 plants are almost normal. These characteristics similar those another mutant, non-phototropic hypocotyl4 (nph4), which loss-of-function AUXIN RESPONSE FACTOR7 (ARF7) (Harper et al., 2000)....

Organ bending through differential growth represents a major mechanism by which plants are able to adaptively alter their morphology in response local changes the environment. Two plant hormones, auxin and ethylene, have been implicated as regulators of responses; however, mechanisms they elicit effects remain largely unknown. Here, we describe isolation NPH4 gene Arabidopsis, is conditionally required for responses aerial tissues, report that encodes auxin-regulated transcriptional...

Regulated secretory vesicle delivery, fusion and rapid membrane recycling are all contentious issues with respect to tip growth in plant, fungal animal cells. To examine the organisation dynamics of movements at growing pollen tube apex address question their relationship growth, we have used stain FM4-64 both as a structural marker quantitative assay. Labelling living Lilium Longiflorum tubes by resulted distinct staining pattern apex, which corresponds spatially previously identified...

Abstract Unilateral application of indole-3-acetic acid (IAA) in a lanolin base to hypocotyls partially etiolated seedlings wild-type Arabidopsis thaliana induced growth curvature dose-dependent manner. The effects IAA concentrations from 1 1000 [mu]M were studied, with maximum IAA-induced at 100 [mu]M. Three IAA-insensitive mutants isolated and are all the same locus, massugu1 (msg1). They did not undergo hypocotyl any tested. msg1 is recessive located on chromosome 5. resistant...

The growing pollen tube provides an excellent single cell model system in which to study the mechanisms determining growth regulation, polarity and periodic behaviour. Previously, using FM4-64, we identified movements within apical vesicle accumulation that were related period of oscillatory growth. This suggested a more complex interdependence between membrane traffic, extension periodicity than previously thought. To investigate this comparison was made normally Brefeldin-A-treated,...

As indicated by various and some overlapped phenotypes of the dominant mutants, Aux/IAA genes Arabidopsis (Arabidopsis thaliana) concomitantly exhibit a functional similarity differentiation. To evaluate contributions their expression patterns determined promoter activity molecular properties gene products to function, we examined transgenic plants expressing green fluorescent protein (GFP)-tagged msg2-1/iaa19, axr2-1/iaa7, or slr-1/iaa14 cDNA MSG2 AXR2 promoter. When driven (pMSG2), each...

Plants have evolved various mechanisms that protect against the harmful effects of UV-B radiation (280–315 nm) on growth and development. Cyclobutane pyrimidine dimer (CPD) photolyase, repair enzyme for UV-B-induced CPDs, is essential protecting cells from radiation. Expression CPD photolyase gene ( PHR ) controlled by light with wavelengths including UV-B, but this regulation remain poorly understood. In study, we investigated expression wavelengths, in particular low-fluence (280 nm, 0.2...

Recovery of the root system following physical damage is an essential issue for plant survival. An injured able to regenerate by increases in lateral (LR) number and acceleration growth. The horticultural technique pruning (root cutting) application this response a common garden controlling Although widely used, molecular mechanisms underlying subsequent changes are poorly understood. In study, was employed as model study regeneration. Notably, LR defects wild-type plants treated with...

Summary Phototropism allows plants to orient their photosynthetic organs towards the light. In A rabidopsis, phototropins 1 and 2 sense directional blue light such that phot1 triggers phototropism in response low fluence rates, while both phot2 mediate this under higher conditions. results from asymmetric growth hypocotyl elongation zone depends on an auxin gradient across embryonic stem. How phototropin activation leads is still poorly understood. Members of phytochrome kinase substrate (...

We have isolated a new recessive mutant of Arabidopsis thaliana for gravitropism, endodermal-amyloplast less1 (eal1). eal1 shows reduced gravitropism in hypocotyl, and completely lacks inflorescence stems; root is not affected. Starch staining with I-KI solution reveals almost no amyloplasts hypocotyls when grown on sucrose-free medium, though the columella cells contain as many wild type. On medium containing 1% sucrose, starch granules those type, suggesting that synthesis affected eal1....

We investigated the physiological and molecular basis of lower fecundity massugu2 ( msg2 ), which is a dominant mutant an auxin primary response gene, IAA19 , in Arabidopsis thaliana . By measuring length all stamens pistils inflorescences reference growth rate pistils, we constructed curves between stages 12 15 flower development. Pistil was found to consist single exponential growth, while stamen consisted three phases. During second phase, filaments ∼10 times greater than rates other two...

Abstract Plants adapt to periodic environmental changes, such as day and night, by using circadian clocks. Cell division elongation are primary steps adjust plant development according their environments. In Arabidopsis, hypocotyl has been studied a representative model understand how the clock regulates cell elongation. However, it remains unknown whether similar phenomena exist in other organs, roots, where clocks regulate physiological responses. Here, we show that root hair is controlled...

Bokashi fertilizer, an organic fertilizer made of plant residue, has been used in Japan not only to fertilize plants but regulate their growth. Lactic acid bacteria have found play important role the fermentation process Bokashi, relationship between these and growth activity clarified. Using adzuki rooting assay, this study identified 3-phenyllactic (PLA) produced by lactic as a root promoting compound Bokashi. PLA showed synergistic effect with tryptophan, no stem elongation activity....

Glutathione S‐transferases (GSTs; EC 2.5.1.18) are encoded by a gene family. Some GSTs have the capacity to bind indole‐3‐acetic acid (IAA), whereas expression of other is regulated auxin. In order assess possible physiological significance auxin binding GST, we investigated effects auxins on activity GST expressed in Escherichia coli. cDNA cloning was carried out for fifth ( GST5 ) Arabidopsis. Although deduced amino sequence remotely related that Arabidopsis (less than 20% identical),...

Host plants benefit from legume root nodule symbiosis with nitrogen-fixing bacteria under nitrogen-limiting conditions. In this interaction, the hosts must regulate numbers and distribution patterns to control degree of maintain growth functions. The host response symbiotic occurs discontinuously but repeatedly at region behind tip growing roots. Here, live-imaging transcriptome analyses revealed oscillating gene expression approximately 6-hour intervals upon bacterial inoculation. Cytokinin...

Abstract Root development is essential for plant survival. The lack of carotenoid biosynthesis in the phytoene desaturase 3 (pds3) mutant results short primary roots (PRs) and reduced lateral root formation. In this study, we showed that short-term inhibition PDS by fluridone suppresses PR growth wild type, but to a lesser extent auxin mutants Arabidopsis (Arabidopsis thaliana). Such an activity increased endogenous indole-3-acetic acid levels, promoted signaling, partially complemented...

The ubiquitin/proteasome pathway plays a crucial role in many biological processes. Here we report novel for the Arabidopsis 19S proteasome subunit RPT2a regulating gene activity at transcriptional level via DNA methylation. Knockout mutation of did not alter global protein levels; however, activities reporter transgenes were severely reduced compared to those wild type. This silencing (TGS) was observed under control either constitutive CaMV 35S promoter or cold-inducible RD29A promoter....

rcd1 is a mutant of Arabidopsis thaliana that more resistant to methyl viologen, but sensitive ozone than the wild type. rcd1-2 caused by single nucleotide substitution results in premature stop codon at Trp-332. The mRNA level does not change significantly with mutation. Since overexpression rcd1-1 cDNA has been shown bring about an rcd1-like phenotype, we created and examined lines RCD1 use cauliflower mosaic virus 35S promoter. transgenic exhibited weak although no resistance viologen was...

Many microorganisms have been reported to produce compounds that promote plant growth and are thought be involved in the establishment maintenance of symbiotic relationships. 3-Phenyllactic acid (PLA) produced by lactic bacteria was previously shown root adzuki cuttings. However, mode action PLA as a root-promoting substance had not clarified. The present study therefore investigated relationship between auxin. found inhibit primary elongation increase lateral density wild-type Arabidopsis,...

Reflection light forms the core of our visual perception world. We can obtain vast information by examining reflection from biological surfaces, including pigment composition and distribution, tissue structure surface microstructure. However, because limitations in system, complete light, which we term 'reflectome', cannot be fully exploited. For example, may miss outside visible wavelengths. In addition, unlike insects, have virtually no sensitivity to polarization. detect non-chromatic...

We have examined the expression pattern of an auxin primary response gene, MSG2/IAA19 , during photo‐ and gravitropic responses hypocotyls using a transgenic Arabidopsis harboring promoter::GUS . The upper portion most etiolated showed uniform β‐glucuronidase (GUS) staining with strongest activity in pericycle. When were irradiated unilateral blue light, GUS on concave side was decreased, resulting differential stronger signal convex side. number differentially stained peaked at 24 h after...

Imaging analysis was carried out during the gravitropic response of etiolated Arabidopsis hypocotyls, using an IAA19 promoter fusion destabilized luciferase as a probe. From bright-field images we obtained local deflection angle to vertical, A, curvature, C, and partial derivative C with respect time, [Formula: see text]. These were determined every 19.9 µm along curvilinear length hypocotyl, at ~10 min intervals over period ~6 h after turning hypocotyls through 90° horizontal. Similarly...