PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Plant Development”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 685 records · Page 38Linked to original sources
PubMed2002

Local and differential control of vegetative storage protein expression in response to herbivore damage in Arabidopsis thaliana.

Vegetative storage proteins (VSPs) are thought to fulfil important nutritional roles during plant development and stress adaptation. Plant responses to mechanical wounding and herbivore damage include an activation of VSP expression. It was recently suggested that vsp is part of the systemic response of Arabidopsis to wounding. To test this proposal, we monitored the spatial regulation of vsp mRNAs and VSP proteins. Arabidopsis contains two vsp genes and real-time quantitative PCR allowed us to characterize their differential expression. The ratio of vsp1 to vsp2 mRNA abundance increased when plants were challenged with diamondback moth larvae or Egyptian cotton worms, but not when they were mechanically wounded. We observed a dramatic increase of vsp1 and vsp2 mRNA as well as VSP protein levels in leaves that experienced herbivore damage. By contrast, there was a relatively minor increase of vsp mRNA and VSP protein levels in undamaged leaves of infested plants. These results clearly demonstrate that VSPs are part of the local plant response to herbivore attack. To obtain additional information on vsp regulation, we analysed a fusion of a soybean vspB promoter fragment to the beta-glucuronidase gene in transgenic Arabidopsis plants. The vspB promoter responded to both jasmonate and herbivore treatments, suggesting that similar signals regulate its expression in both plant species.

Journal Article↗
PubMed2006

OEP37 is a new member of the chloroplast outer membrane ion channels.

The chloroplast outer envelope protein OEP37 is a member of the growing beta-barrel protein family of the outer chloroplast membrane. The reconstituted recombinant protein OEP37 from pea forms a rectifying high conductance channel with a main conductance (lambda) of Lambda= 500 picosiemens (symmetrical 250 mm KCl). The OEP37 channel is cation-selective (P(K+)/P(K-) = 14:1) with a voltage-dependent open probability maximal at V(mem) = 0 mV. The channel pore reveals an hourglass-shaped form with different diameters for the vestibule and restriction zone. The diameters of the vestibule at the high conductance side were estimated by d = 3.0 nm and the restriction zone by d = 1.5 nm. The OEP37 channel displayed a nanomolar affinity for the precursor of the chloroplast inner membrane protein Tic32, which is imported into the chloroplast through a yet unknown pathway. Pre-proteins imported through the usual Toc pathway and synthetic control peptides, however, did not show a comparable block of the OEP37 channel. In addition to the electrophysiological characterization, we studied the gene expression of OEP37 in the model plant Arabidopsis thaliana. Here, transcripts of AtOEP37 are ubiquitously expressed throughout plant development and accumulate in early germinating seedlings as well as in late embryogenesis. The plastid intrinsic protein could be detected in isolated chloroplasts of cotyledons and rosette leaves. However, the knock-out mutant oep37-1 shows that the proper function of this single copy gene is not essential for development of the mature plant. Moreover, import of Tic32 into chloroplasts of oep37-1 was not impaired when compared with wild type. Thus, OEP37 may constitute a novel peptide-sensitive ion channel in the outer envelope of plastids with function during embryogenesis and germination.

Arabidopsis↗
PubMed2003

The effects of air flow and stem flexure on the mechanical and hydraulic properties of the stems of sunflowers Helianthus annuus L.

Many studies have shown that wind affects plant development, causing them to develop shorter and usually stronger stems. Many of these effects have been shown to be due to a response to mechanical flexing of the stem which is known as thigmomorphogenesis. However, it is not known how wind affects the hydraulic properties of stems, nor have the effects of air flow past leaves been examined in isolation from mechanical flexing. This study, therefore, used a factorial experiment to distinguish between the effects of stem flexing and air flow, and examined the morphology, hydraulics and mechanics of developing sunflowers Helianthus annuus. It was found that flexure and air flow had opposite effects on several aspects of development; air flow increased plant height and length-specific stem hydraulic conductivity, k(h), and reduced stem rigidity and strength, while flexing did the reverse. There was also a clear trade-off between hydraulic and mechanical capability: as one increased the other decreased. A plant's response to wind must, therefore, be a complex response to at least two different stimuli and this might help explain why it varies with species and environment.

Algorithms↗
PubMed2004

Expression of cyanobacterial genes involved in heterocyst differentiation and dinitrogen fixation along a plant symbiosis development profile.

Members of the cyanobiont genus Nostoc, forming an endosymbiosis with members of the angiosperm genus Gunnera, undergo a number of characteristic phenotypic changes during the development of the symbiosis, the genetic background of which is largely unknown. Transcription patterns of genes related to heterocyst differentiation and dinitrogen fixation and corresponding protein profiles were examined, using reverse transcription-polymerase chain reaction and Western blots, along a developmental (apex to mature parts) sequence in Gunnera magellanica and G. manicata and under mimicked symbiotic conditions in a free-living Gunnera isolate (Nostoc strain 0102). The hetR gene was highly expressed and correlated positively with an increase in heterocyst frequency and with ntcA expression, whereas nifH expression was already high close to the growing apex and glnB (P(II)) expression decreased along the symbiotic profile. Although gene expression appeared to be regulated to a large extent in the same fashion as in free-living cyanobacteria, significant differences were apparent, such as the overexpression of both hetR and ntcA and the contrasting down-regulation of glnB, features indicating important regulatory differences between symbiotic and free-living cyanobacteria. The significance of these findings is discussed in a symbiotic context.

Bacterial Proteins↗
PubMed2003

Changes in gene expression in Arabidopsis shoots during phosphate starvation and the potential for developing smart plants.

Our aim was to generate and prove the concept of "smart" plants to monitor plant phosphorus (P) status in Arabidopsis. Smart plants can be genetically engineered by transformation with a construct containing the promoter of a gene up-regulated specifically by P starvation in an accessible tissue upstream of a marker gene such as beta-glucuronidase (GUS). First, using microarrays, we identified genes whose expression changed more than 2.5-fold in shoots of plants growing hydroponically when P, but not N or K, was withheld from the nutrient solution. The transient changes in gene expression occurring immediately (4 h) after P withdrawal were highly variable, and many nonspecific, shock-induced genes were up-regulated during this period. However, two common putative cis-regulatory elements (a PHO-like element and a TATA box-like element) were present significantly more often in the promoters of genes whose expression increased 4 h after the withdrawal of P compared with their general occurrence in the promoters of all genes represented on the microarray. Surprisingly, the expression of only four genes differed between shoots of P-starved and -replete plants 28 h after P was withdrawn. This lull in differential gene expression preceded the differential expression of a new group of 61 genes 100 h after withdrawing P. A literature survey indicated that the expression of many of these "late" genes responded specifically to P starvation. Shoots had reduced P after 100 h, but growth was unaffected. The expression of SQD1, a gene involved in the synthesis of sulfolipids, responded specifically to P starvation and was increased 100 h after withdrawing P. Leaves of Arabidopsis bearing a SQD1::GUS construct showed increased GUS activity after P withdrawal, which was detectable before P starvation limited growth. Hence, smart plants can monitor plant P status. Transferring this technology to crops would allow precision management of P fertilization, thereby maintaining yields while reducing costs, conserving natural resources, and preventing pollution.

Arabidopsis↗
PubMed1999

Transgenic overexpression of the transcription factor alfin1 enhances expression of the endogenous MsPRP2 gene in alfalfa and improves salinity tolerance of the plants

Alfin1 cDNA encodes a putative transcription factor associated with NaCl tolerance in alfalfa (Medicago sativa L.). The recombinant protein binds DNA in a sequence-specific manner, including promoter fragments of the NaCl-inducible gene MsPRP2. Alfin1 function was tested in transgenic alfalfa under the control of the 35S promoter in the sense and antisense orientations with the endogenous MsPRP2 as a reporter gene. Calli overexpressing Alfin1 were more resistant to growth inhibition by 171 mM NaCl than vector-transformed controls, whereas calli expressing Alfin1 in the antisense orientation were more sensitive to NaCl inhibition. Transgenic plants overexpressing Alfin1 in the sense orientation grew well. In contrast, the antisense transgenic plants grew poorly in soil, demonstrating that Alfin1 expression is essential for normal plant development. Transgenic calli and plant roots overexpressing Alfin1 showed enhanced levels of endogenous MsPRP2 mRNA accumulation. However, MsPRP2 mRNA accumulation was also regulated in a tissue-specific manner, as shown in leaves of transgenic plants overexpressing Alfin1. These results suggest that Alfin1 acts as a transcriptional regulator in plants and regulates MsPRP2 expression in alfalfa. Alfin1 overexpressing transgenic plants showed salinity tolerance comparable to one of our NaCl-tolerant plants, indicating that Alfin1 also functions in gene regulation in NaCl tolerance.

Journal Article↗
PubMed1972

Translocation and Metabolism of Ricinine in the Castor Bean Plant, Ricinus communis L.

Ricinine-3,5-(14)C (N-methyl-3-cyano-4-methoxy-2-pyridone) administered to senescent leaves of Ricinus communis L. was translocated to all other tissues of the plant. Developing fruit and especially seeds were found to be labeled the most rapidly. Young growing leaves and other developing tissues of the plant imported ricinine from the senescent leaves much more quickly than mature leaves. Relative intensities of the radioactive ricinine imported and deposited in various tissues indicate a possible functional role of ricinine in the castor bean plant. Data on N-demethyl ricinine presented here may stimulate interest in the possible physiological role of the ricinine to N-demethyl ricinine interconversion.

Journal Article↗
PubMed1995

CUE1: A Mesophyll Cell-Specific Positive Regulator of Light-Controlled Gene Expression in Arabidopsis.

Light plays a key role in the development and physiology of plants. One of the most profound effects of light on plant development is the derepression of expression of an array of light-responsive genes, including the genes encoding the chlorophyll a/b binding proteins (CAB) of photosystem II. To understand the mechanism by which light signals nuclear gene expression, we developed a genetic selection to identify mutants with reduced CAB transcription. Here, we describe a new Arabidopsis locus, CUE1 (for CAB underexpressed). Mutations at this locus result in defects in expression of several light-regulated genes, specifically in mesophyll but not in bundle-associated or epidermis cells. Reduced accumulation of CAB and other photosynthesis-related mRNAs in the mesophyll was correlated with defects in chloroplast development in these cells, resulting in a reticulate pattern with veins greener than the interveinal regions of leaves. Moreover, chalcone synthase mRNA, although known to be regulated by both phytochrome and a blue light receptor, accumulated normally in the leaf epidermis. Dark basal levels of CAB expression were unaffected in etiolated cue1 seedlings; however, induction of CAB transcription by pulses of red and blue light was reduced, suggesting that CUE1 acts downstream from both phytochrome and blue light photoreceptors. CUE1 appears to play a role in the primary derepression of mesophyll-specific gene expression in response to light, because cue1 mutants are severely deficient at establishing photoautotrophic growth. Based on this characterization, we propose that CUE1 is a cell-specific positive regulator linking light and intrinsic developmental programs in Arabidopsis leaf mesophyll cells.

Journal Article↗
PubMed1999

[Development and prospect of plant mutation breeding induced by aviation and spaceflight in China].

Since 1987, about fifty species, three hundred varieties of crops have been sent in recoverable satellites or high altitude balloon (HAB). The selected lines include a high-yield, disease-resist, and hybrid-vigorous rice line, a recovered line of Japonica rice restoring sterility of Indica rice, a new green pepper strain which grows fruits over 500 g, a disease-resist, high-quality tomato line, a big-pod rape line, a big-fruit white lotus line and a big-bulb lily. The special conditions in the outer space can induce a variety of mutations in the plants and their progeny, which provides a new way for the plant breeding.

Agriculture↗
PubMed2002

The role of cell wall in plant embryogenesis.

This review presents recent data about cell wall involvement in plant embryogenesis. During plant development, the cell wall is subjected to precise regulation. During this process a bidirectional information exchange between the cell wall and the protoplast is observed. The cell wall also mediates in the cell-cell (apoplastic) and cell to cell (symplastic) information flow. Especially some products derived from the hydrolysis of specific cell wall compounds can act as short distance signal transduction molecules during the development. Oligosaccharins are a group of such products. Their activity and sources focused the researchers' attention on the biochemical composition of the cell wall and the activity of some cell wall enzymes. The dramatic influence on the embryo body shape has also the cell wall synthesis machinery, including vesicular secretion pathways. Moreover, the interplay between the turgor pressure and counteracting cell walls and neighbouring cells (in higher organisms) creates the specific mechanical forces influencing the development of the whole plant. We conclude that discovering factors which can influence cell wall physiology and architecture is crucial for a better understanding of plant embryogenesis. In this review we summarize some recent experimental data reporting plant cell wall involvement in embryogenesis, putting special emphasis on somatic embryogenesis.

Cell Wall↗