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. Plant reproduction is a complex developmental process likely to be disrupted by the unusual environmental conditions in orbital spacecraft. Previous results, reviewed herein, indicated difficulties in obtaining successful seed production in orbit, often relating to delayed plant development during the long-term growth necessary for a complete plant life cycle. Using short-duration exposure to spaceflight,...
Abstract. The distribution of and relationship between F-actin and G-actin were investigated in pollen grains and pollen tubes of Lilium davidii Duch. using a confocal laser scanning microscope after fluorescence and immunofluorescence labeling. Circular F-actin bundles were found to be the main form of microfilament cytoskeleton in pollen grains and pollen tubes. Consistent with cytoplasmic streaming...
Abstract. The cyclin-dependent protein kinases (CDKs) have a central role in cell cycle regulation and can be inhibited by the binding of small protein CDK inhibitors. The first plant CDK inhibitor gene ICK1 was previously identified in Arabidopsis thaliana. In comparison to known animal CDK inhibitors, ICK1 protein exhibits unique structural and functional properties. The expression of ICK1 directed...
Calcium ions play a key role in the elongation and orientation of pollen tubes. We found that significant amounts of 21-kDa polypeptide were specifically released into the extracellular medium when pollen grains of lily, Lilium longiflorum Thunb., were incubated in the presence of EGTA or at low concentrations of Ca2+. This phenomenon was also dependent on pH and on the concentrations of MgCl2 in...
The regulation of developmental pathways in cultured microspores of tobacco (Nicotiana tabacum L) and snapdragon (Antirrhinum majus L) by medium pH is described for the first time. Unicellular tobacco and snapdragon microspores developed into normal, fertile pollen when cultured in media T1 and AT3 at pH7.0 and 25C for 6 and 8days, respectively. First, pollen mitosis was asymmetric and mature pollen...
The role of the heterotrimeric G-protein β-subunit in plant development was studied in transgenic tobacco (Nicotiana tabacum L.) plants with reduced β-subunit levels due to the antisense expression of the β-subunit mRNA. The antisense plants had aberrant anther shape and produced non-germinating pollen. The anthers were sporadically transformed to petals, whereas other floral organs were not affected...
In higher eukaryotes, the condensin complex is a multisubunit apparatus that plays a pivotal role in the coordinated condensation of chromatin during mitosis. The catalytic subunits, CAP-E and CAP-C, members of the SMC family of ATPases, form a heterodimer, the activity of which is controlled by the non-SMC subunits CAP-D2, CAP-G and CAP-H. Here, we report the characterization of a T-DNA insertion...
The developmental expression pattern and localization of calreticulin were studied in Nicotiana tabacum L. anthers, pollen and pollen tubes. High transcript and protein levels were detected throughout anther development. Immunolocalization of calreticulin in the anthers showed particular dense label in tapetum and pollen at developmental stage 2, when the tapetum is highly active and the pollen tetrads...
Arabidopsis UDP-sugar pyrophosphorylase (AtUSP) is a broad substrate enzyme that synthesizes nucleotide sugars. The products of the AtUSP reaction can act as precursors for the synthesis of glycolipids, glycoproteins, and cell wall components including pectin and hemicellulose. AtUSP has no close homologs in Arabidopsis and its biological function has not been clearly defined. We identified two T-DNA...
We have previously described the FERTILIZATION-RELATED KINASE 2 (ScFRK2), a MAP kinase kinase kinase from Solanum chacoense that is predominantly expressed in reproductive tissues. Overexpression of the ScFRK2 gene modifies the cell fate of ovule initials and induces homeotic transformation of ovules into carpelloid structures. Since the ScFRK2 gene is normally expressed also in anthers, we now further...
Although gene expression profile of pollen has been described, there is limited information regarding a particular phase during anther/pollen development. This work characterizes gene expression pattern at desiccation in lily (Lilium longiflorum Thunb. cv Snow Queen) anthers. We have applied a suppression-subtractive hybridization (SSH) strategy, through which 90 clones were identified and sequenced...
The proteome of mature (MP) and in vitro germinating pollen (GP) of canola (Brassica napus) were analyzed using the DIGE technology with the objective of identifying proteins and their function in pollen germination. Of the 2,238 protein spots detected in gel images, 344 were differentially expressed in MP and GP samples of which 165 were subjected to MALDI-TOF/TOF and 130 were successfully identified...
Vacuoles of several types can be observed in pollen throughout its development. Their physiological significance reflects the complexity of the biological process leading to functional pollen grains. Vacuolisation always occurs during pollen development but when ripe pollen is shed the extensive translucent vacuoles present in the vegetative parts in previous stages are absent. Vacuole functions vary...
Arabidopsis caffeoyl coenzyme A dependent O-methyltransferase 1 (CCoAOMT1) and caffeic acid O-methyltransferase 1 (COMT1) display a similar substrate profile although with distinct substrate preferences and are considered the key methyltransferases (OMTs) in the biosynthesis of lignin monomers, coniferyl and sinapoylalcohol. Whereas CCoAOMT1 displays a strong preference for caffeoyl coenzyme A, COMT1...
Commercial cultivars of garlic (Allium sativum) do not produce flowers and seed; hence, information on microgametogenesis and genetic knowledge of this important crop is unavailable. Recently, physiological studies enabled flowering and fertility restoration in garlic bolting genotypes by environmental manipulations, thus broadening of the genetic variation and facilitating genetic studies. The present...
Anterograde vesicle transport from the endoplasmic reticulum to the Golgi apparatus is the start of protein transport through the secretory pathway, in which the transport is mediated by coat protein complex II (COPII)-coated vesicles. Therefore, most proteins synthesized on the endoplasmic reticulum are loaded as cargo into COPII vesicles. The COPII is composed of the small GTPase Sar1 and two types...
The non-specific lipid transfer proteins (LTPs) constitute a large protein family found in all land plants. They are small proteins characterized by a tunnel-like hydrophobic cavity, which makes them suitable for binding and transporting various lipids. The LTPs are abundantly expressed in most tissues. In general, they are synthesized with an N-terminal signal peptide that localizes the protein to...
Main conclusion In this report, we demonstrate thatBrachypodium distachyoncould serve as a relatively high throughputin plantafunctional assay system for Triticeae anther-specific gene promoters.There remains a vast gap in our knowledge of the promoter cis-acting elements responsible for the transcriptional regulation of Triticeae anther-specific genes. In an attempt to identify conserved cis-elements,...
Main conclusion In tobacco, three sequence variants of theTERTgene have been described. We revealed unbalanced levels ofTERTvariant transcripts in vegetative tobacco tissues and enhancedTERTtranscription and telomerase activity in reproductive tissues.Telomerase is a ribonucleoprotein complex responsible for the maintenance of telomeres, structures delimiting ends of linear eukaryotic chromosomes...
Main conclusion In the wheat TCMS line YS3038, the anther development is inhibited from late uninucleate stage to the binucleate stage. The disruption of energy metabolism pathways by aberrant transcriptional regulation causes the male sterility under low temperatures. Abstract The utilization of thermosensitive male sterile (TMS) lines provides a basis for two-line breeding. Previous work, including...
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