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1.
An active transport system for small peptides occurs in the scutellar membrane of germinating barley and serves to move the products of partial hydrolysis of storage proteins from the endosperm into the growing embryo. Transport of peptides, but not amino acids or glucose, is inhibited by the thiol reagents, N-ethylmaleimide and p-chloromercuribenzene sulphonic acid (PCMBS). Peptide substrates protect against PCMBS inactivation. The dithiol-specific reagent, phenylarsine oxide (PAO) also inhibits. The reducing agent, dithiothreitol, reverses the inactivation caused by PCMBS and PAO. We conclude that the peptide transport system contains a redox-sensitive, dithiol-dependent protein. 相似文献
2.
Yizhong Wang Qin Hu Zhenjiang Wu Hui Wang Shiming Han Ye Jin Jin Zhou Zhengfeng Zhang Jiafu Jiang Yun Shen Huazhong Shi Wannian Yang 《Plant, cell & environment》2017,40(12):2972-2986
Plant defence mechanisms are suppressed in the absence of pathogen attack to prevent wasted energy and growth inhibition. However, how defence responses are repressed is not well understood. Histone deacetylase 6 (HDA6) is a negative regulator of gene expression, and its role in pathogen defence response in plants is not known. In this study, a novel allele of hda6 (designated as shi5) with spontaneous defence response was isolated from a forward genetics screening in Arabidopsis. The shi5 mutant exhibited increased resistance to hemibiotrophic bacterial pathogen Pst DC3000, constitutively activated expression of pathogen‐responsive genes including PR1, PR2, etc. and increased histone acetylation levels at the promoters of most tested genes that were upregulated in shi5. In both wild type and shi5 plants, the expression and histone acetylation of these genes were upregulated by pathogen infection. HDA6 was found to bind to the promoters of these genes under both normal growth conditions and pathogen infection. Our research suggests that HDA6 is a general repressor of pathogen defence response and plays important roles in inhibiting and modulating the expression of pathogen‐responsive genes in Arabidopsis. 相似文献
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Nitric oxide: a new player in plant signalling and defence responses 总被引:10,自引:0,他引:10
There is increasing evidence that nitric oxide (NO), which was first identified as a unique diffusible molecular messenger in animals, plays important roles in diverse (patho)physiological processes in plants. NO functions include the modulation of hormonal, wounding and defence responses, as well as the regulation of cell death. Enzymes that catalyse NO synthesis and signalling cascades that mediate NO effects have recently been discovered, providing a better understanding of the mechanisms by which NO influences plant responses to various stimuli. Additionally, growing evidence suggests that NO signalling interacts with the salicylic acid and jasmonic acid signalling pathways. 相似文献
5.
Abscisic acid and gibberellic acid-regulated responses of embryos and aleurone layers isolated from dormant and nondormant barley grains 总被引:2,自引:0,他引:2
Dormant and nondormant isogenic barley grains were obtained by maturing grains under short day (SD) or long day (LD) growth conditions, respectively. Hormonal responses of isolated embryos and aleurone layers from these grains were studied. Addition of abscisic acid (ABA) reduced germination rate and percentage of embryos, and induced Rab (ABA-responsive) mRNA in aleurone layers from both types of grain. Embryos and aleurone layers from dormant grains responded stronger to ABA than those from nondormant grains. Gibberellic acid (GA3 ) increased the germination rate and percentage of embryos from dormant grains and counteracted the ABA-induced inhibition of embryo germination. GA3 did not affect the amount of Rab mRNA in aleurone layers, suggesting that expression of the Rab gene has no direct correlation with germination. The stronger response of embryos and aleurone layers from dormant grains to ABA may not be explained by higher endogenous ABA levels, but might be due to differences in hormone signal transduction. Aleurone protoplasts from dormant grains had a higher cytosolic pH than those from nondormant grains. To inhibit the ABA-induced Rab mRNA, a much higher concentration of weak acid was required for aleurone layers from dormant grains than for those from nondormant grains. A possible difference in ABA signal transduction between dormant and nondormant grains is discussed. 相似文献
6.
Isolation of gibberellin metabolic pathway genes from barley and comparative mapping in barley, wheat and rice 总被引:4,自引:0,他引:4
Spielmeyer W Ellis M Robertson M Ali S Lenton JR Chandler PM 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2004,109(4):847-855
Gene sequences encoding gibberellin (GA) biosynthetic and catabolic enzymes were isolated from Himalaya barley. These genes account for most of the enzymes required for the core pathway of GA biosynthesis as well as for the first major catabolic enzyme. By means of DNA gel blot analysis, we mapped coding sequences to chromosome arms in barley and wheat using barley-wheat chromosome addition lines, nulli-tetrasomic substitution and ditelosomic lines of wheat. These same sequences were used to identify closely related sequences from rice, which were mapped in silico, thereby allowing their syntenic relationship with map locations in barley and wheat to be investigated. Determination of the chromosome arm locations for GA metabolic genes provides a framework for future studies investigating possible identity between GA metabolic genes and dwarfing genes in barley and wheat.Wolfgang Spielmeyer and Marc Ellis have contributed equally to this work. 相似文献
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Katerina Polakova David Laurie Katerina Vaculova Jaroslava Ovesna 《Plant Molecular Biology Reporter》2003,21(4):439-447
β-Amylase is involved in the starch degradation process and therefore influences grain quality. Starch degradation efficiency
is dependent on the enzyme thermostability during malting and mashing. Four alleles resulting in different enzyme thermostability
are known. These alleles are distinguished by coding single nucleotide polymorphism (cSNP). Pyrosequencing was used for cSNP
genotyping of β-amylase alleles in 79 spring barley varieties by using analyser PSQ MA96 System (Pyrosequencing, Biotage).
A new cSNP was revealed by means of Pyrosequencing analysis of sequence flanking cSNP698, thus recognizing a fifth β-amylase allele. Pyrosequencing is a high-throughput, fast, and precise system for barley SNP
genotyping. 相似文献
9.
D.Grahame Hardie 《Phytochemistry》1975,14(8):1719-1722
α-Amylase, limit dextrinase and α-glucosidase were induced by gibberellic acid in barley grain from which the embryos had been excised. The responses to different concentrations of gibberellic acid were similar for the three carbohydrases. However α-glucosidase activity increased before the other two enzymes, and a low level of α-glucosidase was found in ungerminated grain. Experiments with cycloheximide and density-labelling in deuterium oxide suggest that the observed increases in activity are the result of de novo protein synthesis. The induction of these enzymes was reduced by pre-incubation in actinomycin D. 相似文献
10.
Osorio S Castillejo C Quesada MA Medina-Escobar N Brownsey GJ Suau R Heredia A Botella MA Valpuesta V 《The Plant journal : for cell and molecular biology》2008,54(1):43-55
In addition to the role of the cell wall as a physical barrier against pathogens, some of its constituents, such as pectin-derived oligogalacturonides (OGA), are essential components for elicitation of defence responses. To investigate how modifications of pectin alter defence responses, we expressed the fruit-specific Fragaria × ananassa pectin methyl esterase FaPE1 in the wild strawberry Fragaria vesca . Pectin from transgenic ripe fruits differed from the wild-type with regard to the degree and pattern of methyl esterification, as well as the average size of pectin polymers. Purified oligogalacturonides from the transgenic fruits showed a reduced degree of esterification compared to oligogalacturonides from wild-type fruits. This reduced esterification is necessary to elicit defence responses in strawberry. The transgenic F. vesca lines had constitutively activated pathogen defence responses, resulting in higher resistance to the necrotropic fungus Botrytis cinerea . Further studies in F. vesca and Nicotiana benthamiana leaves showed that the elicitation capacity of the oligogalacturonides is more specific than previously envisaged. 相似文献
11.
A cell-free system derived from seed embryos of barley (Hordeum vulgare cv. Zephyr) grain has been used to prepare substrate quantities of radioactively-labelled C5-C20 intermediates of terpenoid biosynthesis. The purification and characterization of high specific activity all-trans farnesyl-[4, 8, 12-3H] and all-trans geranylgeranyl-[4, 8, 12, 16-3H] pyrophosphates, suitable for use in studies of sterol and carotenoid biosynthesis, are described in detail. The effects of the plant growth retardant AMO 1618 on the system are reported. 相似文献
12.
The distribution and fluctuation of sugars in germinating barley seeds were examined by 13C nuclear magnetic resonance (NMR) spectroscopy, 1H-NMR imaging and 1H-NMR localized spectroscopy in relation to morphology. Maltose, sucrose, fructose and oils were detected in intact imbibed seeds by 13C-NMR spectra. During the first 6 d of germination, the maltose content increased and the oil content gradually decreased, whilst the levels of sucrose and fructose remained constant. Sugars were located by 1H-NMR images and 1H-NMR localized spectra in the vascular bundle of the seeds as well as in the solubilized endosperm. They were also detected in the shoots. The sugars detected in an 80% ethanol shoot extract were sucrose and glucose, which were located in the vascular bundles but not in the mesophyll cells of the coleoptile. They were also located in the basal part of the shoot, but not above 7 mm from the scutellum. The data suggest that the sugars are primarily transported through the vascular bundles and, at the same time, rapidly incorporated into mesophyll cells in the leaves. 相似文献
13.
C. H. Granatek A. W. Cockerline 《In vitro cellular & developmental biology. Plant》1978,14(2):212-217
Summary The effect of various plant growth substances as single agents was evaluated in a complex tissue culture system: whole embryo
culture of early differentiating barley embryos. Callus formation in unsupplemented medium derives from the mesocotyl and
is uniquely characteristic of cultures initiated at this stage of embryonic development. This phenomenon could be prevented
or reversed by incorporation of gibberellic acid in the medium resulting in plantlet formation. Indoleacetic acid enhanced
callus growth, whereas kinetin did not promote either callus or meristematic development. Callus tissue markedly accumulated
starch, effectively lowering the cellular osmolarity, while inducing a corresponding rise in the osmolarity of the culture
medium. This osmotic pattern was reversed by gibberellic acid induction of shoot formation. Thise osmotic-hormonal interactions
are interpreted relative to in vivo, in situ normal embryogeny or developmental lesions such as tumours.
Research supported by Inst. Grant No. 994. 相似文献
14.
Anneli Ritala Kristian Aspegren Ulrika Kurtén Marjatta Salmenkallio-Marttila Leena Mannonen Riitta Hannus Veli Kauppinen Teemu H. Teeri Tor-Magnus Enari 《Plant molecular biology》1994,24(2):317-325
Transgenic, fertile barley (Hordeum vulgare L.) from the Finnish elite cultivar Kymppi was obtained by particle bombardment of immature embryos. Immature embryos were bombarded to the embryonic axis side and grown to plants without selection. Neomycin phosphotransferase II (NPTII) activity was screened in small plantlets. One out of a total of 227 plants expressed the transferred nptII gene. This plant has until now produced 98 fertile spikes (T0), and four of the 90 T0 spikes analyzed to date contained the nptII gene. These shoots were further analyzed and they expressed the transferred gene. From green grains, embryos were isolated and grown to plantlets (T1). The four transgenic shoots of Toivo (the T0 plant) produced 25 plantlets as T1 progeny. Altogether fifteen of these T1 plants carried the transferred nptII gene as detected with the PCR technique, fourteen of which expressed the nptII gene. The integration and inheritance of the transferred nptII gene was confirmed by Southern blot hybridization. Although present as several copies, the transferred gene was inherited as a single Mendelian locus into the T2 progeny. 相似文献
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Quantifying the sensitivity of barley seed germination to oxygen, abscisic acid, and gibberellin using a population-based threshold model 总被引:1,自引:0,他引:1
Barley (Hordeum vulgare L.) seeds (grains) exhibit dormancyat maturity that is largely due to the presence of the glumellae(hulls) that reduce the availability of oxygen (O2) to the embryo.In addition, abscisic acid (ABA) and gibberellins (GAS) interactwith O2 to regulate barley seed dormancy. A population-basedthreshold model was applied to quantify the sensitivities ofseeds and excised embryos to O2, ABA, and GA, and to their interactiveeffects. The median O2 requirement for germination of dormantintact barley seeds was 400-fold greater than for excised embryos,indicating that the tissues enclosing the embryo markedly limitO2 penetration. However, embryo O2 thresholds decreased by anotherorder of magnitude following after-ripening. Thus, increasesin both permeability of the hull to O2 and embryo sensitivityto O2 contribute to the improvement in germination capacityduring after-ripening. Both ABA and GA had relatively smalleffects on the sensitivity of germination to O2, but ABA andGA thresholds varied over several orders of magnitude in responseto O2 availability, with sensitivity to ABA increasing and sensitivityto GA decreasing with hypoxia. Simple additive models of O2–ABAand O2–GA interactions required consideration of theseO2 effects on hormone sensitivity to account for actual germinationpatterns. These quantitative and interactive relationships amongO2, ABA, and GA sensitivities provide insight into how dormancyand germination are regulated by a combination of physical (O2diffusion through the hull) and physiological (ABA and GA sensitivities)factors. Key words: Abscisic acid, barley, germination, gibberellin, Hordeum vulgare L., model, oxygen, sensitivity
Received 2 August 2007; Revised 14 November 2007 Accepted 19 November 2007 相似文献
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Micheelsen PO Vévodová J De Maria L Ostergaard PR Friis EP Wilson K Skjøt M 《Journal of molecular biology》2008,380(4):681-690
Subtilisins represent a large class of microbial serine proteases. To date, there are three-dimensional structures of proteinaceous inhibitors from three families in complex with subtilisins in the Protein Data Bank. All interact with subtilisin via an exposed loop covering six interacting residues. Here we present the crystal structure of the complex between the Bacillus lentus subtilisin Savinase and the barley α-amylase/subtilisin inhibitor (BASI). This is the first reported structure of a cereal Kunitz-P family inhibitor in complex with a subtilisin. Structural analysis revealed that BASI inhibits Savinase in a novel way, as the interacting loop is shorter than loops previously reported. Mutational analysis showed that Thr88 is crucial for the inhibition, as it stabilises the interacting loop through intramolecular interactions with the BASI backbone. 相似文献
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Growth responses of barley exposed to SO2 总被引:1,自引:1,他引:0