Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.25.1 (proteasome)
 28,817 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Twelve alpha and beta 20S proteasome subunits cDNAs showing 70-82% identity with the corresponding genes in Arabidopsis or rice, and features of eukaryotic proteasome subunits were cloned in tobacco. Only beta1-tcI 7, alpha3 and alpha6, 20S proteasome subunits encoding genes were up-regulated by cryptogein, a proteinaceous elicitor of plant defence reactions. These results led to the hypothesis that the activation of beta1-tcI 7, alpha3 and alpha6 could induce a specific proteolysis involved in the hypersensitive response and systemic acquired resistance monitored by cryptogein.
J Exp Bot 2001 Sep
PMID:Cryptogein affects expression of alpha3, alpha6 and beta1 20S proteasome subunits encoding genes in tobacco. 1152 Aug 84

The Arabidopsis AtMCP and rice OsMCP genes which encode proteins highly homologous to molybdoenzymes of the sulphite oxidase family were isolated and characterized. Both proteins seemed to possess only a molybdenum cofactor as the redox centre, unlike all the other eukaryotic molybdoenzymes. Putative MCP orthologues were identified in 17 plant species, indicating that MCPs are widely distributed over the plant kingdom [corrected]. An analysis using a green fluorescent protein fusion showed that AtMCP possesses a peroxisomal targeting signal at its C-terminus. Putative peroxisomal targeting signals were also found in all plant MCPs, suggesting the existence of a new redox pathway in this organelle.
J Exp Bot 2002 Aug
PMID:Molecular cloning and characterization of plant genes encoding novel peroxisomal molybdoenzymes of the sulphite oxidase family. 1214 36

Two peach genes homologous to the Arabidopsis ethylene receptor genes ETR1 and ERS1, named Pp-ETR1 and Pp-ERS1 respectively, have been isolated and characterized. Pp-ETR1 and Pp-ERS1 are conserved in terms of exon numbers and intron positions, although the first and fifth introns of Pp-ETR1 have an unusual length. In addition, two putative polyadenylation sites, that may cause an incomplete splicing at the 3' terminus, are present in the fifth intron. A motif of 28 nt, which shows high homology with ethylene responsive elements found in promoters of genes up-regulated by ethylene, is present in the promoter region of Pp-ERS1. Expression analysis, carried out by quantitative RT-PCR, was performed during fruit development and ripening, and leaf and fruitlet abscission. The level of Pp-ETR1 transcripts remained unchanged in all the tissues and developmental stages examined, whereas Pp-ERS1 mRNA abundance increased in ripening mesocarp, in leaf and fruitlet activated abscission zones, and following propylene application. 1-methylcyclopropene (1-MCP), an inhibitor of ethylene action, did not affect Pp-ETR1 transcription, while it down-regulated Pp-ERS1. A rise in ethylene evolution, accompanied by an increase of Pp-ERS1 transcript accumulation occurred within 24 h from the end of 1-MCP treatment. These results indicate that Pp-ERS1 might play a role in abscission and ripening.
J Exp Bot 2002 Dec
PMID:Characterization of two putative ethylene receptor genes expressed during peach fruit development and abscission. 1243 26

In order to investigate the physiological role of ethylene in the initiation and subsequent progression of softening, pear fruit were treated with propylene, an analogue of ethylene or 1-methylcyclopropene (1-MCP), a gaseous inhibitor of ethylene action at the preclimacteric or ripening stages. The propylene treatment at the pre-ripe stage stimulated ethylene production and flesh softening while the 1-MCP treatment at the same stage markedly retarded the initiation of the ripening-related events. Moreover, 1-MCP treatment after the initiation of ripening markedly suppressed the subsequent flesh softening and ethylene production. These results clearly indicate that ethylene is not merely a by-product, but plays a crucial role in both the initiation and maintenance of regulating the softening process during ripening. The observations also suggest that ethylene in ripening is regulated entirely in an autocatalytic manner. The mRNA accumulation of pear polygalacturonases (PG) genes, PC-PG1 and PC-PG2, was in parallel with the pattern of fruit softening in both propylene and 1-MCP treatments. However, the expression pattern of pear endo-1,4-beta-D-glucanases (EGase) genes, PC-EG1 and PC-EG2, was not affected in both treatments. The results suggest that ethylene is required for PGs expression even in the late ripening stage, but not for EGases.
J Exp Bot 2003 Feb
PMID:Ethylene is required for both the initiation and progression of softening in pear (Pyrus communis L.) fruit. 1255 20

Ethylene production in pear fruit was studied at 2 degrees C. Several observations showed that the inhibiting effect of CO2 on ethylene production did not operate only via the binding site of the ethylene binding protein. Ethylene production of freshly harvested pears was stimulated by 1-methylcyclopropene (1-MCP), but unaffected or inhibited by CO2 which points to different action sites for both molecules. In climacteric pears, where ethylene production was strongly inhibited by 1-MCP, a range of applied CO2 partial pressures was able to inhibit ethylene production further, to an extent similar to untreated pears. In the case of pears that had been stored for a period of 25 weeks, CO2 only had a clear effect after 1-MCP pretreatment. Respiration measurements showed that the effect of CO2 on ethylene production did not operate via an effect on respiration. Ethylene production models based on measurements of whole pears were used to study CO2 effects. Kinetic parameters derived from the models point to the conversion from ACC to ethylene by ACC oxidase as a possible action site for CO2 inhibition.
J Exp Bot 2003 Jun
PMID:Carbon dioxide action on ethylene biosynthesis of preclimacteric and climacteric pear fruit. 1273 Feb 72

Proline is an important component of salt-stress responses of plants. In this study the role of proline as part of salt-stress signalling in the desert plant Pancratium maritimum L. was examined. The data showed that salt-stress brought about a reduction of the growth and protein content, particularly at 300 mM NaCl, that was significantly increased by exogenous proline. In the leaves, salt-stress up-regulated ubiquitin, a small protein targeting damaged proteins for degradation via the proteasome, up to 5-fold as detected by western blotting. This change was also affected by proline even in non-stressed leaves. However, salt-stress resulted in a decrease in the amount of ubiquitin-conjugates, particularly in the roots, and this effect was reversed by exogenous proline. Severe salt-stress resulted in an inhibition of the antioxidative enzymes catalase and peroxidase as revealed by spectrophotometric assays and activity gels, but the activity of these enzymes was also maintained significantly higher in the presence of proline. Salt-stress also up-regulated several dehydrin proteins, analysed by western blotting, even in non-stressed plants. It is concluded that proline improves the salt-tolerance of Pancratium maritimum L. by protecting the protein turnover machinery against stress-damage and up-regulating stress protective proteins.
J Exp Bot 2003 Nov
PMID:Proline induces the expression of salt-stress-responsive proteins and may improve the adaptation of Pancratium maritimum L. to salt-stress. 1451 86

Modifications to the cell wall of developing and ripening tomato fruit are mediated by cell wall-degrading enzymes, including a beta-d-xylosidase or alpha-l-arabinofuranosidase, which participate in the breakdown of xylans and/or arabinoxylans. The activity of both enzymes was highest during early fruit growth, before decreasing during later development and ripening. Two beta-d-xylosidase cDNAs, designated LeXYL1 and LeXYL2, and an alpha-l-arabinofuranosidase cDNA, designated LeARF1, were obtained. Accumulation of mRNAs for beta-d-xylosidase and alpha-l-arabinofuranosidase was examined during fruit development and ripening. LeARF1 and LeXYL2 genes were relatively highly expressed during fruit development and decreased after the onset of ripening. By contrast, LeXYL1 was not expressed during fruit development, but was expressed later, particularly during over-ripening. The expression of all three genes was also followed in ripening-impaired mutants, Nr, Nr2, nor, and rin of cv. Ailsa Craig fruit. LeXYL2 mRNA was detected in the ripe fruits of all the mutants and its abundance was similar to that in mature green wild-type fruit. By contrast, LEXYL1 mRNA was expressed only in the ripe fruits of the Nr mutant, suggesting that the two beta-d-xylosidase genes are subject to distinct regulatory control during fruit development and ripening. LeARF1 mRNA was detected in ripe fruits of Nr2, nor and rin, and not in ripe fruit of the Nr mutant. The accumulation of LeARF1 in ripe fruit was restored by 1-methylcyclopropene (1-MCP), an inhibitor of ethylene action, while 1-MCP had no effect on the expression of LeXYL1 or LeXYL2. This suggests that LeARF1 expression is subject to negative regulation by ethylene and that the two beta-d-xylosidase genes are independent of ethylene action.
J Exp Bot 2003 Dec
PMID:Characterization of expression, and cloning, of beta-D-xylosidase and alpha-L-arabinofuranosidase in developing and ripening tomato (Lycopersicon esculentum Mill.) fruit. 1458 20

In order to elucidate the regulation mechanisms of carotenoid biosynthesis in apricot fruit (Prunus armeniaca), carotenoid content and carotenogenic gene expression were analysed as a function of ethylene production in two colour-contrasted apricot varieties. Fruits from Goldrich (GO) were orange, while Moniqui (MO) fruits were white. Biochemical analysis showed that GO accumulated precursors of the uncoloured carotenoids, phytoene and phytofluene, and the coloured carotenoid, beta-carotene, while Moniqui (MO) fruits only accumulated phytoene and phytofluene but no beta-carotene. Physiological analysis showed that ethylene production was clearly weaker in GO than in MO. Carotenogenic gene expression (Psy-1, Pds, and Zds) and carotenoid accumulation were measured with respect to ethylene production which is initiated in mature green fruits at the onset of the climacteric stage or following exo-ethylene or ethylene-receptor inhibitor (1-MCP) treatments. Results showed (i) systematically stronger expression of carotenogenic genes in white than in orange fruits, even for the Zds gene involved in beta-carotene synthesis that is undetectable in MO fruits, (ii) ethylene-induction of Psy-1 and Pds gene expression and the corresponding product accumulation, (iii) Zds gene expression and beta-carotene production independent of ethylene. The different results obtained at physiological, biochemical, and molecular levels revealed the complex regulation of carotenoid biosynthesis in apricots and led to suggestions regarding some possible ways to regulate it.
J Exp Bot 2005 Jul
PMID:Ethylene regulation of carotenoid accumulation and carotenogenic gene expression in colour-contrasted apricot varieties (Prunus armeniaca). 1591 63

Embryogenesis in plants is a unique process in the sense that it can be initiated from a wide range of cells other than the zygote. Upon stress, microspores or young pollen grains can be switched from their normal pollen development towards an embryogenic pathway, a process called androgenesis. Androgenesis represents an important tool for research in plant genetics and breeding, since androgenic embryos can germinate into completely homozygous, double haploid plants. From a developmental point of view, androgenesis is a rewarding system for understanding the process of embryo formation from single, haploid microspores. Androgenic development can be divided into three main characteristic phases: acquisition of embryogenic potential, initiation of cell divisions, and pattern formation. The aim of this review is to provide an overview of the main cellular and molecular events that characterize these three commitment phases. Molecular approaches such as differential screening and cDNA array have been successfully employed in the characterization of the spatiotemporal changes in gene expression during androgenesis. These results suggest that the activation of key regulators of embryogenesis, such as the BABY BOOM transcription factor, is preceded by the stress-induced reprogramming of cellular metabolism. Reprogramming of cellular metabolism includes the repression of gene expression related to starch biosynthesis and the induction of proteolytic genes (e.g. components of the 26S proteasome, metalloprotease, cysteine, and aspartic proteases) and stress-related proteins (e.g. GST, HSP, BI-1, ADH). The combination of cell tracking systems with biochemical markers has allowed the key switches in the developmental pathway of microspores to be determined, as well as programmed cell death to be identified as a feature of successful androgenic embryo development. The mechanisms of androgenesis induction and embryo formation are discussed, in relation to other biological systems, in special zygotic and somatic embryogenesis.
J Exp Bot 2005 Jul
PMID:Androgenic switch: an example of plant embryogenesis from the male gametophyte perspective. 1592 15

Citrus fruits infected with the fungus Penicillium digitatum substantially increase the production of the plant hormone ethylene. In this study, the regulation of ethylene biosynthesis in Citrus sinensis-infected fruits and its putative involvement in an active defence response against P. digitatum infection is examined. Ethylene production is demonstrated as being the result of the co-ordinated and differential up-regulation of at least three ethylene biosynthetic genes: ACS1, ACS2, and ACO. Blocking ethylene perception by 1-MCP resulted in an increased ethylene production and ACS2 expression during infection and mechanical wounding, suggesting that this gene is negatively regulated by ethylene. ACO expression was induced by ethylene in the absence of wounding or infection, although further results indicate that its induction during the course of infection may not be primarily mediated by ethylene. Treatment with 1-MCP also increased susceptibility to Penicillium decay, showing an involvement of ethylene perception in promoting defence responses in citrus fruits. The changes in the expression of two defence-related genes up-regulated during infection were also studied: the ones coding for phenylalanine ammonia-lyase (PAL) and an acidic class II chitinase (ACR311). The onset of PAL expression after mechanical wounding or inoculation was not changed in 1-MCP-pretreated fruits, while its later increase during the course of infection was abolished. Chitinase gene induction was more related to mechanical damage and was partially repressed by ethylene. These studies indicate distinct possible regulatory mechanisms of plant fruit defence genes in the context of fungal infection and ethylene perception.
J Exp Bot 2005 Aug
PMID:Involvement of ethylene biosynthesis and perception in the susceptibility of citrus fruits to Penicillium digitatum infection and the accumulation of defence-related mRNAs. 1598 11


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