ABSTRACT
This study examined the physiological effects of different amounts of nitrogen (N) supplementation (0 to 2.72 kg/year) on the citrus cultivar Huangguogan (Citrus reticulata × Citrus sinensis). Root activity, chlorophyll content, and fruit quality were measured, and the activities of the antioxidant enzymes superoxide dismutase (SOD), guaiacol peroxidase (POD), and catalase (CAT), and the contents of malondialdehyde (MDA) and soluble protein in root, leaf, and fruit tissues were examined at different developmental stages. Root activity, chlorophyll content, fruit quality, antioxidant enzyme activity, MDA content, and soluble protein content increased in plants treated with an appropriate amount of N. Both excessive N and N deficiency decreased the content of MDA and the activities of antioxidant enzymes. Application of 1.36-1.81 kg N/year is suggested for citrus fertilization and the lower end of this range is recommended for minimizing environmental impact and production cost.
Subject(s)
Antioxidants/metabolism , Catalase/metabolism , Citrus/enzymology , Citrus/growth & development , Nitrogen/administration & dosage , Peroxidase/metabolism , Superoxide Dismutase/metabolism , Chlorophyll/metabolism , Citrus/metabolism , Malondialdehyde/metabolism , Plant Proteins/metabolism , Plant Structures/enzymology , Plant Structures/metabolismABSTRACT
Cultivation of oilseed rape requires application of specific fungicides. Besides their protective role, they can potentially influence the expression and activity of crucial enzymes in the plant. Among the large number of enzymes expressed in plants, aminopeptidases play a key role in all crucial physiological processes during the whole life cycle (e.g. storage protein mobilization and thus supplying plant with needed amino acids, as well as plant aging, protection and defense responses). In the present paper, we evaluate for the first time, the influence of the treatment of winter oilseed rape with commercially available fungicides (Pictor 400 SC, Propulse 250 SE and Symetra 325 SC), on the activity of aminopeptidases expressed in each plant organ (flowers, leaves, stems and pods separately). Fungicides were applied once, at one of the three stages of oilseed rape development (BBCH 59-61, BBCH 63-65 and BBCH 67-69). The aminopeptidase activity was determined using six different amino acid p-nitroanilides as substrates. The results have shown, that in control plants, at the beginning of intensive pods development and seeds production, hydrophobic amino acids with bulky side chains (Phe, Leu) were preferentially hydrolysed. In control plants, the activity was ~3.5 times higher in stems and pods, compared to leaves. The treatment with all pesticides caused significant increase in aminopeptidases hydrolytic activity toward small amino acids Gly, Ala as well as proline, mostly in flowers and leaves. These amino acids are proven to be crucial in the mechanisms of delaying of plant aging, development of better resistance to stress and plant defense. It can be suggested, that studied fungicides enhance such mechanisms, by activating the expression of genes coding for aminopeptidases, which are active in hydrolysis of N-terminal amino acids such as Gly, Ala, Pro from storage peptides and proteins. Depending on fungicide, the major increase of aminopeptidase activity was observed after application at BBCH 67-69 (Pictor 400 SC and Symetra 325 SC) and BBCH 63-65 (Propulse 250 SE) stages of development. Our study revealed, that agrochemical treatment and time of application, influenced the expression and activity of aminopeptidases, even though they were not molecular targets of applied fungicides. Since aminopeptidases are widely distributed throughout all organisms and are crucial in many key physiological processes, it can be expected, that factors influencing their expression and activity in plants, can also influence these enzymes in other organisms, especially humans and other mammals.
Subject(s)
Aminopeptidases/genetics , Aminopeptidases/metabolism , Brassica rapa/enzymology , Crops, Agricultural/enzymology , Fungicides, Industrial/pharmacology , Seasons , Alanine/metabolism , Amino Acids/metabolism , Aminopeptidases/chemistry , Brassica rapa/growth & development , Crops, Agricultural/growth & development , Gene Expression Regulation, Enzymologic/drug effects , Gene Expression Regulation, Plant/drug effects , Glycine/metabolism , Hydrolysis , Hydrophobic and Hydrophilic Interactions , Plant Structures/drug effects , Plant Structures/enzymology , Plant Structures/metabolism , Proline/metabolism , Substrate SpecificityABSTRACT
The alternative oxidase (AOX) protein is present in plants, fungi, protozoa and some invertebrates. It is involved in the mitochondrial respiratory chain, providing an alternative route for the transport of electrons, leading to the reduction of oxygen to form water. The present study aimed to characterize the family of AOX genes in mandarin (Citrus clementina) and sweet orange (Citrus sinensis) at nucleotide and protein levels, including promoter analysis, phylogenetic analysis and C. sinensis gene expression. This study also aimed to do the homology modeling of one AOX isoform (CcAOXd). Moreover, the molecular docking of the CcAOXd protein with the ubiquinone (UQ) was performed. Four AOX genes were identified in each citrus species. These genes have an open reading frame (ORF) ranging from 852 bp to 1150 bp and a number of exons ranging from 4 to 9. The 1500 bp-upstream region of each AOX gene contained regulatory cis-elements related to internal and external response factors. CsAOX genes showed a differential expression in citrus tissues. All AOX proteins were predicted to be located in mitochondria. They contained the conserved motifs LET, NERMHL, LEEEA and RADE-H as well as several putative post-translational modification sites. The CcAOXd protein was modeled by homology to the AOX of Trypanosona brucei (45% of identity). The 3-D structure of CcAOXd showed the presence of two hydrophobic helices that could be involved in the anchoring of the protein in the inner mitochondrial membrane. The active site of the protein is located in a hydrophobic environment deep inside the AOX structure and contains a diiron center. The molecular docking of CcAOXd with UQ showed that the binding site is a recessed pocket formed by the helices and submerged in the membrane. These data are important for future functional studies of citrus AOX genes and/or proteins, as well as for biotechnological approaches leading to AOX inhibition using UQ homologs.
Subject(s)
Citrus/enzymology , Citrus/genetics , Mitochondrial Proteins/genetics , Mitochondrial Proteins/metabolism , Oxidoreductases/genetics , Oxidoreductases/metabolism , Plant Proteins/genetics , Plant Proteins/metabolism , Amino Acid Sequence , Conserved Sequence , Exons , Gene Expression Regulation, Plant/physiology , Hydrophobic and Hydrophilic Interactions , Mitochondria/metabolism , Molecular Docking Simulation , Phylogeny , Plant Structures/enzymology , Plant Structures/genetics , Promoter Regions, Genetic , Protein Processing, Post-Translational , Protein Structure, Secondary , Sequence Homology, Amino Acid , Species Specificity , Ubiquinone/metabolismABSTRACT
Monolignol glucosides and their ß-glucosidases are found in monocots, but their biological roles are unclear. Phylogenetic analysis of rice (Oryza sativa L.) glycoside hydrolase family GH1 ß-glucosidases indicated that Os4BGlu14, Os4BGlu16, and Os4BGlu18 are closely related to known monolignol ß-glucosidases. An optimized Os4BGlu16 cDNA and cloned Os4BGlu18 cDNA were used to express fusion proteins with His6 tags in Pichia pastoris and Escherichia coli, respectively. The secreted Os4BGlu16 fusion protein was purified from media by immobilized metal affinity chromatography (IMAC), while Os4BGlu18 was extracted from E. coli cells and purified by anion exchange chromatography, hydrophobic interaction chromatography and IMAC. Os4BGlu16 and Os4BGlu18 hydrolyzed the monolignol glucosides coniferin (kcat/KM, 21.6mM(-1)s(-1) for Os4BGlu16 and for Os4BGlu18) and syringin (kcat/KM, 22.8mM(-1)s(-1) for Os4BGlu16 and 24.0mM(-1)s(-1) for Os4BGlu18) with much higher catalytic efficiencies than other substrates. In quantitative RT-PCR, highest Os4BGlu14 mRNA levels were detected in endosperm, embryo, lemma, panicle and pollen. Os4BGlu16 was detected highest in leaf from 4 to 10 weeks, endosperm and lemma, while Os4BGlu18 mRNA was most abundant in vegetative stage from 1 week to 4 weeks, pollen and lemma. These data suggest a role for Os4BGlu16 and Os4BGlu18 monolignol ß-glucosidases in both vegetative and reproductive rice tissues.
Subject(s)
Cellulases/metabolism , Cinnamates/metabolism , Glucosides/metabolism , Lignin/metabolism , Oryza/enzymology , Phenylpropionates/metabolism , Plant Structures/enzymology , beta-Glucosidase/metabolism , Amino Acid Sequence , Cellulases/genetics , DNA, Complementary , Escherichia coli , Flowers/enzymology , Genes, Plant , Molecular Sequence Data , Oryza/genetics , Phylogeny , Pichia , Plant Leaves/enzymology , Plant Proteins/genetics , Plant Proteins/metabolism , RNA, Messenger/metabolism , Seeds/enzymology , beta-Glucosidase/geneticsABSTRACT
We have isolated a severe dwarf mutant derived from a Ds (Dissociation) insertion mutant rice (Oryza sativa var. japonica c.v. Dongjin). This severe dwarf phenotype, has short and dark green leaves, reduced shoot growth early in the seedling stage, and later severe dwarfism with failure to initiate flowering. When treated with bioactive GA3 , mutants are restored to the normal wild-type phenotype. Reverse transcription PCR analyses of 22 candidate genes related to the gibberellin (GA) biosynthesis pathway revealed that among 22 candidate genes tested, a dwarf mutant transcript was not expressed only in one OsKS2 gene. Genetic analysis revealed that the severe dwarf phenotype was controlled by recessive mutation of a single nuclear gene. The putative OsKS2 gene was a chromosome 4-located ent-kaurene synthase (KS), encoding the enzyme that catalyses an early step of the GA biosynthesis pathway. Sequence analysis revealed that osks2 carried a 1-bp deletion in the ORF region of OsKS2, which led to a loss-of-function mutation. The expression pattern of OsKS2 in wild-type cv Dongjin, showed that it is expressed in all organs, most prominently in the stem and floral organs. Morphological characteristics of the dwarf mutant showed dramatic modifications in internal structure and external morphology. We propose that dwarfism in this mutant is caused by a point mutation in OsKS2, which plays a significant role in growth and development of higher plants. Further investigation on OsKS2 and other OsKS-like proteins is underway and may yield better understanding of the putative role of OsKS in severe dwarf mutants.
Subject(s)
Genes, Plant , Gibberellins/genetics , Oryza/genetics , Phenotype , Plant Proteins/genetics , Plant Structures/metabolism , Sequence Deletion , Alkyl and Aryl Transferases/genetics , Alkyl and Aryl Transferases/metabolism , Amino Acid Sequence , Gene Expression , Gene Expression Regulation, Plant , Gibberellins/biosynthesis , Molecular Sequence Data , Oryza/enzymology , Oryza/growth & development , Oryza/metabolism , Phylogeny , Plant Proteins/metabolism , Plant Structures/enzymology , Plant Structures/growth & development , Sequence Homology, Amino AcidABSTRACT
In higher plants, cellulose is synthesized by cellulose synthase complexes, which contain multiple isoforms of cellulose synthases (CESAs). Among the total 10 CESA genes in Arabidopsis, recessive mutations at three of them cause the collapse of mature xylem cells in inflorescence stems of Arabidopsis (irx1(cesa8), irx3(cesa7) and irx5(cesa4)). These CESA genes are considered secondary cell wall CESAs. The others (the function CESA10 is still unknown) are thought to be specialized for cellulose synthesis in the primary cell wall. A split-ubiquitin membrane yeast two-hybrid system was used to assess interactions among four primary CESAs (CESA1, CESA2, CESA3, CESA6) and three secondary CESAs (CESA4, CESA7, CESA8). Our results showed that primary CESAs could physically interact with secondary CESAs in a limited fashion. Analysis of transgenic lines showed that CESA1 could partially rescue irx1(cesa8) null mutants, resulting in complementation of the plant growth defect, collapsed xylem and cellulose content deficiency. These results suggest that mixed primary and secondary CESA complexes are functional using experimental set-ups.
Subject(s)
Arabidopsis Proteins/metabolism , Arabidopsis/enzymology , Cell Wall/enzymology , Cellulose/metabolism , Genes, Plant , Glucosyltransferases/metabolism , Plant Structures/enzymology , Arabidopsis/genetics , Arabidopsis/growth & development , Arabidopsis Proteins/genetics , Cellulose/genetics , Glucosyltransferases/genetics , Inflorescence/enzymology , Mutation , Plant Stems/enzymology , Plants, Genetically Modified , Protein Isoforms , Two-Hybrid System Techniques , Xylem/enzymologyABSTRACT
Total 95 isolates of Aureobasidium pullulans were isolated from different flowers and leaves samples, out of which 11 thermotolerant strains produced pullulan. One thermotolerant non-melanin pullulan producing strain, designated as RG-5, produced highest pullulan (37.1±1.0 g/l) at 42ºC, pH 5.5 in 48h of incubation with 3% sucrose and 0.5% ammonium sulphate in a non-stirred fed batch fermentor of 6 liters capacity. The two liters of initial volume of fermentation medium was further fed with the 2 liters in two successive batches at 5 h interval into the fermentor. The sterile air was supplied only for 10h at the rate of 0.5 vvm.
Subject(s)
Plant Structures/enzymology , Fermentation , Flowers/enzymology , Plant Leaves/enzymology , Fungicides, Industrial/analysis , Mitosporic Fungi/enzymology , Mitosporic Fungi/isolation & purification , Yeasts/isolation & purification , Polysaccharides/analysis , Incubators , MethodsABSTRACT
Use of natural tannin in the screening of tannase producing microbes is really promising. The present work describes about the possibility and integrity of the newly formulated method over the previously reported methods. Tannin isolated from Terminalia belerica Roxb. (Bahera) was used to differentiate between tanninolytic and nontanninolytic microbes. The method is simple, sensitive and superior for the rapid screening and isolation of tannase-producing microbes.
Subject(s)
Plant Structures/enzymology , Fermentation , Tanacetum parthenium/enzymology , Hydrolyzable Tannins/analysis , Hydrolyzable Tannins/isolation & purification , Enzyme Activation , Hydrolysis , MethodsABSTRACT
Amylases are among the most important enzymes used in modern biotechnology particularly in the process involving starch hydrolysis. Fungal amylase has large applications in food and pharmaceutical industries. Considering these facts, endophytic fungi isolated from the plant Alpinia calcarata (Haw.) Roscoe were screened for amylolytic activity on glucose yeast extract peptone agar (GYP) medium. Among thirty isolates of endophytic fungi, isolate number seven identified as Cylindrocephalum sp. (Ac-7) showed highest amylolytic activity and was taken for further study. Influence of various physical and chemical factors such as pH, temperature, carbon and nitrogen sources on amylase production in liquid media were studied. The maximal amylase production was found to be at 30ºC and at pH 7.0 of the growth medium. Among the various carbon and nitrogen sources tested, maltose at 1.5% and Sodium nitrate at 0.3% respectively gave optimum amylase production.
Subject(s)
Alpinia , Amylases/analysis , Amylases/isolation & purification , Plant Structures/enzymology , Peptones/analysis , Yeasts , Enzyme Activation , Hydrolysis , Methods , PlantsABSTRACT
Physiological studies were conducted to determine the optimum cultural conditions for maximal carboxymethyl cellulase (CMCase) formation by Aspergillus terreus DSM 826. Shaking condition at 150 rpm is favorable for the production of CMCase from rice straw and sugar cane bagasse. The highest enzyme yield was obtained at the third day of incubation at 30ºC for both cases; however CMCase formation occurred at a broad range of pH values, with maximal formation of A. terreus DSM 826 CMCase at pH 4.5 and 5.0 when rice straw and sugar cane bagasse were used as sole carbon source, respectively. Carboxymethyl cellulose (CMC) was found to be a good inducer for CMCase formation in both agricultural wastes with CMC concentrations of 0.5 and 1.0 % (w/v) in case of rice straw and sugar cane bagasse, respectively. High level of enzyme formation was obtained with the addition of ammonium chloride as nitrogen source in both cases and at a concentration of 0.4 % (v/v Tween-80) as an addition to medium containing rice straw. However this addition did not influence the production of CMCase in case of using sugar cane bagasse as carbon source.
Subject(s)
Aspergillus/isolation & purification , Carboxymethylcellulose Sodium/analysis , Carboxymethylcellulose Sodium/isolation & purification , Plant Structures/enzymology , Oryza/enzymology , Saccharum/enzymology , Enzyme Activation , Food Samples , Methodology as a SubjectABSTRACT
Various carbon sources were evaluated for production of inulinase by yeast, Kluyveromyces marxianus MTCC 3995. Highest inulinase activity was observed with Dahlia extract (25.3 nkat mL-1) as carbon source. The enzyme activity was 1.4 folds higher than that observed in media containing pure chicory inulin (17.8 nkat mL-1). The yeast showed good growth on a simple medium containing dahlia extract (20% w/v) and yeast extract (2%w/v) as carbon and nitrogen source respectively, in 96 h. at 28°C and 120 rpm. Lowest inulinase yield (4.8 nkat mL-1) was seen in the medium containing glucose as C-source. Although varied inulinase levels were noticed on different C- sources, Inulinase: Sucrase (I/S) ratios were noticed to be similar. Among various protein sources tested, yeast extract was found to be the best source followed by beef extract (17.9 nkat mL-1) and peptone (13.8 nkat mL-1). The enzyme was optimally active at pH (4.0) and 50°C. TLC analysis of end product revealed that inulinase hydrolyzed inulin exclusively into fructose. Results suggest that the dahlia extract induced exoinulinase synthesis in Kluyveromyces marxianus and can be utilized as a potential substrate for inulinase production.
Subject(s)
Plant Structures/enzymology , Plant Extracts/analysis , Fructose/analysis , Inulin/analysis , Inulin/isolation & purification , Kluyveromyces/isolation & purification , Yeasts/isolation & purification , Dahlia , Enzyme Activation , MethodsABSTRACT
The endoperoxide sesquiterpene lactone artemisinin which is isolated from the plant Artemisia annua, and its semi-synthetic derivatives, are potent, novel, antimalarial drugs. They are effective against multidrug-resistant Plasmodium strains and have become essential components of the so-called Artemisinin-based Combination Therapy, that is recommended by the World Health Organization as the treatment of choice for malaria tropica. Moreover, artemisinin and its derivatives show additional anti-parasite, antitumor, and anti-viral properties. The plants, however, are very poor resources for the drug, as the content of artemisinin is low (from 0,1 to 1,5 % of dried leaves) and dependent on seasonal and somatic variations as well as the infestation of bacteria, fungi and insects. A chemical synthesis of the compound is complex and uneconomic. Therefore, artemisinin is in short supply and remains unaffordable for most people in malaria-endemic countries. Thus, many researchers have focused on enhancing the production of artemisinin, first, through traditional breeding and in in vitro plant tissue cultures and, then, by heterologous expression systems (a semi-synthetic approach) with the use of genetically-modified or transgenic microbes. In this review, we summarize the progress made in the production of artemisinin by the biotechnological approach.
Subject(s)
Antimalarials/isolation & purification , Artemisinins/isolation & purification , Escherichia coli , Genetic Engineering/methods , Plants, Genetically Modified/chemistry , Saccharomyces cerevisiae , Technology, Pharmaceutical/methods , Antimalarials/chemical synthesis , Antimalarials/metabolism , Artemisia annua/chemistry , Artemisia annua/enzymology , Artemisia annua/genetics , Artemisia annua/growth & development , Artemisia annua/microbiology , Artemisinins/chemical synthesis , Artemisinins/metabolism , Biosynthetic Pathways/genetics , Escherichia coli/enzymology , Escherichia coli/genetics , Genetic Engineering/trends , Plant Structures/chemistry , Plant Structures/enzymology , Plant Structures/growth & development , Plant Structures/microbiology , Plants, Genetically Modified/enzymology , Plants, Genetically Modified/growth & development , Plants, Genetically Modified/microbiology , Saccharomyces cerevisiae/enzymology , Saccharomyces cerevisiae/genetics , Technology, Pharmaceutical/trendsABSTRACT
The seasonal change and host preference of arbuscular mycorrhizal (AM) colonization and community composition of five common plant species Agropyron cristatum, Anemarrhena asphodeloides, Cleistogenes squarrosa, Leymus chinensis, and Stipa grandis in the Inner Mongolia steppe were investigated. The AM root length colonization rates were different among the five plant species and were generally high in early (May and June) and late (September) growth seasons and low in August. A total of 18 AM fungal species representing five genera were isolated from rhizosphere soils of the five plant species, and most AM fungi had not host specificity, except that Acaulospora sp., Glomus constrictum, G. diaphanum and Glomus sp. showed a certain degree of host preference. Glomus albidum, G. etunicatum and G. geosporum were the dominant species and showed various sporulation patterns in the five plants during the growth seasons. The AM fungal spore densities and species richness increased from May to September and decreased in October and were different in the same month in the five plants. Multivariate analyses revealed that season and host significantly co-affected the AM fungal spore density, species richness, and Shannon-Wiener diversity index, and the season had higher influence than the host.
Subject(s)
Biodiversity , Ecosystem , Plant Structures/growth & development , Plant Structures/enzymology , Genetic Variation , Mycorrhizae/growth & development , Mycorrhizae/genetics , Pasture/methods , Methods , Plants , Sensitivity and Specificity , Spores , MethodsABSTRACT
Self-incompatibility in the Solanaceae is mediated by S-RNase alleles expressed in the style, which confer specificity for pollen recognition. Nicotiana alata has been successfully used as an experimental model to elucidate cellular and molecular aspects of S-RNase-based self-incompatibility in Solanaceae. However, S-RNase alleles of this species have not been surveyed from natural populations and consequently the S-haplotype diversity is poorly known. Here the molecular and functional characterization of seven S-RNase candidate sequences, identified from a natural population of N. alata, are reported. Six of these candidates, S ( 5 ), S ( 27 ), S ( 70 ), S ( 75 ), S ( 107 ), and S ( 210 ), showed plant-specific amplification in the natural population and style-specific expression, which increased gradually during bud maturation, consistent with the reported S-RNase expression. In contrast, the S ( 63 ) ribonuclease was present in all plants examined and was ubiquitously expressed in different organs and bud developmental stages. Genetic segregation analysis demonstrated that S ( 27 ), S ( 70 ), S ( 75 ), S ( 107 ), and S ( 210 ) alleles were fully functional novel S-RNases, while S ( 5 ) and S ( 63 ) resulted to be non-S-RNases, although with a clearly distinct pattern of expression. These results reveal the importance of performing functional analysis in studies of S-RNase allelic diversity. Comparative phylogenetic analysis of six species of Solanaceae showed that N. alata S-RNases were included in eight transgeneric S-lineages. Phylogenetic pattern obtained from the inclusion of the novel S-RNase alleles confirms that N. alata represents a broad sample of the allelic variation at the S-locus of the Solanaceae.
Subject(s)
Gene Expression Regulation, Enzymologic/genetics , Gene Expression Regulation, Plant/genetics , Nicotiana/enzymology , Nicotiana/genetics , Ribonucleases/genetics , Self-Fertilization , Alleles , Gene Expression Regulation, Developmental/genetics , Genetic Variation/genetics , Haplotypes/genetics , Plant Structures/enzymology , Plant Structures/genetics , Plant Structures/growth & development , Plants, Genetically Modified/enzymology , Plants, Genetically Modified/genetics , Plants, Genetically Modified/growth & development , RNA, Plant/genetics , RNA, Plant/metabolism , Ribonucleases/metabolism , Solanaceae/enzymology , Solanaceae/genetics , Nicotiana/growth & developmentABSTRACT
As the outermost layer on aerial tissues of the primary plant body, the cuticle plays important roles in plant development and physiology. The major components of the cuticle are cutin and cuticular wax, both of which are composed primarily of fatty acid derivatives synthesized in the epidermal cells. Long-chain acyl-CoA synthetases (LACS) catalyze the formation of long-chain acyl-CoAs and the Arabidopsis genome contains a family of nine genes shown to encode LACS enzymes. LACS2 is required for cutin biosynthesis, as revealed by previous investigations on lacs2 mutants. Here, we characterize lacs1 mutants of Arabidopsis that reveals a role for LACS1 in biosynthesis of cuticular wax components. lacs1 lacs2 double-mutant plants displayed pleiotropic phenotypes including organ fusion, abnormal flower development and reduced seed set; phenotypes not found in either of the parental mutants. The leaf cuticular permeability of lacs1 lacs2 was higher than that of either lacs1 or lacs2 single mutants, as determined by measurements of chlorophyll leaching from leaves immersed in 80% ethanol, staining with toluidine blue dye and direct measurements of water loss. Furthermore, lacs1 lacs2 mutant plants are highly susceptible to drought stress. Our results indicate that a deficiency in cuticular wax synthesis and a deficiency in cutin synthesis together have compounding effects on the functional integrity of the cuticular barrier, compromising the ability of the cuticle to restrict water movement, protect against drought stress and prevent organ fusion.
Subject(s)
Arabidopsis Proteins/metabolism , Arabidopsis/enzymology , Coenzyme A Ligases/metabolism , Mutation/genetics , Plant Epidermis/enzymology , Plant Structures/anatomy & histology , Plant Structures/enzymology , Arabidopsis/cytology , Arabidopsis/genetics , Arabidopsis Proteins/genetics , Coenzyme A Ligases/genetics , Droughts , Gene Expression Profiling , Gene Expression Regulation, Plant , Gene Knockout Techniques , Organ Specificity , Permeability , Phenotype , Plant Epidermis/cytology , Plant Epidermis/genetics , Plant Transpiration , Protein Transport , Stress, Physiological , Subcellular Fractions/enzymology , Waxes/metabolismABSTRACT
Arginine decarboxylase (ADC) is a key enzyme in plants that converts arginine into putrescine, an important mediator of abiotic stress tolerance. Adc genes have been isolated from a number of dicotyledonous plants but the oat and rice Adc genes are the only representatives of monocotyledonous species described thus far. Rice has a small family of Adc genes, and OsAdc1 expression has been shown to fluctuate under drought and chilling stress. We identified and characterized a second rice Adc gene (OsAdc2) which encodes a 629-amino-acid protein with a predicted molecular mass of 67 kDa. An unusual feature of the OsAdc2 gene is the presence of an intron and a short upstream open reading frame in the 5'-UTR. Sequence comparisons showed that OsAdc2 is more closely related to the oat Adc gene than to OsAdc1 or to its dicot homologs, and mRNA analysis showed that the two rice genes are also differently regulated. Whereas OsAdc1 is expressed in leaf, root and stem, OsAdc2 expression is restricted to stem tissue. Protein expression was investigated with specific antibodies against ADC1 and ADC2, corroborating the mRNA data. We discuss the expression profiles of OsAdc1 and OsAdc2 and potential functions for the two corresponding proteins.
Subject(s)
Carboxy-Lyases/genetics , Genes, Plant , Multigene Family , Oryza/genetics , Plant Proteins/genetics , 5' Untranslated Regions/genetics , Amino Acid Sequence , Base Sequence , Biogenic Polyamines/metabolism , Carboxy-Lyases/biosynthesis , Carboxy-Lyases/immunology , Chloroplasts/metabolism , Conserved Sequence , Gene Expression Regulation, Plant , Introns , Molecular Sequence Data , Open Reading Frames , Organ Specificity , Oryza/enzymology , Plant Proteins/biosynthesis , Plant Proteins/immunology , Plant Structures/enzymology , Plants/genetics , Protein Sorting Signals/genetics , Pseudogenes/genetics , RNA, Messenger/biosynthesis , RNA, Plant/biosynthesis , Sequence Alignment , Sequence HomologyABSTRACT
Acid phosphatase (AcPase) activities are involved in the degeneration process of cytoplasm in plants. In this study, acid phosphatase was detected by the method of lead nitrate and cytochemical electron microscopy during the development of nonarticulated laticifers in Euphorbia kansui Liou. The most important feature in the differentiation of the laticifers in E. kansui is that the development of small vacuoles arises from endoplasmic reticulum (ER). The mature laticifers possess a thin layer of electron-dense peripheral cytoplasm in which the organelle cannot be distinguished and a large central vacuole filled with latex particles. AcPase cytochemistry studies show AcPase reaction products congregated into heaps are distributed along the tonoplast of central vacuole and around the mitochondria and plastids. Some small vacuoles which develop at later developmental stages of laticifers contain AcPase reaction products. As a result, the central vacuole is formed by cellular autophagy and fusion of small vacuoles which apparently arises from ER.
Subject(s)
Acid Phosphatase/metabolism , Euphorbia/enzymology , Euphorbia/ultrastructure , Microscopy, Electron, Transmission , Plant Structures/enzymology , Plant Structures/ultrastructureABSTRACT
In plants, various chitinases have been identified and categorized into several groups based on the analysis of their sequences and domains. We have isolated SafchiA, a novel class of chitinase from saffron (Crocus sativus L.). The cDNA encoding SafchiA is mainly expressed in roots and corms, and its expression is induced by elicitor treatment, methyl jasmonate, wounding, and by the fungi Fusarium oxysporum, Beauveria and Phoma sp., suggesting a defence role of the protein. Furthermore, in vitro assays with the recombinant native protein showed chitinolytic, and antifungal activity. The deduced protein shares high similarity with chitinases belonging to family 19 of glycosyl-hydrolases, although some changes in the enzyme active site are present. To explore the properties of SafchiA we have expressed recombinant SafchiA in Escherichia coli and generated four different mutants affected in residues involved in the catalytic activity. One glutamic acid essential for family 19 chitinases activity is not present in C. sativus chitinase suggesting that only one acidic residue is necessary for the enzyme activity, in a similar manner as family 18 glycosyl-hydrolases.
Subject(s)
Chitinases/metabolism , Crocus/enzymology , Plant Proteins/metabolism , Plant Structures/enzymology , Amino Acid Sequence , Antifungal Agents/pharmacology , Ascomycota/drug effects , Ascomycota/physiology , Beauveria/drug effects , Beauveria/physiology , Catalysis , Catalytic Domain/genetics , Chitinases/classification , Chitinases/genetics , Chitinases/isolation & purification , Cloning, Molecular , Crocus/genetics , Crocus/microbiology , DNA, Complementary/chemistry , DNA, Complementary/genetics , Fusarium/drug effects , Fusarium/physiology , Gene Expression Regulation, Enzymologic , Gene Expression Regulation, Plant , Host-Pathogen Interactions , Molecular Sequence Data , Mutation , Phylogeny , Plant Diseases/microbiology , Plant Proteins/genetics , Plant Proteins/isolation & purification , Plant Structures/genetics , Plant Structures/microbiology , Recombinant Proteins/isolation & purification , Recombinant Proteins/metabolism , Recombinant Proteins/pharmacology , Reverse Transcriptase Polymerase Chain Reaction , Sequence Analysis, DNA , Sequence Homology, Amino Acid , Stress, MechanicalABSTRACT
A cotton (Gossypium hirsutum L.) genomic clone encompassing a 17.9-kb DNA fragment was found to contain a delta-12 fatty acid desaturase gene (designated FAD2-4). The FAD2-4 open reading frame has 1,155bp and is uninterrupted, encoding a conceptual FAD2-4 polypeptide of 384 amino acids that has 98% identity with the cotton FAD2-3 polypeptide. The FAD2-4 gene has a single intron of 2,780 bp in its 5'-untranslated region (5'-UTR). The 3'-flanking regions and 5'-UTR introns in the FAD2-4 and FAD2-3 genes are quite different, indicating that the genes might be paralogs in the cotton genome. Reverse transcriptase (RT)-PCR analysis indicated that the FAD2-4 and FAD2-3 genes were expressed in all tissues examined, including seeds, seedling tissues, young and mature leaves, roots, stems, developing flower buds, and ovule fibers. These constitutive patterns of expression were notably different from that of the FAD2-1 gene, which was restricted to seeds and developing flower buds, or to the expression of a newly-identified FAD2-2 gene isoform, which was barely detectable in roots, hypocotyls, stems, and fibers, but was expressed in all other tissues. The FAD2-4 coding region was expressed in yeast and shown to encode a functional delta-12 desaturase, converting oleic acid (C18:1) to linoleic acid (C18:2) in recombinant yeast cells. In addition, both the FAD2-4 and the FAD2-3 genes were transferred into the Arabidopsis thaliana fad2-1 mutant background where they effectively restored wild type fatty acid composition and growth characteristics. Finally, the cotton FAD2-4 green fluorescent protein (GFP) fusion polypeptide appeared to be localized in the endomembrane system of transgenic Arabidopsis plants in the complemented fad2-1 mutant background, supporting a functional ER location for the cotton FAD2-4 polypeptide in this heterologous plant system. Thus, a new functional member of the FAD2 gene family in cotton has been characterized, indicating a complex regulation of membrane lipid desaturation in this important fiber/oilseed crop.
Subject(s)
Arabidopsis/genetics , Fatty Acid Desaturases/genetics , Gene Expression , Genes, Plant , Gossypium/genetics , Saccharomyces cerevisiae/genetics , Arabidopsis/enzymology , DNA, Plant/genetics , Endoplasmic Reticulum , Fatty Acid Desaturases/metabolism , Gossypium/enzymology , Linoleic Acid/genetics , Linoleic Acid/metabolism , Molecular Sequence Data , Oleic Acid/genetics , Oleic Acid/metabolism , Plant Oils/metabolism , Plant Structures/enzymology , Plant Structures/genetics , Plant Structures/metabolism , Plants, Genetically Modified/genetics , Plants, Genetically Modified/metabolism , Reverse Transcriptase Polymerase Chain Reaction , Saccharomyces cerevisiae/enzymology , Transformation, GeneticABSTRACT
Inoculation with Fusarium oxysporum f. sp. lycopersici (FOL) protects pepper plants from subsequent infection with Phytophthora capsici. In the present paper, the level of local and systemic protection achieved by plants induced with FOL was evaluated by quantifying the pathogen biomass and using real-time PCR. Differences in the amount of pathogen were found in stems and roots between FOL-treated and untreated plants, while pathogen biomass could not be detected in leaves of induced plants. Five defence-related genes coding for a PR-1 protein, a beta-1,3-glucanase, a chitinase, a peroxidase and a sesquiterpene cyclase were up-regulated 48 h after treatment in all the tissues studied, and maximal mRNAs levels were found in leaves.