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At least 19 recordsLinked to original sources
PubMed2001

Accumulation of plastid lipid-associated proteins (fibrillin/CDSP34) upon oxidative stress, ageing and biotic stress in Solanaceae and in response to drought in other species.

Plastid lipid-associated proteins, also termed fibrillin/CDSP34 proteins, are known to accumulate in fibrillar-type chromoplasts such as those of ripening pepper fruit, and in leaf chloroplasts from Solanaceae plants under abiotic stress conditions. It is shown here that treatments generating active oxygen species (high light combined with low temperature, gamma irradiation or methyl viologen treatment) result in potato CDSP34 gene induction and protein accumulation in leaves. Using transgenic tomato plants containing the pepper fibrillin promoter, a significant increase in promoter activity in leaves subjected to biotic stress, namely bacterial infections, was observed. In WT, a higher level of the endogenous fibrillin/CDSP34 protein is also observed after infection by E. chrysanthemi strain 3739. In addition to stress-related induction, a progressive increase in the fibrillin promoter activity is noticed during ageing in various tomato photosynthetic tissues and this increase correlates with a higher abundance of the endogenous protein in WT leaves. It is proposed that a mechanism related to oxidative events plays an essential role in the regulation of fibrillin/CDSP34 genes during stress and also during development. Using a biolistic transient expression assay, the pepper fibrillin promoter is found to be active in various dicot species, but not in monocots. Further, substantially increased levels of fibrillin/ CDSP34 proteins are shown in various dicotyledonous and monocotyledonous plants in response to water deficit.

Adaptation, Physiological↗
PubMed2006

Role of DREB transcription factors in abiotic and biotic stress tolerance in plants.

Abiotic and biotic stresses negatively influence survival, biomass production and crop yield. Being multigenic as well as a quantitative trait, it is a challenge to understand the molecular basis of abiotic stress tolerance and to manipulate it as compared to biotic stresses. Lately, some transcription factor(s) that regulate the expression of several genes related to stress have been discovered. One such class of the transcription factors is DREB/CBF that binds to drought responsive cis-acting elements. DREBs belong to ERF family of transcription factors consisting of two subclasses, i.e. DREB1/CBF and DREB2 that are induced by cold and dehydration, respectively. The DREBs are apparently involved in biotic stress signaling pathway. It has been possible to engineer stress tolerance in transgenic plants by manipulating the expression of DREBs. This opens an excellent opportunity to develop stress tolerant crops in future. This review intends to focus on the structure, role of DREBs in plant stress signaling and the present status of their deployment in developing stress tolerant transgenic plants.

Abscisic Acid↗
PubMed2005

Diagnosis of abiotic and biotic stress factors using the visible symptoms in foliage.

Visible symptoms in the foliage of trees are recorded to monitor the effects of abiotic and biotic stress. Difficulties are reported in diagnosing the origin of stress. The present paper discusses several diagnostic criteria which are usable in different species for a better determination of the stress factor type. A new diagnosis scheme to differentiate between classes of abiotic and biotic stress factors is supplied. Abiotic stress generates gradients of symptoms. The symptom specificity is determined by the degree of interaction between the stress factor and plant defense system. Symptoms caused by abiotic stress and natural autumnal senescence can be morphologically different or undistinguishable according to the stress and plant species. With biotic stress, the class of parasitic is generally recognizable on the basis of the visible symptoms. Structurally and physiologically based explanations of the symptom morphology are still missing for many stress factors.

Ecology↗
PubMed2006

Diagnosis of abiotic and biotic stress factors using the visible symptoms in foliage.

Visible symptoms in the foliage of trees are recorded to monitor the effects of abiotic and biotic stress. Difficulties are reported in diagnosing the origin of stress. The present paper discusses several diagnostic criteria which are usable in different species for a better determination of the stress factor type. A new diagnosis scheme to differentiate between classes of abiotic and biotic stress factors is supplied. Abiotic stress generates gradients of symptoms. The symptom specificity is determined by the degree of interaction between the stress factor and plant defense system. Symptoms caused by abiotic stress and natural autumnal senescence can be morphologically different or undistinguishable according to the stress and plant species. With biotic stress, the class of parasitic is generally recognizable on the basis of the visible symptoms. Structurally and physiologically based explanations of the symptom morphology are still missing for many stress factors.

Ecology↗
PubMed2004

Crosstalk in the responses to abiotic and biotic stresses in Arabidopsis: analysis of gene expression in cytochrome P450 gene superfamily by cDNA microarray.

From Arabidopsis full-length cDNA libraries, we collected ca. 7000 (7K) independent full-length cDNAs to prepare a cDNA microarray. The 7K cDNA collection contains 49 cytochrome P450 genes. In this study, expression patterns of these cytochrome P450 genes were analyzed by a full-length cDNA microarray under various treatments, such as hormones (salicylic acid, jasmonic acid, ethylene, abscisic acid), pathogen-inoculation ( Alternaria brassicicola , Alternaria alternata ), paraquat, rose bengal, UV stress (UV-C), heavy metal stress (CuSO4), mechanical wounding, drought, high salinity and low temperature. Expression of 29 cytochrome P450 genes among them was induced by various treatments. Inoculation with A. brassicicola and A. alternata as biotic stresses increased transcript levels of 12 and 5 genes in Arabidopsis plants, respectively. In addition, some of the genes were also expressed by abiotic stresses. This suggests crosstalk between abiotic and biotic stresses. The promoter sequences and cis -acting elements of each gene were studied on the basis of full-length cDNA sequences. Most cytochrome P450 genes induced by both abiotic and biotic stresses contained the recognition sites of MYB and MYC, ACGT-core sequence, TGA-box and W-box for WRKY transcription factors in their promoters. These cis -acting elements are known to participate in the regulation of plant defense. The response of each gene to multiple stresses is strictly regulated.

Abscisic Acid↗
PubMed2004

Accumulation of HDMBOA-Glc is induced by biotic stresses prior to the release of MBOA in maize leaves.

The effects of biotic stresses on the contents of benzoxazinones (Bxs) were investigated in maize leaves. When the causal agent of southern corn leaf blight, Bipolaris maydis, was inoculated on the third leaf, the amount of 2-hydroxy-4,7-dimethoxy-1,4-benzoxazin-3-one glucoside (HDMBOA-Glc) increased, reaching a maximum level 48 h after inoculation. The inoculation of weakly pathogenic Curvularia lunata and non-pathogenic Alternaria alternata also resulted in accumulation of HDMBOA-Glc, and filtrates of the cultures of B. maydis, C. lunata and A. alternata also showed the accumulation of elicitor-active compounds by the fungi. Furthermore the infection of B. maydis induced formation of dark brown lesions, where most abundant Bx-related compound was 6-methoxy-2-benzoxazolinone (MBOA). The later is formed by degradation of DIMBOA and HDMBOA, whereas HDMBOA-Glc was most abundant in the surrounding green tissues. Among the Bx-related compounds, MBOA exhibited the strongest inhibition of the germination of the conidia and of the growth of germ tubes of B. maydis, C. lunata and A. alternata. In addition to fungal infection, the feeding by rice armyworm larvae resulted in HDMBOA-Glc accumulation. These findings are discussed in relation to the possible ecological relevance of the conversion of DIMBOA-Glc into HDMBOA-Glc.

Animals↗
PubMedDate not supplied

[Photosynthetic pigments of tomato under conditions of biotic stress and effects of furostanol glycosides].

Adaptogenic effect of furostanol glycosides (FG) on biosynthesis of photosynthetic pigments in tomato plants (Lycopersicon esculentum Mill.) were studied under conditions of biotic stress caused by root-knot nematode (Meloidogyne incognita Kofoid et White). Treatment of plants with 5 x 10(-4) M FG was accompanied by an increase in the rate of biosynthesis of pigments (particularly, chlorophyll b and carotenoids), which was observed against the background of a decrease in the relative contribution of beta-carotene and an increase in the relative contribution of pigments of violaxanthin cycle (VXC) to the overall pool of carotenoids. It was suggested that FG stimulated phytoimmunity by shifting metabolism of carotenoids toward enhanced biosynthesis of VXC pigments. These pigments play a protective role and facilitate stabilization of photosynthetic apparatus, which is particularly important under stress conditions.

Animals↗
PubMed2006

Can metals defend plants against biotic stress?

Farmers have used metal compounds in phytosanitary treatments for more than a century; however, it has recently been suggested that plants absorb high concentrations of metals from the substrate as a self-defense mechanism against pathogens and herbivores. This metal defense hypothesis is among the most attractive proposals for the 'reason to be' of metal hyperaccumulator species. On a molecular basis, metal defense against biotic stress seems to imply common and/or complementary pathways of signal perception, signal transduction and metabolism. This does not imply a broad band of co-resistance to different stress types but reflects a continuous cross talk during the coevolution of plants, pathogens and herbivores competing in an environment where efficient metal ion acquisition and ion homeostasis are essential for survival.

Metals↗
PubMed2006

Crosstalk between abiotic and biotic stress responses: a current view from the points of convergence in the stress signaling networks.

Plants have evolved a wide range of mechanisms to cope with biotic and abiotic stresses. To date, the molecular mechanisms that are involved in each stress has been revealed comparatively independently, and so our understanding of convergence points between biotic and abiotic stress signaling pathways remain rudimentary. However, recent studies have revealed several molecules, including transcription factors and kinases, as promising candidates for common players that are involved in crosstalk between stress signaling pathways. Emerging evidence suggests that hormone signaling pathways regulated by abscisic acid, salicylic acid, jasmonic acid and ethylene, as well as ROS signaling pathways, play key roles in the crosstalk between biotic and abiotic stress signaling.

Plant Diseases↗
PubMed2006

Molecular cloning of growth hormone from silver sea bream: effects of abiotic and biotic stress on transcriptional and translational expression.

The pituitary growth hormone (GH) gene of silver sea bream (Sparus sarba) was cloned and characterized and found to be 615 base pairs encoding a protein of 204 amino acids. Using a bacterial expression system, recombinant protein was prepared and rabbit polyclonal antibody was raised. Transcript and protein amounts of GH were measured in fish that were adapted to a range of salinities, acclimated to different temperatures, or undergoing a natural time course of Vibrio alginolyticus infection. Isoosmotic salinity (12 ppt) adaptation resulted in increased GH transcript and protein in comparison to freshwater (0 ppt) and seawater (33 ppt) adapted fish. It was also found that cold temperature (12 degrees C) acclimated sea bream had higher amounts of pituitary GH transcript and protein when compared to warm temperature (25 degrees C) acclimated fish. Finally, the amounts of GH transcript and protein were found to be rapidly downregulated from an early stage of disease. The results from the present study demonstrate how GH can be modulated during both abiotic and biotic stress in fish.

Adaptation, Physiological↗
PubMed2004

Molecular and biochemical characterization of the Capsicum annuum calcium-dependent protein kinase 3 (CaCDPK3) gene induced by abiotic and biotic stresses.

The isolated full-length Capsicum annuum calcium-dependent protein kinase 3 (CaCDPK3) cDNA clone was selected from the chili pepper expressed sequence tag database (http://www.pdrc.re.kr/ks200201/pepper.html). Phylogenetic analysis based on the deduced amino acid sequence of CaCDPK3 cDNA revealed significant sequence similarity to the winter squash (Cucurbita maxima) CmCPK2 gene (81% identity). Genomic gel blot analysis disclosed that CaCDPK3 belongs to a multigene family in the pepper genome. CaCDPK3 expression was root tissue-specific, as shown by Northern blot data. The gene was rapidly induced in response to various osmotic stress factors and exogenous abscisic acid application in pepper leaves. Moreover, CaCDPK3 RNA expression was induced by an incompatible pathogen and by plant defense-related chemicals such as ethephon, salicylic acid and jasmonic acid. The biochemical properties of CaCDPK3 were investigated using a CaCDPK3 and glutathione S-transferase (GST) fusion protein. The recombinant proteins retained calcium-binding ability, and displayed autophosphorylation activity in vitro in a calcium-dependent manner. Further transient-expression studies showed that CaCDPK3 fused with soluble modified green fluorescent protein (smGFP) localized to the cytosol in chili pepper protoplasts. We propose that CaCDPK3 is implicated in biotic and abiotic stresses in pepper plants.

Amino Acid Sequence↗
PubMed2001

OARE-1, a Ty1-copia retrotransposon in oat activated by abiotic and biotic stresses.

Transcriptionally active Ty1-copia LTR-retrotransposons were found in oat using RT-PCR for amplifying the reverse transcriptase domain. Sequence analysis of the RT-PCR clones suggested that oat LTR-retrotransposons consist of at least seven groups, which were tentatively designated as Oatrt1 to Oatrt7. A full length copy of Oatrt1 was isolated from an oat genomic library, and was designated OARE-1. OARE-1 was 8,665 bp long and a member of the BARE-1 subgroup. The oat genome carried it in multiple copies (at least 10,000 copies / a hexaploid genome). The expression of OARE-1 was intensively induced by wounding, UV light, jasmonic acid and salicylic acid, and its pattern was very similar to that of the PAL (phenylalanin ammonia lyase) gene. Furthermore, OARE-1 was highly activated by infection with an incompatible race of the crown rust fungus, Puccinia coronata. These results suggest that OARE-1 is highly sensitive to various abiotic and biotic stimuli leading to plant defense responses.

Amino Acid Sequence↗
PubMed2007

Ubiquitin, hormones and biotic stress in plants.

BACKGROUND: The covalent attachment of ubiquitin to a substrate protein changes its fate. Notably, proteins typically tagged with a lysine48-linked polyubiquitin chain become substrates for degradation by the 26S proteasome. In recent years many experiments have been performed to characterize the proteins involved in the ubiquitylation process and to identify their substrates, in order to understand better the mechanisms that link specific protein degradation events to regulation of plant growth and development. SCOPE: This review focuses on the role that ubiquitin plays in hormone synthesis, hormonal signalling cascades and plant defence mechanisms. Several examples are given of how targeted degradation of proteins affects downstream transcriptional regulation of hormone-responsive genes in the auxin, gibberellin, abscisic acid, ethylene and jasmonate signalling pathways. Additional experiments suggest that ubiquitin-mediated proteolysis may also act upstream of the hormonal signalling cascades by regulating hormone biosynthesis, transport and perception. Moreover, several experiments demonstrate that hormonal cross-talk can occur at the level of proteolysis. The more recently established role of the ubiquitin/proteasome system (UPS) in defence against biotic threats is also reviewed. CONCLUSIONS: The UPS has been implicated in the regulation of almost every developmental process in plants, from embryogenesis to floral organ production probably through its central role in many hormone pathways. More recent evidence provides molecular mechanisms for hormonal cross-talk and links the UPS system to biotic defence responses.

Plant Growth Regulators↗
PubMed2005

The expression of the hydroxyproline-rich glycopeptide systemin precursor A in response to (a)biotic stress and elicitors is indicative of its role in the regulation of the wound response in tobacco (Nicotiana tabacum L.).

Two hydroxyproline-rich glycopeptide systemin (TobHS) precursor proteins known as preproTobHypSys-A and B were recently discovered in tobacco (Nicotiana tabacum L.) [Pearce et al. in Nature 411:817-820, 2001]. In this work, the effect of elicitors, insect damage, and abiotic stress on the expression of preproTobHypSys-A ppTobHS-A) in tobacco plants was evaluated. Foliar application of methyl jasmonate preferentially induced the systemic expression of ppTobHS-A in leaves phyllotactically one position above-treated leaves. Abscisic acid strongly induced ppTobHS-A, but water-stress did not. Mechanical wound-induction of ppTobHS-A in young plantlets was rapidly (1 h) and simultaneously detected in wounded and upper unwounded leaves, whereas in older plants induction was slow (12 h) and localized. ppTobHS-A was induced in plants infested with Bemisia tabaci or damaged by herbivory with Manduca sexta larvae. Compared to mechanical wounding, larval herbivory induced a stronger and more stable expression of ppTobHS-A. Moreover, exposure to Manduca-damaged plants induced its expression in neighboring intact plants. In most treatments, the expression patterns of ppTobHS-A coincided with those of selected wound-responsive (WR) genes (e.g., PIOX, NtPI-I, TPI). This correlation was tighter in the wounded and MeJA-treated leaves, whereas in distal, undamaged leaves, it appeared to depend on the type of WR gene examined and on the type of damage sustained by the plant. These results are consistent with the perceived role of the TobHS in defense signaling.

Abscisic Acid↗
PubMed2006

Simultaneous quantitative LC-ESI-MS/MS analyses of salicylic acid and jasmonic acid in crude extracts of Cucumis sativus under biotic stress.

Salicylic acid (SA) and jasmonic acid (JA) are plant hormones involved in basal resistance against plant pathogens and also in induced resistance. The aim of this study is to develop a fast and sensitive method to determine simultaneously the levels of both these hormones. The present paper proposes a method that includes hormone extraction with MeOH-H(2)O-HOAc (90:9:1, v/v), evaporation of the extracts, and injection into the liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) system in multiple reaction monitoring (MRM). Endogenous SA and JA levels in noninfested control cucumber cotyledons were 30.96 and 0.73ngg(-1) fresh weight, respectively. In roots, the levels were 8.31 and 15.82ngg(-1) FW, respectively. In plants treated with the biological control agent Trichoderma asperellum strain T-34, the levels of SA and JA did not differ from control plants. Rhizoctonia solani-diseased cucumber plants showed higher levels of SA and JA compared to noninfested controls (up to 2 and 13-fold higher, respectively). Detection limits for SA and JA were 0.45 and 0.47ngg(-1) fresh weight, respectively. The results of our research include the development of a method that is both fast and highly sensitive in the simultaneous quantitation of SA and JA from crude cucumber plant extracts, avoiding any purification and derivatization steps.

Chromatography, Liquid↗
PubMed2003

Early phosphorylation events in biotic stress.

Several kinases are activated during the defence response following microbial elicitation. While studying the regulation of these kinases in greater detail, it has become clear that the means by which phosphorylation events transmit specific information to the cell is highly complex. To gain a better understanding of the molecular events leading to a response, it will be increasingly important to identify not only the protein targets of phosphorylation but also the specific sites of phosphorylation. New developments in peptide-based phosphoproteome analysis appear to hold the promise of achieving these goals at the whole-cell level.

Mitogen-Activated Protein Kinases↗
PubMed2002

Regulation of CDPKs, including identification of PAL kinase, in biotically stressed cells of French bean.

Changes in protein kinase activity have been investigated during the early response of suspension cultured cells of French bean to fungal elicitor. One of the kinases activated has a known target, phenylalanine ammonia-lyase (PAL), which has an important role in plant defence responses, and was purified. Kinase acivity during purification was monitored for both the PAL-derived peptide and syntide-2, which it also phosphorylated. The kinase had an Mr of 55,000 on the basis of gel migration, 45Ca2+ binding, autophosphorylation and phosphorylation of various substrates using in-gel assays. The kinase has been characterised with respect to kinetics and other properties in vitro and appears to be a CDPK. In-gel assays were also used to show that this kinase and a number of other CDPKs of similar Mr showed complex changes in elicitor-treated suspension-cultured cells of French bean. An activation was observed within 10 min and was maintained for up to 4 h. The time course of activation was different from MAP kinase and casein kinase assayed in the same extracts. However, at 5 min after addition of elicitor there is a transient inactivation of the CDPKs before activation. This inactivation can be mimicked by adding forskolin to the cells 30 min before elicitation, which brings about changes in the cellular pH. Forskolin potentiates the oxidative burst when elicitor is subsequently added while the CDPK cannot be activated by elicitor upon forskolin treatment. In contrast, intracellular acidification brought about by forskolin brings about slight activation of MAPkinase.

Benzylamines↗