scholarly journals Two PR-1 Genes from Tomato Are Differentially Regulated and Reveal a Novel Mode of Expression for a Pathogenesis-Related Gene During the Hypersensitive Response and Development

1997 ◽  
Vol 10 (5) ◽  
pp. 624-634 ◽  
Author(s):  
Pablo Tornero ◽  
José Gadea ◽  
Vicente Conejero ◽  
Pablo Vera
Keyword(s):  
Expression Pattern ◽  
Hypersensitive Response ◽  
Constitutive Expression ◽  
Developmental Expression ◽  
Gus Gene ◽  
Cortical Cells ◽  
Pathogenesis Related ◽  
Genes Encoding ◽  
Refractory State ◽  
Pathogenesis Related Gene

Pathogenesis-related (PR) proteins form a heterogeneous family of plant proteins that are likely to be involved in defense and are inducible by pathogen attacks. One group of PRs, represented by the subfamily PR-1, are low-molecular-weight proteins of unknown biochemical function. Here we describe the cloning and characterization of two closely related genes encoding a basic and an acidic PR-1 protein (PR1b1 and PR1a2) from tomato (Lycopersicon esculentum). We present a comparative study of the mode of transcriptional regulation of these two genes in transgenic tobacco plants using a series of promoter-GUS fusions. Unexpectedly, the chimeric PR1a2/GUS gene is not induced by pathogenic signals but instead shows constitutive expression with a reproducible developmental expression pattern. It is expressed in shoot meristems, trichomes, and cortical cells as well as in vascular and nearby tissues of the mature stem. This constitutive expression pattern may represent preemption of plant defenses against potential pathogens. Conversely, the chimeric PR1b1/GUS gene does not show any constitutive expression in the plant, but it is transcriptionally activated following pathogen attack. Upon infection by tobacco mosaic virus, the PR1b1 gene is strongly activated locally in tissues undergoing the hypersensitive response but not systemically in uninoculated tissues. Furthermore, its expression is induced by both salicylic acid and ethylene precursors, two signals that coexist and apparently mediate the activation of local defenses during the hypersensitive response. We speculate that the different mode of expression of the two genes presented here, together with that reported previously for the induction of other PR-1 genes in systemic, uninoculated tissues, may all be complementary and necessary for the plant to acquire an efficient refractory state to resist pathogen attacks.

scholarly journals Constitutive Expression of Arabidopsis Senescence Associated Gene 101 in Brachypodium distachyon Enhances Resistance to Puccinia brachypodii and Magnaporthe oryzae

Plants ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 1316
Author(s):  
Ning Wang ◽  
Na Song ◽  
Zejun Tang ◽  
Xiaojie Wang ◽  
Zhensheng Kang ◽  
...  
Keyword(s):  
Transgenic Plants ◽  
Magnaporthe Oryzae ◽  
Plant Immunity ◽  
Brachypodium Distachyon ◽  
Constitutive Expression ◽  
Wild Type ◽  
Homologous Genes ◽  
Pathogenesis Related ◽  
Salicylic Acid Accumulation ◽  
Pathogenesis Related Gene

Brachypodium distachyon, as an effective model of cereal grains, is susceptible to most destructive cereal pathogens. Senescence associated gene 101 (SAG101) has been studied extensively in Arabidopsis. SAG101 is one of the important regulators of plant immunity. However, no homologous genes of AtSAG101 were found in B. distachyon. In this study, the AtSAG101 gene was transformed into B. distachyon. Three transgenic plant lines containing the AtSAG101 gene were confirmed by PCR and GUS gene activity. There were fewer Puccinia brachypodii urediospores in the AtSAG101-overexpressing plants compared to wild type plants. P. brachypodii biomass was obviously decreased in AtSAG101 transgenic plants. The length of infection hyphae and infection unit areas of P. brachypodii were significantly limited in transgenic plants. Moreover, there were small lesions in AtSAG101 transgenic plants challenged by Magnaporthe oryzae. Salicylic acid accumulation was significantly increased, which led to elevated pathogenesis-related gene expression in transgenic B. distachyon inoculated by P. brachypodii or M. oryzae compared to wild type plants. These results were consistent with infected phenotypes. Overexpression of AtSAG101 in B. distachyon caused resistance to M. oryzae and P. brachypodii. These results suggest that AtSAG101 could regulate plant resistance in B. distachyon.

scholarly journals Regulatory Mechanisms Controlling Expression of the DAN/TIR Mannoprotein Genes During Anaerobic Remodeling of the Cell Wall in Saccharomyces cerevisiae

Genetics ◽  
2001 ◽  
Vol 157 (3) ◽  
pp. 1169-1177
Author(s):  
Natalia E Abramova ◽  
Brian D Cohen ◽  
Odeniel Sertil ◽  
Rachna Kapoor ◽  
Kelvin J A Davies ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Consensus Sequence ◽  
Ectopic Expression ◽  
Constitutive Expression ◽  
Anaerobic Growth ◽  
Zinc Cluster ◽  
Sterol Transport ◽  
Genes Encoding ◽  
Altered Regulation ◽  
Repression Domain

Abstract The DAN/TIR genes of Saccharomyces cerevisiae encode homologous mannoproteins, some of which are essential for anaerobic growth. Expression of these genes is induced during anaerobiosis and in some cases during cold shock. We show that several heme-responsive mechanisms combine to regulate DAN/TIR gene expression. The first mechanism employs two repression factors, Mox1 and Mox2, and an activation factor, Mox4 (for mannoprotein regulation by oxygen). The genes encoding these proteins were identified by selecting for recessive mutants with altered regulation of a dan1::ura3 fusion. MOX4 is identical to UPC2, encoding a binucleate zinc cluster protein controlling expression of an anaerobic sterol transport system. Mox4/Upc2 is required for expression of all the DAN/TIR genes. It appears to act through a consensus sequence termed the AR1 site, as does Mox2. The noninducible mox4Δ allele was epistatic to the constitutive mox1 and mox2 mutations, suggesting that Mox1 and Mox2 modulate activation by Mox4 in a heme-dependent fashion. Mutations in a putative repression domain in Mox4 caused constitutive expression of the DAN/TIR genes, indicating a role for this domain in heme repression. MOX4 expression is induced both in anaerobic and cold-shocked cells, so heme may also regulate DAN/TIR expression through inhibition of expression of MOX4. Indeed, ectopic expression of MOX4 in aerobic cells resulted in partially constitutive expression of DAN1. Heme also regulates expression of some of the DAN/TIR genes through the Rox7 repressor, which also controls expression of the hypoxic gene ANB1. In addition Rox1, another heme-responsive repressor, and the global repressors Tup1 and Ssn6 are also required for full aerobic repression of these genes.

scholarly journals Six mouse alpha-tubulin mRNAs encode five distinct isotypes: testis-specific expression of two sister genes.

1986 ◽  
Vol 6 (7) ◽  
pp. 2409-2419 ◽  
Author(s):  
A Villasante ◽  
D Wang ◽  
P Dobner ◽  
P Dolph ◽  
S A Lewis ◽  
...  
Keyword(s):  
Duplication Event ◽  
Developmental Expression ◽  
Untranslated Regions ◽  
Coding Region ◽  
Specific Expression ◽  
Translational Initiation ◽  
Alpha Tubulin ◽  
Tubulin Isotypes ◽  
Tubulin Isotype ◽  
Genes Encoding

Five mouse alpha-tubulin isotypes are described, each distinguished by the presence of unique amino acid substitutions within the coding region. Most, though not all of these isotype-specific amino acids, are clustered at the carboxy terminus. One of the alpha-tubulin isotypes described is expressed exclusively in testis and is encoded by two closely related genes (M alpha 3 and M alpha 7) which have homologous 3' untranslated regions but which differ at multiple third codon positions and in their 5' untranslated regions. We show that a subfamily of alpha-tubulin genes encoding the same testis-specific isotype also exists in humans. Thus, we conclude that the duplication event leading to a pair of genes encoding a testis-specific alpha-tubulin isotype predated the mammalian radiation, and both members of the duplicated sequence have been maintained since species divergence. A second alpha-tubulin gene, M alpha 6, is expressed ubiquitously at a low level, whereas a third gene, M alpha 4, is unique in that it does not encode a carboxy-terminal tyrosine residue. This gene yields two transcripts: a 1.8-kilobase (kb) mRNA that is abundant in muscle and a 2.4-kb mRNA that is abundant in testis. Whereas the 1.8-kb mRNA encodes a distinct alpha-tubulin isotype, the 2.4-kb mRNA is defective in that the methionine residue required for translational initiation is missing. Patterns of developmental expression of the various alpha-tubulin isotypes are presented. Our data support the view that individual tubulin isotypes are capable of conferring functional specificity on different kinds of microtubules.

scholarly journals Mountain stoneflies may tolerate warming streams: evidence from organismal physiology and gene expression

2019 ◽  
Author(s):  
Scott Hotaling ◽  
Alisha A. Shah ◽  
Kerry L. McGowan ◽  
Lusha M. Tronstad ◽  
J. Joseph Giersch ◽  
...  
Keyword(s):  
Thermal Stress ◽  
Constitutive Expression ◽  
High Elevation ◽  
Cellular Level ◽  
Cellular Stress Response ◽  
Mountain Stream ◽  
Sequencing Data ◽  
Stream Insects ◽  
Short Term Exposure ◽  
Genes Encoding

AbstractRapid glacier recession is altering the physical conditions of headwater streams. Stream temperatures are predicted to rise and become increasingly variable, putting entire meltwater-associated biological communities at risk of extinction. Thus, there is a pressing need to understand how thermal stress affects mountain stream insects, particularly where glaciers are likely to vanish on contemporary timescales. In this study, we tested the critical thermal maximum (CTMAX) of stonefly nymphs representing multiple species and a range of thermal regimes in the high Rocky Mountains, USA. We then collected RNA-sequencing data to assess how organismal thermal stress translated to the cellular level. Our focal species included the meltwater stonefly, Lednia tumana, which was recently listed under the U.S. Endangered Species Act due to climate-induced habitat loss. For all study species, critical thermal maxima (CTMAX > 20°C) far exceeded the stream temperatures mountain stoneflies experience (< 10°C). Moreover, while evidence for a cellular stress response was present, we also observed constitutive expression of genes encoding proteins known to underlie thermal stress (i.e., heat shock proteins) even at low temperatures that reflected natural conditions. We show that high-elevation aquatic insects may not be physiologically threatened by short-term exposure to warm temperatures and that longer term physiological responses or biotic factors (e.g., competition) may better explain their extreme distributions.

Identification of a putative expansin gene expressed in the subventral glands of the cereal cyst nematode Heterodera avenae

Nematology ◽  
2012 ◽  
Vol 14 (5) ◽  
pp. 571-577 ◽  
Author(s):  
Haibo Long ◽  
Deliang Peng ◽  
Wenkun Huang ◽  
Yanke Liu ◽  
Huan Peng
Keyword(s):  
Cyst Nematode ◽  
Developmental Expression ◽  
Heterodera Avenae ◽  
Parasitic Nematodes ◽  
Secretory Proteins ◽  
Expansin Gene ◽  
Genes Encoding ◽  
Juvenile Stages ◽  
Stage Process ◽  
Parasitism Genes

Parasitism genes encoding secretory proteins expressed in the pharyngeal glands of plant-parasitic nematodes play important roles in the parasitic process. A new expansin gene (Ha-expb1) expressed in the subventral glands of the sedentary cyst nematode, Heterodera avenae, was cloned. Southern blot analysis suggested that Ha-expb1 is a member of a multigene family. The deduced protein Ha-EXPB1 consists of a signal peptide, a CBM II and an expansin domain, and was significantly similar to expansins and expansin-like proteins from the potato cyst nematode, Globodera rostochiensis, and the pine wood nematodes, Bursaphelenchus spp. In situ hybridisation showed that Ha-expb1 transcript specifically accumulated in the two subventral gland cells of the second-stage juveniles. Developmental expression confirmed that its transcript abundances were high in the motile juvenile stages and low in the sedentary stage of the nematode, implying a role in the early parasitic-stage process, most likely in aiding migration within the plant.

scholarly journals Relationship Between Localized Acquired Resistance (LAR) and the Hypersensitive Response (HR): HR Is Necessary for LAR to Occur and Salicylic Acid Is Not Sufficient to Trigger LAR

1999 ◽  
Vol 12 (8) ◽  
pp. 655-662 ◽  
Author(s):  
Laurent Costet ◽  
Sylvain Cordelier ◽  
Stéphan Dorey ◽  
Fabienne Baillieul ◽  
Bernard Fritig ◽  
...  
Keyword(s):  
Salicylic Acid ◽  
Hypersensitive Response ◽  
Acquired Resistance ◽  
Defense Responses ◽  
Pr Proteins ◽  
Tobacco Plants ◽  
Tobacco Leaves ◽  
Pathogenesis Related ◽  
Tobacco Mosaic Virus Infection ◽  
Mosaic Virus Infection

In tobacco plants reacting hypersensitively to pathogen infection, localized acquired resistance (LAR) is induced in a sharp zone surrounding hypersensitive response (HR) lesions. Using a fungal glycoprotein inducing HR and LAR when infiltrated at 50 nM into tobacco leaves, we have shown previously that a plant signal(s) is released by HR cells and diffuses to induce LAR. Here we address two questions: does LAR occur when HR is not induced, and is salicylic acid the (or one of the) mobile LAR signal? We found that application to tobacco leaves of 0.25 nM glycoprotein triggered defense responses without HR and without an H2O2 burst. The analyzed responses include changes in expression of O-methyltransferase (OMT), 3-hydroxy-3-methylglutarylCoA reductase, pathogenesis-related (PR) proteins, and changes in levels of the signal salicylic acid. No defense responses and no increased resistance to tobacco mosaic virus infection were found beyond the elicitor-infiltrated tissue, providing strong evidence that there is no LAR without HR. Treatments of NahG tobacco leaves with 50 nM elicitor induced the HR and, in the sharp zone surrounding the HR lesion, a strong activation of OMT and of basic PR proteins, but not of acidic PR-1 proteins. This indicates that a signal different from salicylic acid is diffusing.

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