Accumulation Of Pathogenesis-related Proteins Research Articles

Ethylene Signal Is Transduced via Protein Phosphorylation Events in Plants.

A plethora of abiotic and biotic environmental stresses exert their influence on plants via the gaseous hormone ethylene. In addition, aspects of plant development and climacteric fruit ripening are regulated by ethylene. Sensitivity to ethylene is presumably mediated by a specific ethylene receptor whose activation signal is then transduced via an unknown cascade pathway. We have used the plant pathogenesis response, exemplified by the induction of pathogenesis-related (PR) genes, as a paradigm to investigate ethylene-dependent signal transduction in the plant cell. Ethylene application induced very rapid and transient protein phosphorylation in tobacco leaves. In the presence of the kinase inhibitors H-7 and K-252a, the transient rise in phosphorylation and the induced expression of PR genes were abolished. Similarly, these inhibitors blocked the response induced by an ethylene-dependent elicitor, [alpha]-AB. Reciprocally, application of okadaic acid, a specific inhibitor of phosphatases type 1 and type 2A, enhanced total protein phosphorylation and by itself elicited the accumulation of PR proteins. In the presence of H-7 and K-252a, PR protein accumulation induced by okadaic acid was blocked. In contrast to the action of ethylene and [alpha]-AB, xylanase elicits the accumulation of PR protein by an ethylene-independent pathway. Xylanase-induced PR protein accumulation was not affected by H-7 and K-252a. The results indicate that responsiveness to ethylene in leaves is transduced via putative phosphorylated intermediates that are regulated by specific kinases and phosphatases.

Endogenous Salicylic Acid Levels Correlate with Accumulation of Pathogenesis-Related Proteins and Virus Resistance in Tobacco

Salicylic acid (SA) is hypothesized to be an endogenous regulator of local and systemic disease resistance and an inducer of pathogenesis-related (PR) proteins among plants. High levels of PR proteins have been observed in an uninoculated amphidiploid hybrid of Nicotiana glutinosa [times] N. debneyi, which is highly resistant to tobacco mosaic virus (TMV). Fluoresence, UV, and mass spectral analysis established that the levels of SA in healthy N. glutinosa [times] N. debneyi leaves were 30 times greater than in N. tabacum [open quotes]Xanthi-nc[close quotes] tobacco, which does not constitutively express PR proteins and is less resistant to TMV. Upon TMV-inoculation SA levels increased at least 70-fold leaves of Xanthi-nc but role only slightly in the hybrid. Phloem exudates of N. glutinosa [times] N. debneyi contained at least 500 times more SA than those of Xanthi-nc. SA treatment caused the appearance of PR-1 protein in Xanthi-nc but did not affect constitutively high levels of PR-1 protein in N. glutinosa [times] N. debneyi. In contrast to Xanthi-nc tobacco, TMV-inoculated N. glutinosa [times] N. debneyi kept at 32 C accumulated more than 0.5 [mu]g SA/g fresh weight, maintained high levels of PR proteins, and developed a hypersensitive response to TMV. PR proteins havemore » previously been shown to accumulate in the lower leaves of healthy, flowering Xanthi-nc tobacco, which exhibited increased resistance to TMV. These developmentally induced increases in resistance and PR-1 proteins positively correlated with tissue levels of SA. These results affirm the regulatory role of SA in disease resistance and PR protein production. 31 refs., 9 figs., 1 tab.« less

Xylanase, a Novel Elicitor of Pathogenesis-Related Proteins in Tobacco, Uses a Non-Ethylene Pathway for Induction

Antisera to acidic isoforms of pathogenesis-related proteins were used to measure the induction of these proteins in tobacco (Nicotiana tabacum) leaves. Endo-(1-4)-beta-xylanase purified from culture filtrates of Trichoderma viride was a strong elicitor of pathogenesis-related protein synthesis in tobacco leaves. The synthesis of these proteins was localized to tissue at the area of enzyme application. The inhibitors of ethylene biosynthesis and ethylene action, 1-aminoethoxyvinylglycine and silver thiosulfate, inhibited accumulation of pathogenesis-related proteins induced by tobacco mosaic virus and alpha-aminobutyric acid, but did not inhibit elicitation by xylanase. Likewise, the induction of these proteins by the tobacco pathogen Pseudomonas syringae pv. tabaci was not affected by the inhibitors of ethylene biosynthesis and action. The leaf response to tobacco mosaic virus and alpha-aminobutyric acid was dependent on light in normal and photosynthetically incompetent leaves. In contrast, the response of leaves to xylanase was independent of light. Tobacco mosaic virus and alpha-aminobutyric acid induced concerted accumulation of pathogenesis-related proteins. However, xylanase elicited the accumulation of only a subset of these proteins. Specifically, the plant (1-3)-beta-glucanases, which are normally a part of the concerted response, were underrepresented. These experiments have revealed the presence of a novel ethylene-independent pathway for pathogenesis-related protein induction that is activated by xylanase.

The gene-for-gene relationship between Capsicum annuum L. and tobacco mosaic virus: effects on virus multiplication, ethylene synthesis and accumulation of pathogenesis-related proteins

Pepper ( Capsicum annuum) plants containing the L 1 or L 3 genes for resistance to tobacco mosaic virus, and susceptible hosts (L +), were inoculated with TMV strains overcoming neither, one or both of the resistance genes. Diverse symptoms were produced in the different host-virus combinations. Measurements of virus multiplication confirmed, in quantitative terms, the operation of a gene-for-gene relationship between host resistance and virulence in the virus. Host metabolism was studied during different types of host-virus interaction. Accumulation of pathogenesis-related (PR) proteins was examined on native and denaturing gels. Major PR proteins with molecular masses of 11, 18, 21 and 28 kD were found, together with several other bands: all were trypsin-resistant. One host protein disappeared after certain types of infection. PR proteins were induced mainly in necrotically-infected inoculated leaves, and in necrotic or non-necrotic, systemically-infected leaves. TMV strain SL, which caused no necrosis on any host, was an efficient inducer of PR proteins. Little evidence was found for any acquired systemic resistance in the host-virus combinations tested. The relationships between ethylene synthesis and necrosis and PR protein accumulation were examined. Necrotic infections stimulated ethylene synthesis, but symptomless inoculated leaves with enhanced ethylene production were also found. The non-necrotic strain SL did not significantly enhance ethylene production. Cases were found where ethylene was increased without PR protein accumulation, and conversely, where PR proteins increased without major ethylene increase.

Pathogenesis-related proteins are developmentally regulated in tobacco flowers.

The accumulation of pathogenesis-related proteins (PR) in tobacco leaves has been casually related to pathogen and specific physiological stresses. The known enzymatic function of some of these proteins is potentially antimicrobial. By using antibodies specific to three classes of pathogenesis-related proteins, we examined tobacco plants during their normal growth. The pathogenesis-related proteins accumulated during the normal development of the tobacco flower. The PR-1 class of proteins (biological function unknown) is located in sepal tissue. PR-P, Q polypeptides are endochitinases and are present in pedicels, sepals, anthers, and ovaries. A glycoprotein serologically related to the PR-2,N,O class is a (1,3)-beta-glucanase and is present in pistils. Differential appearance during flower development, in situ localization, and post-translational processing of floral pathogenesis-related proteins point to a hitherto unsuspected function these classes of pathogenesis-related proteins play in the normal process of flowering and reproductive physiology.

Isolation and nucleotide sequence of a novel cDNA clone encoding the major form of pathogenesis-related protein R

Pathogenesis-related (PR) proteins are acid-soluble, protease-resistant proteins which accumulate in the intercellular spaces of many plants as a result of the hypersensitive reaction to a pathogen [10]. The accumulat ion of PR proteins has also been observed in leaves of plants treated with certain chemical inducers such as acetylsalicylic acid and polyacrylic acid [4, 11]. The presence of PR proteins correlates with the onset o f a broad-range systemic resistance [3, 10] which suggests that the PR proteins may have a role in the establishment or maintenence of the resistant state. The predominant PR proteins expressed after TMV infection in tobacco are PRla, lb, lc, -2, -N, -O, -P, -Q, -R and -S [7, 10]. In an effort to isolate cDNA clones for PR proteins, Bol and colleagues at the University of Leiden constructed a cDNA library from TMV-infected tobacco leaves (Nicotiana tabacurn cv Samsun NN) and cDNA clones were isolated from this library that were induced upon TMV infection [2, 5, 6]. One group of these cDNA clones was shown to encode a protein with 65% identity to the sweet-tasting protein, thaumat in [1]. Later it was found that the thaumatin-like protein has about 60% identity to a maize t rypsin/a-amylase inhibitor [9]. Recently, the thaumatin-like protein has been identified as the tobacco pathogenesis-related protein, PR-R [8]. PR-R exists as two isoforms in tobacco, a major and a minor form which are expressed at a ratio of approximately 3:2 [8]. Cornelissen et al. described the isolation and sequence of the minor form of PR-R [1]. Here we present the sequence of a clone isolated from a cDNA library generated from RNA isolated from leaves of TMV-infected N. tabacum cv. Xanthi-nc which encodes the major form of PR-R. The two cDNA clones of PR-R share 95% identity at the nucleic acid level and 98% identity at the level of the encoded amino acid sequence. When 11 cDNA clones were randomly isolated and partially sequenced it was found that 8 code for the major form of PR-R and 3 code for the minor form of PR-R. Our deduced amino acid sequence for the major and minor forms of PR-R agrees with the protein sequence data from Pierpoint et al. [8] at every position except the asparagine residue at position 26 of the major form. There is no obvious reason for this one discrepancy. The DNA sequence for the minor form of PR-R does encode an asparagine at position 26 ([1], our unpublished results); however, the DNA sequence analysis resulting from sequencing both strands of two independent cDNA clones confirms that there is indeed a G at base 166 which would code for an aspartate.

Virus and pathogenesis-related protein accumulation after tobacco-mosaic-virus infection of tobacco

Conference Article| October 01 1984 Virus and pathogenesis-related protein accumulation after tobacco-mosaic-virus infection of tobacco J. F. ANTONIW; J. F. ANTONIW *Department of Biochemistry, Rothamsted Experimental Station, Harpenden, Herts, AL5 2JQ, U.K. Search for other works by this author on: This Site PubMed Google Scholar R. F. WHITE; R. F. WHITE †Department of Plant Pathology, Rothamsted Experimental Station, Harpenden, Herts, AL5 2JQ, U.K. Search for other works by this author on: This Site PubMed Google Scholar D. J. BARBARA; D. J. BARBARA ‡Department of Plant Pathology, East Mailing Research Station, Maidstone, Kent ME19 6BJ, U.K. Search for other works by this author on: This Site PubMed Google Scholar A. LONGLEY A. LONGLEY †Department of Plant Pathology, Rothamsted Experimental Station, Harpenden, Herts, AL5 2JQ, U.K. Search for other works by this author on: This Site PubMed Google Scholar Biochem Soc Trans (1984) 12 (5): 828. https://doi.org/10.1042/bst0120828 Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Facebook Twitter LinkedIn MailTo Cite Icon Cite Get Permissions Citation J. F. ANTONIW, R. F. WHITE, D. J. BARBARA, A. LONGLEY; Virus and pathogenesis-related protein accumulation after tobacco-mosaic-virus infection of tobacco. Biochem Soc Trans 1 October 1984; 12 (5): 828. doi: https://doi.org/10.1042/bst0120828 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentAll JournalsBiochemical Society Transactions Search Advanced Search Keywords: e.l.i.s.a., enzyme-linked immunosorbent assay; PR, pathogenesis-related; TMV, tobacco mosaic virus This content is only available as a PDF. © 1984 Biochemical Society1984 Article PDF first page preview Close Modal You do not currently have access to this content.

Are 'Pathogenesis-related' Proteins Involved in Acquired Systemic Resistance of Tobacco Plants to Tobacco Mosaic Virus?

SUMMARY Four host-coded ‘pathogenesis-related’ proteins accumulate systemically in local-lesion-forming varieties of tobacco after infection with tobacco mosaic virus. It has been suggested that they are involved in the acquired systemic resistance of plants to a second inoculation. Pathogenesis-related protein concentration and amount of resistance (reduction in size and number of lesions formed in the second inoculation) were measured at various times after the first inoculation. The results showed no quantitative or temporal relationship between amounts of resistance and pathogenesis-related proteins. In particular, resistance could be demonstrated in leaves before detectable accumulation of pathogenesis-related protein. Abscisic acid sprayed on plants induced an apparent resistance without inducing pathogenesis-related proteins. Low doses of methyl benzimidazol-2yl-carbamate caused accumulation of pathogenesis-related protein but not resistance. Nicotiana glutinosa plants accumulated large amounts of a similar protein after infection, but became more susceptible to a second inoculation. All these results suggest that the pathogenesis-related proteins do not play a central role in the mechanism of acquired systemic resistance.