scholarly journals cDNA Cloning of a Sorghum Pathogenesis-Related Protein (PR-10) and Differential Expression of Defense-Related Genes Following Inoculation with Cochliobolus heterostrophus or Colletotrichum sublineolum

1999 ◽  
Vol 12 (6) ◽  
pp. 479-489 ◽  
Author(s):  
Sze-Chung Clive Lo ◽  
John D. Hipskind ◽  
Ralph L. Nicholson
Keyword(s):  
Fungal Pathogens ◽  
Sequence Similarity ◽  
Defense Responses ◽  
Cochliobolus Heterostrophus ◽  
Colletotrichum Sublineolum ◽  
Pathogenesis Related Protein ◽  
Pathogenesis Related ◽  
Time Courses ◽  
Related Proteins ◽  
Phytoalexin Synthesis

A sorghum cDNA clone was isolated by differential screening of a cDNA library prepared from mesocotyls (cultivar DK18) inoculated with fungal pathogens. The deduced translation product shows sequence similarity to a family of intracellular pathogenesis-related proteins (PR-10) with a potential ribonuclease function. We studied the accumulation of PR-10 and chalcone synthase (CHS) transcripts in mesocotyls following inoculation with Cochliobolus heterostrophus or Colletotrichum sublineolum. CHS is involved in phytoalexin synthesis in sorghum. Coordinate expression of PR-10 and CHS genes was localized in the area of inoculation along with the accumulation of phytoalexins. C. heterostrophus is a nonpathogen of sorghum and cytological studies indicated that cultivar DK18 is resistant to C. sublineolum, a sorghum pathogen. We demonstrated that the two fungi triggered different time courses of plant defense reactions. Inoculation with C. heterostrophus resulted in rapid accumulation of PR-10 and CHS transcripts after appressoria had become mature. Accumulation of these transcripts was delayed in plants inoculated with C. sublineolum until penetration of host tissue had been completed and infection vesicles had formed. Results suggest that different recognition events are involved in the expression of resistance to the two fungi used or that C. sublineolum suppresses the nonspecific induction of defense responses.

scholarly journals A Faster and a Stronger Defense Response: One of the Key Elements in Grapevine Explaining Its Lower Level of Susceptibility to Esca?

2013 ◽  
Vol 103 (10) ◽  
pp. 1028-1034 ◽  
Author(s):  
Carole Lambert ◽  
Ian Li Kim Khiook ◽  
Sylvia Lucas ◽  
Nadège Télef-Micouleau ◽  
Jean-Michel Mérillon ◽  
...  
Keyword(s):  
Defense Response ◽  
Defense Mechanisms ◽  
Defense Responses ◽  
Cabernet Sauvignon ◽  
Susceptible Cultivar ◽  
Pathogenesis Related ◽  
Leaf Level ◽  
Plant Pathogen Interaction ◽  
Related Proteins ◽  
Stilbene Compounds

Wood diseases like Esca are among the most damaging afflictions in grapevine. The defense mechanisms in this plant–pathogen interaction are not well understood. As some grapevine cultivars have been observed to be less susceptible to Esca than others, understanding the factors involved in this potentially stronger defense response can be of great interest. To lift part of this veil, we elicited Vitis vinifera plants of two cultivars less susceptible to Esca (‘Merlot’ and ‘Carignan’) and of one susceptible cultivar (‘Cabernet Sauvignon’), and monitored their defense responses at the leaf level. Our model of elicitation consisted in grapevine cuttings absorbing a culture filtrate of one causal agent of Esca, Phaemoniella chlamydospora. This model might reflect the early events occurring in Esca-affected grapevines. The two least susceptible cultivars showed an earlier and stronger defense response than the susceptible one, particularly with regard to induction of the PAL and STS genes, and a higher accumulation of stilbene compounds and some pathogenesis-related proteins.

scholarly journals Molecular Insights into Defense Responses of Vietnamese Maize Varieties to Fusarium verticillioides Isolates

2021 ◽  
Vol 7 (9) ◽  
pp. 724
Author(s):  
Trang Minh Tran ◽  
Maarten Ameye ◽  
Sofie Landschoot ◽  
Frank Devlieghere ◽  
Sarah De Saeger ◽  
...  
Keyword(s):  
Expression Profiles ◽  
Fusarium Verticillioides ◽  
Gene Expression Profiles ◽  
Defense Responses ◽  
Ear Rot ◽  
In Planta ◽  
Resistant Lines ◽  
Maize Varieties ◽  
Pathogenesis Related ◽  
Related Proteins

Fusarium ear rot (FER) caused by Fusarium verticillioides is one of the main fungal diseases in maize worldwide. To develop a pathogen-tailored FER resistant maize line for local implementation, insights into the virulence variability of a residing F. verticillioides population are crucial for developing customized maize varieties, but remain unexplored. Moreover, little information is currently available on the involvement of the archetypal defense pathways in the F. verticillioides–maize interaction using local isolates and germplasm, respectively. Therefore, this study aims to fill these knowledge gaps. We used a collection of 12 F. verticillioides isolates randomly gathered from diseased maize fields in the Vietnamese central highlands. To assess the plant’s defense responses against the pathogens, two of the most important maize hybrid genotypes grown in this agro-ecological zone, lines CP888 and Bt/GT NK7328, were used. Based on two assays, a germination and an in-planta assay, we found that line CP888 was more susceptible to the F. verticillioides isolates when compared to line Bt/GT NK7328. Using the most aggressive isolate, we monitored disease severity and gene expression profiles related to biosynthesis pathways of salicylic acid (SA), jasmonic acid (JA), abscisic acid (ABA), benzoxazinoids (BXs), and pathogenesis-related proteins (PRs). As a result, a stronger induction of SA, JA, ABA, BXs, and PRs synthesizing genes might be linked to the higher resistance of line Bt/GT NK7328 compared to the susceptible line CP888. All these findings could supply valuable knowledge in the selection of suitable FER resistant lines against the local F. verticllioides population and in the development of new FER resistant germplasms.

scholarly journals The Maize Lethal Leaf Spot 1 Mutant Has Elevated Resistance to Fungal Infection at the Leaf Epidermis

1998 ◽  
Vol 11 (11) ◽  
pp. 1110-1118 ◽  
Author(s):  
Carl Simmons ◽  
Sabine Hantke ◽  
Susan Grant ◽  
Gurmukh S. Johal ◽  
Steven P. Briggs
Keyword(s):  
Leaf Spot ◽  
Fungal Pathogens ◽  
Hyphal Growth ◽  
Leaf Epidermis ◽  
Puccinia Sorghi ◽  
Leaf Maturity ◽  
Pathogenesis Related ◽  
Lesion Number ◽  
Related Proteins ◽  
Germination And Growth

The maize lethal leaf spot 1 (lls1) mutant exhibits enhanced resistance to fungal pathogens. The lls1 resistance to Cochliobolus heterostrophus has two components: (i) lesion number is reduced 40% relative to wild type; and (ii) the lesions that do form often do not contain viable fungus. This lesion sterility is dependent upon leaf maturity and light, whereas reduced lesion number is not. The lls1 lesions express pathogenesis-related proteins at high levels, so lesion sterility likely results from activation of defense systems and necrosis. Reduced lesion number is correlated with a reduction of C. heterostrophus spore germination, hyphal growth, and haustoria formation on the leaf epidermis. The rust pathogen Puccinia sorghi has reduced pustule formation on lls1, and its germination and growth are also slowed on the epidermis. However, after entering the mesophyll through stomata, P. sorghi can form pustules on lls1, and even green islands within necrotic lls1 lesions. In situ mRNA hybridization shows that Lls1 is predominantly expressed in the leaf epidermis, coincident with the site of resistance in the mutant.

Defense responses in tomato landrace and wild genotypes to early blight pathogenAlternaria solaniinfection and accumulation of pathogenesis-related proteins

2011 ◽  
Vol 44 (12) ◽  
pp. 1147-1164 ◽  
Author(s):  
Abida Puthenpeedikal Salim ◽  
Krishnaveni Saminaidu ◽  
Murugan Marimuthu ◽  
Yasodha Perumal ◽  
Velazhahan Rethinasamy ◽  
...  
Keyword(s):  
Early Blight ◽  
Defense Responses ◽  
Pathogenesis Related Proteins ◽  
Pathogenesis Related ◽  
Related Proteins ◽  
Tomato Landrace

scholarly journals Identification and Molecular Mechanisms of Key Nucleotides Causing Attenuation in Pathogenicity of Dahlia Isolate of Potato Spindle Tuber Viroid

2020 ◽  
Vol 21 (19) ◽  
pp. 7352
Author(s):  
Shoya Kitabayashi ◽  
Daiki Tsushima ◽  
Charith Raj Adkar-Purushothama ◽  
Teruo Sano
Keyword(s):  
Symptom Severity ◽  
Molecular Mechanisms ◽  
Infected Plant ◽  
Potato Spindle Tuber Viroid ◽  
Defense Responses ◽  
Tomato Cultivar ◽  
Qpcr Analysis ◽  
Pathogenesis Related Protein ◽  
Pathogenesis Related ◽  
Chalcone Synthase Genes

While the potato spindle tuber viroid (PSTVd) variant, PSTVd-Dahlia (PSTVd-D or PSTVd-Dwt) induces very mild symptoms in tomato cultivar ‘Rutgers’, PSTVd-Intermediate (PSTVd-I or PSTVd-Iwt) induces severe symptoms. These two variants differ by nine nucleotides, of which six mutations are located in the terminal left (TL) to the pathogenicity (P) domains. To evaluate the importance of mutations located in the TL to the P domains, ten types of point mutants were created by swapping the nucleotides between the two viroid variants. Bioassay in tomato plants demonstrated that two mutants created on PSTVd-Iwt at positions 42 and 64 resulted in symptom attenuation. Phenotypic and RT-qPCR analysis revealed that mutation at position 42 of PSTVd-Iwt significantly reduced disease severity and accumulation of the viroid, whereas mutation at position 64 showed a significant reduction in stunting when compared to the PSTVd-Iwt infected plant. RT-qPCR analysis on pathogenesis-related protein 1b1 and chalcone synthase genes showed a direct correlation with symptom severity whereas the expansin genes were down-regulated irrespective of the symptom severity. These results indicate that the nucleotides at positions 42 and 64 are in concert with the ones at positions 43, 310, and 311/312, which determines the slower and stable accumulation of PSTVd-D without eliciting excessive host defense responses thus contributing in the attenuation of disease symptom.

scholarly journals Pseudomonas fluorescens DN16 Enhances Cucumber Defense Responses Against the Necrotrophic Pathogen Botrytis cinerea by Regulating Thermospermine Catabolism

2021 ◽  
Vol 12 ◽  
Author(s):  
Lin Zhu ◽  
Nana Qian ◽  
Yujun Sun ◽  
Xiaoming Lu ◽  
Haiming Duan ◽  
...  
Keyword(s):  
Pseudomonas Fluorescens ◽  
Botrytis Cinerea ◽  
Defense Responses ◽  
Pathogen Infection ◽  
Necrotrophic Pathogen ◽  
Catabolic Enzymes ◽  
Catabolic Genes ◽  
Pathogenesis Related Protein ◽  
Pathogenesis Related

Plants can naturally interact with beneficial rhizobacteria to mediate defense responses against foliar pathogen infection. However, the mechanisms of rhizobacteria-mediated defense enhancement remain rarely clear. In this study, beneficial rhizobacterial strain Pseudomonas fluorescens DN16 greatly increased the resistance of cucumber plants against Botrytis cinerea infection. RNA-sequencing analyses showed that several polyamine-associated genes including a thermospermine (TSpm) synthase gene (CsACL5) and polyamine catabolic genes (CsPAO1, CsPAO5, and CsCuAO1) were notably induced by DN16. The associations of TSpm metabolic pathways with the DN16-mediated cucumber defense responses were further investigated. The inoculated plants exhibited the increased leaf TSpm levels compared with the controls. Accordantly, overexpression of CsACL5 in cucumber plants markedly increased leaf TSpm levels and enhanced defense against B. cinerea infection. The functions of TSpm catabolism in the DN16-mediated defense responses of cucumber plants to B. cinerea were further investigated by pharmacological approaches. Upon exposure to pathogen infection, the changes of leaf TSpm levels were positively related to the enhanced activities of polyamine catabolic enzymes including polyamine oxidases (PAOs) and copper amine oxidases (CuAOs), which paralleled the transcription of several defense-related genes such as pathogenesis-related protein 1 (CsPR1) and defensin-like protein 1 (CsDLP1). However, the inhibited activities of polyamine catabolic enzymes abolished the DN16-induced cucumber defense against B. cinerea infection. This was in line with the impaired expression of defense-related genes in the inoculated plants challenged by B. cinerea. Collectively, our findings unraveled a pivotal role of TSpm catabolism in the regulation of the rhizobacteria-primed defense states by mediating the immune responses in cucumber plants after B. cinerea infection.

scholarly journals Changes in mycelial structure of Botrytis cinerea induced by removal of the glucan matrix

OENO One ◽  
2007 ◽  
Vol 41 (3) ◽  
pp. 149
Author(s):  
Nurit Bar-Nun ◽  
Annie L'Hyvernay ◽  
Bernard Donèche ◽  
Alfred M. Mayer
Keyword(s):  
Botrytis Cinerea ◽  
Fungal Pathogens ◽  
Extra Cellular Matrix ◽  
Fungal Mycelium ◽  
Fungal Virulence ◽  
Pathogenesis Related ◽  
Normal Diameter ◽  
Plant Pathogen Interactions ◽  
Related Proteins ◽  
Cellular Matrix

<p style="text-align: justify;"><strong>Aims</strong>: b-1,3-glucanase is one of the main pathogenesis related proteins of plants, involved in plant-pathogen interactions. Its effect on fungal pathogens is not entirely known. The hyphae of Botrytis cinerea are covered by an extra cellular matrix, mainly composed of a b-1,3-D-glucan. This matrix also contains a variety of enzymes, lipids and melanin which may play a role in fungal virulence.</p><p style="text-align: justify;"><strong>Methods and results</strong>: Cultures of Botrytis cinerea are made in presence of b-1,3-glucanase. The structure of the mycelium of Botrytis cinerea after exposure to b-1,3-glucanase during growth was examined by staining with Schiff's reagent and using the electron microscope. Without glucanase, hyphae have a normal diameter and were surrounded by a glucan matrix. Cytoplasm is dense and contains little vacuoles. The glucanase treatment removed most of the glucan sheath, but did not kill the fungus. The structure of the hyphae was changed by the treatment and their diameter increased. Membrane structure showed marked changes, the cytoplasm of the cells was less dense, but more inclusions were observed, including an increase in what appeared to be lipids.</p><p style="text-align: justify;"><strong>Conclusion</strong>: The appearance of the mycelium, whose glucan sheath has been removed, was that of cells under stress. The possible implications of the function of the glucan sheath during the interaction of Botrytis cinerea with its host during pathogenesis are discussed.</p><p style="text-align: justify;"><strong>Significance and impact of study</strong>: These changes following glucanase treatment would lead to a fungal mycelium which will be more sensitive to antifungal agents and might suggest ways of combating Botrytis infections by preventing the formation of the extra-cellular matrix.</p>

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