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

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.

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Zeamatin-Like Protein (ZLP) Gene is Associated with Resistance against A. niger in Maize (Zea mays L.)

Cercetari Agronomice in Moldova ◽

10.1515/cerce-2016-0013 ◽

2016 ◽

Vol 49 (2) ◽

pp. 29-39

Author(s):

A.M. Sajjad ◽

T. Bahsir ◽

S. Saeed ◽

M. Iqbal ◽

S. Islam ◽

...

Keyword(s):

Zea Mays ◽

Zea Mays L ◽

Hyphal Growth ◽

Antimicrobial Activities ◽

Fungal Species ◽

High Rate ◽

Sds Page ◽

Pathogenesis Related ◽

Enhanced Expression ◽

Related Proteins

Abstract Maize (Zea mays L.) constitutes one of the most important crops worldwide with multi-billion dollar annual revenue. The plant is however a good substrate for growth, development and activity of filamentous fungi. A large number of fungal species causes spoilage and accumulation of mycotoxins. Plants restrict the hyphal growth by producing pathogenesis related proteins. So far 17 groups of such proteins are identified. PR-5 group comprises of the thaumatin-like proteins (TLPs), which have diverse modes of actions and act at various stages of fungal attack. Zeamatin-like protein (ZLP) is a member of TLPs, which is basically localized in seeds with enhanced expression during physiological growth and cellular differentiation. However a basal quantity is found in the leaves of many crop plants. Here we report the response of maize plant tissues against A. niger inoculation by measuring the variation in expression profile of a zeamatin-like gene. Conventional PCR coupled with RT-qPCR identifies a significant change in the expression magnitude of ZLP in pre- and post-inoculated plant samples. SDS-PAGE, followed by antimicrobial activities against A. niger, E.coli, P. aeruginosa, B. cereus, S. aureus and S. typhimurium, however, do not register a direct relationship with enhancement in gene expression. It is in line with the fact that response to pathogenesis in plants is a multigenic activity involving a series of responsible/induced genes. The assay developed is useful in primary sorting out of the maize hybrids with respect to their resistance against Aspergillus spp., especially in areas with high rate of incidence of fungal pathogenesis.

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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

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi.1999.12.6.479 ◽

1999 ◽

Vol 12 (6) ◽

pp. 479-489 ◽

Cited By ~ 71

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.

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

OENO One ◽

10.20870/oeno-one.2007.41.3.843 ◽

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

Aims: 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.Methods and results: 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.Conclusion: 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.Significance and impact of study: 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.

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Mildew Resistance Locus O Genes CsMLO1 and CsMLO2 Are Negative Modulators of the Cucumis sativus Defense Response to Corynespora cassiicola

International Journal of Molecular Sciences ◽

10.3390/ijms20194793 ◽

2019 ◽

Vol 20 (19) ◽

pp. 4793 ◽

Cited By ~ 1

Author(s):

Guangchao Yu ◽

Qiumin Chen ◽

Xiangyu Wang ◽

Xiangnan Meng ◽

Yang Yu ◽

...

Keyword(s):

Cucumis Sativus ◽

Defense Response ◽

Leaf Spot ◽

Resistance Locus ◽

Corynespora Cassiicola ◽

Membrane Expression ◽

Mildew Resistance ◽

Pathogenesis Related Proteins ◽

Pathogenesis Related ◽

Related Proteins

Corynespora leaf spot caused by Corynespora cassiicola is one of the major diseases in cucumber (Cucumis sativus L.). However, the resistance mechanisms and signals of cucumber to C. cassiicola are unclear. Here, we report that the mildew resistance locus O (MLO) genes, CsMLO1 and CsMLO2, are both negative modulators of the cucumber defense response to C. cassiicola. Subcellular localization analysis showed that CsMLO1 and CsMLO2 are localized in the plasma membrane. Expression analysis indicated that the transcript levels of CsMLO1 and CsMLO2 are linked to the defense response to C. cassiicola. Transient overexpression of either CsMLO1 or CsMLO2 in cucumber cotyledons reduced resistance to C. cassiicola, whereas silencing of either CsMLO1 or CsMLO2 enhanced resistance to C. cassiicola. The relationships of pathogenesis-related proteins, reactive oxygen species (ROS)-associated genes, and abscisic acid (ABA)-related genes to the overexpression and silencing of CsMLO1/CsMLO2 in non-infested cucumber plants were investigated. The results indicated that CsMLO1 mediated resistance against C. cassiicola by regulating the expression of pathogenesis-related proteins and ROS-associated genes, as well as through ABA signaling pathway-associated genes. The CsMLO2-mediated resistance against C. cassiicola primarily involves regulation of the expression of pathogenesis-related proteins. Our findings will guide strategies to enhance the resistance of cucumber to corynespora leaf spot.

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