Resistance of wheat to Mycosphaerella graminicola involves early and late peaks of gene expression

Adhikari, Tika B.; Balaji, Boovaraghan; Breeden, Jill; Goodwin, Stephen B.

doi:10.1016/j.pmpp.2007.10.004

Cited by 67 publications

(70 citation statements)

References 67 publications

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“…The long symptomless phase of wheat leaf colonization by M. graminicola is well suited to the analysis of pathogen gene expression but also to temporal analysis of host defense gene expression. We hypothesized that plants inoculated with the DMg3LysM mutant strains would accelerate, and perhaps amplify, the expression of Pathogenesis-Related (PR) gene homologs, which are normally triggered immediately prior to symptom formation during fully susceptible disease interactions (Adhikari et al, 2007;Motteram et al, 2009). Therefore, we inoculated wheat leaves with either the DMg3LysM mutant strains or the wild-type strain and collected leaf material throughout the symptomless phase of colonization for analysis of host defense gene expression by real-time RT-PCR.…”

Section: Graminicola Mg3lysm Mutants Are Severely Compromised In Vmentioning

confidence: 99%

Analysis of Two in Planta Expressed LysM Effector Homologs from the FungusMycosphaerella graminicolaReveals Novel Functional Properties and Varying Contributions to Virulence on Wheat

et al. 2011

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Secreted effector proteins enable plant pathogenic fungi to manipulate host defenses for successful infection. Mycosphaerella graminicola causes Septoria tritici blotch disease of wheat (Triticum aestivum) leaves. Leaf infection involves a long (approximately 7 d) period of symptomless intercellular colonization prior to the appearance of necrotic disease lesions. Therefore, M. graminicola is considered as a hemibiotrophic (or necrotrophic) pathogen. Here, we describe the molecular and functional characterization of M. graminicola homologs of Ecp6 (for extracellular protein 6), the Lysin (LysM) domain-containing effector from the biotrophic tomato (Solanum lycopersicum) leaf mold fungus Cladosporium fulvum, which interferes with chitin-triggered immunity in plants. Three LysM effector homologs are present in the M. graminicola genome, referred to as Mg3LysM, Mg1LysM, and MgxLysM. Mg3LysM and Mg1LysM genes were strongly transcriptionally up-regulated specifically during symptomless leaf infection. Both proteins bind chitin; however, only Mg3LysM blocked the elicitation of chitin-induced plant defenses. In contrast to C. fulvum Ecp6, both Mg1LysM and Mg3LysM also protected fungal hyphae against plant-derived hydrolytic enzymes, and both genes show significantly more nucleotide polymorphism giving rise to nonsynonymous amino acid changes. While Mg1LysM deletion mutant strains of M. graminicola were fully pathogenic toward wheat leaves, Mg3LysM mutant strains were severely impaired in leaf colonization, did not trigger lesion formation, and were unable to undergo asexual sporulation. This virulence defect correlated with more rapid and pronounced expression of wheat defense genes during the symptomless phase of leaf colonization. These data highlight different functions for MgLysM effector homologs during plant infection, including novel activities that distinguish these proteins from C. fulvum Ecp6.

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Section: Graminicola Mg3lysm Mutants Are Severely Compromised In Vmentioning

confidence: 99%

Analysis of Two in Planta Expressed LysM Effector Homologs from the FungusMycosphaerella graminicolaReveals Novel Functional Properties and Varying Contributions to Virulence on Wheat

et al. 2011

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“…and wheat is the presence of two peaks of gene expression in resistant cultivars, one within the first 2-3 days after inoculation and the second after 14-16 days (Adhikari et al 2007). The second peak occurs just prior to symptom expression and corresponds to the time when rapid growth of the pathogen is observed in susceptible interactions (Adhikari et al 2004a).…”

Section: S99mentioning

confidence: 99%

Development of isogenic lines for resistance to Septoria tritici blotch in wheat

Goodwin

Thompson²

2011

CZECH J GENET PLANT

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Septoria tritici blotch (STB), caused by the fungus Mycosphaerella graminicola (asexual stage: Septoria tritici), is one of the most economically important diseases of wheat worldwide. During the past decade 13 genes for resistance to STB have been identified and several molecular markers have been developed. However, analysis of resistance gene expression and utility for plant improvement programs would be increased if the resistance genes were isolated in a common susceptible background. To address this problem, a program was begun to backcross resistance genes Stb1-8 into two susceptible wheat cultivars. Work with genes Stb2, Stb3, Stb6 and Stb8 has proceeded the farthest. Resistance gene Stb3 is dominant, while Stb2 may be recessive. This will be the first report of recessive resistance to STB if confirmed. Molecular markers linked to the resistance genes are being validated in the backcross progeny and should provide the materials for efficient introgression of these genes into elite germplasm for future wheat improvement.

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“…Advances in regeneration and transformation protocols have led to the successful development of transgenic cotton with improved agronomic characters. There are several types of fungal resistance genes that were used for disease resistance of plants [48,49] : Among them chitinase was proved as one of the best fungal resistant genes.…”

Section: Expression Of Chitinasementioning

confidence: 99%

Transgenic Indian Cotton (Gossypium hirsutum) Harboring Rice Chitinase Gene (Chi II) Confers Resistance to Two Fungal Pathogens

Ganesan¹,

Bhanumathi²,

Kumari³

et al. 2009

American J. of Biochemistry and Biotechnology

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Problem statement: The present investigation described a simple and reproducible protocol for transgenic cotton regeneration and characterization of chitinase (Chi II) gene expression against two different fungal pathogens in cotton. Approach: Transgenic cotton (Gossypium hirsutum cv. SVPR2) plants were produced by pCambia-bar-Chi II (13.8 kb) under the control of the CaMV 35S promoter, harbored in the strain LBA 4404 Agrobacterium tumefaciens by using shoot tip explants. Results: Finally, from the 10 experiments, 21.8% of transformation frequency was recorded. Segregation ratio of 3:1 was recorded in the T 0 plant seeds. Polymerase chain reaction and southern blotting analysis were used to confirm the integration of Chi II transgene in the T 0 plants genome of putative transgenics. Quantitiave and qualitative (SDS-PAGE) analyses were also carried out to confirm the expression of chitinase enzyme in T 0 plants. Further, randomly selected transgenic plants (T 0 ) were analyzed for disease tolerance by evaluating them with spores of Fusarium oxysporum and Alternaria macrospora. All the selected PCR positive plants showed enhanced disease resistance against Fusarium wilt. The plants selected randomly showed an enhanced survival rate compared with the control when they were grown in earthen pots inoculated with 1×10 5 spores 100 −1 g of soil mixture.Another four randomly selected plantlets were sprayed with spores of Alternaria macrospora in order to test their tolerance to Alternaria leaf spot disease. After 20 days of culture, the number of lesions per leaf and the lesion length per leaf spot in non-transferred leaves increased. In the case of transgenic plantlets, lesion formation was completely absent. Conclusion: The disease resistance against Fusarium wilt and Alternaria leaf spot in cotton strains would serve as good breeding materials for producing fungal disease resistant cotton varieties.

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Resistance of wheat to Mycosphaerella graminicola involves early and late peaks of gene expression

Cited by 67 publications

References 67 publications

Analysis of Two in Planta Expressed LysM Effector Homologs from the FungusMycosphaerella graminicolaReveals Novel Functional Properties and Varying Contributions to Virulence on Wheat

Analysis of Two in Planta Expressed LysM Effector Homologs from the FungusMycosphaerella graminicolaReveals Novel Functional Properties and Varying Contributions to Virulence on Wheat

Development of isogenic lines for resistance to Septoria tritici blotch in wheat

Transgenic Indian Cotton (Gossypium hirsutum) Harboring Rice Chitinase Gene (Chi II) Confers Resistance to Two Fungal Pathogens

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