Genetic engineering of disease resistance in cereals

Bushnell, W. R.; Somers, David A.; Giroux, Randal W.; Szabo, Les J.; Zeyen, R. J.

doi:10.1080/07060669809500419

Cited by 21 publications

(7 citation statements)

References 68 publications

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“…Therefore, we have developed a transient assay system for the functional assessment of defence‐related genes in wheat ( Schweizer et al . 1999 ) that is similar to the systems recently described for barley ( Bushnell et al . 1998 ; Nelson & Bushnell 1997; Shirasu et al .…”

Section: Introductionsupporting

confidence: 68%

Transient expression of members of the germin‐like gene family in epidermal cells of wheat confers disease resistance

1999

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The wheat genome encodes a family of germin-like proteins that differ with respect to regulation and tissue specificity of expression of the corresponding genes. While germin exhibits oxalate oxidase (E.C. 1.2.3.4.) activity, the germin-like proteins (GLPs) have no known enzymatic activity. A role of oxalate oxidase in plant defence has been proposed, based on the capacity of the enzyme to produce H2O2, a reactive oxygen species. The role in defence of germin and other members of the germin-like gene family was functionally assessed in a transient assay system based on particle bombardment of wheat leaves. Transient expression of the pathogen-induced germin gf-2.8 gene, but not of the constitutively expressed HvGLP1 gene, reduced the penetration efficiency of Blumeria (syn. Erysiphe) graminis f.sp. tritici, the causal agent of wheat powdery mildew, on transformed cells. Two engineered germin-gf-2.8 genes and the TaGLP2a gene, which all encoded proteins without oxalate oxidase activity, also reduced the penetration efficiency of the fungus, demonstrating that oxalate oxidase activity is not required for conferring enhanced resistance. Instead, activity tagging experiments showed that in cells transiently expressing the germin gf-2.8 gene, the transgene product became insolubilized at sites of attempted fungal penetration where localised production of H2O2 was observed. Thus, germin and GLPs may play a structural role in cell-wall re-enforcement during pathogen attack.

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Section: Introductionsupporting

confidence: 68%

Transient expression of members of the germin‐like gene family in epidermal cells of wheat confers disease resistance

1999

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“…The successful formation of a mature haustorium, a structure for nutrient extraction during Bgh development, is usually considered as a compatible interaction between barley and Bgh (Bushnell et al . ). It was found that Stpk‐V could prevent haustorium formation, so it mediated the before‐haustorium formation resistance (Cao et al .…”

Section: Resultsmentioning

confidence: 97%

Molecular characterisation of the broad‐spectrum resistance to powdery mildew conferred by the Stpk‐V gene from the wild species Haynaldia villosa

et al. 2017

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A key member of the Pm21 resistance gene locus, Stpk-V, derived from Haynaldia villosa, was shown to confer broad-spectrum resistance to wheat powdery mildew. The present study was planned to investigate the resistance mechanism mediated by Stpk-V. Transcriptome analysis was performed in Stpk-V transgenic plants and recipient Yangmai158 upon Bgt infection, and detailed histochemical observations were conducted. Chromosome location of Stpk-V orthologous genes in Triticeae species was conducted for evolutionary study and over-expression of Stpk-V both in barley and Arabidopsis was performed for functional study. The transcriptome results indicate, at the early infection stage, the ROS pathway, JA pathway and some PR proteins associated with the SA pathway were activated in both the resistant Stpk-V transgenic plants and susceptible Yangmai158. However, at the later infection stage, the genes up-regulated at the early stage were continuously held only in the transgenic plants, and a large number of new genes were also activated in the transgenic plants but not in Yangmai158. Results indicate that sustained activation of the early response genes combined with later-activated genes mediated by Stpk-V is critical for resistance in Stpk-V transgenic plants. Stpk-V orthologous genes in the representative grass species are all located on homologous group six chromosomes, indicating that Stpk-V is an ancient gene in the grasses. Over-expression of Stpk-V enhanced host resistance to powdery mildew in barley but not in Arabidopsis. Our results enable a better understanding of the resistance mechanism mediated by Stpk-V, and establish a solid foundation for its use in cereal breeding as a gene resource.

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“…In the case of protoplast-derived barley plants, evaluation of the progeny in the field did not show any abnormal phenotypes, but some agronomic characters were affected (Kihara et al, 1998). The adverse effects of somaclonal variation have led to the suggestion that identification of useful transformants might be precluded (Bushnell et al, 1998; see also Section 2.1.2.2).…”

Section: In Vitro Culture and Somaclonal Variationmentioning

confidence: 99%

Barley

Ganeshan

Chibbar

Dahleen

et al. 2008

Compendium of Transgenic Crop Plants

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The value of barley ( Hordeum vulgare L.) has steadily gained importance over the years. The economic and consumer importance of barley is constantly being re‐evaluated as new market niches and end‐uses become evident. Improvement strategies have generally employed conventional breeding methods, including mutation‐breeding approaches. However newer technology‐driven improvement strategies offer promising new perspectives and include genetic transformation. Barley was generally recalcitrant to tissue culture and transformation, but is now fairly amenable to genetic transformation by particle bombardment as well as by Agrobacterium . Target traits for modification have encompassed malting, nutritional and disease‐resistance attributes in barley. However, with the emerging trends in high‐throughput genomic sequencing and the need for functional validation of cloned genes, genetic transformation of barley has become an important tool and use of approaches such as transposable elements mediated transformation offers the possibility of producing large numbers of transgenic barley plants. Approaches based on the RNAi technology are also likely to advance understanding of the functions of cloned genes in barley. In this chapter, there is a wide‐ranging discussion on barley genetic transformation, prospects, challenges and risk assessment and environmental concerns.

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Genetic engineering of disease resistance in cereals

Cited by 21 publications

References 68 publications

Transient expression of members of the germin‐like gene family in epidermal cells of wheat confers disease resistance

Transient expression of members of the germin‐like gene family in epidermal cells of wheat confers disease resistance

Molecular characterisation of the broad‐spectrum resistance to powdery mildew conferred by the Stpk‐V gene from the wild species Haynaldia villosa

Barley

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