Mutations in the Arabidopsis homoserine kinase gene DMR1 confer enhanced resistance to Fusarium culmorum and F. graminearum.

Abstract

BACKGROUND:

Mutation of Arabidopsis DMR1, encoding homoserine kinase, leads to elevation in homoserine and foliar resistance to the biotrophic pathogens Hyaloperonospora arabidopsidis and Oidium neolycopersici through activation of an unidentified defence mechanism. This study investigates the effect of mutation of dmr1 on resistance to the ascomycete pathogens Fusarium graminearum and F. culmorum, which cause Fusarium Ear Blight (FEB) disease on small grain cereals.

RESULTS:

We initially found that the dmr1-2 mutant allele confers increased resistance to F. culmorum and F. graminearum silique infection, and decreased colonisation of rosette leaves. Meanwhile the dmr1-1 allele supports less rosette leaf colonisation but has wild type silique resistance. Three additional dmr1 alleles were subsequently examined for altered F. culmorum susceptibility and all showed increased silique resistance, while leaf colonisation was reduced in two (dmr1-3 and dmr1-4). Amino acid analysis of dmr1 siliques revealed homoserine accumulation, which is undetectable in wild type plants. Exogenous application of L-homoserine reduced bud infection in both dmr1 and wild type plants, whilst D-homoserine application did not. Delayed leaf senescence was also observed in dmr1 plants compared to wild type and correlated with reduced Fusarium leaf colonisation.

CONCLUSIONS:

These findings suggest that common Arabidopsis DMR1 mediated susceptibility mechanisms occur during infection by both obligate biotrophic oomycete and hemi-biotrophic fungal pathogens, not only in vegetative but also in reproductive plant tissues. This has the potential to aid the development of cereal crops with enhanced resistance to FEB.

• Authors: Helen C Brewer, Nathaniel D Hawkins, Kim E Hammond-Kosack
• Journal: BMC plant biology (BMC Plant Biol) Vol. 14 Pg. 317 (Nov 29 2014) ISSN: 1471-2229 [Electronic] England
• PMID: 25432266 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Plant Proteins
• Phosphotransferases (Alcohol Group Acceptor)
• homoserine kinase

Topics

• Arabidopsis (genetics, microbiology)
• Disease Resistance (genetics)
• Fruit (metabolism)
• Fusarium (physiology)
• Gene Expression Regulation, Plant
• Molecular Sequence Data
• Mutation
• Phosphotransferases (Alcohol Group Acceptor) (genetics, metabolism)
• Plant Diseases (genetics, immunology, microbiology)
• Plant Leaves (metabolism)
• Plant Proteins (genetics)
• Sequence Analysis, Protein
• Species Specificity