The Arabidopsis thaliana-Alternaria brassicicola pathosystem: A model interaction for investigating seed transmission of necrotrophic fungi

Plant Methods

Claire Campion⁴  Philippe Simoneau⁴  Isabelle Debeaujon²  Romain Berruyer⁴  Marjorie Juchaux¹  Sonia Georgeault³  Beatrice Iacomi-Vasilescu⁵  Thomas Guillemette⁴  Emmanuel Terrasson⁴  Stephanie Pochon⁴ 

[1] Université d’Angers, SFR QUASAV, IMAC, rue Georges Morel, Beaucouzé cedex, F-49071, France;INRA, UMR1318 IJPB, Saclay Plant Sciences, Route de Saint-Cyr, Versailles Cedex 78026, France;Université d’Angers, SCIAM, IBS, 4 rue Larrey, Angers cedex, F-49933, France;Agrocampus-Ouest, UMR 1345 IRHS, 2 Bd Lavoisier, Angers cedex, F-49045, France;USAMV, 59 Bd Marasti, Bucharest, Ro-71331, Romania

关键词: Osmotic stress;    Transparent testa;    Seed colonization;    Arabidopsis thaliana;    Alternaria brassicicola;    Seed transmission;   

Others  :  822524
DOI  :  10.1186/1746-4811-8-16

 received in 2012-01-23, accepted in 2012-05-09,  发布年份 2012

【 摘 要 】

Background

Seed transmission constitutes a major component of the parasitic cycle for several fungal pathogens. However, very little is known concerning fungal or plant genetic factors that impact seed transmission and mechanisms underlying this key biological trait have yet to be clarified. Such lack of available data could be probably explained by the absence of suitable model pathosystem to study plant-fungus interactions during the plant reproductive phase.

Results

Here we report on setting up a new pathosystem that could facilitate the study of fungal seed transmission. Reproductive organs of Arabidopsis thaliana were inoculated with Alternaria brassicicola conidia. Parameters (floral vs fruit route, seed collection date, plant and silique developmental stages) that could influence the seed transmission efficiency were tested to define optimal seed infection conditions. Microscopic observations revealed that the fungus penetrates siliques through cellular junctions, replum and stomata, and into seed coats either directly or through cracks. The ability of the osmosensitive fungal mutant nik1Δ3 to transmit to A. thaliana seeds was analyzed. A significant decrease in seed transmission rate was observed compared to the wild-type parental strain, confirming that a functional osmoregulation pathway is required for efficient seed transmission of the fungus. Similarly, to test the role of flavonoids in seed coat protection against pathogens, a transparent testa Arabidopsis mutant (tt4-1) not producing any flavonoid was used as host plant. Unexpectedly, tt4-1 seeds were infected to a significantly lower extent than wild-type seeds, possibly due to over-accumulation of other antimicrobial metabolites.

Conclusions

The Arabidopsis thaliana-Alternaria brassicicola pathosystem, that have been widely used to study plant-pathogen interactions during the vegetative phase, also proved to constitute a suitable model pathosystem for detailed analysis of plant-pathogen interactions during the reproductive phase. We demonstrated that it provides an excellent system for investigating the impact of different fungal or plant mutations on the seed transmission process and therefore paves the way towards future high-throughput screening of both Arabidopsis and fungal mutant.

【 授权许可】

   
2012 Pochon et al.; licensee BioMed Central Ltd.

【 图 表 】

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