Latest SCI publications
Endophytic Sebacinales and arbuscular mycorrhiza: putative synergists in plant growth promotion and biocontrol of Fusarium oxysporum f. sp. lycopersici
Research project (§ 26 & § 27)
Duration : 2017-05-01 - 2020-04-30
Soil-borne pathogens pose particular challenges in the field of plant protection. Apart from direct antagonistic effects of certain fungi and bacteria also beneficial microorganisms such as arbuscular mycorrhizal fungi (AMF) and fungal endophytes can increase the resistance of plants to soil-borne pathogens. Although fungal endophytes such as Sebacinales have originally been isolated from AMF spores there is hardly any information available about their putative interactions in tomato plant health. For this project two European species of Sebacinales will be used. Serendipita williamsii as well as Serendipita herbamans have not been investigated yet for their putative role in plant growth promotion and against soil-borne pathogens. Therefore, in the first objective the effects of selected Serendipita spp. alone and in combination with AMF on tomato plant growth and disease control will be investigated. In the second objective, the colonization process of tomato roots by S. herbamans and S. williamsii alone and in combination with F. oxysporum f. sp. lycopersici and AMF will be analyzed by different microscopic analyses. Finally, in the third objective systemic effects of Serendipita spp. in tomato on F. oxysporum and AMF will be analyzed in split-root systems. Since P. williamsii and S. herbamans will be investigated for the first time for their plant growth promotion and bioprotective effects in tomato this proposal offers great innovative potential and will give the applicants the opportunity to be among the first ones in this new emerging direction. To visualize the colonization process of the roots the two sebacinoid fungi will be transformed with plasmids containing yellow fluorescent protein (eYFP) and red fluorescent protein (mRFP1), respectively, and investigated under a fluorescent microscope. Furthermore, FISH (fluorescence in situ hybridization) will be used to investigate the interactions within the root tissue. Additionally, transmission electron microscopy will be performed. In order to investigate growth and bioprotective effects greenhouse experiments will be conducted. Disease incidence and severity will be assessed by visual rating and roots will be scanned and analyzed by the software WinRhizo®. Colonization of roots by sebacinoid and AM fungi will be quantified by qPCR. Furthermore, expression of defense-related genes will be estimated by real-time qPCR and selected secondary metabolites will be monitored by HTLC to investigate bioprotective effects in greater detail.
Altered sucrose metabolism during the interaction Piriformospora indica-Arabidopsis and its impact on the parasitism of plant-parasitic nematodes
Research project (§ 26 & § 27)
Duration : 2017-02-04 - 2020-02-05
The beneficial endophytic fungus Piriformospora indica colonizes roots of many plant species, including the model plant Arabidopsis thaliana, and promotes their growth, development and seed production as well as confers resistance to various biotic and abiotic stresses. Similar to arbuscular mycorrhiza fungi, for this service this endophyte withdraws carbohydrates from the host, most probably hexoses, such as glucose and fructose. In the course of this proposal the up to date widely unknown sugar metabolism in P. indica-colonized Arabidopsis roots will be analysed in detail. First, qPCR will be applied to elucidate whether the fungus specifically changes the expression of several sucrose synthase (SUS) and invertase (INV) genes, which are responsible for conversion of sucrose to glucose and fructose. Further, SUS and INV mutants will be used to test the colonization efficiency of the fungus. In addition, an invertase activity assay as well a sugar pool analysis of plants colonized with P. indica will shed light on the changes in sugar household during this mutualistic interaction. Recently it was shown that P. indica colonization as well as the application of its exudates and cell wall extracts significantly affects the development of cyst nematodes. Therefore, systemic effects of P. indica on the parasitism of both cyst and root-knot nematodes, Heterodera schachtii and Meloidogyne javanica, respectively, in split-root system will be tested. Finally, to elucidate the role of P. indica-derived SUS and INV, knockdown transformants of the fungus will be generated using electroporation and RNA interference. Subsequently, the role of knockdown sucrose processing enzymes during plant colonization as well as their impact on nematode parasitism will be characterized. The results obtained in the course of this proposal will widen our knowledge about interaction between P. indica and its host plant and could have promising potential for improving crop productivity and protection against plant-parasitic nematodes.
Research project (§ 26 & § 27)
Duration : 2016-12-01 - 2018-03-31
In Austria tomatoes are one of the most popular vegetables due to their taste, their versatility in use and their health benefits. The Austrian tomato production, which is concentrated to greenhouses or polytunnels in Vienna, some areas of lower Austria and Burgenland, is characterized by high quality fresh produce. To ensure such high quality, biotic stress factors like plant diseases need to be managed properly. In the recent years microbial products based on different bacteria and fungi have gained more and more attention with regard to increased plant health and vitality. Their effects can range from plant growth promotion to the reduction of plant diseases and can be important management tools in sustainable production systems. In this work the effects of the endophytic fungus Sebacina vermifera on tomato plant growth and plant health will be investigated. The effects will be investigated in in-vitro assays and in a greenhouse experiment. In the in-vitro assays effects on early plant development, activation of defence genes and disease suppression potential against Fusarium oxysporum f. sp. lycopersici (Fol) will be investigated by using different microscope techniques and real-time PCR. In the greenhouse experiments parameters such as flowering time, fruit development, root morphology and disease control will be investigated. The results of this proposal will help to assess the potential of S. vermifera for sustainable tomato production and will provide important results for future work in the field of plant─pathogen─endophyte interactions.