Projects / Programmes
Molecular bases of interactions among the grapevine and phytoplasmal causing agents of the grapevine yellows diseases
| Code |
Science |
Field |
Subfield |
| 1.03.00 |
Natural sciences and mathematics |
Biology |
|
| Code |
Science |
Field |
| B006 |
Biomedical sciences |
Agronomics |
| Code |
Science |
Field |
| 1.06 |
Natural Sciences |
Biological sciences |
BN, Ca. P. solani, C. roseus, effectors, FD, functional genomics, grapevine yellows, miRNA, modeling, NGS, phenotyping, RNAseq, transcriptomics
Researchers (15)
Organisations (2)
Abstract
The overall goal of the project is to significantly improve our understanding of the molecular interaction between grapevine and phytoplasmas as the causal agents of grapevine yellows diseases (GYs). This will be achieved by the integration of research approaches of the Slovenian and Austrian teams and with the support of world leading teams in research fields of plant physiology and phytoplasmas – still very poorly explored phytopathogenic bacteria from the Mollicutes class. Here we will perform a comprehensive molecular study in which we will use natural and model experimental systems and innovative data analysis for identification of the key components of plant responses to infection with these highly adapted bacteria. Besides high scientific value of expected results, they will also be directly applicable to viticulture practices for managing GYs.
Europe is the world’s main producer and exporter of grapevine planting material and wine. This very important sector for Slovene and Austrian economy is facing epidemic threats of several GYs caused by taxonomically unrelated phytoplasmas. In Europe, the main GYs are the widespread “bois noir” associated with the presence of ‘Candidatus Phytoplasma solani’ (BNp) from the ribosomal group 16SrXII-A and “flavescence dorée”, associated with the presence of quarantine phytoplasmas belonging to 16SrV (FDp). BN became one of the most important grapevine diseases, with the infection rates reaching 50–80% in some areas during the last 15 years. In addition, because BNp causes the same symptoms on the grapevine as FDp, presumably by similar mechanisms, we will use it as a working model to avoid research problems associated with the quarantine status of FDp.
We propose to characterize the current wave of BN disease in Austria and Slovenia by evaluating the infection rate and strain composition in BNp insect vectors, alternative weed hosts and grapevine. Characterization of the strain composition will be evaluated by marker genes and strains will be transferred to grapevine and to a model plant for phytoplasma research – Catharanthus roseus – to extend the already existing collection of different epidemiological relevant BNp strains in C. roseus. A similar collection in C. roseus will be also established for FDp strains. For the transfers we will focus on insect vectors, grafting techniques and phytoplasma enrichments. Based on the first step in cultivation of phytoplasmas achieved by members of the proposed team, molecularly characterized BNp and FDp strains will be used for isolation in axenic cultures and the obtained isolates will then be used in re-infection trials.
To gain knowledge on the overall strain variability of BNp in Slovenia and Austria, samples of grapevine and C. roseus infected with different strains will be sequenced. The next generation sequencing will give the basis for comparative genomics of a group of closely related strains showing different disease symptoms in C. roseus and also allow the establishment of an effector catalogue of closely related phytoplasmas occurring in prevalent strains and strains inducing different disease symptoms. The expression of potential effectors and small non-coding RNAs will be evaluated by comparative analysis in planta. Selection of candidate phytoplasma and plant genes with potential influence on disease development will be driven after studies on expression analysis and plant responses using functional analysis approach of agroinfiltration of grapevine leaves and subsequent analysis of metabolites associated with phytoplasma diseases. Moreover, stable transformations with selected bacterial effectors and plant genes will be evaluated for their phenotype and gene expression for the ultimate aim to characterize the interaction and attack points of phytoplasmas in plants.
All results will be exploited for construction of an improved model of the phytoplasma/host system and analysis thereof.
Significance for science
The results of the completed proposed project will significantly contribute to understanding of molecular basis of grapevine yellows diseases and to the overall basic knowledge on phytoplasma/plant host/insect vector interactions that is still very rudimentary, mainly because of phytoplasmas' small size, low titer, uneven distribution in the host plant and our inability to routinely cultivate these bacteria that are highly adapted to their host. Recognition of phytoplasmas as the causal agents of the diseases of many important crops worldwide has intensified their research and in recent years resulted in few sequenced phytoplasma genomes. This data will be a starting point for the proposed study of effector molecules and plant micro miRNAs involved in pathogenesis that have been only slightly addressed in studies of phytoplasmas. Moreover, we aim to address several topics that have not been studied in phytoplasmas yet, e.g. functional genomics. We believe that the obtained knowledge could be also extended to other similar pathogen-host interactions.
Significance for the country
The results of the proposed project will have direct implications for practical application in agriculture. The obtained results on epidemiology of BNp can be directly applied to viticultural practices by growers and wine producers for managing the vectors and host plants of BNp and thus prevent or limited the spreading of this important disease of grapevine in Slovenia and Austria. Based on the results, a coordinated cross border measures against BN will be suggested to the relevant officials. In addition, the revealed possible molecular markers of BN disease could be applied in early diagnostic of BN, before development of symptoms. The results of the project will provide a solid basis for better modeling of disease, which is difficult to predict due to the complicated host-pathogen interaction. The results of the functional approaches applied in the project may be used for developing strategies for resistance breeding.
Most important scientific results
Interim report,
final report
Most important socioeconomically and culturally relevant results
Interim report,
final report
