De Storme Lab
LABORATORY FOR PLANT GENETICS AND CROP IMPROVEMENT
Projects
Novel strategies for resistance against scab disease (Venturia inaequalis) in apple
The domesticated apple (Malus x domestica), deciduous fruit species of temperate climate zones, is an important strategic plant for its major role in fruit growing in Flanders. It is threatened by the fungal pathogen Venturia inaequalis, the causal agent of apple scab disease, which is currently controlled by extensive fungicide applications. One of the alternative control strategies is the application of polyploidy. The polyploidy effect in various plant species can result in different organ size, flower colour and growth rate. It has also been indicated that polyploid apples perform better under stress conditions. The ultimate goal of the project is to elucidate the role of polyploidy and plant defence induction via defense priming in M. x domestica - V. inaequalis pathosystem. In this project, we aim to unravel novel aspects at the phenotypic, transriptomic, proteomic and metabolic level. Furthermore, parallels between defence response in diploid and tetraploid plants of resistant cultivars, and the defense response after priming in susceptible cultivars will be drawn.
Unravelling the molecular mechanism of the pear self-incompatibility mechanism
In pear, self-incompatibility is a genetically controlled mechanism that prevents fertilization and fruit set after self-pollination. It is regulated by the S-locus which contains the S-RNase gene, which is expressed in the flower pistil, and multiple S-locus F-box (SFBB) genes, which are expressed in the pollen. Although this trait is advantageous for maintaining genetic diversity in plant populations, it has important drawbacks in breeding and fruit production. However, the molecular mechanism of the pear self-incompatibility system is still not fully understood, especially the functioning of the SFBBs and the way they interact with the various S-RNases. The goal of our research regarding self-incompatibility is therefore to determine the Pyrus S-locus structure and identify SFBB genes so that we can next try to unravel the complex interaction between the SFBBs and their S-RNase targets.
Towards novel strategies for generating new triploid apple cultivars
Most apple cultivars have two sets of chromosomes, however, some cultivars have three sets, these are called triploids. These triploid cultivars often have some very interesting agronomical properties. However, current methods for breeding triploids are very slow, cumbersome and do not result in individuals living up to their full potential. Additionally, most of the succesful triploid cultivars we have today, like Jonagold for example, are the result of defects during reproduction in which one of the parents has formed a diploid gamete.The goal of my research is to learn more about the reproductive defects leading to the production of these diploid gametes and how to induce these peculiar gametes in order to efficiently develop high-quality triploid apple cultivars.
Molecular regulation of juvenility and biennial bearing in apple
Genetic improvement of trees, especially fruit trees, has clearly lagged behind that of annual plant species and one of the main reasons that explain this phenomenon is the presence of an extended juvenile phase. In apple, for example, seedling-based trees remain juvenile for a variable period of 6-8 years to even up to 12 years. Interestingly, there is evidence that the mechanism that governs juvenility in some plants species mediates the annual induction of flowers in perennial crops and thus, is involved in the regulation of biennial bearing. My PhD project is in association with apple breeding company better3fruit (b3f) and the main goal of it is to develop a genetic toolbox as well as agronomic methods to shorten the juvenility phase in apple. In addition, within my research we also aim to characterize the underlying genetic factors in the b3f breeding germplasm as well as to identify dedicated agrochemical applications to reduce seasonal fluctuations in fruit set in commercial apple orchards.
Harnessing flower bud dormancy to safeguard apple production in the Ethiopian highlands
Ethiopian highlands are almost devoid of fruit production, since they are neither suitable for tropical fruit nor for temperate fruit production, including crops such as apple. One of the major problems that are struggled with during the production of these crops is insufficient exposure to required winter chilling, resulting in delayed blooms, irregular fruit sets, reduced fruit yields and quality. Less than required accumulations of chilling time affects the period of bud dormancy, which in turn results in irregular bud breaking and flowering that negatively impact the tree structure and fruit production. Therefore, in this project we try to gain in-depth knowledge on mechanisms controlling the dynamic behavior of flower bud dormancy in apple, particularly on exogenous stimuli, and thoroughly quantify and/or model specific essential chilling requirements for different apple cultivars.
