Use of fluorescent in situ hybridization techniques for cytogenetic characterization of Araceae somatic hybridization products (PROTOPLASTARACEAE)

When crossing plants, not only genes of interest are transmitted into the seedling, but also undesired DNA. Using cell fusion, is it possible to achieve somatic hybrids that contain only a fraction of the genetic material of one of both contributing species? How should we fragment the genetic material of this 'donor' parent?  Can we fuse those fragments with the complete 'acceptor' parent? And how should we regenerate the fused cells into mature plants? The aim of this project is to evaluate and integrate the different steps in the development of these so-called 'asymmetric somatic hybrids' and to monitor the whole process through chromosome staining techniques. Araceae, a plant family with a high regeneration capacity and a limited chromosome number, are used as model crops.  

We use different Spathiphyllum, Anthurium and Zantedeschia genotypes as protoplast source. We define the chromosomal constitution of the test plants through karyotyping as a control, prior to somatic hybrid development. We also use as a chemical approach (polyethylen glycol mediated) as well as an electrical approach (through electroporation) for fusion. We then evaluate which approach is most efficient. For fragmentation, we will focus on isolation of microprotoplasts that do not contain all chromosomes of the original cell. During in vitro protoplast regeneration we test several parameters such as genotype, explant type, fusion treatments and others. We apply cytogenetic staining techniques to reveal the chromosomal composition of the fusion products.

The goal of this research project is fundamentally scientific. In this project, we develop new technology for asymmetric somatic fusion. We hereby expand the field of knowledge on fragmentation, fusion and regeneration and evaluate in what way practical applications are possible in diverse breeding programmes. The development of screening technology in these crops is also very relevant. Chromosomal staining techniques may form an important tool to characterize innovative asymmetric hybrids and to 'guide' the process. Araceae breeding is inhibited by several crossing barriers that make many interesting genes non-transferable (eg. Erwinia resistance and flower colour in Zantedeschia, flower colour and shape in Anthurium…). This technology may offer an alternative for impossible interspecific sexual crosses within the family. Over the long term, a new breeding strategy will be created.