Synthetic Biology

Biography

Biography: De Storme Nico

Abstract

Apomixis is a specialized form of plant reproduction, in which clonal seeds are formed through a short-circuiting of the female sexual pathway. Due to its ability to fix genotypes over successive generations, apomixis is considered the holy grail for plant breeding, particularly in the view of hybrid fixation and polyploid stability. Although apomixis is a natural occurring phenomenon, it has not been retrieved in major crop species. Hence, current research is focused on the genetic engineering of apomixis and on the identification of genes that underlie its major developmental components, including female apomeiosis and parthenogenesis. Here, we present an alternative method to genetically engineer clonal seed formation in plants; namely ‘male apomixis’. Basically, in this process, male meiosis is converted into a mitotic division and resulting clonal pollen are used to fertilize eggs that selectively eliminate their own genome input. In plants, parent-specific genome elimination (GE) can be obtained by uniparental alterations in the centromeric chromatin status (CENH3). Male apomeiosis, on the other hand, can be achieved by eliminating both meiotic recombination and reductional cell division, as for example by the combined loss of AtSPO11-1 and JAS. By using resulting 2n atspo11-/-jas-/- pollen in the fertilization of a GE line we obtained diploid progeny plants genetically identical to the pollen donor. Although the efficiency of clonal seed formation is rather low, these findings demonstrate that the combined loss of two genes can confer male apomeiosis and hence provides a molecular basis for the synthetic engineering of ‘male apomixis’ in plants.