Research in our lab centers on the developmental processes and signaling events associated plant reproduction. Our main focus currently is on the heteromorphic self-incompatibility (HSI) system in Turnera species. HSI promotes out-breeding by combining a set of morphological characteristics that differ between mating types, with a physiological recognition system. In Turnera there are two floral mating types, which exhibit reciprocally positioned male and female organ, the anthers and stigma. Pollen number and size, and the size and shape of stigmatic and stylar cells also differ between morphs, and these characters act synergistically to promote out-crossing, whilst a biochemical recognition system prevents pollen from the same mating type effecting fertilization. HSI is controlled by a diallelic S-locus, the short style morph is determined by the dominant S allele being Ss in genotype and the long styled morph is homozygous recessive (ss).
Traditional genetic studies suggested that this S-locus is in fact a supergene – a number of tightly linked genes inherited as a single unit. Identification and characterization of the genes which make up the supergene has the potential to make a significant impact of our understanding of floral biology, not just in the functioning and evolution of HSI systems, but also in the regulation of floral morphology (cell size and shape) and male reproductive capacity (pollen number). We have combined transcriptomic approaches to identify genes that are differentially expressed in floral tissues of the two mating types, with identifying and sequencing genomic BAC clones linked to the S-locus to unravel the molecular basis of this breeding system.
This project offers an opportunity to study several key aspects of plant reproductive biology and promises to provide new insights into the evolution and control of plant breeding systems. In addition recent developments in the use of transgenic crops have led to concerns about the escape of transgenes into wild relatives. One way to address this problem would be to reproductively isolate crop species. Through our studies we hope to make a valuable contribution to achieving this goal.