Genomics approaches to identify meiotic genes in wheat

Abstract

In contrast to the recent advancements made in meiotic gene discovery for plants such as Arabidopsis, the progress for wheat has been difficult, hampered principally by a large, polyploid genome. We report here on genomics approaches to identify and characterise genes involved in meiosis in wheat. The first approach used comparative genetics to define the genic content of the 3DS region deleted in the pairing homoeologous mutant ph2a (a deletion mutant at the Ph2 locus). More than 200 genes linked to Ph2 have been identified, several as candidates for the Ph2 gene(s). The degree of synteny at the gene level in wheat and rice across the region analysed has been established in detail and the extent of the deleted segment in ph2a clarified. Furthermore, the spatial transcriptional characteristics of genes linked to Ph2 have been analysed using data from wheat expressed sequence tag (EST) databases in combination with recently developed analysis software. The second approach used a cDNA microarray derived from an anther library to examine gene expression in a temporal series experiment from pre-meiosis to the tetrad stage of meiotic development. We report on these results and their relevance to meiotic and anther developmental processes.