Utilization of the IWGSC Wheat Survey Sequence for RNAseq Analysis of Water Stress Effects in Developing Wheat Heads

The genes/enzymes involved in supplying carbon to the developing head in wheat are not well characterized.  The activities of cell wall invertases (IVR1s) are known to be important in supplying sugars to pollen during the early stages of head development. Recently multiple IVR1 isoforms were identified on the wheat genome (Webster et al 2012; Funct Plant Biol 39: 569 - 579; GRDC-GRS10028) and were found to be located on a number of chromosome arms.  These findings in addition to the existence of IVR1 inhibitors, provides evidence to suggest a complex regulatory network exists, which controls the flow of sugars to maturing pollen.  A reduction in supply of sugars to pollen in response to water stress during the early stages of maturation leads to sterility.  A large water stress experiment was carried out to analyse the transcriptome using RNASeq and RNA from developing wheat heads.  RNASeq performed on tissues extracted from developing heads, extending from immature floret formation through to anthesis, enabled temporal profiling of transcript expression in response to water stress and non-limited water conditions.  The IWGSC wheat genome survey sequence data was used as the reference to assign chromosome arm locations of those transcripts showing expression in the RNASeq data. Mapping individual transcripts to an IWGSC survey sequence contig facilitated downstream functional and biological characterisation to identify key genes involved in the supply of carbon to developing wheat heads.