The Genetics and Transcriptional Profiles of the Cellulose Synthase-Like HvCslF Gene Family in Barley (Hordeum vulgare L.)

Rachel A. Burton , Stephen A. Jobling , Andrew J. Harvey , Neil J. Shirley , Diane E. Mather , Antony Bacic , and Geoffrey B. Fincher ^*

Australian Centre for Plant Functional Genomics, School of Agriculture, Food and Wine, University of Adelaide, Waite Campus, Glen Osmond, SA 5064, Australia; CSIRO Food Futures Flagship, GPO Box 1600, ACT 2601, Australia; Molecular Plant Breeding Cooperative Research Centre, School of Agriculture, Food and Wine, University of Adelaide, Waite Campus, Glen Osmond, SA 5064, Australia; Australian Centre for Plant Functional Genomics, School of Botany, University of Melbourne, Parkville, VIC 3010, Australia

^* Corresponding author; email: geoff.fincher{at}adelaide.edu.au.

Cellulose synthase-like CslF genes have been implicated inthe biosynthesis of (1,3;1,4)- ${beta}$ -D-glucans, which are major cellwall constituents in grasses and cereals. Seven CslF genes frombarley can be divided into two classes on the basis of intron-exonarrangements. Four of the HvCslF genes have been mapped to asingle locus on barley chromosome 2H, in a region correspondingto a major quantitative trait locus (QTL) for grain (1,3;1,4)- ${beta}$ -D-glucancontent. The other HvCslF genes map to chromosomes 1H, 5H and7H, and in two cases the genes are close to other QTLs for grain(1,3;1,4)- ${beta}$ -D-glucan content. Spatial and temporal patterns oftranscription of the seven genes have been defined through quantitativePCR. In developing barley coleoptiles HvCslF6 mRNA is most abundant.Transcript levels are maximal in 4-5 day coleoptiles, at a timewhen (1,3;1,4)- ${beta}$ -D-glucan content of coleoptile cell walls alsoreaches maximal levels. In the starchy endosperm of developinggrain, HvCslF6 and HvCslF9 transcripts predominate. Two peaksof transcription are apparent. One occurs just after endospermcellularization, 4-8 days after pollination, while the secondoccurs much later in grain development, more than 20 days afterpollination. Marked varietal differences in transcription ofthe HvCslF genes are observed during endosperm development.Given the commercial importance of cereal (1,3;1,4)- ${beta}$ -D-glucansin human nutrition, in stock-feed and in malting and brewing,the observation that only two genes, HvCslF6 and HvCslF9, aretranscribed at high levels in developing grain is of potentialrelevance for the future manipulation of grain (1,3;1,4)- ${beta}$ -D-glucanlevels.