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Examines the quantitative trait loci and comparative genomics of cereal cell wall composition. Effect of QTL in the content of xylose; Prediction of P1-derived artificial chromosomes rice clones covering the QTL to encode 117 and 125 proteins; Process of cell wall biosynthesis.

The article presents information about beta glucan, an enzyme that synthesizes a polysaccharide in plant cell walls. It is a major cell wall component in grains, including the barleys used in brewing. Its presence can not only negatively affect fermentation, but can also inhibit the filtration process, leaving beer with an unappealing haze. Thus, it is not surprising that plant breeders have sought to identify the genes that determine how much beta glucan is produced in barley. A region of genomic DNA that controls the production of this polysaccharide in barley grains has been mapped to chromosome 2. To identify the genes and proteins responsible for beta glucan biosynthesis, some researchers have taken advantage of this information and the conserved genome structure between barley and rice, whose genome has been completely sequenced. The cellulose synthase like genes were first identified in the model plant Arabidopsis thaliana and rice genomes. Sequence analyses indicate that the cellulose synthase superfamily contains multiple subfamilies.

We sequenced and annotated the genome of the filamentous fungus Fusarium graminearum, a major pathogen of cultivated cereals. Very few repetitive sequences were detected, and the process of repeat-induced point mutation, in which duplicated sequences are subject to extensive mutation, may partially account for the reduced repeat content and apparent low number of paralogous (ancestrally duplicated) genes. A second strain of F. graminearum contained more than 10,000 single-nucleotide polymorphisms, which were frequently located near telomeres and within other discrete chromosomal segments. Many highly polymorphic regions contained sets of genes implicated in plant-fungus interactions and were unusually divergent, with higher rates of recombination. These regions of genome innovation may result from selection due to interactions of F. graminearum with its plant hosts. [ABSTRACT FROM AUTHOR]