Abstract
Shiitake mushroom is a common edible mushroom due to its nutritional value and attractive flavor. It has been studied at molecular, physiological and agricultural level for improvement of growth and yields. We aim to identify genes that are indicative to fast mycelial growth rates and fruit body numbers using cDNA microarray. We have thousands of gene sequences, including ESTs from Shiitake L54 primordium and cDNA clones from subtractive library of L54 mycelium, robotically dotted onto the microarray slides. Thirty strains of Shiitake found in different locations of Mainland China were collected and grown in the same condition. Their growth rates and fruit body production capacities in terms of numbers and yields were analyzed. To screen genes that may relate to mycelial growth rate and fruit body numbers, strains with contrasting characters were selected to synthesize cDNA probes and analyzed using the microarrays. We made cDNA probes from 10 strains and hybridized with thousands of microarray spots. The array data were then analyzed using the TIGR MeV software. All the five hybridized results were clustered and about 10 annotated genes were found expressed at higher levels in strains with larger number of fruit body generated. These genes include homologs to xylitol dehydrogenase, aldehyde dehydrogenase, Streptavidin v2 precursor, fruit body cap cDNA, homologs to ribosomal proteins and hypothetical proteins. About 15 annotated genes were found differentially expressed in strains with faster mycelial growth rates. They include homologous to ubiquitin, xylitol dehydrogenase, RIB4 protein and some ribosomal proteins. The expression of these candidates will be validated by Northern Blotting. By cDNA microarray, genes putatively related to growth and fruit body formation were identified, and all candidates can be further studied for their specific roles. This study enhances our knowledge concerning mycelial growth rate and fruit body in mushroom strain improvement.
