| The mycelial development and fruiting body formation of Lentinula edodes [(Berk.) Pegler] is a complex systematic process, the molecular regulation mechanism of which hasn’t been fully developed. Lentinula edodes, a typical tetrapolar heterothallism basidiomycetes, is one of the important cultivated mushrooms. Two different mating-type monocaryon hyphae can fuse and form a heterocaryotic mycelium, thus the yield and the quality could be increased by the crossbreeding. It is of great importance to go deeper into the developmental regulating mechanism of Lentinula edodes, thus finding out the preliminary screening method and forecasting technique of excellent hybrids by observation of the biological characteristics(cultivation properties and agronomic traits) of both the hybrids and parents, surveying the mRNA differential expression of Lentinula edodes under different developmental stages and then figuring out the relationship between biological characteristics and the mRNA differential expression.In this study, two cultivated strains W1, L205and two wild strains SHL12, SHL44were selected as parents. Three pairs of complementary crossing combination (W1×SHL12, L205×SHL12, L205×SHL44) are formed through Mon-Mon crossing. True hybrids were identified by observing clamp connections. Then according to the speed of mycelia growth, laccase activity and cultivation test conducted, three normal fruiting of hybrids were selected respectively from each combination named as XZ-8, XZ-10, XZ-19, XZ-40, XZ-47, XZ-49, XZ-60, XZ-66and XZ-69. The biological characteristics of both the hybrids and parents are analyzed including pileus diameter, pileus thickness, stipe diameter, stipe length, average fruitbody weight, average fruitbody weight per bag and period from inoculation to fruiting.The technique of mRNA differential display is used to investigate the differential gene expression between mycelia and fruitbody of hybrids and parents.6106stable expression bands of which30.65%are differential expression are obtained in the mycelia stage by two-round mRNA differential display. While6555were obtained in the fruitbody stage of which38.44%are differential expression fragments.Four patterns of mRNA differential expression were observed in the study:(1) fragments observed in both parents but not in F1(W1);(2)fragments observed only in one parent but not in F1and another parent(W2);(3)fragments observed only in F1but not in parents(W2);(4)fragments observed in one parent and F1but not in another parent(W4). In mycelia stage, the average proportions of four differential gene expression patterns are4.34%,9.78%,5.50%and11.02%respectively, with a total of30.64%; While the average proportions in fruitbody stage are5.40%,11.99%,6.32%and14.75%, with a total of38.46%. It can be concluded from the aforementioned data, which suggests obviously the higher ratio of the differential gene expression patterns in fruitbody stage, that the expressed genes in the fruitbody stage outnumber that in the mycelia stage.Preliminary analysis indicates that the laccase activity in the mycelia stage is significantly positively correlated with W1, W2and W4, and that pileus thickness in the fruitbody stage is significantly negatively correlated with W1while stipe length is significantly negatively correlated with W2.The molecular mechanism of the mycelial development and fruiting body formation of L.edodes is very complex, which involves the regulation of a great quantity of structure genes and function genes. The study analyze the relativity between biological characteristics and the differential gene expression patterns of L.edodes at a macroscopic aspect which lay the foundation for the further study of cloning, sequencing and functional identification of differential expressed genes as well as the revelation of the relationship between biological characteristics and the differential gene expression patterns. |
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