Identification of Fruiting-related Genes and the Endocytic Pathway of the Basidiomycete, Coprinopsis cinerea

Coprinopsis cinerea, is a model organism for studying developmental processes in basidiomycetous fungi. It has a short life cycle, easy to be cultivated in laboratory and can be accessed by various genetic and molecular techniques. Recently, its complete genome sequence was released. The fruiting body development in C. cinerea is a rapid yet complicated process. It is under the regulation of various factors such as mating type genes, nutrients depletion, light and temperature. However, the underlying mechanism and molecular events involved during fruiting body initiation and development remains unclear.;In this study, fruiting body developmental stages including mycelium, fruiting initials, stage 2 primordium, young and mature fruiting body, were analyzed with a comprehensive NimbleGen microarray. 11,815 out of 13,320 predicted gene models were expressed in at least one of the stages. 707 genes were differentially expressed during fruiting body initiation. Potential players involved in nutrients sensing, morphogenesis, signaling pathways and stress response were identified. In particular, expression patterns of all transcription factors, kinome and cytochrome P450s were analyzed.;The fruiting body development of C. cinerea is synchronized with the light/dark cycle. Differentially expressed genes were found in dark stipe produced by keeping fruiting initials in complete darkness. 101 genes, which are likely to be involved in maturation of primordium were identified.;Endocytosis is an essential process in eukaryotes through which cells take up extracellular substrates by membrane invaginations. Rab5 and Rab7 control the early and late stage of endocytosis respectively. The C. cinerea endocytic machinery composed of 110 genes models. The endocytic pathway was traced by FM4-64 and was found to be actin- and energy-dependent. Temporal and spatial expressions of Cc.Rab5 and Cc.Rab7 during fruiting body development were studied. Cc.Rab5 expressed constitutively from mycelium to young fruiting body stage, and reached the highest in the mature fruiting body. The expression of Cc.Rab7 increased continually from mycelium to mature fruiting body stage. From the in situ RNA-RNA hybridization results, both transcripts were localized at the hymenium layer in the young fruiting body and throughout the gill tissue of the mature cap. Knock-down of Cc.Rab5 and Cc.Rab7 by siRNA resulted in retarded growth of the stage 2 primordium and abnormal mature fruiting body. Cc.Rab5 and Cc.Rab7 may be involved in the formation of basidiospores. Endocytosis may play some roles during fruiting body development in C. cinerea. .