RNA-seq Profiling Showed Divergent Carbohydrate-Active Enzymes (CAZymes) Expression Patterns in Lentinula edodes at Brown Film Formation Stage Under Blue Light Induction.

Xiying Huang,Yunfu Gu,Qiang Chen,Runji Zhang,Ke Zhao,Haibing Wu,Xiaoping Zhang,Petri Penttinen,Xiumei Yu,Yijie Qiu,Quanju Xiang

doi:10.3389/fmicb.2020.01044

Xiying Huang, Yunfu Gu + Show 9 more

Open Access

https://doi.org/10.3389/fmicb.2020.01044

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Abstract

Lentinula edodes (shiitake mushroom) is one of the most important edible mushrooms worldwide. The L. edodes cultivation cycle includes a unique developing stage called brown film formation that directly affects the development of primordium and the quality of fruiting body. Brown film formation is induced by light, especially blue light. To promote our understanding of the role of blue light in brown film formation mechanisms of L. edodes, we used RNA-seq and compared the transcriptomes of L. edodes grown under blue light and in dark, and validated the expression profiles using qRT-PCR. Blue light stimulated the formation of brown film and increased the content of polysaccharides in L. edodes. Blue light also promoted L. edodes to absorb more polysaccharides by enhancing the activities of enzymes. Among the 730 differentially expressed genes (DEGs), 433 genes were up-regulated and 297 were down-regulated. Most of the DEGs were in the oxidoreductase activity group. Pentose and glucuronic acid conversion and starch and sucrose metabolism were the most important pathways in the formation of brown film. A total of 79 genes of DEGs were identified as genes encoding carbohydrate-active enzymes (CAZymes). Fifty-one of the CAZymes genes were up-regulated, suggesting that CAZymes play important roles in brown film formation to provide sufficient nutrition for L. edodes. The results will facilitate future functional investigations of the genes involved in the developmental control of L. edodes.

Highlights

IntroductionLentinula edodes (shiitake mushroom) is one of the most important edible mushrooms in China and worldwide (Yoo et al, 2019)
Lentinula edodes is one of the most important edible mushrooms in China and worldwide (Yoo et al, 2019)
Color of the L. edodes mycelium changed from white to brown in 45 days, which revealed that blue light induced the formation of brown film; the mycelium in the dark grown control forms a brown film, but the area of brown film was not as big as under blue light (Figures 1A,B)

Summary

Introduction

Lentinula edodes (shiitake mushroom) is one of the most important edible mushrooms in China and worldwide (Yoo et al, 2019). The L. edodes cultivation cycle stages include hyphal knot growth, light-induced brown film formation by the mycelia, primordium initiation, and fruiting body development, out of which the brown film formation is considered the most important. The brown film formation is a unique developing stage in L. edodes cultivation cycle; the depth and the thickness of the brown film directly affect the development of primordium and the quality of fruiting body. The white collar proteins that are parts of the blue light photoreceptors are essential in photomorphogenesis and fruiting body development in Coprinopsis cinerea (Kuratani et al, 2010; Tang et al, 2013) and play an important regulatory role in secondary metabolism (Estrada and Avalos, 2008)

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