Expression Profile of Laccase Gene Family in White-Rot Basidiomycete Lentinula edodes under Different Environmental Stresses

Lianlian Yan,Ruiping Xu,Yinbing Bian,Hongxian Li,Yan Zhou

doi:10.3390/genes10121045

Abstract

Laccases belong to ligninolytic enzymes and play important roles in various biological processes of filamentous fungi, including fruiting-body formation and lignin degradation. The process of fruiting-body development in Lentinula edodes is complex and is greatly affected by environmental conditions. In this paper, 14 multicopper oxidase-encoding (laccase) genes were analyzed in the draft genome sequence of L. edodes strain W1-26, followed by a search of multiple stress-related Cis-elements in the promoter region of these laccase genes, and then a transcription profile analysis of 14 laccase genes (Lelcc) under the conditions of different carbon sources, temperatures, and photoperiods. All laccase genes were significantly regulated by varying carbon source materials. The expression of only two laccase genes (Lelcc5 and Lelcc6) was induced by sodium-lignosulphonate and the expression of most laccase genes was specifically upregulated in glucose medium. Under different temperature conditions, the expression levels of most laccase genes decreased at 39 °C and transcription was significantly increased for Lelcc1, Lelcc4, Lelcc5, Lelcc9, Lelcc12, Lelcc13, and Lelcc14 after induction for 24 h at 10 °C, indicating their involvement in primordium differentiation. Tyrosinase, which is involved in melanin synthesis, was clustered with the same group as Lelcc4 and Lelcc7 in all the different photoperiod treatments. Meanwhile, five laccase genes (Lelcc8, Lelcc9, Lelcc12, Lelcc13, and Lelcc14) showed similar expression profiles to that of two blue light receptor genes (LephrA and LephrB) in the 12 h light/12 h dark treatment, suggesting the involvement of laccase genes in the adaptation process of L. edodes to the changing environment and fruiting-body formation. This study contributes to our understanding of the function of the different Lelcc genes and facilitates the screening of key genes from the laccase gene family for further functional research.

Highlights

IntroductionLaccase (benzenediol: oxygen oxidoreductase, EC 1.10.3.2) is a group of phenoloxidases containing copper atoms in the catalytic center, and is a member of the blue multicopper oxidase family (MCO) [1]
Laccase is a group of phenoloxidases containing copper atoms in the catalytic center, and is a member of the blue multicopper oxidase family (MCO) [1]
The coding sequences (CDS) sequences of Lelcc1, Lelcc6, and Lelcc8 were divided into more than 20 parts by introns, indicating that these three laccases were more complicated than the other laccase genes with respect to gene structure

Summary

Introduction

Laccase (benzenediol: oxygen oxidoreductase, EC 1.10.3.2) is a group of phenoloxidases containing copper atoms in the catalytic center, and is a member of the blue multicopper oxidase family (MCO) [1]. Sequence comparison and transcription analysis of several fungi demonstrated that laccases were encoded by multigene families [8,9,10,11]. This gene redundancy suggests the differences in their physicochemical and regulatory mechanisms, especially their physiological roles in response to nutrition change and environmental stress [12,13]. The intricacy of laccase genes families in fungi cumbers the further study of these genes

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