Genome-Wide Identification and Characterization of the Cyclophilin Gene Family in the Nematophagous Fungus Purpureocillium lilacinum.

Chenmi Mo,Xueqiong Xiao,Chong Xie,Gaofeng Wang,Qiuyan Hao,Juan Liu,Yannong Xiao

doi:10.3390/ijms20122978

Chenmi Mo, Xueqiong Xiao + Show 5 more

Open Access

https://doi.org/10.3390/ijms20122978

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Abstract

Purpureocillium lilacinum has been widely used as a commercial biocontrol agent for the control of plant parasitic nematodes. Whole genome analysis promotes the identification of functional genes and the exploration of their molecular mechanisms. The Cyclophilin (CYP) gene family belongs to the immunophillin superfamily, and has a conserved cyclophilin-like domain (CLD). CYPs are widely identified in prokaryotes and eukaryotes, and can be divided into single- and multi-domain proteins. In the present study, 10 CYP genes possessing the CLD, named PlCYP1–P10, were identified from the genome of P. lilacinum strain 36-1. Those 10 PlCYPs were predicted to have different cellular localizations in P. lilacinum. Phylogenetic and gene structure analysis revealed the evolutionary differentiation of CYPs between Ascomycotina and Saccharomycotina fungi, but conservation within the Ascomycotina fungi. Motif and gene structure distributions further support the result of phylogenetic analysis. Each PlCYP gene had a specific expression pattern in different development stages of P. lilacinum and its parasitism stage on eggs of Meloidogyne incognita. In addition, the 10 PlCYP genes exhibited different expression abundances in response to abiotic stresses, among which PlCYP4 was highly expressed at a high temperature (35 °C), while PlCYP6 was up-regulated under 5 mM of H2O2 stress. Furthermore, the heterologous expression of PlCYP4 and PlCYP6 in Escherichia coli enhanced the cellular tolerance against a high temperature and H2O2. In summary, our study indicates the potential functions of PlCYPs in virulence and the stress response, and also provides a frame for further analysis of the CYP gene family in Ascomycotina fungi.

Highlights

Plant parasitic nematodes infect almost all cultivated plants worldwide and cause huge economic losses of up to $157 billion per year [1]
We identified candidate PlCYPs associated with parasitism to nematodes, and investigated the function of PlCYPs in response to abiotic stresses
To identify CYP genes in P. lilacinum, the amino acid sequences of human CYPA (hCYPA) (GenBank: AAI37059.1) were used to search against the P. lilacinum strain 36-1 genome and transcriptome database to obtain homologous sequences which were further confirmed by domain analysis [10]

Summary

Introduction

Plant parasitic nematodes infect almost all cultivated plants worldwide and cause huge economic losses of up to $157 billion per year [1]. The control of plant parasitic nematodes mainly depends on the application of nematicides, including carbofuran, ethoprophos, and aldicarb, while these pesticides have gradually been forbidden due to their adverse effects on the environment and human health. The nematophagous fungus, Purpureocillium lilacinum, is one of the most extensively tested fungi for controlling plant parasitic nematodes [3]. The application of P. lilacinum could effectively control second-stage juveniles, eggs, or egg masses of root-knot nematodes in pot experiments [4]. The combination of Syncephalastrum racemosum and P. linacinum can significantly decrease galls and nematodes in soil [5]. P. lilacinum has been registered as a biocontrol agent to control nematodes [7]

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