Transcriptional analysis of oligopeptide transporter gene family under metal stress of Ganoderma lucidum

Abstract:

[Objective] Substrates in the environment can be transported into the cell by oligopeptide transporters (OPTs), and then contribute to various biological processes. OPTs proteins are involved in metal transports and distributions in plants, which can promote the plants to use and adapt various metals. However, if OPTs from fungi participates in this process is still unknown. To explore if OPTs play a role in the adaptation process of Ganoderma lucidum to metals. [Methods] Mycelium growth and biomass of G. lucidum (No. 1 Rongbao) were tested in the presence of different concentrations of Cu2+, Se4+ and Fe2+. The specific or differential expression profiles of OPTs were analyzed by real-time quantitative PCR (RT-PCR) from the samples cultured for 15 d and 30 d. [Results] Growth and biomass were inhibited under all metal concentrations of Cu2+, Fe2+ and Se4+. The results of RT-PCR showed that, except three genes (OPT7, OPT8 and OPT9), whose transcripts were not detected, the other 10 OPT genes have differential expression profiles. At the early culture stage (15 d), the relative expression levels of 6 OPT genes (OPT1, OPT3-6 and OPT10) were up-regulated under Cu2+ stress, but the expression levels of all OPTs gene were down-regulated under Fe2+ and Se4+ treatments. At the later culture stage (30 d), the relative expression levels of all OPTs gene were down-regulated under Se4+ stress, but the expression levels were significantly up-regulated under Cu2+ and Fe2+ treatments. [Conclusion] These results indicate that these metals can affect the growth and biomass of G. lucidum, while the oligopeptide transporter genes responded to metal stress at transcriptional levels, suggesting that OPT genes may function in the metal adaption processes in G. lucidum.