Identification of the bHLH Gene Family in Tricholoma matsutake and Its Expression Analysis under Heavy Metal Stress

LANG Qian; ZHANG Min; WANG Hao; GONG Lei; ZHOU Yu

doi:10.15933/j.cnki.1004-3268.2025.07.008

Abstract：The bHLH(basic helix-loop-helix)transcription factors are widely involved in plant growth,development and stress response.In order to clarify the detailed information of the bHLH family members in Tricholoma matsutake and their response to heavy metal stress,we identified the bHLH family members based on Tricholoma matsutake genome by using bioinformatics methods.The physicochemical properties and structure of the proteins,the conserved domains and the promoter cis-acting elements of the genes were analyzed,and the expression patterns of the bHLH family members in different developmental stages of Tricholoma matsutake fruit bodies,at different time of refrigeration,and under different heavy metal stresses were also investigated.The results showed that a total of 12 bHLH genes were identified in the Tricholoma matsutake genome,which were evenly distributed on 9 chromosomes.Physicochemical property analyses showed that the number of amino acids,theoretical molecular weight of protein,isoelectric point,and instability coefficient encoded by the bHLH(TmabHLH)genes were in the ranges of 96-878,10.72-96.02 ku,4.72-10.81,and 33.55-89.90,respectively.Subcellular localization analyses showed that all the genes were localized in the nucleus and were mainly hydrophilic and unstable nuclear proteins.In addition,the tertiary structure of TmabHLH protein mainly consisted of α-helices and irregular convolutions,and the promoter sequences of the TmabHLH genes contained a large number of light-responsive elements,hormone-responsive elements,and abiotic stress-responsive elements,suggesting that they may be involved in the growth and development and stress response of Tricholoma matsutake.Transcriptome analysis showed that most of the TmabHLH genes were abundantly expressed in the early development of Tricholoma matsutake fruit bodies,while most of the TmabHLH genes showed a decreasing trend in expression with prolonged cold storage time.The qRT-PCR assay revealed that all six TmabHLH genes responded to the four heavy metal stresses and had different expression patterns at different concentrations,e.g.,the genes responded more drastically under arsenic(As)stress than under mercury(Hg),cadmium(Cd)and lead(Pb)stress.In summary,the Tricholoma matsutake bHLH gene family has the function of regulating the response of matsutake to heavy metal stress,which lays an important foundation for further revealing the specific functions of TmabHLHs under heavy metal stress.