红三叶TpLHC基因家族分析以及铅胁迫下的表达模式OA

Lead contamination is a major abiotic stress that reduces crop yield,causes plant death,and degrades the environment.Red clover(Trifolium pratense)is an important forage legume with substantial potential for lead tolerance.Based on previously generated transcriptome data from red clover exposed to different lead concentrations,the present study identified and characterized the LHC gene family using bio-informatics approaches.A total of 21 TpLHC genes were identified and assigned to the LHCA(5 mem-bers)and LHCB(16 members)families.Phylogenetic analysis of TpLHC proteins and their homologs in Arabidopsis thaliana and Medicago truncatula classified the TpLHCA and TpLHCB families into five and seven subfamilies,respectively.Subcellular localization analysis predicted that most TpLHC proteins were localized to chloroplasts,whereas TpLHCA6 and TpLHCB7 were localized to the plasma membrane.Expression analysis under 0,500,1 000,2 000,and 3 000 mg/kg lead treatments showed that,after 45 d of exposure,expression of all TpLHCB8 subfamily members was strongly suppressed under 500 mg/kg lead stress,TpLHCA1,TpLHCA6,TpLHCB1.1,TpLHCB1.6,TpLHCB4.1,TpLHCB5,and TpL-HCB7 were upregulated under 3 000 mg/kg lead stress.qRT-PCR analysis showed that,after 48 h of exposure to 1 000 mg/kg lead,all LHCA family members except TpLHCA6 were downregulated.Among the LHCB genes,except for TpLHCB1.2 and TpLHCB7,the expression levels of the remaining members increased at 48 h under stress compared to those under non-stress conditions,suggesting that LHCB genes may be more strongly associated with lead-stress tolerance.