LAUSR

Trichoderma asperellum ZZY has good tolerance to Pb2+, but the tolerance mechanism is not clear. The manuscript aimed to clarify the tolerance mechanism from the perspective of the response changes of related active ingredients. The synthesis of polysaccharides, proteins and thiol compounds in Trichoderma asperellum can be accelerated with Pb2+ stress. Under Pb2+ stress, Trichoderma asperellum can synthesize oxalic acid and secrete it extracellularly. In addition, high concentration of Pb2+ can inhibit the synthesis and extracellular secretion of formic acid and malic acid. The tolerance of Trichoderma asperellum to Pb2+ is the results of multiple reactions. The Pb2+ can promote the synthesis of polysaccharides, proteins, thiol compounds and oxalic acid. In the early stage of Pb2+ stress, Trichoderma asperellum can rapidly initiate an extracellular emergency mechanism, synthesize oxalic acid in mycelia and secrete it extracellularly to remove free Pb2+ and alleviate the toxicity of Pb2+ to cells. With the transport of Pb2+ into cells, it can promote the synthesis of polysaccharides, proteins, thiol compounds to adsorb and transform the Pb2+ and ease the damage to the cells. The manuscript provides theoretical support and scientific explanation for the application of Trichoderma asperellum.