Abstract:LaeA， as a global regulatory factor， is involved in numerous biological processes such as the growth， development， and secondary metabolism of filamentous fungi. In this study， the Agrobacterium-mediated homologous recombination method combined with hygromycin resistance screening was adopted to construct the Penicillium expansum laeA knockout strain（ΔPelaeA）， and the growth and development， patulin production， and pigment accumulation of the laeA knockout mutant strain were analyzed. The results showed that， compared with that of the wild-type （WT） strain， the colony of the ΔPelaeA strain had a lighter color， a rough surface， and obvious annual ring patterns， while there was no significant change in the colony diameter.The spore production volume and the number of conidiophores significantly decreased， and the spore formation cycle was obviously delayed. The accumulation of patulin and the pigmentation significantly decreased.Further research revealed that the expressions of the genes related to conidiospore formation （AbaA， BrlA， and WetA） and those related to patulin synthesis （PatA-PatO） all significantly decreased. In the presence of various stresses， the growth of both the WT strain and the ΔPelaeA strain was obviously inhibited， but there was no significant difference in the relative growth inhibition rate between the two， indicating that LaeA itself was not sensitive to these stress reagents. In conclusion， PeLaeA positively regulated the sporogenesis， as well as the accumulation of pigments and patulin in Penicillium expansum.