Involvement of LaeA in various biological processes of filamentous fungi has been demonstrated. However, its role in Penicillium digitatum, the causal agent of citrus postharvest green mold, remains unclear. In this study, a ΔPdLaeA mutant was constructed using homologous recombination. The production of conidia by the ΔPdLaeA mutant was reduced by half compared with that of the wild‐type strain. The sensitivity of the ΔPdLaeA mutant increased under alkaline conditions. The virulence assay revealed that PdLaeA was dispensable for the virulence of P. digitatum. Comparative transcriptome analysis revealed that the function loss of PdLaeA resulted in the reduced expression of several secondary metabolite gene clusters. In addition, expression of several key regulators of conidiation (BrlA, FlbA, FlbC, FlbD, and FluG) was also downregulated in the ΔPdLaeA mutant. In summary, the present work demonstrated that PdLaeA was involved in the regulation of SM biosynthesis, as well as the development and environmental adaptation of P. digitatum.

中文翻译：

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LaeA 参与调节指状青霉分生孢子的产生和应激反应

已经证明 LaeA 参与丝状真菌的各种生物过程。然而，其在柑橘采后绿色霉菌的致病因子 Penicillium digitatum 中的作用仍不清楚。在本研究中，使用同源重组构建了 ΔPdLaeA 突变体。与野生型菌株相比，ΔPdLaeA 突变体的分生孢子产量减少了一半。ΔPdLaeA 突变体的敏感性在碱性条件下增加。毒力测定表明 PdLaeA 对于 P. digitatum 的毒力是可有可无的。比较转录组分析显示 PdLaeA 的功能丧失导致几个次级代谢物基因簇的表达降低。此外，几个关键的分生孢子调节因子（BrlA、FlbA、FlbC、FlbD、和 FluG) 在 ΔPdLaeA 突变体中也被下调。总之，目前的工作表明 PdLaeA 参与了 SM 生物合成的调节，以及 P. digitatum 的发育和环境适应。