转录组和蛋白组联合分析揭示Ubr1介导的白僵菌萌发和极性生长

Analysis of Ubr1-mediated germination and polar growth of Beauveria bassiana based on the combination of transcriptome and proteome

摘要:

【目的】通过比较球孢白僵菌野生型和ubr1基因缺失菌株分生孢子在同一时间点转录组学和蛋白组学的差异表达基因和蛋白及其所属通路，阐明Ubr1影响球孢白僵菌极性生长的机制，为提高球孢白僵菌生物防治潜能提供理论依据。【方法】通过对转录组学和蛋白组学的KEGG分析，获得差异表达基因和蛋白所在代谢调控通路，利用显微镜拍摄菌株在各萌发培养基(germination medium，GM)衍生板中分生孢子萌发的图像验证双组学分析中显著差异的调控通路对分生孢子极性生长的影响。【结果】ubr1基因缺失使分生孢子萌发受损，形成异常弯曲或钩状的芽管。且不论是以转录组，还是以蛋白质组为核心进行双组学KEGG联合分析，二者都能富集到氮代谢、精氨酸和脯氨酸代谢和醚脂类代谢通路。进一步的验证实验表明，球孢白僵菌中ubr1基因缺失引起的精氨酸代谢异常是分生孢子极性生长紊乱的一个重要原因，而半乳糖和氮代谢异常则会导致分生孢子的萌发速率变慢。【结论】Ubr1的缺失使精氨酸代谢受阻，进而导致分生孢子萌发管极性生长异常；同时，也使半乳糖和氮代谢异常导致分生孢子萌发速率延迟。本研究的发现对于认识极性生长的机制具有一定贡献，也拓展了丝状真菌侵染循环中体壁穿透过程的理论认识。

Abstract:

[Objective] To clarify the mechanism of Ubr1 affecting the polar growth of Beauveria bassiana based on the differentially expressed genes (DEGs) and proteins (DEPs) and their pathways in the conidia of the wild-type (WT) and ubr1-deleted (Δubr1) strains at the same time point and thus to lay a theoretical basis for improving potential of B. bassiana for biocontrol. [Methods] Through KEGG analysis of the transcriptome and proteome, the pathways of the DEGs and DEPs were clarified. The germinated conidia in each germination medium (GM)-derived plate were photographed with a microscope to verify the influence of the differential pathways on polar growth of the conidia.[Results] ubr1 deletion impaired the germination of conidia, resulting in abnormally curved or hook-shaped germ tubes. Both the DEGs and DEPs were involved in nitrogen metabolism, arginine and proline metabolism, and ether ester metabolism. Further verification showed that abnormal arginine metabolism caused by ubr1 deletion was an important reason for the disorder of conidial polar growth and that abnormal metabolism of galactose and nitrogen led to slow germination of conidia. [Conclusion]The absence of ubr1 blocks arginine metabolism, resulting in abnormal polar growth of germ tube. The abnormal metabolism of galactose and nitrogen also delays the germination of conidia. The findings are expected to enhance the understanding of the mechanism of polar growth and the penetration process in the infection cycle of filamentous fungi.