Gpn2 is a highly conserved protein essential for the assembly of RNA polymerase II (RNAPII) in eukaryotic cells. Mutations in Gpn2, specifically Phe105Tyr and Leu164Pro, confer temperature sensitivity and significantly impair RNAPII assembly. Despite its crucial role, the complete range of Gpn2 functions remains to be elucidated. To further explore these functions, we conducted large-scale multicopy suppressor screening in budding yeast, aiming to identify genes whose overexpression could mitigate the growth defects of a temperature-sensitive gpn2 mutant (gpn2^ts) at restrictive temperatures. We screened over 30,000 colonies harboring plasmids from a multicopy genetic library and identified 31 genes that rescued the growth defects of gpn2^ts to various extents. Notably, we found that PAB1, CDC5, and RGS2 reduced the drug sensitivity of gpn2^ts mutants. These findings lay a theoretical foundation for future studies on the function of Gpn2 in RNAPII assembly.

Northern corn leaf blight (NCLB), caused by Setosphaeria turcica (S. turcica), is one of the devastating foliar diseases of maize (Zea mays) in maize-producing regions globally. Previous research has predominantly centered on elucidating the infection strategy and process of the pathogen, but the molecular mechanism of maize response to the pathogen is still largely unknown. In this study, we employed transcriptomics technology to comprehensively analyze alterations in RNA expression profiles within maize leaves at critical time points (hours post-infestation, 24 hpi, and 72 hpi) during S. turcica infection. Our study identified 7196 differentially expressed genes (DEGs) involved in the maize leaf response to S. turcica infection compared to the control (CK at 0 hpi). Functional analysis revealed that these DEGs were enriched in multiple metabolic pathways. Notably, genes associated with “benzoxazinone biosynthesis”, “tetracyclic pyrrole biosynthesis”, and “photosynthesis” were all down-regulated. In contrast, DEGs related to “phenol metabolism” and “phenylpropanoid metabolism” were significantly upregulated. Moreover, the genes belonging to the NAC, MYB-related, HB, and WRKY transcription factor families were also significantly enriched among the DEGs. The expression levels of six randomly selected DEGs were validated using qRT-PCR, confirming the accuracy of the RNA-Seq findings. This study delves into the functional genes and metabolic pathways closely associated with maize’s response to S. turcica infection, providing foundational data for a deeper understanding of the molecular mechanisms underlying the interaction between S. turcica and maize.