Plants adapt to low temperatures through transcriptomic reprogramming, yet how the core spliceosome maintains splicing fidelity during cold-regulated development remains poorly understood. Here, we investigated the role of the U4/U6.U5 tri-snRNP-associated protein 2 (AtUAP2) in Arabidopsis using genetic, transcriptomic, and biochemical approaches. Under normal conditions (22 °C), uap2, brr2b, and uap2 brr2b mutants showed no obvious developmental defects. Upon low-temperature treatment, however, uap2 displayed a severe impairment in cold-dependent hypocotyl elongation. RNA-sequencing revealed that UAP2 deficiency induced widespread pre-mRNA mis-splicing under cold stress. Ectopic expression of correctly spliced AtGRP7 and AtLOS2 cDNAs in uap2 partially restored hypocotyl growth under cold conditions, supporting their roles as key downstream effectors. Mechanistically, protein interaction assays demonstrated that UAP2 physically binds to the U5 RNA helicase BRR2b. While brr2b mutants exhibited a hypocotyl growth phenotype similar to uap2, the uap2 brr2b double mutant displayed an enhanced growth defect under low temperatures. Overall, our findings suggest that the UAP2-BRR2b complex operates as a functional module required to sustain spliceosomal efficiency under low temperature, providing insights into the potential connection between core splicing machinery dynamics and cold-induced hypocotyl growth responses in Arabidopsis.

As a class of synthetic organic compounds widely used in varieties of industrial products, polybrominated diphenyl ethers (PBDEs) have attracted increasing attention for the properties of toxicity, bioaccumulation and persistence. In this paper, the phyllospheric yeast strain capable of aerobic degradation of 4-brominated diphenyl ether (BDE-3) was originally isolated from Populus tomentosa. Based on the morphological properties and the ITS sequence analysis, the obtained yeast was identified as Wickerhamomyces anomalus and designated Y1. The endurance ability of Y1 to BDE- 3 exposure was determined by BDE-3 concentration gradient experiment. BDE-3 removal efficiency analysis was conducted by applying GC-μECD with initial BDE-3 content of 40 mg/L. Results showed Y1 could remove 83.58±2.60% of 40 mg/L BDE-3 in 3-day aerobic incubation. The tolerance range of pH and NaCl concentration were determined for further engineering application. It could be the first report about PBDEs degradation by yeast strain, isolated from the phyllosphere of P. tomentosa at the non-contaminated site of a subastral ecological niche, and might be advantageous in comprehensive exploitation of phytoremediation.

Cold stress is a major environmental factor limiting the productivity and geographical distribution of horticultural crops. Here, we investigated the role of the spliceosome U4/U6.U5 tri-snRNP-associated protein 1 (UAP1) in modulating low-temperature responses across three dicotyledonous species: tomato (Solanum lycopersicum), soybean (Glycine max), and Arabidopsis thaliana. Using CRISPR/Cas9-mediated gene editing, we generated UAP1 knockout orthologs in two dicotyledonous species: tomato and soybean. The sluap1 and gmuap1 mutants exhibited significantly enhanced cold resilience, characterized by reduced membrane damage, lower reactive oxygen species accumulation, and higher survival rates after cold stress. To elucidate the underlying molecular mechanism, we further characterized the uap1 mutants in Arabidopsis, which displayed alterations in cold-regulated hypocotyl elongation. Transcriptome-wide analysis revealed that the loss of AtUAP1 results in widespread differential alternative splicing under cold stress. Notably, we identified a critical intron retention event in the circadian clock gene AtPRR3, leading to a truncated, non-functional protein. Genetic evidence confirmed that atprr3 mutants mimic the low-temperature growth phenotype of atuap1, and heterologous expression of SlUAP1 or GmUAP1 effectively rescued the atuap1 mutant, demonstrating high functional conservation at the molecular level. Our findings establish the UAP1-mediated splicing module participates in cold-regulated growth and stress responses in dicotyledonous plants, providing insights into post-transcriptional regulation under low temperature.