NtDHS1-NteIF5A complex regulates leaf senescence by modulating gene translation in Nicotiana tabacum

DEOXYHYPUSINE SYNTHASE (DHS) is a critical enzyme involved in the post-translational activation of the eukaryotic TRANSLATION INITIATION FACTOR 5A (eIF5A), which plays a key role in protein synthesis and stress responses in plants. Understanding the function of DHS is essential for uncovering mechanisms that regulate plant growth and development, particularly in relation to leaf senescence. In this study, we investigated the role of NtDHS1 in Nicotiana tabacum (N. tabacum, K326) by creating Ntdhs1 knockout mutants using CRISPR/Cas9 technology. Our results showed that the absence of NtDHS1 led to abnormal chlorophyll content and delayed leaf senescence in the N. tabacum. RNA-seq and Ribo-seq analyses revealed that, despite fluctuations in the transcription levels of photosynthesis-related genes, their translation rates were significantly increased in the mutants, suggesting enhanced photosynthetic efficiency as a compensatory mechanism for reduced chlorophyll content. Additionally, we found that NtDHS1 physically interacts with NteIF5A, indicating that NtDHS1 may influence the translation of photosynthesis-related genes through NteIF5A. These findings provide new insights into the function of DHS in plant development and offer potential strategies for delaying leaf senescence through genetic engineering.