Unveiling enhanced photosynthesis in tetraploid sour jujube through transcriptome analysis

Polyploidization, which can potentially impact phenotypic traits and photosynthetic performance of plants, is an important goal in breeding. In this study, diploid sour jujube and autotetraploid 'W219' were examined to understand the effects of polyploidization on photosynthesis. By comparing the phenotypic and photosynthetic differences between 'W219' and diploid sour jujube, it was found that 'W219' exhibited increased leaf length, leaf width, leaf area, and plant height, as well as enhanced chlorophyll content and photosynthetic efficiency. To explore the molecular mechanisms underlying these variations, comparative transcriptome analysis was conducted between 'W219' and diploid, resulting in the identification of 2892 differentially expressed genes (DEGs), with 993 up-regulated and 1899 down-regulated in 'W219'. GO enrichment analysis revealed that most DEGs were related to biological processes, primarily enriched in metabolic processes. Further KEGG pathway analysis revealed significant differences in photosynthetic pathways between 'W219' and diploid, mainly involving key processes such as photosystem II, photosynthetic electron transport, and chloroplast protein synthesis. This study revealed the internal mechanism of enhanced photosynthesis in autotetraploid sour jujube 'W219' through comprehensive analysis at the morphological, physiological, and transcriptomic levels, providing a basis for explaining its unique photosynthetic characteristics.