OsNUC1 encodes rice nucleolin, which has been shown to be involved in salt stress responses.  Expression of the full-length OsNUC1 gene in Arabidopsis resulted in the hypersensitivity to ABA during germination.  Transcriptome analysis of the transgenic lines, in comparison with wild type, revealed that RNA abundance of more than 1,900 genes was significantly changed under normal growth conditions, while under salt stress conditions the RNAs of 999 genes were found to be significantly regulated.  Gene enrichment analysis showed that under normal conditions OsNUC1 resulted in repression of genes involving in photosynthesis, while in salt stress conditions OsNUC1 increased expression of the genes involving in light-harvesting complex. Correspondingly, the net photosynthesis rate of the transgenic lines was increased under salt stress. Transgenic rice lines with overexpression of OsNUC1-L gene were generated and tested for photosynthesis performance under salt stress condition. The transgenic rice lines treated with salt stress at booting stage had higher photosynthetic rate and stomatal conductance in flag leaves and second leaves than wild type. Moreover, higher contents of chlorophyll a and carotenoids were found in flag leaves of the transgenic rice. These results suggest a role for OsNUC1 in the modification of the transcriptome, especially the gene transcripts responsible for photosynthesis, leading to photosynthesis stabilization under salt stress condition.

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