Identification of differentially-expressed genes of rice in overlapping responses to bacterial infection by Xanthomonas oryzae pv. oryzae and nitrogen deficiency

Bacterial blight of rice caused by Xanthomonas oryzae pv. oryzae (Xoo) is one of high nitrogen (N) responsive diseases. Rice plants became more disease resistant with decreasing N suggesting that the crosstalk between disease resistance and N utilization pathways might exist. However, the co-regulatory components in such crosstalk have not been elucidated. Here, we comparatively analyzed the gene expression profiling of rice under Xoo inoculation, low N treatment, or a combination of both stresses, and identified the differentially-expressed genes (DEGs) in overlapping responses. These DEGs were involved in different biological processes, including innate immunity and nitrogen metabolism. The randomly-selected DEGs expression was validated by quantitative real-time PCR assays. Temporal expression of six genes from different functional categories suggested that N condition was the dominant factor when both stresses were present. These DEGs identified provide novel insights into the coordinated regulatory mechanism in biotic and abiotic stress responses in rice.