Search

The eicosanoid signaling pathway mediates insect immune reactions to a wide range of stimuli. This pathway begins with the biosynthesis of arachidonic acid (AA) from the hydrolysis of phospholipids catalyzed by phospholipase A

Iron (Fe) deficiency is a world-wide serious agricultural problem. Maize secretes 2'-deoxymugineic acid (DMA) to uptake and utilize Fe from the soil. In order to explore the gene expression patterns of the DMA secretion channel gene YS3, we cloned the 2813 bp YS3 promoter, and constructed the plant expression vector pCAMBIA-YS3GUS. The promoter contains a lot of TATA-boxes and CAAT-boxes, and cis-acting regulatory elements such as the light responsive elements and the hormone responsive elements. Arabidopsis was transformed via Agrobacterium tumefacients-mediated procedures to obtain the pYS3::GUS transgenic plants, which were confirmed by GUS staining. Then, the stained tissue was observed using paraffin section methods and the YS3 promoter activity was also analyzed. We found that the promoter could drive GUS gene expression specifically in the root epidermal cells. Mechanical damage could activate the promoter, and drive the GUS gene expression adjacent to the damage sites. Our results provide a molecular basis to understand the DMA secretion process in maize.

Plants are often subjected to iron (Fe)-deficiency stress because of its low solubility. Plants have evolved two distinct strategies to solubilize and transport Fe to acclimate to this abiotic stress condition. Transcriptomic profiling analysis was performed using Illumina digital gene expression to understand the mechanism underlying resistance responses of roots to Fe starvation in maize, an important Strategy II plant. A total of 3,427, 4,069, 4,881, and 2,610 genes had significantly changed expression levels after Fe-deficiency treatments of 1, 2, 4 or 7 days, respectively. Genes involved in 2′-deoxymugineic acid (DMA) synthesis, secretion, and Fe(III)–DMA uptake were significantly induced. Many genes related to plant hormones, protein kinases, and protein phosphatases responded to Fe-deficiency stress, suggesting their regulatory roles in response to the Fe-deficiency stress. Functional annotation clustering analysis, using the Database for Annotation, Visualization and Integrated Discovery, revealed maize root responses to Fe starvation. This resulted in 38 functional annotation clusters: 25 for up-regulated genes, and 13 for down-regulated ones. These included genes encoding enzymes involved in the metabolism of carboxylic acids, isoprenoids and aromatic compounds, transporters, and stress response proteins. Our work provides integrated information for understanding maize response to Fe-deficiency stress.