Abstract
Expression patterns of 7K and 22K genes were analyzed by full-length cDNA and oligo microarrays, respectively, under various treatments, such as hormones (SA, JA, ET, ABA), pathogen-inoculation (Alternaria brassicicola, Alternaria alternata, Colletotrichum higginsianum), paraquat, rose bengal, UV stress, heavy metal stress, mechanical wounding, drought, high salinity and low temperature. When challenged with the crucifer pathogen C. higginsianum, Arabidopsis thaliana ecotype Columbia (Col-0) was colonized by the fungus within 2-3 days, developing brown necrotic lesions surrounded by a yellow halo. The ecotype Eil-0 was highly resistant, with symptoms limited to necrotic flecking and with only very limited fungal colonization. Expression analyses with microarrays indicated that the defense reaction (basal defense and host-resistance) depends primarily on the JA/ET-dependent signaling pathways, and to a lesser extent on the SA-dependent signaling pathway. These results show that microarray analysis is a powerful tool for identifying defense-signaling pathways and multiple stress-responsive genes.
