Overexpression of Arabidopsis thaliana cysteine2/histidine2-type transcription factor 6 gene enhances plant resistance to a bacterial pathogen

Abstract

Transcription factors can be used to engineer plants for enhanced productivity. However, the mechanism(s) by which the C2H2-type zinc finger transcription factor enhances pathogen resistance in cells is not fully understood. Here, Agrobacterium tumefaciens carrying the gene for Arabidopsis thaliana cysteine2/histidine2-type transcription factor 6 (ZAT6) was used to engineer rice (Oryza sativa L.), cotton (Gossypium hirsutum L.), and slash pine (Pinus elliottii Engelm.) to generate transgenic cell lines. Transgenic cells were then inoculated with the pathogenic bacterium Pseudomonas syringae. Compared to the control, cell viability of transgenic cells increased 39–47% and growth rate increased 9–15% by 7 days after inoculation in rice, cotton and slash pine. Acid phosphatase activity and alkaline phosphatase activity and transcript levels of Ca2+-dependent protein kinase genes OsCPK1, OsCPK2, OsCPK6, and OsCPK8 and mitogen-activated protein kinase genes OsMAPK1, OsMAPK2, OsMAPK3, and OsMAPK8 increased significantly in transgenic rice cells by 3 day after inoculation, and extracellular pH had decreased by 10–14% by 96 min after inoculation in transgenic rice, cotton and slash pine cells. These results suggest that ZAT6 enhances P. syringae resistance in plant cells by modulating transcription of CPK and MAPK and oxidase activity.