Transcriptional Profiling of Rice Leaves Undergoing a Hypersensitive Response Like Reaction Induced by Xanthomonas oryzae pv. oryzae Cellulase

Gopaljee Jha,Madhumita Dasgupta,Ramesh Palaparthi,Ramesh V Sonti,Hitendra Kumar Patel

doi:10.1007/s12284-009-9033-z

Abstract

Abstract A secreted cellulase of Xanthomonas oryzae pv. oryzae induces innate immune responses in rice including a hypersensitive response (HR) like reaction. Microarray analysis was conducted using RNA isolated 12 h following ClsA treatment of leaves. BLAST searches were performed for the 267 (152 up- and 115 downregulated) differentially expressed (≥2-fold) genes. A number of defense and stress-response functions are upregulated while a number of functions involved in metabolism and transport are downregulated following induction of HR. A significant proportion of the differentially expressed genes (41/267) are predicted to encode transcription factors. Co-infiltration of X. oryzae pv. oryzae suppresses ClsA-induced expression of two transcription factors, OsAP2/ethylene response factor (ERF) and OsRERJ1, that are predicted to be involved in the jasmonic-acid-mediated defense pathway. Transient transfer of OsAP2/ERF via Agrobacterium results in the induction of callose deposition, programmed cell death, and resistance against subsequent X. oryzae pv. oryzae infection.

Highlights

Plants have powerful innate immune responses that help them ward off most potential pathogens
The Probe Logarithmic Intensity Error (PLIER; Affymetrix Inc 2005) and Robust Multichip Average (RMA; Irizarry et al 2003a, b) algorithms used in the analysis picked different numbers of genes at p
The gene ontology (GO) enrichment analysis of ≥1.5fold change rice genes differentially expressed upon ClsA treatment have revealed that genes with GO terms associated with response to stress are overrepresented among upregulated genes while those associated with primary and secondary metabolism, photosynthesis, chloroplast, and plastids are overrepresented among downregulated genes

Summary

Introduction

Plants have powerful innate immune responses that help them ward off most potential pathogens These immune responses are triggered following recognition of common microbe-associated molecular pattern molecules (MAMPS) or pathogen-associated molecular pattern molecules (He et al 2007; Bent and Mackey 2007). For bacterial pathogens, such MAMPS include elicitors such as lipopolysaccharides (Newman et al 2002), cold shock protein (Felix and Boller 2003), flagellin (Felix et al 1999), elongation factor Tu (Kunze et al 2004), an extracellular signaling molecule called AvrXa21 (Lee et al 2006), etc. This ability of plant pathogenic bacteria to suppress host innate immunity is considered to be a precondition for their ability to cause disease (Grant et al 2006; Bent and Mackey 2007; Jha et al 2007; He et al 2007)

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Conclusion