Hydrogen peroxide regulates elicitor PB90-induced cell death and defense in non-heading Chinese cabbage

• Published in: Physiological and molecular plant pathology 2005-09, Vol.67 (3), p.220-230
• Main Authors: Li, Jun, Zhang, Zheng-Guang, Ji, Rui, Wang, Yuan-Chao, Zheng, Xiao-Bo
• Format: Article
• Language: English
• Subjects: apoptosis; Biological and medical sciences; Brassica; Brassica rapa subsp. chinensis; chitinase; Colletotrichum; enzyme activity; Erwinia carotovora; Fundamental and applied biological sciences. Psychology; fungal diseases of plants; fungal proteins; gene expression; Generalities. Disease free stocks; green leafy vegetables; Hydrogen peroxide; Hypersensitive cell death; hypersensitive response; induced resistance; leaves; Non-heading Chineses cabbage; oxidation; oxidative burst; pathogenesis-related proteins; PB90; phenylalanine ammonia-lyase; Phytopathology. Animal pests. Plant and forest protection; Phytophthora; Phytophthora boehmeriae; Phytophthora bohemeriae; plant pathogenic fungi; reverse transcriptase polymerase chain reaction; Systemic acquired resistance
• ISSN: 0885-5765; 1096-1178
• DOI: 10.1016/j.pmpp.2006.02.002

PB90, a protein elicitor secreted by Phytophthora boehmeriae, can induce a hypersensitive response and systemic acquired resistance in tobacco. In this study, we first developed a novel plant-elicitor interaction system between PB90 and non-heading Chinese cabbage, and then reported PB90-induced programmed cell death and defense regulated by hydrogen peroxide (H 2O 2) in the plant leaves. The PB90-induced cell death shared common morphological characteristics of apoptosis with mammalian cell death, including rapid chromatin condensation and cytoplasmic shrinkage, suggesting that cell death is a programmed occurrence. At the same time, elicitor treatment strongly activated and enhanced phenylalanine ammonia-lyase (PAL) activity. PB90 treatment also resulted in enhanced PR-1 and Chitinase expression, as evaluated by a reverse transcriptase–polymerase chain reaction, concomitant with enhanced resistance of plants to infection by Colletotrichum higginsianum and Erwinia carotovora var. carotovora. Moreover, a PB90-induced oxidative burst, the result of H 2O 2 accumulation over approximately 3 h, preceded PB90-triggered cell death by 12 h post-infiltration with PB90. Infiltration with antioxidants (DTT, glutathione, and ascorbic acid) and DPI, an inhibitor of NADPH oxidase, into leaves 30 min before treatment with PB90 significantly suppressed PB90-induced cell death and expression of PR-1 and Chitinase. We therefore, provided evidence that a PB90-induced H 2O 2 burst triggered programmed cell death and defense in non-heading Chinese cabbage.