Faculty Collaboration Database

Involvement of specific calmodulin isoforms in salicylic acid-independent activation of plant disease resistance responses. Proc Natl Acad Sci U S A 1999 Jan 19;96(2):766-71

Date

01/20/1999

Pubmed ID

9892708

Pubmed Central ID

PMC15211

DOI

10.1073/pnas.96.2.766

Scopus ID

2-s2.0-0033582172 (requires institutional sign-in at Scopus site)   235 Citations

Abstract

The Ca2+ signal is essential for the activation of plant defense responses, but downstream components of the signaling pathway are still poorly defined. Here we demonstrate that specific calmodulin (CaM) isoforms are activated by infection or pathogen-derived elicitors and participate in Ca2+-mediated induction of plant disease resistance responses. Soybean CaM (SCaM)-4 and SCaM-5 genes, which encode for divergent CaM isoforms, were induced within 30 min by a fungal elicitor or pathogen, whereas other SCaM genes encoding highly conserved CaM isoforms did not show such response. This pathogen-triggered induction of these genes specifically depended on the increase of intracellular Ca2+ level. Constitutive expression of SCaM-4 and SCaM-5 in transgenic tobacco plants triggered spontaneous induction of lesions and induces an array of systemic acquired resistance (SAR)-associated genes. Surprisingly, these transgenic plants have normal levels of endogenous salicylic acid (SA). Furthermore, coexpression of nahG gene did not block the induction of SAR-associated genes in these transgenic plants, indicating that SA is not involved in the SAR gene induction mediated by SCaM-4 or SCaM-5. The transgenic plants exhibit enhanced resistance to a wide spectrum of virulent and avirulent pathogens, including bacteria, fungi, and virus. These results suggest that specific CaM isoforms are components of a SA-independent signal transduction chain leading to disease resistance.

Author List

Heo WD, Lee SH, Kim MC, Kim JC, Chung WS, Chun HJ, Lee KJ, Park CY, Park HC, Choi JY, Cho MJ

Author

Sang H. Lee PhD Professor in the Pharmacology and Toxicology department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Calcium
Calmodulin
Fusarium
Gene Expression Regulation, Plant
Genes, Plant
Immunity, Innate
Phenotype
Phytophthora
Plant Diseases
Plant Proteins
Plants, Genetically Modified
Plants, Toxic
Pseudomonas
Salicylic Acid
Transcriptional Activation