Open AccessA novel link between tomato GRAS genes, plant disease resistance and mechanical stress response
Author(s) -
MAYROSE MAYA,
EKENGREN SOPHIA K.,
MELECHBONFIL SHIRI,
MARTIN GREGORY B.,
SESSA GUIDO
Publication year - 2006
Publication title -
molecular plant pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.945
H-Index - 103
eISSN - 1364-3703
pISSN - 1464-6722
DOI - 10.1111/j.1364-3703.2006.00364.x
Subject(s) - pseudomonas syringae , biology , jasmonic acid , gene , elicitor , hypersensitive response , solanum , genetics , biotic stress , plant disease resistance , gene silencing , gene family , abiotic stress , r gene , gene expression , botany
SUMMARY Members of the GRAS family of transcriptional regulators have been implicated in the control of plant growth and development, and in the interaction of plants with symbiotic bacteria. Here we examine the complexity of the GRAS gene family in tomato ( Solanum lycopersicum ) and investigate its role in disease resistance and mechanical stress. A large number of tomato ESTs corresponding to GRAS transcripts were retrieved from the public database and assembled in 17 contigs of putative genes. Expression analysis of these genes by real‐time RT‐PCR revealed that six SlGRAS transcripts accumulate during the onset of disease resistance to Pseudomonas syringae pv. tomato . Further analysis of two selected family members showed that their transcripts preferentially accumulate in tomato plants in response to different avirulent bacteria or to the fungal elicitor EIX, and their expression kinetics correlate with the appearance of the hypersensitive response. In addition, transcript levels of eight SlGRAS genes, including all the Pseudomonas ‐inducible family members, increased in response to mechanical stress much earlier than upon pathogen attack. Accumulation of SlGRAS transcripts following mechanical stress was in part dependent on the signalling molecule jasmonic acid. Remarkably, suppression of SlGRAS6 gene expression by virus‐induced gene silencing impaired tomato resistance to P. syringae pv. tomato . These results support a function for GRAS transcriptional regulators in the plant response to biotic and abiotic stress.