Defense activation triggers differential expression of phospholipase-C (PLC) genes and elevated temperature induces phosphatidic acid (PA) accumulation in tomato.
Recently, we provided the first genetic evidence for the requirement of tomato PLC4 and PLC6 genes in defense activation and disease resistance. The encoded enzymes were catalytically active as they were able to degrade phosphatidylinositol (PI), thereby producing diacylglycerol (DG). Here we report differential PLC gene expression following the initiation of defense signaling by the interaction between Cladosporium fulvum resistance (R) protein Cf-4 and its matching effector Avr4 in tomato hybrid seedlings that express both Cf-4 and Avr4. Furthermore, we observed that PLC3 and PLC6 gene expression is upregulated by elevated temperature in the control seedlings. This upregulation coincides with an increase in the levels of phosphatidic acid (PA) and a decrease in the levels of PI and phosphatidylinositol phosphate (PIP). The decrease in PI and PIP levels matches with the activation of PLC. In addition, the levels of the structural phospholipids phosphatidylcholine (PC), phosphatidylethanolamine (PE) and phosphatidylglycerol (PG) declined transiently during recovery after the exposure to elevated temperature., Further studies will be required to explain the mechanism causing the sustained accumulation of PA during recovery, combined with a reduction in the levels of structural phospholipids.
Laboratory of Phytopathology, Wageningen University, Wageningen, The Netherlands.
Ahmed
A
Abd-El-Haliem
Harold J G
HJ
Meijer
Wladimir I L
WI
Tameling
Jack H
JH
Vossen
Matthieu H A J
MH
Joosten
D000222:Adaptation, Physiological / Q000235:genetics; D002963:Cladosporium; D060467:Disease Resistance / Q000235:genetics*; D005656:Fungal Proteins / Q000378:metabolism; D015870:Gene Expression; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D006358:Hot Temperature; D006824:Hybridization, Genetic; D018551:Solanum lycopersicum / Q000201:enzymology / Q000235:genetics* / Q000382:microbiology; D008562:Membrane Glycoproteins / Q000378:metabolism; D010712:Phosphatidic Acids / Q000378:metabolism*; D010713:Phosphatidylcholines / Q000378:metabolism; D010716:Phosphatidylinositols / Q000378:metabolism; D010743:Phospholipids / Q000378:metabolism; D010935:Plant Diseases / Q000235:genetics* / Q000382:microbiology; D010940:Plant Proteins / Q000378:metabolism; D036226:Seedlings; D013312:Stress, Physiological / Q000235:genetics; D010738:Type C Phospholipases / Q000235:genetics* / Q000378:metabolism; D015854:Up-Regulation
C085987:AVR4 protein, Cladosporium fulvum; C109609:Cf protein, Lycopersicon esculentum; D005656:Fungal Proteins; D008562:Membrane Glycoproteins; D010712:Phosphatidic Acids; D010713:Phosphatidylcholines; D010716:Phosphatidylinositols; D010743:Phospholipids; D010940:Plant Proteins; D010738:Type C Phospholipases