Ambient pH controls the expression of endopolygalacturonase genes in the necrotrophic fungus Sclerotinia sclerotiorum.
In the necrotrophic fungus Sclerotinia sclerotiorum, secretion of polygalacturonases (PGs) and decrease of the environmental pH via oxalic acid production are considered as the main pathogenicity determinants. In order to evaluate the relationship between these two aspects of the infection process, we analyzed the expression of the endoPG-encoding genes pg1-3. Transcription of pg1-3 was not carbon regulated but was strictly controlled by pH and highly favored in a narrow range of acidic pH. During plant infection, a pH gradient was established in relation to oxalic acid secretion. Transcripts of pg1-3 were localized to the zone of colonization of healthy tissues while transcripts of genes encoding other lytic enzymes were restricted to the more acidic zones of the infected tissues. Our results show that progressive acidification of the ambient medium by the fungus is a major strategy for the sequential expression of pathogenicity factors.
Laboratoire de Biologie Cellulaire Fongique, UMR 5122 CNRS INSA UCB, Bat Lwoff, 10 rue Dubois, Université C. Bernard Lyon 1, 69622 cedex, Villeurbanne, France. cotton@biomserv.univ-lyon1.fr
Pascale
P
Cotton
Zsolt
Z
Kasza
Christophe
C
Bruel
Christine
C
Rascle
Michel
M
Fèvre
D001203:Ascomycota / Q000201:enzymology* / Q000235:genetics; D002244:Carbon / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal; D006863:Hydrogen-Ion Concentration; D019815:Oxalic Acid / Q000378:metabolism; D010935:Plant Diseases / Q000382:microbiology; D011096:Polygalacturonase / Q000235:genetics / Q000378:metabolism*; D012097:Repressor Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic
D012097:Repressor Proteins; D002244:Carbon; D019815:Oxalic Acid; D011096:Polygalacturonase