Fungus–plant interactions in Aptian Tropical Equatorial Hot arid belt: White rot in araucarian wood from the Crato fossil Lagerstätte (Araripe Basin, Brazil)

Abstract

For the first time, this study describes the dynamics of white rot fungal decay in a petrified conifer branch with clear araucarian affinity from the late Aptian Crato Lagerstätte (Santana Formation, Araripe Basin, northeastern Brazil). High resolution optical microscopy was used to identify tridimensional chemical and anatomical evidence in different regions of the bark and xylem tissues of permineralized shoots, and results support the hypothesis that the host responded to disease that may have started when it was still alive. The wood decay pattern was strongly indicative of the selective decay by white rot. The general pattern of interaction is consistent with pathogenic rather than saprophytic fungal activity. Analysis of fungus–plant interactions associated with growth ring patterns imply intermittent periods of favorable temperature-moisture inputs that were crucial for fungal activity during the deposition of the Crato fossil Lagerstätte included in the Tropical Equatorial Hot arid belt.