Like other pathogens, plant parasitic nematodes employ effector proteins to alter plant cellular functions and successfully infect their hosts. We have generated a library of ORFs encoding putative Globodera rostochiensis apoplastic effectors in vectors for expression in planta. These clones were assessed for morphological and developmental effects on plants as well as their ability to induce or suppress plant defenses. Predicted cell wall-modifying proteins induced necrosis and chlorosis, consistent with roles in cell fate alteration and tissue invasion, respectively. We showed a novel role for an apoplastic expansin-like protein (GrEXPB2) in suppressing intra-cellular defense responses. GrEXPB2 also elicited defense response in species- and sequence-specific manner.
COBISS.SI-ID: 4630888
Secondary metabolites of a strain of Microcyclospora malicola (Capnodiales) were analyzed for the identification of potentially novel bioactive natural products. The fungus belongs to a group of slowly growing sooty blotch fungi that can survive in the wax layers of plant cuticles, specifically apple fruits, without causing significant fruit rot or plant diseases. Bioassay guided fractionation and subsequent structure elucidation by spectroscopic and spectrometric methods led to the identification of obionin A and additional derivatives (pyranonaphtoquinone metabolites) showing cytotoxic effects and antifungal activity. The compound, originally isolated from the marine ascomycete Leptosphaeria obiones, may account for the antagonism between M. malicola and other epiphytic fungi competing for the same ecological niche on fruit surfaces.
COBISS.SI-ID: 4984424