Transcriptional analysis of the response of Sclerotinia sclerotiorum after exposure to aliphatic and indolic isothiocyanates (ITCs)

Resumen del póster presentado en Saint-Malo, Francia, entre el 1 y el 4 de julio de 2018.White mold caused by fungus Sclerotinia sclerotiorum (Ss) is a major disease of Brassica crops. Antimicrobial secondary metabolites represent an important component of plant defense. Glucosinolates and their main break down product isothiocyanates (ITCs), present in Brassicaceae plants, show inhibitory effect on growth and development of Ss. Mechanism trough ITCs exert their toxicity and the way fungus can overcome it are not completely understood. This study aimed to identify molecular mechanism underlying response of Ss after exposure to ITCs through next generation sequencing. Fungi in vegetative growth stage were treated with two classes of ITCs: the aliphatic allyl ITC and the indolic indol-3-carbinol. Transcriptomic analysis of both treatments and controls was carried out by MACE. The transcriptomic analysis revealed that the expression of 2012 genes (1156 up and 1056 down regulated) was altered by allyl-ITC and 654 genes (149 up and 505 down regulated) by indol-3-carbinol. Gene ontology analysis showed that categories related to detoxification of reactive oxygen species (ROS) and protection against oxidative damage were up regulated, confirming that toxicity of ITCs is mainly conducted through oxidative stress. Oxidative stress alleviation against long exposure to ITCs in Ss was in part driven from amino acid homeostasis. In the fungus treated with allyl ITC, genes related to production of proline are up regulated, whereas in fungus treated with indol-3 carbinol, the production of serine is being induced. Proline can stabilize proteins and membranes, besides having osmo-protective and termo-tolerant properties and can act as a ROS quencher. Serine has a role in oxidative stress mitigation via supporting methionine cycle and glutathione pathway, involved in detoxification of ROS. Results provide new insights into the stress biology of fungus and revealed two distinct profiles of response to oxidative stress caused by ITCs on Ss.Peer reviewe