AUTHOR=Balthazar Carole , Cantin Gabrielle , Novinscak Amy , Joly David L. , Filion Martin 

TITLE=Expression of Putative Defense Responses in Cannabis Primed by Pseudomonas and/or Bacillus Strains and Infected by Botrytis cinerea

JOURNAL=Frontiers in Plant Science

VOLUME=11

YEAR=2020

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2020.572112

DOI=10.3389/fpls.2020.572112

ISSN=1664-462X

ABSTRACT=<p>Cannabis (<italic>Cannabis sativa</italic> L.) offers many industrial, agricultural, and medicinal applications, but is commonly threatened by the gray mold disease caused by the fungus <italic>Botrytis cinerea</italic>. With few effective control measures currently available, the use of beneficial rhizobacteria represents a promising biocontrol avenue for cannabis. To counter disease development, plants rely on a complex network of inducible defense pathways, allowing them to respond locally and systemically to pathogens attacks. In this study, we present the first attempt to control gray mold in cannabis using beneficial rhizobacteria, and the first investigation of cannabis defense responses at the molecular level. Four promising <italic>Pseudomonas</italic> (LBUM223 and WCS417r) and <italic>Bacillus</italic> strains (LBUM279 and LBUM979) were applied as single or combined root treatments to cannabis seedlings, which were subsequently infected by <italic>B. cinerea.</italic> Symptoms were recorded and the expression of eight putative defense genes was monitored in leaves by reverse transcription quantitative polymerase chain reaction. The rhizobacteria did not significantly control gray mold and all infected leaves were necrotic after a week, regardless of the treatment. Similarly, no systemic activation of putative cannabis defense genes was reported, neither triggered by the pathogen nor by the rhizobacteria. However, this work identified five putative defense genes (<italic>ERF1</italic>, <italic>HEL</italic>, <italic>PAL</italic>, <italic>PR1</italic>, and <italic>PR2</italic>) that were strongly and sustainably induced locally at <italic>B. cinerea</italic>’s infection sites, as well as two stably expressed reference genes (<italic>TIP41</italic> and <italic>APT1</italic>) in cannabis. These markers will be useful in future researches exploring cannabis defense pathways.</p>