AUTHOR=Koseoglou Eleni , Hanika Katharina , Mohd Nadzir Mas M. , Kohlen Wouter , van der Wolf Jan M. , Visser Richard G. F. , Bai Yuling 

TITLE=Inactivation of tomato WAT1 leads to reduced susceptibility to Clavibacter michiganensis through downregulation of bacterial virulence factors

JOURNAL=Frontiers in Plant Science

VOLUME=14

YEAR=2023

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2023.1082094

DOI=10.3389/fpls.2023.1082094

ISSN=1664-462X

ABSTRACT=<p>Tomato bacterial canker caused by <italic>Clavibacter michiganensis</italic> (Cm) is considered to be one of the most destructive bacterial diseases of tomato. To date, no resistance to the pathogen has been identified. While several molecular studies have identified (<italic>Cm</italic>) bacterial factors involved in disease development, the plant genes and mechanisms associated with susceptibility of tomato to the bacterium remain largely unknown. Here, we show for the first time that tomato gene <italic>SlWAT1</italic> is a susceptibility gene to <italic>Cm</italic>. We inactivated the gene <italic>SlWAT1</italic> through RNAi and CRISPR/Cas9 to study changes in tomato susceptibility to <italic>Cm</italic>. Furthermore, we analysed the role of the gene in the molecular interaction with the pathogen. Our findings demonstrate that <italic>SlWAT1</italic> functions as an S gene to genetically diverse <italic>Cm</italic> strains. Inactivation of <italic>SlWAT1</italic> reduced free auxin contents and ethylene synthesis in tomato stems and suppressed the expression of specific bacterial virulence factors. However, CRISPR/Cas9 <italic>slwat1</italic> mutants exhibited severe growth defects. The observed reduced susceptibility is possibly a result of downregulation of bacterial virulence factors and reduced auxin contents in transgenic plants. This shows that inactivation of an S gene may affect the expression of bacterial virulence factors.</p>