Cross-kingdom communication between Ralstonia and Fusarium mediate tomato wilt disease and microbial survival
Nandhitha Venkatesh: University of Wisconsin
<div><span class="gmail-s1"><i>Ralstonia <g id="14" class="gr_ gr_14 gr-alert gr_spell gr_inline_cards gr_run_anim ContextualSpelling" data-gr-id="14">solanacearum</g></i> (<i>Rs</i>) and <i>Fusarium <g id="15" class="gr_ gr_15 gr-alert gr_spell gr_inline_cards gr_run_anim ContextualSpelling" data-gr-id="15">oxysporum</g></i> <i>f. sp. <g id="16" class="gr_ gr_16 gr-alert gr_spell gr_inline_cards gr_run_anim ContextualSpelling" data-gr-id="16">lycopersici</g></i> (<i>Fol</i>) are vascular wilt pathogens that result in heavy yield losses in susceptible hosts such as tomato. Although both pathogens occupy the xylem, the consequences of mixed infections on wilt disease are unknown. Our previous <i>in vitro </i>studies had identified a <i>Rs </i>lipopeptide, <g id="18" class="gr_ gr_18 gr-alert gr_spell gr_inline_cards gr_run_anim ContextualSpelling" data-gr-id="18">ralsolamycin</g>, that induces chlamydospore formation in fungi including <i><g id="17" class="gr_ gr_17 gr-alert gr_spell gr_inline_cards gr_run_anim ContextualSpelling ins-del multiReplace" data-gr-id="17">Fol</g></i>. Bacteria have been observed to invade the chlamydospores and is proposed to impact the survival of both microbes. Here we show that <i>Fol</i> responds to <g id="19" class="gr_ gr_19 gr-alert gr_spell gr_inline_cards gr_run_anim ContextualSpelling" data-gr-id="19">ralsolamycin</g> exposure with the production of antibacterial metabolites (e.g. bikaverin and beauvericin) and explore interactions between the pathogens in tomato plants with corresponding secondary metabolite mutants of both the bacterium and the fungus. <i>In planta </i>co-infection experiments with <i>Rs</i> and <i>Fol</i> provide evidence for an antagonistic behavior of the fungus towards <i>Rs</i> with a significant reduction in bacterial wilt severity. Co-infections with metabolite mutants of both <i>Rs</i> and <i>Fol</i> will be assessed for disease progress and survival of both pathogens, including the ability of the bacterium to overwinter in fungal chlamydospores. These experiments coupled with RNAseq</span><span class="gmail-s2"> </span><span class="gmail-s1">and metabolomics analyses are expected to reveal key communication molecules which may form the basis for novel strategies to control vascular wilt diseases.</span></div>
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