Influence of quorum sensing and copper on the interactions between the rhizosphere microorganisms Pseudomonas capeferrum and Papiliotrema laurentii

PABLO M. FERNANDEZ; LEGUINA, ANA CAROLINA DEL V.; CASTELLANOS DE FIGUEROA, LUCÍA I.; LACOSEGLIAZ, MARIANO J.; CARLOS G. NIETO PEÑALVER

Simposio; ISME Virtual Microbial Ecology Summit; 2020

Microbial interactions occurring in therhizosphere have a great influence on plant health and on soil quality. Severalof this inter-communications are mediated by quorum sensing (QS). QS is a cell-to-cellsignaling mechanism that control the microbial physiology in response to smallsignal molecules. Even though fungi are essential componentsof agricultural soils, yeasts rolesor how they relate with other rhizomicroorganisms is still an open question. Upto date, copper compounds are broadly used in agriculture to battlephytopathogenic fungi, which has led to its accumulation in soils, resultingdetrimental for soil microbiota and their interactions. The aim of this workwas to evaluate the interactions mediated by QS between rhizosphere bacteriaand yeasts, and the influence of copper contamination on them. For this purpose,we used as models the rhizo-yeast Papiliotremalaurentii YL2 and the rhizo-bacterium Pseudomonascapeferrum WCS358. Promotor activities of QS genes from WCS358 wereevaluated in the presence and absence of copper and YL2. The capability of YL2to inactivate the QS signals that WCS358 utilize in its QS system, and theeffect of copper was also analyzed. Finally, the influence of copper and YL2 onthe QS signals production by WCS358 was studied. The results showed that copperand YL2 differentially affect negatively the activities of the QS gene promoters.YL2 was able to inactivate 2 out of 3 QS signals molecules produced by WCS358,though no significant modifications by copper were determined. The presence ofthe metal and the yeast also altered the QS signals production in WCS358. Theresults of the present work suggest that YL2 could modify the QS regulation andhence the QS-dependent phenotypes in WCS358, and that copper contaminationcould interfere with bacteria-yeast interaction.