Modulation of tomato root architecture and root hair traitsby Pseudomonas brassicacearum and Variovorax paradoxus containing 1-aminocyclopropane-1-carboxylate deaminase

By decreasing root 1-aminocyclopropane-1-carboxylate (ACC) content and plant ethylene production, the microbial enzyme ACC deaminase is a widespread beneficial trait of growth-promoting rhizobacteria (PGPR), ameliorating ethylene-mediated growth inhibition. However, relatively little known about whether bacterial modulates architecture hair traits. Thus dwarf tomato (Solanum lycopersicum) cultivar Micro-Tom was inoculated in vitro with Pseudomonas brassicacearum Am3, its deficient mutant T8-1, PGPR strain Variovorax paradoxus 5C-2 or chemically treated agents that promoted inhibited production sensitivity (Ag+, Co2+, ACC). treatment reduced both elongation number lateral roots, while inhibitors Co2+) V. primary elongation, but differentially affected length number. Ag+ stimulated development, Co2+ did not. Inoculation P. Am3 T8-1 roots at high inoculum concentration (106 cells cm3). All strains significantly increased hairs, these effects more pronounced than T8-1. Treatment formation had opposite effects. no effect on density. While inhibition caused by independent deaminase, promotion density this augmented activity. can modulate morphological impacts bacteria response affecting content.