17Plant microbial communities' complexity provide a rich model for investigation on biochemical and 18 regulatory strategies involved in interbacterial competition. Within these niches, the soft rot 19 Enterobacteriaceae (SRE) comprise an emerging group of plant-pathogens inflicting soft rot/black-20 leg diseases and causing economic losses worldwide in a variety of crops. In this report, a range of 21 molecular and computational techniques are utilized to survey the contribution of antimicrobial 22Pcb1692 inhibits growth of other SRE and several potato endophytes using either the type VI 51 secretion, carbapenem or bacteriocins. Carbapenem plays a role in both inter and intrabacterial 52 competition in vitro, while the Pcb1692T6SS plays a role in interbacterial competition in planta (in 53 potato tubers). We also demonstrate that carbapenem regulation requires the presence of 54 environmental iron and oxygen in a complex network consisting of Pcb1692 Fur, SlyA, and ExpI. 55