This work develops a modular interkingdom communication channel between bacteria and plants, enabling bacteria to convey environmental stimuli to plants. The system involves a "sender device" in *Pseudomonas putida* and *Klebsiella pneumoniae* that produces the small molecule *p*-coumaroyl-homoserine lactone (pC-HSL) when a sensor or circuit turns on. This molecule triggers a "receiver device" in the plant to activate gene expression. The system is validated in *Arabidopsis thaliana* and *Solanum tuberosum* (potato) grown hydroponically and in soil, demonstrating its modularity by swapping bacteria that process different stimuli, including IPTG, aTc, and arsenic. The programmable communication channels between bacteria and plants will enable microbial sentinels to transmit information to crops and provide the building blocks for designing artificial consortia. The study also explores the design of bacterial sensors for various chemicals and the implementation of logic gates to process multiple signals, demonstrating the potential for complex interkingdom communication and signal processing.This work develops a modular interkingdom communication channel between bacteria and plants, enabling bacteria to convey environmental stimuli to plants. The system involves a "sender device" in *Pseudomonas putida* and *Klebsiella pneumoniae* that produces the small molecule *p*-coumaroyl-homoserine lactone (pC-HSL) when a sensor or circuit turns on. This molecule triggers a "receiver device" in the plant to activate gene expression. The system is validated in *Arabidopsis thaliana* and *Solanum tuberosum* (potato) grown hydroponically and in soil, demonstrating its modularity by swapping bacteria that process different stimuli, including IPTG, aTc, and arsenic. The programmable communication channels between bacteria and plants will enable microbial sentinels to transmit information to crops and provide the building blocks for designing artificial consortia. The study also explores the design of bacterial sensors for various chemicals and the implementation of logic gates to process multiple signals, demonstrating the potential for complex interkingdom communication and signal processing.