Alteration of the phyllosphere microbiota in lettuces by different light spectra

To investigate light quality how to shape phyllosphere microbial communities on crop leaves, we analyzed the microbiota of lettuces grown under five light treatments: nature light (CK), Red light (RL), Yellow light (YL), Blue light (BL) and white light (WL) using high-throughput sequencing. The results revealed that light quality significantly altered both bacterial and fungal compositions in the lettuces phyllosphere. At the genus level, in comparison with nature light (CK), RL and YL enriched bacterial genera, such as Rothia , Bradyrhizobium , and fungal genera, such as Cladosporium , Phialosimplex . Notably Rickettsia was uniquely enriched under RL, along with fungal genera Trametes and Ramichloridium . Similarly, YL specifically enriched bacterial genera Hyphomicrobium and Novosphingobium , fungal genera Myrothecium , Talaromyces and Sporobolomyces . In contrast, Exiguobacterium and Cystobasidium were enriched across CK, BL, and WL treatments, while Rhodococcus and Pseudocercospora were uniquely abundant under WL treatment. Function prediction further indicated that symbiotrophic fungi were significantly enriched under RL, whereas WL promoted the proliferation of potentially pathogenic bacteria and fungi (e.g., Pseudocercospora ). Collectively, these findings demonstrate that light quality is a key driver of phyllosphere microbial assembly in lettuce. provide new insights into light-driven microbial assembly on lettuce leaves and set the stage for functional studies on plant-microbe interactions under controlled light spectra.