Genetius

The study examined how elevated atmospheric CO₂ (550 ppm) affects immunity in the C₄ cereal maize (Zea mays L.) by exposing plants grown under ambient and elevated CO₂ to a range of pathogens. Elevated CO₂ increased susceptibility to sugarcane mosaic virus, decreased susceptibility to several bacterial and fungal pathogens, and left susceptibility to others unchanged, with reduced bacterial disease linked to heightened basal immune responses. These findings provide a baseline for future investigations into CO₂‑responsive defense mechanisms in C₄ crops.

The study identifies fungal effectors from Ustilago maydis that interact with plant TOPLESS corepressors and induce gall formation by hijacking maize lateral root initiation pathways, notably through upregulation of LBD transcription factors. Transgenic expression of class II effectors derepresses auxin signaling, leading to pluripotent calli without external hormones, and maize mutants in LBD genes show reduced gall development.