To survive and reproduce in ever-changing environments, plants rely on a complex nutrient signaling network, balancing growth and development with resource availability. At the core of this network lies Snf-1-related kinase 1 (SnRK1), traditionally viewed as a metabolic gauge that suppresses growth and promotes catabolism ensuring survival under restrictive conditions. Recent findings, however, including those from the De Jaeger lab, revealed that beyond its stress-related functions, SnRK1 plays also an essential, constitutive role in meristem development and source-sink transport. Despite these insights, the precise functions and regulatory mechanisms underlying this constitutive role remain poorly understood. This project seeks to unravel the tissue-specific roles of SnRK1 by mapping its interactome using proximity labeling and identifying its associated phosphoproteome in tissues showing high constitutive SnRK1 activity, all closely linked to meristem development and source-sink transport. By uncovering cell-type-specific regulatory mechanisms and substrates, we aim to shed light on how SnRK1 orchestrates these critical processes. To deepen our understanding, we will validate and perform functional analyses on identified tissue-specific regulators and substrates. This comprehensive approach will provide new insights into the fundamental mechanisms of SnRK1, advancing our knowledge of its role in plant development and resource allocation.