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Abstract RAF-like kinases, members of the mitogen-activated protein kinase kinase kinase (MAPKKK) family, are central integrators of external and internal signals in plant stress responses and growth regulation. These kinases mediate signaling through multiple hormone pathways, including abscisic acid-dependent and -independent pathways, ethylene signaling, and rapid auxin responses. Unlike typical MAPKKKs that function through kinase cascades, RAF-like kinases primarily employ direct phosphorylation of downstream targets and dynamic subcellular localization to mediate specific physiological responses. Here, we review the emerging roles of RAF-like kinases in Arabidopsis thaliana, highlighting their integrative functions in hormone signaling, stress responses, and growth control. The complex interplay between different RAF-like kinase subgroups and their diverse cellular targets underscores the intricate regulatory mechanisms plants have evolved to coordinate environmental responses with development. 

Abstract The gaseous plant hormone ethylene is a key developmental and growth regulator, and a pivotal endogenous response signal to abiotic and biotic interactions, including stress. Much of what is known about ethylene biosynthesis, perception, and signaling comes from decades of research primarily in Arabidopsis thaliana and other eudicot model systems. In contrast, detailed knowledge on the ethylene pathway and response to the hormone is markedly limited in maize (Zea mays L.), a global cereal crop that is a major source of calories for humans and livestock, as well as a key industrial biofeedstock. Recent reports of forward screens and targeted reverse genetics have provided important insight into conserved and unique differences of the ethylene pathway and downstream responses. Natural and edited allelic variation in the promoter regions and coding sequences of ethylene biosynthesis and signaling genes alters maize shoot and root architectures, and plays a crucial role in biomass and grain yields. This review discusses recent advances in ethylene research in maize, with an emphasis on the role of ethylene in regulating growth and development of the shoot and root systems, and ultimately how this crucial hormone impacts plant architecture and grain yield.