The peanut PIN-LIKES protein AhPILS regulates growth habit via gravitropism-dependent auxin redistribution

This is the authors' abstract. We don't add key points for this paper.

Shoot architecture is a crucial agronomic trait in peanut ( Arachis hypogaea L.) that affects adaptability to mechanized farming, pegging efficiency, yield potential, and disease management. Shoot architecture is mainly determined by the lateral branch angle; however, the genetic and molecular basis of this trait remains unclear. In this study, we characterized an erect-branching mutant designated eg06g , which was previously isolated from a γ-ray mutagenized population of the spreading peanut cultivar Georgia-06G (G06G). Phenotypic assays revealed that the eg06g mutant exhibits enhanced shoot gravitropism under gravistimulation, along with greater accumulation of starch granules at the base of lateral branches compared to the wild type. Map-based cloning identified a G-to-A single-nucleotide substitution in the promoter region of Arahy.M37AJ6, which encodes a PIN-LIKES (PILS) protein; we therefore named this gene AhPILS . Genetic analysis confirmed that the erect phenotype of eg06g was caused by a mutation in AhPILS . Furthermore, metabolite profiling detected a higher accumulation of the auxin indole-3-acetic acid (IAA) and auxin-related metabolites in the lower side of the lateral branch base in eg06g plants. Moreover, heterologous overexpression of AhPILS in Arabidopsis thaliana significantly enhanced the gravitropic bending capacity of transgenic seedlings and increased the expression of auxin-responsive genes upon gravistimulation. Collectively, our results demonstrate that AhPILS-mediated polar auxin transport establishes a basipetal auxin gradient that induces cell elongation, ultimately resulting in a switch from spreading lateral branches to upright growth. This study establishes a foundation for elucidating the mechanisms underlying peanut branching and provides valuable genetic resources for breeding cultivars with optimized plant architecture.