Insights into Candidate Pathways Associated with Multi-Pistil Formation in Chinese Chestnut (Castanea mollissima Bl.): Evidence from Anatomy, Physiology, and Molecular Biology

Abstract

Simple Summary Chinese chestnut is an economically important nut crop, and its yield is strongly influenced by the pistil number of each female inflorescence. However, the molecular basis for the formation of multi-pistil female flower clusters remains poorly understood. In this work, comparative analyses between multi-pistil and normal female flower clusters were performed by combining anatomical observation, targeted phytohormone metabolomics, and transcriptome sequencing. The observations indicate that pistil primordium differentiation is the critical stage for multi-pistil formation, during which extra floral meristems expand continuously and give rise to new flower primordia. Changes in several plant hormones, including auxin, cytokinin, jasmonic acid, and gibberellin, were observed alongside this process. We also identified a number of candidate genes that may be involved in hormone regulation and flower development. These findings provide a useful foundation for further research and may support future breeding efforts to improve chestnut yield.