Anatomical, molecular and computational analysis of vascularization in peduncles of reproductive organs of Coffea arabica L.
Coffee beans are an important agricultural product primarily grown in tropical countries. The flowering of coffee plants is necessary for bean development but can be uneven, leading to inconsistent fruit maturation, especially in Brazil where mechanized harvesting mixes green and ripe beans, impacting quality. In addition, non-uniform flowering complicates pest and disease control. The reproductive period of coffee plants depends on photoperiod and water availability. Once induced, floral organs progress through developmental stages classified based on size and coloration. Floral buds enter a dormancy period between 3-6 mm in size, coinciding with dry periods in Minas Gerais, Brazil. Sporadic rains during this period can trigger growth in larger buds, exacerbating developmental variability. Due to floral bud sensitivity to water availability, understanding vascular development in reproductive organs, especially peduncles connecting inflorescences to branches, is essential. Our focus includes anatomical and molecular factors influencing vascular development in coffee's reproductive organs, using combined anatomical, molecular, and computational analyses. Key transcription factors in model species initiate vascular bundle development. We identified, characterized, and evaluated three key genes: HD14 (HD-ZIP Class III) for procambium development, OCTOPUS for phloem cell identity, and VND7 for protoxylem and metaxylem development. Our integrated approach of anatomical peduncle characterization and RNAseq/RT-qPCR analyses unravels molecular control mechanisms in coffee vascular development. This foundational research aims to enhance coffee production and improve strategies for other globally important crops.