Genome-wide identification of MADS-box genes and functional analysis of EgMADS3 in oil palm flower development

Oil palm (Elaeis guineensis) is a high-yielding crop of global economic importance, contributing significantly to the food, biofuel, and pharmaceutical industries. The role of flower development in fruit formation and overall productivity is well established; however, the specific regulatory networks governing floral transition remain poorly understood.

This study aimed to identify members of the MADS-box gene family and investigate the functional roles of EgMADS3 and EgMADS45 in the reproductive growth and development of oil palm. A total of 61 MADS-box genes were identified in the oil palm genome and classified into two major types and 15 subfamilies based on phylogenetic analysis. Conserved motif structures, gene architectures, and cis-regulatory elements supported the functional conservation of these genes. All identified EgMADS-box genes were mapped onto 14 chromosomes. Collinearity and gene duplication analyses identified 17 pairs of segmentally duplicated paralogous EgMADS-box genes, contributing to the expansion of this gene family. RNA-seq data indicated that type II EgMADS genes are likely involved in floral development, with qRT-PCR confirming the tissue-specific expression patterns of 6 EgMADS genes across various floral organs. Functional validation in transgenic Arabidopsis thaliana showed that overexpression of EgMADS3 and EgMADS45 induced early flowering and abnormal floral morphology, suggesting their regulatory role in floral development.

These findings offer new insights into the molecular functions of EgMADS genes and provide promising targets for molecular breeding strategies aimed at improving oil palm yield and productivity.