Genome-Wide Identification of Arachis hypogaea LEC1s, FUS3s, and WRIs and Co-Overexpression of AhLEC1b, AhFUS3b, AhWRI1a and AhWRI1d Increased Oil Content in Arabidopsis Seeds

Peanut (<i>Arachis hypogaea</i>) is an important oil and economic crop widely cultivated worldwide. Increasing the oil yield is a major objective for oilseed crop improvement. Plant LEAFY COTYLEDON1s (LEC1s), FUSCA3s (FUS3s), and WRINKLED1s (WRI1s) are known master regulators of seed development and oil biosynthesis. While previous studies in peanut have primarily focused on two <i>AhLEC1s</i> and one <i>AhWRI1</i> genes, this study identified a broader set of regulators, including two <i>AhLEC1s</i>, two <i>AhFUS3s</i>, nine <i>AhWRI1s</i>, two <i>AhWRI2s,</i> and four <i>AhWRI3s</i> from the variety HY917. The analyses of phylogenetic trees, gene structures, conserved domains, sequence alignment and identity, and collinearity revealed that they were highly similar to their homologs in other plants. Expression profiling demonstrated that two <i>AhLEC1s</i>, two <i>AhFUS3s</i>, and three <i>AhWRI1s</i> (<i>AhWRI1a/b/c</i>) were specifically expressed in developing seeds, suggesting critical roles in seed development, whereas <i>AhWRI1d</i>, <i>AhWRI1f</i>, and <i>AhWRI1g</i> showed high expression in root nodules, pointing to potential functions in symbiosis and nodulation. Furthermore, co-overexpression of <i>AhLEC1b</i>, <i>AhFUS3b</i>, <i>AhWRI1a</i>, and <i>AhWRI1d</i> in <i>Arabidopsis</i> significantly enhanced seed oil content and thousand-seed weight, but also led to reduced germination rate, plant height, and silique length. The findings allow for the extensive evaluation of <i>AhLEC1s</i>, <i>AhFUS3s,</i> and <i>AhWRIs</i> gene families, establishing a useful foundation for future research into their multiple roles in peanut development.