Hyperoside, a flavonoid, induces <i>lnc187</i> and <i>lnc999</i> to enhance pigeon pea pollen tube growth and seed production.

Abstract

Flavonoid hyperoside boosts okra reproduction; its role in pigeon pea, with poor seed set, remains unclear. We found that hyperoside increases pigeon pea seed set by promoting pollen tube growth, a process that benefits from long noncoding RNAs (lncRNAs). Two lncRNAs, <i>lnc187</i> and <i>lnc999</i>, are regulated by hyperoside and synergize to regulate target genes. Among them, <i>lnc187</i> is the key effector; its loss may abolish downstream function. These lncRNAs up-regulate CcGPP (GRAS phosphorylase) kinase expression by binding to its promoter and acting as a scaffold to connect MRP23 and RNA polymerase while simultaneously inhibiting CcGDP (GRAS dephosphorylase) phosphatase activity by binding to key protein sites. Genetic evidence also confirms the relationship between <i>lnc187</i>/<i>lnc999</i>, MRP23, and the downstream CcGPP/CcGDP. This study clarifies the flavonoid hyperoside triggered regulatory axis where <i>lnc187</i>/<i>lnc999</i> promotes hyperphosphorylated CcGRAS to regulate pollen tube growth and seed set in pigeon pea, offering insights into reproductive development research for high-value woody species.