A plant single nucleotide polymorphism impacts nectar sugar composition, microbial diversity and pollinator visits

作者：Guillaume Tueux, Nicolas Pouilly, Jordan Bernigaud-Samatan, Nicolas Blanchet, Marie‐Claude Boniface, Olivier Catrice, Sébastien Carrère, Jérôme Gouzy, Marie-Pierre Jacquemot, Emmanuelle Lauber, Alexandra Legendre, Sandra Moreau, Marco M. Moroldo, Amandine Roldan, Aurélien Carlier, Nicolas Bernard Langlade · 发表于：bioRxiv (Cold Spring Harbor Laboratory) · 年份：2026 · DOI：10.64898/2026.04.09.717461 · 研究领域：Plant and animal studies、Plant Reproductive Biology、Plant and fungal interactions

Abstract Nectar is a hub for plant-pollinator interactions, yet gene-level causal links between plant genetic variation, pollinator foraging and nectar microbial assembly remain poorly resolved. Using near-isogenic lines, innovative field time-lapse monitoring of pollinator visits and long-read amplicon sequencing of nectar microbiota, we show that a natural single-nucleotide variant at a cell-wall invertase gene ( HaCWINV2 ) controls sunflower nectar chemistry and influences both pollinators and microbes. Plants homozygous for a loss-of-function HaCWINV2 allele produce sucrose-rich nectar, resulting in fewer bee visits under field conditions, while bumblebee visitation remained unaffected. In pollinator-excluded flowers, invertase-deficient plants harboured greater fungal diversity and compositionally distinct communities, indicating that nectar sugar profiles act as ecological filters shaping the nectar microbiome. This loss-of-function allele was found rarely and only at the heterozygote state in wild sunflowers and was fixed in 35% of cultivated lines indicating a positive selection during domestication. Our findings establish a causal link between a single gene and nectar chemistry with cascading ecological effects in a plant–pollinator system, illustrating how subtle genetic changes scale up to alter nectar traits, microbial assembly and pollinator foraging behaviour.