Genetics and evolution of the GoP1 gene regulating yellow pollen coloration enhancing pollinator attraction in cotton

Pollen is produced in the anthers of angiosperm stamens and serves a crucial role in pollination and plant reproduction. The coloration of floral organs is known to attract pollinators, thereby enhancing pollination efficiency and seed production. However, the genetic basis of pollen pigmentation in tetraploid cotton, a major source of renewable fiber worldwide, remains obscure. In this study, we found that yellow pollen pigmentation significantly increased pollinator honeybee visitation to cotton flowers. Here, we fine-mapped and identified a dominant yellow pollen gene, GoP1, which encodes phytoene synthase (PSY), a gateway enzyme in the carotenoid biosynthesis pathway. Silencing GoP1 in the yellow pollen parent J8891 using virus-induced gene silencing and CRISPR/Cas9-mediated targeted mutagenesis disrupted synthesis of carotenoid and other pigments, resulting in significantly reduced carotenoid levels in mature pollen and a white pollen phenotype. Additionally, genomic analysis of a resequencing panel comprising 497 cotton accessions revealed that the yellow pollen trait was gradually lost under negative selection during the domestication and improvement of upland cotton. White pollen plants, which attracted fewer pollinators, helped maintain higher variety purity in production, making them more favored by breeders. Our findings provide new perspectives on the genetic mechanisms of pollen coloration and uncover a promising approach to enhance cotton productivity.