Candidate genes and molecular mechanisms regulating tiller development in wild Kentucky bluegrass

Poa pratensis has important ecological, aesthetic and economic value as a high-quality cold-season turfgrass and natural grassland species. Tillering is crucial for forage yield, seed production and turf quality and is regulated by endogenous hormone networks and metabolic pathways. In this study, two Kentucky bluegrass varieties, a strong tillering type (SN) and a weak tillering type (QS) were used to explore the molecular mechanisms shaping tiller development via morphological comparisons of tiller nodes, quantitative assessments of endogenous hormone levels, and a joint transcriptome-proteome analysis. The SN variety had a higher number of initial tiller buds and greater developmental activity, while QS showed delayed tiller bud development. These phenotypic differences were closely linked to changes in hormone levels, with significantly higher amounts of abscisic acid, auxin, and strigolactones in QS than in SN; brassinosteroid levels remained consistently high in SN. A joint omics analysis revealed co-expression of photosynthetic carbon metabolism pathways and plant hormone signal transduction pathways at the mRNA and protein levels. regulation center represented by IAA16, JAR2, SRK2A, and ZIM, which collaborate Multi-omics WGCNA analysis further unveiled key regulatory networks, identifying a transcriptional regulatory network that regulates hormone signaling and carbon metabolism. Concurrently, at the protein network level, a functional execution center represented by RLK S_2 and CYPRO4 was uncovered. This study elucidates that the tillering mechanism of Kentucky bluegrass is synergistically regulated by photosynthetic carbon metabolism, phenylpropanoid biosynthesis, and hormone signaling networks. This achievement not only provides new insights into the tillering mechanism of this species, but also identifies valuable candidate genes and proteins resource library, laying a theoretical foundation for the cultivation of new high-yield varieties of turfgrass and forage in the future, and providing key genetic targets.