Abstract
Understanding the genetic architecture of adventitious root and related shoot traits will facilitate the cultivation of superior genotypes. In this study, we measured 12 adventitious root and related shoot traits of 434 F1 genotypes originating from Populus deltoides ‘Danhong’ × Populus simonii ‘Tongliao1’ and conducted an integrative analysis of quantitative trait locus (QTL) mapping and RNA-Seq data to dissect their genetic architecture and regulatory genes. Extensive segregation, high repeatability, and significant correlation relationship were detected for the investigated traits. A total of 150 QTLs were associated with adventitious root traits, explaining 3.1–6.1% of phenotypic variation (PVE); while 83 QTLs were associated with shoot traits, explaining 3.1–19.8% of PVE. Twenty-five QTL clusters and 40 QTL hotspots were identified for the investigated traits. Ten QTL clusters were overlapped in both adventitious root traits and related shoot traits. Transcriptome analysis identified 10,172 differentially expressed genes (DEGs) among two parents, three fine rooting and three poor-rooting genotypes, 143 of which were physically located within the QTL intervals. K-means cluster and weighted gene co-expression network analysis showed that PtAAAP19 (Potri.004G111400) encoding amino acid transport protein was tightly associated with adventitious roots and highly expressed in fine-rooting genotypes. Compare with ‘Danhong’, 153 bp deletion in the coding sequence of PtAAAP19 in ‘Tongliao1’ gave rise to lack one transmembrane domain, which might cause the variation of adventitious roots. Taken together, this study deciphered the genetic basis of adventitious root and related shoot traits and provided potential function genes for genetic improvement of poplar breeding.
Highlights
Forest trees constitute the largest pool of biomass carbon in the terrestrial ecosystem, providing great ecological and economic values [1]
The hybrid parents exhibited a difference in adventitious root and related shoot traits, which contributed to distinct separation in the
We investigated the genetic architecture of adventitious root and related shoot traits of the F1 population originating from a cross between P. deltoides ‘Danhong’ × P. simonii ‘Tongliao1’
Summary
Forest trees constitute the largest pool of biomass carbon in the terrestrial ecosystem, providing great ecological and economic values [1]. Plant biomass production and distribution depend on the interactions between below-ground root and above-ground shoot. Root absorbs water and nutrients to offer growth substances for carbon fixation process in shoot leaves, while shoots provide mechanical support and transfer pathway for organic substances [2]. The biomass partitioning patterns between root and shoot are related to plant growth rate, life habitats, nutrient density, and environmental adaptability [3,4,5]. Vegetative propagation is an important reproductive pattern in many woody species, and adventitious root formation is a limiting step in vegetative propagation [6]. Enhancing the ability to regenerate the adventitious root can promote the wide cultivation of elite genotypes. Dissecting the genetic basis of adventitious root and shoot traits will accelerate plant breeding progress for cultivating the genotypes with high biomass and reproduction capability
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