Quantitative trait locus mapping of Populus bark features and stem diameter

Abstract

BackgroundBark plays important roles in photosynthate transport and storage, along with physical and chemical protection. Bark texture varies extensively among species, from smooth to fissured to deeply furrowed, but its genetic control is unknown. This study sought to determine the main genomic regions associated with natural variation in bark features and stem diameter. Quantitative trait loci (QTL) were mapped using an interspecific pseudo-backcross pedigree (Populus trichocarpa x P. deltoides and P. deltoides) for bark texture, bark thickness and diameter collected across three years, two sites and three biological replicates per site.ResultsQTL specific to bark texture were highly reproducible in shared intervals across sites, years and replicates. Significant positive correlations and co-localization between trait QTL suggest pleiotropic regulators or closely linked genes. A list of candidate genes with related putative function, location close to QTL maxima and with the highest expression level in the phloem, xylem and cambium was identified.ConclusionCandidate genes for bark texture included an ortholog of Arabidopsis ANAC104 (PopNAC128), which plays a role in lignified fiber cell and ray development, as well as Pinin and Fasciclin (PopFLA) genes with a role in cell adhesion, cell shape and migration. The results presented in this study provide a basis for future genomic characterization of genes found within the QTL for bark texture, bark thickness and diameter in order to better understand stem and bark development in Populus and other woody perennial plants. The QTL mapping approach identified a list of prime candidate genes for further validation using functional genomics or forward genetics approaches.Electronic supplementary materialThe online version of this article (10.1186/s12870-017-1166-4) contains supplementary material, which is available to authorized users.

Breeding progress and preparedness for mass‐scale deployment of perennial lignocellulosic biomass crops switchgrass, miscanthus, willow and poplar

“…GWAS approaches have provided a deeper understanding of genome function as well as allelic architectures of complex traits (Huang et al, ) and have been widely implemented in poplar for wood characteristics (Porth et al, ), stomatal patterning, carbon gain versus disease resistance (McKown et al, ), height and phenology (Evans et al, ), cell wall chemistry (Muchero et al, ), growth and cell walls traits (Fahrenkrog et al., ), bark roughness (Bdeir et al, ) and height and diameter growth (Liu et al, ). Using high‐throughput sequencing and genotyping platforms, an enormous amount of SNP markers have been used to characterize the linkage disequilibrium (LD) in poplar (e.g., Slavov et al, , discussed below).…”

Mobile forms of carbon in trees: metabolism and transport

“…Phloem unloading in trees is governed by the arrangement of the different tissues that form the stem ( Figure 4A ). The trunk is composed; of the bark, the outer layer that provides protection ( Bdeir et al 2017 ); the phloem, the living cell conducting system that transports C and other metabolites from the source tissues to the sink tissues ( Furze et al 2018 ); and the vascular cambium, which by repeated division produces phloem cells to the outside and xylem cells to the inside forming the bulk of the trunk biomass ( Mellerowicz et al 2001 , Campbell and Turner 2017 ). Each of these tissues is comprised of a variety of different cell types organized into an axial and a radial system ( Ek et al 2009 ).…”

QTL mapping of drought-related traits in the hybrids of Populus deltoides ‘Danhong’×Populus simonii ‘Tongliao1’

“…Research on QTL mapping in forest trees started after that of crops, but greater progress has been made [ 15 ]. The QTL mapping work on poplar primarily focused on important economic traits such as growth and wood properties [ 16 – 18 ]. At present, there are few studies on the deep analysis of drought tolerance-related quantitative characteristics in poplar, and it is an urgent problem to solve [ 5 , 19 ].…”