Populus trichocarpa cell wall chemistry and ultrastructure trait variation, genetic control and genetic correlations

Abstract

SummaryThe increasing ecological and economical importance of Populus species and hybrids has stimulated research into the investigation of the natural variation of the species and the estimation of the extent of genetic control over its wood quality traits for traditional forestry activities as well as the emerging bioenergy sector. A realized kinship matrix based on informative, high-density, biallelic single nucleotide polymorphism (SNP) genetic markers was constructed to estimate trait variance components, heritabilities, and genetic and phenotypic correlations.Seventeen traits related to wood chemistry and ultrastructure were examined in 334 9-yr-old Populus trichocarpa grown in a common-garden plot representing populations spanning the latitudinal range 44°to 58.6°. In these individuals, 9342 SNPs that conformed to HardyWeinberg expectations were employed to assess the genomic pair-wise kinship to estimate narrow-sense heritabilities and genetic correlations among traits.The range-wide phenotypic variation in all traits was substantial and several trait heritabilities were > 0.6. In total, 61 significant genetic and phenotypic correlations and a network of highly interrelated traits were identified.The high trait variation, the evidence for moderate to high heritabilities and the identification of advantageous trait combinations of industrially important characteristics should aid in providing the foundation for the enhancement of poplar tree breeding strategies for modern industrial use.

Biofuels Get in the Fast Lane: Developments in Plant Feedstock Production and Processing

“…Moreover, modern molecular biology-based techniques can efficiently exploit the natural genetic diversity of feedstocks and benefit breeding efforts. Genomic regions associated with lignin content were detected in Populus and Eucalyptus, providing markers for the identification and development of plants with reduced lignin content [194][195][196]. However, cultivation conditions can also alter lignin content and composition, as it has been demonstrated for nitrogen supply [197,198].…”

Evolutionary quantitative genomics ofPopulus trichocarpa

“…older variants established at much higher frequencies within the population over time) as a wide distribution of allele frequencies (MAF>0.05) was considered for the analysis. Phenotyping of genotype accessions within the common gardens and climate of origin data were obtained from previously published work (for full phenotyping details, see [38,37], [45]). In brief, phenology, ecophysiology, biomass [45], leaf stomatal anatomy [44] and leaf rust (Melampsora xcolumbiana) resistance traits [38] were repeatedly measured from accessions planted at the University of British Columbia's research field through replication in space (clonal ramets) and in time (measurements across years).…”

“…In brief, phenology, ecophysiology, biomass [45], leaf stomatal anatomy [44] and leaf rust (Melampsora xcolumbiana) resistance traits [38] were repeatedly measured from accessions planted at the University of British Columbia's research field through replication in space (clonal ramets) and in time (measurements across years). Wood chemistry and ultrastructure traits were measured from wood cores of the nine-year-old ortets representing the same genotypes and growing in Surrey [37].…”

“…We also performed F ST outlier Note: P-value obtained by comparison of the observed Q ST -F ST to the quantile of the simulated Q ST -F ST distribution for a neutral trait [96]. a biomass trait [45] b ecophysiology trait [45] c leaf rust resistance trait [38] d phenology trait [45] e wood trait [37] f leaf stomata traits [44] *spatially adjusted trait [45] Evolutionary Quantitative Genomics analysis on climate clusters. While the mean F ST value for the complete dataset (29,354 SNPs) was 0.0108, we obtained a mean neutral F ST value (0.0078) after removing loci identified to be potentially under selection [41].…”

“…the decrease of genetic similarity among populations with increasing geographical distance between these populations reflected in continuous patterns of genetic differentiation and allele frequency variation in the species [34] as opposed to natural barriers causing discrete local genetic clusters), introgression and adaptation [36]. We explored the extensive body of data on the genetics of P. trichocarpa, including genome-wide coverage of SNPs [35], and comprehensive GWAS results from wood characteristics [37], leaf rust fungus (Melampsora xcolumbiana) resistance [38], biomass, ecophysiology, leaf stomata and phenology traits [39]. We studied the divergence patterns of phenotypic variation and SNPs among distinct climate clusters in 433 unrelated P. trichocarpa genotypes originally collected throughout the northern two-thirds of the species' latitudinal range (excluding the highly diverged Californian population Tahoe: [34], [40]).…”