Metabolite profiling reveals complex relationship between developing xylem metabolism and intra-ring checking in Pinus radiata

Globally, there has been an increasing amount of wood harvested from younger, fast-growing trees derived from plantation forests. As a consequence, producers and industrial consumers of wood products are becoming increasingly concerned with not only growth rates, but specific wood attributes that affect processing efficiencies and final product quality. Intra-ring checking is a problem that down-grades an unacceptably high proportion of radiata pine clearwood. Methods of identifying trees prone to this undesirable behaviour have been relatively destructive and time consuming, and from a breeding perspective, to date, there is no reliable method of predicting which selected progeny will later show a propensity to check. Using 120, 7-year-old Pinus radiata clones sampled from a common site, displaying difference in the propensity to form intra-ring checks, a GC/MS-based global metabolic profiling technique was employed to demonstrate that metabolomics can be used to accurately identify the checking phenotype. Metabolic profiling coupled with statistical tests was then used to develop models with greater than 90% efficiency to predict the intra-ring checking phenotype. Moreover, an inspection of unique metabolites contributing to the models indicated that coniferin, which is often found as a storage compound in rays, is a strong indicator of intra-ring checking, and indeed those genotypes that displayed the propensity to check inherently had a greater number of ray cells per unit area.