Development of a genetic linkage map for Pinus radiata and detection of pitch canker disease resistance associated QTLs

Abstract

Key message The heritability of genetic resistance of radiata pine against Fusarium circinatum was not clear. We demonstrated that there are at least 3 QTLs that could be involved in this resistance/susceptibility. Abstract A genetic linkage map was developed for Pinus radiata, using Amplified Fragment Length Polymorphism (AFLP), Inter-Simple Sequence Repeat (ISSR), Selective Amplification of Microsatellite Polymorphic Loci (SAMPL), and Simple Sequence Repeat (SSR) molecular markers, based on a two-way pseudo-testcross strategy, using 86 individuals of a F1 full-sib family and 787 molecular markers for genotyping. Linkage analysis generated a map of medium to high density for each parent, with 1,060 and 1,258 cM for parents XO and XP, respectively. A total of 458 markers were mapped on 12 linkage groups (LG) in XO and XP, which equals the number of haploid chromosomes present in P. radiata. Analysis of quantitative trait loci (QTL) for resistance against pitch canker disease caused by Fusarium circinatum was made using Bayesian Information Criterion (BIC). In the XO parental map, two groups (LG-1 and LG-9) showed high probabilities for one or more QTLs. Only one group in the XP parental map showed probability for one or more QTLs. The results indicate that resistance to pitch canker is inherited from both parents. These results provide the basis for further studies focused on structure, evolution, and function of the P. radiata genome.

Genomic architecture of complex traits in loblolly pine

“…For example, pitch canker resistance, carbon isotope and expression of xylem development genes were associated with 1–17 SNPs per trait; whereas metabolic traits were found to be associated with up to 448 SNPs. In the case of pitch canker disease resistance, our study reports 18 associated SNPs, twice or more the amount of previously reported associations for the same trait (Quesada et al ., ; Moraga‐Suazo et al ., ; Lu et al ., ). In relation to carbon isotope discrimination, our study found only two associated SNPs, less than found in previous studies using the same phenotypic dataset (four SNPs in Lu et al ., ; and 14 SNPs in Cumbie et al ., ).…”

Control of Fusarium spp. causing damping-off of pine seedlings by means of selected essential oils

“…In particular, Fusarium oxysporum has been linked to several forest nursery diseases (Gordon et al, 2001), including pre-and post-emergence damping-off, cotyledon blight of young germinants, as well as stem and root decay of young seedlings (James and Dumroese, 2006). Currently, pine cultivars with innate resistance against F. oxysporum are being developed to offer an alternative approach to disease control (Moraga-Suazo et al, 2014).…”

Environmentally friendly methods for controlling pine pitch canker

“…But this history of potential success is not free of significant drawbacks that need careful consideration. To properly exploit genetic resistance against F. circinatum, special attention should be paid to (i) improving and standardizing the current screening protocols (Oak et al, 1987;Roux et al, 2007); (ii) developing genomic selection protocols (Quesada et al, 2010;Moraga-Suazo et al, 2014;Donoso et al, 2015;Carrasco et al, 2017); (iii) discovery of durable and stable resistance operational across different environmental conditions, F. circinatum strains and tree ontogenetic stages; (iv) quantifying the consequences of putative trade-offs between resistance and other life functions (e.g. growth-defence trade-off) (Matheson et al, 2006a;Vivas et al, 2012b); and (v) exploration of other sources of variation with genetic backgrounds, such as inducibility Moreira et al, 2013), maternal effects (Vivas et al, 2013) or the attraction and susceptibility of trees to vectoring insects (Erbilgin et al, 2005).…”