The genetics of exapted resistance to two exotic pathogens in pedunculate oak

Abstract

Exotic pathogens cause severe damage in natural populations in the absence of coevolutionary dynamics with their hosts. However, some resistance to such pathogens may occur in naive populations. The objective of this study was to investigate the genetics of this so-called 'exapted' resistance to two pathogens of Asian origin (Erysiphe alphitoides and Phytophthora cinnamomi) in European oak.Host-pathogen compatibility was assessed by recording infection success and pathogen growth in a full-sib family of Quercus robur under controlled and natural conditions. Two high-resolution genetic maps anchored on the reference genome were used to study the genetic architecture of resistance and to identify positional candidate genes.Two genomic regions, each containing six strong and stable quantitative trait loci (QTLs) accounting for 12-19% of the phenotypic variation, were mainly associated with E. alphitoides infection. Candidate genes, especially genes encoding receptor-like-kinases and galactinol synthases, were identified in these regions. The three QTLs associated with P. cinnamomi infection did not colocate with QTLs found for E. alphitoides.These findings provide evidence that exapted resistance to E. alphitoides and P. cinnamomi is present in Q. robur and suggest that the underlying molecular mechanisms involve genes encoding proteins with extracellular signaling functions.

The timing and asymmetry of plant–pathogen–insect interactions

“…small, whitish colonies) failed to establish within a week, leaves were inoculated again until infection was established. Differences in infection probability were likely caused by different levels of quantitative resistance [46,50]. As seedlings were randomized among treatments, we note that any effect of plant resistance would merely increase the residual error in the statistical models, and not affect estimates of among-treatment differences.…”

Integrative Pre-Breeding for Biotic Resistance in Forest Trees

“…RLKs and RLPs are structurally similar proteins. The former are involved in plant development and cell surface defense, deployment of plant receptors to detect pathogens, and signal translation through activated signaling pathways to trigger innate immune responses [17]. It should be noted that not all RLPs are involved in disease resistance, some may play a role in plant development [30].…”

Oaks as Beacons of Hope for Threatened Mixed Forests in Central Europe

“…The increasing availability of reference genomes for different oak species is the prerequisite to identify the underlying genes/genomic loci and develop diagnostic genetic markers for breeding programs (Badenes et al, 2016). First success is shown, for example, in the quantitative trait loci (QTL) study which identified two regions associated with Erysiphe alphitoides infection in the Q. robur genome (Bartholomé et al, 2020).…”