Resistance to Plum Pox Virus (PPV) in apricot (Prunus armeniaca L.) is associated with down-regulation of two MATHd genes
View/ Open
Metadata
Show full item recordDate
2018Cita bibliográfica
Zuriaga, E., Romero, C., Blanca, J. M., & Badenes, M. L. (2018). Resistance to Plum Pox Virus (PPV) in apricot (Prunus armeniaca L.) is associated with down-regulation of two MATHd genes. BMC plant biology, 18(1), 25.Abstract
Plum pox virus (PPV), causing Sharka disease, is one of the main limiting factors for Prunus production
worldwide. In apricot (Prunus armeniaca L.) the major PPV resistance locus (PPVres), comprising ~ 196 kb, has been
mapped to the upper part of linkage group 1. Within the PPVres, 68 genomic variants linked in coupling to PPV
resistance were identified within 23 predicted transcripts according to peach genome annotation. Taking into
account the predicted functions inferred from sequence homology, some members of a cluster of meprin and
TRAF-C homology domain (MATHd)-containing genes were pointed as PPV resistance candidate genes.
Results: Here, we have characterized the global apricot transcriptome response to PPV-D infection identifying six
PPVres locus genes (ParP-1 to ParP-6) differentially expressed in resistant/susceptible cultivars. Two of them (ParP-3 and
ParP-4), that encode MATHd proteins, appear clearly down-regulated in resistant cultivars, as confirmed by qRT-PCR.
Concurrently, variant calling was performed using whole-genome sequencing data of 24 apricot cultivars (10 PPVresistant
and 14 PPV-susceptible) and 2 wild relatives (PPV-susceptible). ParP-3 and ParP-4, named as Prunus armeniaca
PPVres MATHd-containing genes (ParPMC), are the only 2 genes having allelic variants linked in coupling to PPV
resistance. ParPMC1 has 1 nsSNP, while ParPMC2 has 15 variants, including a 5-bp deletion within the second exon that
produces a frameshift mutation. ParPMC1 and ParPMC2 are adjacent and highly homologous (87.5% identity)
suggesting they are paralogs originated from a tandem duplication. Cultivars carrying the ParPMC2 resistant (mutated)
allele show lack of expression in both ParPMC2 and especially ParPMC1.
Conclusions: Accordingly, we hypothesize that ParPMC2 is a pseudogene that mediates down-regulation of its
functional paralog ParPMC1 by silencing. As a whole, results strongly support ParPMC1 and/or ParPMC2 as host
susceptibility genes required for PPV infection which silencing may confer PPV resistance trait. This finding may
facilitate resistance breeding by marker-assisted selection and pave the way for gene edition approaches in Prunus.