Identifying resistance in wild and ornamental cherry towards bacterial canker caused by Pseudomonas syringae

Abstract

Plant diseases caused by bacteria remain problematic for the global horticultural industry due to a lack of effective control measures (Sundin et al., 2016). The genus Prunus contains over 400 species, a selection of which are grown for top fruit, ornamental use and timber production (Bortiri et al., 2001). Bacterial canker, caused by members of the Pseudomonas syringae species complex, can be a major limiting factor in the cultivation of Prunus spp. (Omrani et al., 2019;Vicente et al., 2004). The disease is primarily characterized by necrosis, gummosis and/ or dieback of woody plant tissues. In addition, the pathogens colonize other plant tissues where they exist epiphytically or invade to cause leaf and fruit spots, and blossom blight. These tissues can act as reservoirs

Genetic dissection of the tissue-specific roles of type III effectors and phytotoxins in the pathogenicity ofPseudomonas syringaepv.syringaeto cherry

“…Although P. incisa leaves are resistant to low inoculum concentrations of Pss 9644 (2x10 6 per ml), at high concentration (2x10 8 per ml) infections, the symptoms that develop and the bacterial growth mirror those produced by low concentrations in sweet cherry leaves indicating a susceptible interaction (Hulin et al, 2022). )Fig.…”

“…The nature of the resistance of P. incisa to low concentrations of inocula has not been explored. The ornamental cherry is resistant to all canker producing strains including PsmR1 and PsmR2 as well as Pss (Hulin et al, 2022). One explanation for the broad-spectrum resistance is that P. incisa has a strong MAMP response to Ps.…”

“…363 genomes belonging to the same group as Pss 9644 were kept for further analysis and Pph 1448A (a phylogroup 3) strain was kept as an out-group. Genomes of low quality (>5% contamination, <95% complete and N50 < 40,000 bp) were removed as in previous work (Hulin et al, 2022), leaving 324 genomes. Panaroo v1.3.2 (Tonkin-Hill et al, 2020) was utilised to generate a filtered core gene alignment of 3,943,305 nucleotides from 3825 core genes.…”

“…Certain sweet cherry varie es have been found to possess significant resistance to bacterial canker in the field, for example cv. Merton Glory, but resistance is not clearly apparent following ar ficial inocula on (Crosse and Garret, 1966, Hulin et al, 2022, Hulin et al, 2018b.…”

Genetic dissection of the tissue‐specific roles of type III effectors and phytotoxins in the pathogenicity of Pseudomonas syringae pv. syringae to cherry

“…The nature of the resistance of P. incisa to low concentrations of inocula has not been explored. The ornamental cherry is resistant to all canker-producing strains including Psm races 1 and 2 as well as Pss (Hulin et al, 2022).…”