Identification of pathovars and races of Pseudomonas syringae, the main causal agent of bacterial disease in pea in North-Central Spain, and the search for disease resistance

Abstract

A total of 298 bacterial isolates were collected from pea cultivars, landraces and breeding lines in North-Central Spain over several years. On the basis of biochemical-physiological characteristics and molecular markers, 225 of the isolates were identified as Pseudomonas syringae, either pv. pisi (110 isolates) or pv. syringae (112), indicating that pv. syringae is as frequent as pv. pisi as causal agent of bacterial diseases in pea. Most strains (222) were pathogenic on pea. Further race analyses of P. syringae pv. pisi strains identified race 4 (59.1% of the isolates of this pathovar), race 2 (20.0%), race 6 (11.8%), race 5 (3.6%) and race 3 (0.9%). Five isolates (4.6%) showed a not-previously described response pattern on tester pea genotypes, which suggests that an additional race 8 could be present in P. syringae pv. pisi. All the isolates of P. syringae pv. syringae were highly pathogenic when inoculated in the tester pea genotypes, and no significant pathogenic differences were observed. Simultaneous infections with P. syringae pv. pisi and pv. syringae in the same fields were observed, suggesting the importance of resistance to both pathovars in future commercial cultivars. The search for resistance among pea genotypes suitable for production in this part of Spain or as breeding material identified the presence of resistance genes for all P. syringae pv. pisi races except for race 6. The pea cultivars Kelvendon Wonder, Cherokee, Isard, Iceberg, Messire and Attika were found suitable sources of resistance to P. syringae pv. syringae.

A TaqMan real-time PCR assay targeting the cytochrome o ubiquinol oxidase subunit II gene for detection of several pathovars ofPseudomonas syringae

“…pisi as well as P. syringae pv. syringae were detected and identified at similar frequencies in infected Pea trees (Hollaway et al, 2007;Martín-Sanz et al, 2011). Also, P. syringae pv.…”

“…syringae and P. syringae pv. pisi on pea (Hollaway et al, 2007;Martín-Sanz et al, 2011) and P. syringae pv. syringae and P. syringae pv.…”

Comparative Efficacy of Different New Fungicides against Powdery Mildew Disease of Fieldpea (Pisum sativum L.)

“…Half of this production is used for livestock feed, and the remaining half for human consumption, mainly in developing countries (Martin-Sanz et al, 2011). In India, field pea occupies an area of 0.77 million hectare with a production 0.71 million tonnes and productivity 915 kg ha -1 (Singh, 2008).…”

“…The average yield in major pea growing countries viz., France (15.5 q ha -1 ), Hungary (15.5 q ha -1 ) and Netherland (14.3 q ha -1 ) (Anonymous, 2002), while in India, the average yield is 9.15 q ha -1 (Singh, 2008), the wide gap between the attainable yield potentials and farmers field are due to various biotic, abiotic and socio-economic factors. Despite the potential for pea crops in agriculture, they still face challenges due to competition from weeds, insect attack, disease incidence, instability of productivity and a lack of successful nodulation (Date, 2000;Lemerle et al, 2006;Martin-Sanz et al, 2011).…”

Genetic, biochemical and pathogenic diversity of Pseudomonas syringae pv. pisi strains

“…On the basis of the differential response of eight pea genotypes, seven pathogenic races (1–7) of Ppi were described (Bevan et al. , 1995), and a new race (race 8) was recently described by Martín‐Sanz et al. (2011).…”