To examine if the toxins produced by Pss22d are responsible for antagonistic effects in planta, the pathogen Psg was co-inoculated with either Pss22d wild-type, a syringopeptin/syringomycin-negative double mutant (Pss22d.ΔsypA/syrE), or a MeArg-negative mutant (Pss22d.1) into wounds of pin-pricked leaves of greenhouse-grown soybean plants, respectively. In all three cases, the wild-type Pss22d and its toxin-deficient mutants prevented development of disease symptoms normally caused by Psg. These results indicated that neither syringopeptin, nor syringomycin, nor MeArg
was required for Pss22d’s antagonistic activity in planta. Consequently, factors other than the three toxins may contribute PLX3397 supplier to the intra-species antagonism in planta. “
“Weeds are alternative hosts of plant pathogens and when colonized may not exhibit disease symptoms. In 2008 and 2009, samples of weeds and plant debris were collected from 12 locations in eastern Croatia,
and 300 Fusarium isolates colonizing them were identified. Strains were grouped and identified based on morphology and amplified fragment length polymorphism (AFLP) patterns. VX-809 research buy Portions of the β-tubulin and translocation elongation factor 1-α genes were sequenced from representative strains of each group to confirm the identifications. Fourteen Fusarium species were identified with F. graminearum (20%), F. verticillioides (18%), F. oxysporum (16%), F. subglutinans (13%) and F. proliferatum (11%) all present as more than 10% of the population. Fusarium acuminatum, F. avenaceum, F. concolor, F. crookwellense (F. cerealis), F. equiseti, F. semitectum, F. solani, F. sporotrichioides and F. venenatum, were all present at frequencies < 8%. Our results indicate FER that economically important Fusarium spp. may be isolated from numerous alternative hosts during the off season and that weeds and plant debris can serve as a reservoir of genetically diverse inoculum. “
“Rapid and accurate polymerase chain reaction (PCR) and real-time PCR methods were developed for the detection of Colletotrichum lagenarium,
the causal agent of anthracnose, in tissues of squash (Cucurbita moschata), watermelon (Citrullus lanatus), cucumber (Cucumis sativus) and muskmelon (Cucumis melo). PCR assays amplified different internal transcribed spacer sequences from C. lagenarium, so effectively detected this pathogen in infected tissues. PCR analysis with the primer co-m-337F1/R1 was able to differentiate C. lagenarium from other fungal pathogens, including Colletotrichum spp., Fusarium spp., Alternaria spp. and Didymella spp. An optimized real-time PCR assay was developed to detect and monitor C. lagenarium in both infected plant tissues and soil samples. The sensitivity of real-time PCR can detect down to 1 pg of DNA. Thus, PCR-based analysis is a useful technique for rapid detection and diagnosis of C. lagenarium in infected plants or infested soils.