Response to Fungicides of Colletotrichum spp. Isolated from Red Peppers in Sunchang, Korea

In August 2020, 377 anthracnose strains were isolated from anthracnose-infected peppers collected from 25 farms in Sunchang-gun, Jeollabuk-do. Inhibition rate of mycelial growth of 11 pepper anthracnose fungicides registered in Korea was investigated for 62 strains selected by region and the degree of susceptibility to each fungicide was investigated. As a result of the fungicide susceptibility test of anthracnose to the fungicide, no resistant strains were observed in fluazinam, prochloraz manganese, and benomyl, but resistant strains appeared in at least three areas for other fungicides, and all strains in all regions were resistant to dithianon. Through this, it was confirmed that the fungicide resistance was expressed in the strain group due to the continuous treatment of the fungicide in some areas. By region, resistant strains to seven pesticides appeared in Sunchang-eup and Paldeok-myeon, and resistant strains to six pesticides appeared in Geumgwa-myeon, Bokheung-myeon, Ssangchi-myeon, Yudeung-myeon, and Pungsan-myeon. There was no significant correlation between fungicide registration time and emergence of resistant strains.

Potato virus Y biological strain group YD: hypersensitive resistance genes elicited and phylogenetic placement

Potato virus Y (PVY) disrupts healthy seed potato production and causes tuber yield and quality losses globally. Its subdivisions consist of strain groups defined by potato hypersensitive resistance (HR) genes and phylogroups defined by sequencing. When PVY isolate PP was inoculated to potato cultivar differentials with HR genes, the HR phenotype pattern obtained resembled that caused by strain group PVYD isolate KIP1. A complete genome of isolate PP was obtained by high throughput sequencing. After removal of its short terminal recombinant segment, it was subjected to phylogenetic analysis together with 30 complete non-recombinant PVY genomes. It fitted within the same minor phylogroup PVYO3 sub-clade as KIP1. Putative HR gene Nd was proposed previously to explain the unique HR phenotype pattern that developed when differentials were inoculated with PVYD. However, an alternative explanation was that PVYD elicits HR, with HR genes Nc and Ny instead. To establish which gene(s) it elicits, isolates KIP1 and PP were inoculated to F1 potato seedlings from: (i) crossing Kipfler and White Rose with Ruby Lou, and (ii) self-pollinated Desiree and Ruby Lou; where Kipfler is susceptible (S) but White Rose, Desiree and Ruby Lou develop HR. With both isolates, the HR:S segregation ratios obtained fitted 5:1 for Kipfler x Ruby Lou, 11:1 for White Rose x Ruby Lou, and 3:1 for Desiree. Those for Ruby Lou were 68:1 (isolate PP) and 52:0 (isolate KIP1). Since potato is tetraploid, these ratios suggest PVYD elicits HR with Ny from Ruby Lou (duplex condition) and Desiree (simplex condition), and Nc from White Rose (simplex condition), but provide no evidence that Nd exists. Therefore, our differential cultivar inoculations and inheritance studies highlight that PVYD isolates elicit an HR phenotype in potato cultivars with either of two HR genes, Nc or Ny, so putative gene Nd can be discounted. Moreover, phylogenetic analysis placed the complete genome of isolate PP within the same minor phylogroup PVYO3 sub-clade as KIP1 which constitutes the most basal divergence within overall major phylogroup PVYO.

Comparison of two attenuated infectious bursal disease vaccine strains focused on safety and antibody response in commercial broilers

Background and Aim: Infectious bursal disease (IBD) or Gumboro disease is one of the most detrimental diseases in the poultry industry worldwide. Previous scientific studies have shown that live IBD vaccination might induce transient immunosuppression, leading to suboptimal vaccine responses, and therefore lack of protection against other infectious diseases; therefore, selecting an IBD vaccine in commercial farms is a concern. This study aims to compare two commercially attenuated IBD vaccines (intermediate and intermediate-plus strains) in terms of safety and antibody response to IBD and Newcastle disease viruses (NDV) in commercial broilers. Materials and Methods: Overall, 216 Cobb broiler chickens were divided into three groups based on the IBD vaccine strain administered: V217 strain (Group 1), M.B. strain (Group 2), and an unvaccinated group (Group 3). Groups 1 and 2 were orally vaccinated with Hitchner B1 NDV vaccine strain 7 days after IBD vaccination. Blood samples were collected at IBD vaccination day (15 days of age) and at 7, 14, 21, and 28 days post-IBD vaccination. The immunosuppressive effects of the IBD vaccination were determined by NDV antibody response, the bursa:body weight (B:BW) ratio, and the histopathological lesion scores of the bursa of Fabricius. Phylogenetic analysis was also performed. Results: Phylogenetic analysis revealed that the M.B. strain belonged to a very virulent IBD strain, whereas the V217 strain belonged to a classical IBD virus strain. NDV antibody titers of the two vaccinated groups increased after ND vaccination, reaching their maximum at 14 days post-ND vaccination and decreasing thereafter. The V217 group presented the highest NDV humoral response from 7 days post-vaccination (dpv) to the end of the study. The mean NDV antibody titer of the V217 group was significantly (p<0.05) higher than that of the M.B. group at 14 dpv. In addition, the V217 strain-induced lower bursal lesions post-IBD vaccination and a higher B:BW ratio at 7 and 21 dpv compared to the M.B. group. The higher B:BW ratio, lower bursal lesions, and higher ND antibody response present in the V217 group indicate that the V217 strain induces lower immunosuppressive effects compared to the M.B. strain. Conclusion: The results of this study indicate that IBD vaccine selection merits consideration, as avoiding the immunosuppressive effects induced by live IBD vaccination and the consequent impact on response to other vaccines is important.

Genetic Diversity of Potato virus Y in Potato Production Areas in Northeast China

In 2011–2014, ELISA or nucleic acid spot hybridization (NASH) testing for common potato viruses or Potato spindle tuber viroid (PSTVd) was performed on 500 leaf samples collected in potato fields in the northeast provinces Heilongjiang and Inner Mongolia, China. The results revealed that 38.4% (Heilongjiang) and 27.7% (Inner Mongolia) were positive for Potato virus Y (PVY). To unveil the strain composition and population structure of PVY in the region, the multiplex RT-PCR described by Chikh-Ali et al. was performed on all of the ELISA-PVY-positive samples. Of the 158 samples whose PVY strain scenarios could be determined, PVYNTN-NW-SYR-II and PVYN-Wi were the most abundant strains, occurring in 58.9 and 47.5% samples, followed by PVYNTN-NW-SYR-I (31.0%), PVYN:O (19.6%), Eu-PVYNTN (7.6%), NA-PVYN (1.3%), and PVYO (0.6%). In the 84 single-strain-infected samples, PVYN-Wi accounted for 41.7%, PVYNTN-NW-SYR-II for 40.5%, PVYNTN-NW-SYR-I for 14.3%, and PVYN:O and Eu-PVYNTN for 3.6% each. Seven isolates representing PVYNTN-NW-SYR-I (HLJ-6-1 and HLJ-9-4), PVYNTN-NW-SYR-II (INM-W-369-12 and SC-1-1-2), PVYN:O (HLJ-30-2), and PVYN-Wi (HLJ-BDH-2 and HLJ-C-429) were sequenced and analyzed molecularly. Whereas the sequence identities for isolates belonging to the same strain group were >98.5%, they fell for isolates belonging to different strain groups to 92.7–98.1% at the genome level and 96.1–98.4% at the polyprotein level. Interestingly, the exact location of the recombination events varied among isolates within a strain group. Phylogenetic analysis of all 42 full length PVY sequences from China indicated that most clustered to various recombinant groups, despite the fact that the PVY isolates were isolated from at least five host species. Pathological analysis of four isolates representing PVYN:O, PVYN-Wi, PVYNTN-NW-SYR-I, and PVYNTN-NW-SYR-II revealed that the PVYNTN-NW-SYR-II isolate incited the most severe symptoms on potato cultivar Kexin 13, followed by PVYNTN-NW-SYR-I, PVYN:O and PVYN-Wi. The PVYNTN-NW-SYR-I and PVYNTN-NW-SYR-II isolates also caused necrotic ringspots on the tubers of Kexin 13, indicating their ability to induce the potato tuber necrotic ringspot disease in potato.

Genetic Determinants of Potato virus Y Required to Overcome or Trigger Hypersensitive Resistance to PVY Strain Group O Controlled by the Gene Ny in Potato

Potato virus Y (PVY) (genus Potyvirus) is the most economically damaging and widely distributed virus in potato. Spread of PVY in the field is controlled by growing resistant cultivars. The dominant potato gene Nytbr for hypersensitive resistance (HR) controls ordinary PVY strains (PVYO) but is overcome by PVYN strains. Studies with infectious PVY chimeras and mutants indicated that the viral determinants necessary and sufficient to overcome Nytbr reside within the helper component proteinase (HC-Pro) (residues 227 to 327). Specifically, eight residues and the modeled three-dimensional conformation of this HC-Pro region distinguish PVYN from PVYO strains. According to the model, the conserved IGN and CCCT motifs implicated in potyvirus replication and movement, respectively, are situated in a coiled structure and an α-helix, respectively, within this region in PVYO; however, their locations are reversed in PVYN. Two residues (R269 and K270) are crucial for the predicted PVYO-specific HC-Pro conformation. Two viral chimeras triggered Nytbr and induced veinal necrosis in tobacco, which is novel for PVY. One chimera belonged to strain group PVYE. Our results suggest a structure–function relationship in recognition of PVYO HC-Pro by Nytbr, reveal HC-Pro amino acid signatures specific to PVYO and PVYN, and facilitate identification of PVY strains overcoming Nytbr.

Performance and Economic Suitability of Three Fast Growing Broiler Strains Raised Under Farming Condition in Bangladesh

The performance and profitability of three commercial broiler strains reared under farming system were investigated in this study. Day-old broiler chicks (n=156) of three different commercial strains (Hubbard classic, Cobb-500 and MPK) were assigned to three treatment groups in a completely randomized block design, each treatment replicated four times, 13 birds per replicate. The birds were reared from d1 to 35 days of age with similar housing, feeding and environmental management condition. Regarding to all parameters collected, live weight and body weight gain were higher (P<0.001) in T2(Cobb-500) group, while the birds of T3 (MPK) group were the lowest. Birds of T1(Hubbard Classic) and T2 (Cobb-500) strain group consumed higher (P<0.001) feeds, while the birds of T3(MPK) had the lowest feed intake. Cobb-500 broiler strain achieved superior (P<0.001) FCR, while the birds of T1 (Hubbard classic) strain group had poorer FCR. Liveability of the broiler strains was unaffected by all the treatment groups. Higher net profit and lower production cost observed in T2(Cobb-500) group than those of other strains, although the difference between the treatment groups was similar. The highly significant measurements of live body weight, weight gain and better FCR values were recorded for Cobb-500 broiler strain, followed by Hubbard classic and MPK, respectively. In conclusion, Cobb-500 broiler strain is appeared to be the most economic to rear amongst the three broiler strains investigated here in response to their performance records. DOI: http://dx.doi.org/10.3329/ijarit.v1i1-2.13931 Int. J. Agril. Res. Innov. & Tech. 1 (1&2): 37-43, December, 2011

Efficacy of High-dose Nebulized Colistin in Ventilator-associated Pneumonia Caused by Multidrug-resistant Pseudomonas aeruginosa and Acinetobacter baumannii

Background Colistin often remains the only active agent against multidrug-resistant Gram-negative pathogens. The aim of the study was to assess efficacy of nebulized colistin for treating ventilator-associated pneumonia (VAP) caused by multidrug-resistant Pseudomonas aeruginosa and Acinetobacter baumannii. Methods One hundred and sixty-five patients with VAP caused by P. aeruginosa and A. baumannii were enrolled in a prospective, observational, and comparative study. The sensitive strain group included 122 patients with VAP caused by P. aeruginosa and A. baumannii susceptible to β-lactams, aminoglycosides, or quinolones and treated with intravenous antibiotics for 14 days. The multidrug-resistant strain group included 43 patients with VAP caused by multidrug-resistant P. aeruginosa and A. baumannii and treated with nebulized colistin (5 million international units every 8 h) either in monotherapy (n=28) or combined to a 3-day intravenous aminoglycosides for 7-19 days. The primary endpoint was clinical cure rate. Aerosol was delivered using vibrating plate nebulizer. Results After treatment, clinical cure rate was 66% in sensitive strain group and 67% in multidrug-resistant strain group (difference -1%, lower limit of 95% CI for difference -12.6%). Mortality was not different between groups (23 vs. 16%). Among 16 patients with persisting or recurrent P. aeruginosa infection, colistin minimum inhibitory concentration increased in two patients. Conclusion Nebulization of high-dose colistin was effective to treat VAP caused by multidrug-resistant P. aeruginosa or A. baumannii. Its therapeutic effect was noninferior to intravenous β-lactams associated with aminoglycosides or quinolones for treating VAP caused by susceptible P. aeruginosa and A. baumannii.

Molecular and Serological Typing of Potato virus Y Isolates from Brazil Reveals a Diverse Set of Recombinant Strains

In Brazil, Potato virus Y (PVY) currently presents a significant problem for potato production, reducing tuber yield and quality. Recombinant tuber necrotic isolates of PVY had been reported to occur in the country but no systematic study of the PVY isolate diversity was conducted thus far. Here, a panel of 36 PVY isolates, randomly collected in Brazil from potato between 1985 and 2009, was subjected to a systematic molecular and serological typing using reverse-transcription polymerase chain reaction and a series of PVYO- and PVYN-specific monoclonal antibodies. The data collected were combined with biological characterization of the same isolates in tobacco. Of the 36 isolates tested, 3 were typed as PVYO, 10 as PVYN:O/N-Wi, 21 as PVYNTN, and 2 as “unusual” or inconclusive. Of the 10 isolates from the recombinant PVYN:O/N-Wi strain group, 1 isolate, MAF-VOY, was found to have an unusual serological profile identical to the nonrecombinant PVYO-O5 strain group. The 21 tested PVYNTN isolates included 1 isolate that did not induce vein necrosis in tobacco and 2 isolates with an unusual serological profile (i.e., displaying negative reactivity to one commercial PVYN-specific monoclonal antibody). Whole genome sequences were determined for four PVY isolates from Brazil, representing PVYO, PVYNTN, and PVYN-Wi strains. The genome of the MAF-VOY isolate was found to be recombinant, having characteristic N-Wi structure with two recombinant junctions and carrying a single mutation in the capsid protein at position 98, which led to an unusual O5 serological reactivity. Taken together, the data obtained suggest that the two recombinant strains, PVYNTN and PVYN:O/N-Wi, now are apparently dominant in the Brazilian potato crop. The data also suggest that recombinant isolates in Brazil often have unusual serological reactivity which may hamper their correct identification by conventional typing based on enzyme-linked immunosorbent assay.