PLPKI: A novel serine protease inhibitor as a potential biochemical marker involved in horizontal resistance to Phytophthora infestans

Potato leaves infected with Phytophthora infestans produced a serine protease inhibitor (PLPKI) with specificity for microbial proteases. Sequencing of the first twenty residues at the NH₂‐terminus of the mature PLPKI polypeptide demonstrated that PLPKI is a novel member of the potato protease inhibitor I family. PLPKI inhibited the activity of extracellular proteases produced by two pathogens of potato, P. infestans and Rhizoctonia solani, but was inactive against proteases secreted into the culture media by the binucleate Rhizoctonia N2, a non‐pathogenic fungus for potato. Western blot analysis showed a positive correlation between the levels of PLPKI and the degree of horizontal resistance, showing its highest accumulation in clone OKA 5632.11, which has been described as highly resistant. This correlation, together with the ability of PLPKI to completely abolish the secreted serine protease activity of P. infestans, suggests that PLPKI may have an active role in protecting potato plants from this pathogenic oomycete and that it could be used as a suitable biochemical marker to help breeders in the selection of cultivars with high degree of horizontal resistance.     

Analysis of the biodiversity of hawthorn (<Emphasis Type="Italic">Crataegus</Emphasis> spp.) from the morphological,molecular, and ethnobotanical approaches,and implications for genetic resource conservation in scenery of increasing cultivation: the case of Mexico

One hundred and forty Mexican hawthorn (Crataegus spp.) accessions from six regions are preserved at the BGT-UACH germplasm bank (Mexico), comprising the most comprehensive living collection of Mexican hawthorns with different degrees of human management. The objective of this study was to assess the biodiversity of this valuable collection from morphological, molecular (microsatellite), and ethnobotanical viewpoints in order to delineate the most adequate strategy for the conservation of the native hawthorn germplasm in the present scenario of incipient establishment of commercial hawthorn plantations, which is likely to increase. Molecular characterisation revealed that the biodiversity was chiefly (90%) placed within the regions. Morphological characterisation indicated that the group from Chiapas was the most different germplasm pool compared with the other five. This was confirmed by molecular analysis, because in spite of the lack of a phylogeographical pattern, two germplasm pools were detected: one composed mainly by accessions from Chiapas and the other mainly by accessions from the other regions. The only clear differences among the regions in the ethnobotanical study were those derived from putting hawthorns into commercial cultivation, which occurred in just one region in the centre of the country (Mexico–Puebla–Tlaxcala). As a consequence, an ex situ conservation programme is necessary for those regions shifting patterns of cultivation from traditional to commercial, regardless of whether other on-farm programmes are also implemented. The germplasm collections within each region must be exhaustive due to their high genetic diversity.     

Detection and genetic characterization of Pasteurella multocida from alpaca (Vicugna pacos) pneumonia cases

Tropical Animal Health and Production - Pasteurella multocida is a common constituent of upper respiratory tract microbiota but is frequently isolated of alpaca lung tissues from pulmonary...     

Manufacture of Biquara (Haemulon Plumierii - Lacepède, 1801) Fishburger with Addition of Wheat Bran

Biquara is one of the main fish species caught in the northeast coast of Brazil but presents low commercial value. Therefore, the elaboration of biquara-based products with the addition of plant bran as a source of dietary fiber should be studied as a way to add value to biquara. The objective of the present study was to evaluate the physicochemical, microbiological, and sensory aspects of fishburgers made with biquara fillet with the addition of wheat bran (WB) (0, 1, 2, and 3%). The increase in WB decreased moisture and increased protein levels, ash, fiber, carbohydrates, and energy value. In addition, the inclusion of WB increased the cooking shrinkage and decreased hardness and cohesiveness of the samples. The fishburgers with the greatest WB levels presented a reddish-yellow hue. The microbial counts of the products were below the maximum limit allowed by the Brazilian legislation. The overall acceptance of the fishburgers improved with the addition of 0 to 2% WB. Therefore, the biquara fillets have a potential for the elaboration of fishburgers with the addition of 2% WB, once the products presented suitable physicochemical composition, sensory acceptance, and hygienic sanitary control according to the current national legislation.     

Nutrients return from leaves and litterfall in a mediterranean cork oak (<Emphasis Type="Italic">Quercus suber</Emphasis> L.) forest in southwestern Spain

The knowledge of the cycle of nutrients is fundamental for the correct comprehension of the tree–soil relationship and for an adequate forest management. In order to analyse the nutrients return from leaves and litterfall in a Mediterranean cork oak forest in southwestern Spain, 12 trees were randomly selected and litterfall collected for 2 years. Samples were taken monthly and separated in different fractions (leaves, twigs, catkins, acorns and miscellaneous), then leaves nutrients were analyzed. Simultaneously, we analyzed the nutrient content of living leaves from the same trees in each season during 1 year. The analyzed nutrients were C, N, P, K, Ca, Mg, Fe, Mn, S, Cu, Zn and Mo. Annual patterns of each nutrient in fallen leaves were characterized and compared with seasonal values of these nutrients in living leaves. Leaves fall has two annual maximum, first and most important in spring around April coinciding with renewal of foliar cover and second around October. Main concentration patterns of N, P and K are related with phenological patterns, in consequence minimum concentration in leaves fall were obtained in periods of growing and maximum litterfall. Concentrations of Ca, Fe and Mn increase with the age of the leaves and maximum concentrations were obtained before periods of maximum litterfall while concentrations of Cu, Mo and Mg stay stable. Seasonal analysis of nutrients in living leaves collected from the same trees in four different periods of the year allowed to corroborate the patterns of leaves fall and the probable osmotic function of K.     

Molecular characterization of the VP1 gene of a Mexican isolate of infectious pancreatic necrosis virus

The presence of infectious pancreatic necrosis virus (IPNV) in salmonids predominantly produces a high mortality rate in first-feeding fry. Genomic analysis of the vp2 gene sequence is most commonly used to determine the genetic diversity of IPNV isolates. Recently, information obtained from the vp1 gene allowed for efficient analysis of the genetic diversity of IPNV. In this study, the vp1 gene from a Mexican IPNV isolate was characterized and compared with IPNV isolates from Europe, North America, and Asia. The results indicate that the Mexican isolate is most closely related genetically to the 2310 strain from Spain.     

Azospirillum inoculation and nitrogen fertilization effect on grain yield and on the diversity of endophytic bacteria in the phyllosphere of rice rainfed crop

We assessed the Azospirillum inoculation and N-fertilization effect on grain yield and on the phyllosphere endophytic diversity of nitrogen-fixing bacteria in a rice rainfed crop. We used cultivation-based techniques and cultivation-independent methods involving PCR-16S rRNA and denaturing gradient gel electrophoresis (DGGE). In general, we observed that grain yield was improved when inoculated with Azospirillum (depending on the genotype) and/or fertilized with urea. A similar behavior was observed in total N-content in grain and the MPN determination, as the highest values occurred when seeds were inoculated with A. brasilense REC3 (S1) than with A brasilense 13-2C (S2). A positive nitrogenase activity and PCR-nifH amplification suggests that the bacteria associated to inner tissues of rice phyllosphere could have contributed to the different N-contents detected. The bacterial diversity, observed in the number and intensity of DGGE profiles, showed a higher number of bands when total DNA was obtained using only CTAB than with CTAB + PVP. The DGGE profiles revealed great stability in the dominating bands, which presumably represent numerically dominant species. Application of A. brasilense strains as inoculants did not influence the dominant members of the endophytic microbial communities in the phyllosphere, but improved N-content and production of rainfed rice crop.