Subcelullar localization of proteins associated with <Emphasis Type="Italic">Prune dwarf virus</Emphasis> replication

The fungus Colletotrichum lindemuthianum is the causal agent of anthracnose, one of the most severe diseases of the common bean (Phaseolus vulgaris). The infection process begins with the adhesion of conidia to the plant’s surface. Appressoria are then formed, allowing penetration of the fungus. Next, the biotrophic phase begins, followed by the necrotrophic phase. Due to the peculiar nutrition mode of the fungus, including both of the previously mentioned stages, it is of great interest to determine which genes are involved in the transition between the two phases during the infection process. To determine this, suppression subtractive hybridization (SSH) was used in association with qRT-PCR in the present study. These methods allowed for the identification of genes that were differentially expressed at each developmental stage of the fungus in the plant. This is the first report on the use of the cited techniques to evaluate the infectious cycle of the fungus. A total of 175 sequences exhibited significant identity (e?≤?10^?5) with sequences present in the sequenced genomes of P. vulgaris and C. lindemuthianum; approximately 41 % of those were determined to belong to the fungus, and 59 % were determined to belong to the plant. Of the predicted sequences, 68 % were of unknown function or were not found in the databases. Among the analyzed expressed sequence tags (ESTs), sequences were found that encode proteins related to: primary and secondary metabolism; the transport of different compounds; the degradation/modification of proteins; cell regulation and signaling; cellular stress response; and the degradation of exogenous compounds. The obtained results allowed for the identification of sequences encoding proteins that are essential for the progression of anthracnose. Furthermore, it was possible to identify new genes, the functions of which have not yet been described, and even to identify unique genes of C. lindemuthianum that are involved in the pathogenicity and virulence of this fungus.     

Effects of some integrated management options on parthenium interference in sorghum

Parthenium is widely distributed across the uncropped areas of the tropics. It has slowly encroached into many crops and causes considerable yield loss. It heavily infests sorghum, which is widely cultivated by the resource‐poor farmers in Africa and Asia. Its interference and management in sorghum in these cropping systems is not well understood. Therefore, this experiment was undertaken to determine the appropriate parthenium management techniques to use in sorghum crops. All the studied weeds, in combination with parthenium, offered greater competition to sorghum than parthenium alone. Similarly, under a composite stand of weeds, parthenium was inferior in competitiveness to the other weeds until 60 days after sowing (DAS); by 90 DAS, it could accumulate a higher dry weight due to its consistent growth. A pre‐emergence treatment of atrazine (0.75 kg ha^‐1) with wheat straw mulch (5.0 t ha^?1) brought about a consistent and significant reduction in the parthenium growth and, consequently, increased the sorghum yield by 90.8%. Cowpea intercropping with and without pendimethalin (1.0 kg ha^?1) as a pre‐emergence treatment could not control parthenium between 0 and 60 DAS, but could reduce the parthenium growth during the later period of 60–90 DAS, which resulted in a significant increase in sorghum growth. These intercropping treatments increased the sorghum grain yield by 156.2% and 142.4%, respectively, over the unweeded control and by 18.5% and 12.1%, respectively, over the weed‐free control. These treatments also promoted a higher uptake of N, P, and K by the sorghum crop. Thus, cowpea intercropping was the most effective method for parthenium management vis‐à‐vis sorghum yield improvement, followed by cowpea intercropping with pendimethalin and then by atrazine as a pre‐emergence treatment with wheat straw mulch.     

Collagen content and architecture of the pectoralis muscle in male chicks and broilers reared under various nutritional conditions

Varying chicken growth rates were induced with different nutritional regimes, and the collagen content and architecture of M. pectoralis (PT) were compared among 21‐day‐old chicks and broilers at 80 or 95 days of age. The percentage of muscle weight to live weight was higher in rapid growing chicks (8.4%) than slow growing chicks (6.3%). The 80‐day‐old broilers engaged in compensatory growth after the early slow growth period producing PT muscle at 11% of live weight. The 80‐ and 95‐day‐old chicks with restricted late growth after an early rapid growth period showed PT weight at 8% and 9% of live weight, respectively. Collagen content of the PT muscle markedly decreased from the chicks to the broilers. The collagen concentration was higher in the late‐growth restricted broilers (1.67–1.88 mg/g) than the compensatory growth broilers (1.01–1.10 mg/g). Collagen concentration did not differ between the rapid and slow growing chicks (2.72 and 2.94 mg/g). Scanning electron micrographs showed thick and thin perimysia, and honeycomb endomysia. In the perimysia, a stack layer of collagen platelets and a reticular layer of collagen fiber cords were distinguished and collagen baskets of adipocytes were observed. The perimysial collagen fibers became thicker during growth of the chicks to broilers. However, in the late‐growth restricted broilers, the perimysial collagen fibers seemed to have retarded development compared with the compensatory growth birds. The PT muscle of chickens develops optimally when body growth is enhanced. The PT muscle of the compensatory growth broilers had improved collagen architecture regardless of the marked decrease in collagen content.     

Effects of flood duration and season on germination of black,cherrybark, northern red,and water oak acorns

Effects of flood duration (0, 10, 20, and 30 days) and season (winter and spring) on acorn germination were tested for two upland oaks [black and northern red oak (Quercus velutina Lam. and Q. rubra L.)] and two bottomland oaks [cherrybark and water oak (Q. pagoda Raf. and Q. nigra L.)]. Acorns were stratified for 30 days before flooding at a depth of 15 cm along the edge of a small pond. After flooding, acorns were sowed in sand-filled plastic cups and germinated for 40 days. Flood duration and season strongly affected radicle and epicotyl emergence of the upland oaks, but effects were generally limited to spring flooding. Embryo axes of the upland oak acorns were severely damaged with as little as 10 days of spring flooding. Almost no epicotyls developed, but radicles developed from the connective tissues between embryo axes and the cotyledons of many acorns. Spring flooding also significantly increased the percentage of decayed acorns for the upland oaks. In contrast, germination of the bottomland oaks was slightly improved by flooding during both seasons. Results demonstrated that the effects of flooding on the distribution of species within bottomlands can begin with seed storage and germination.     

Status of Banana Streak Disease in Africa: Problems and Future Research Needs

Streak disease of banana and plantain caused by banana streak virus (BSV) was first reported in the Ivory Coast in 1974 and occurs in at least 16 countries in Africa. Based on genomic characteristics, BSV has been shown to be a member of genus Badnavirus. Efficient and reliable diagnostic methods for BSV have recently become widely available. This paper summarizes the current knowledge on its causal agent, geographical distribution, symptomatology, transmission, host range, available diagnostic techniques and management options for the disease in Africa. Further research needs are identified in light of the widespread occurrence of BSV in most plantain/banana germplasms and the difficulties in obtaining BSV-free plantlets through tissue culture.     

Northern prairie songbirds are more strongly influenced by grassland configuration than grassland amount

Context

The relative influence of habitat loss versus configuration on avian biodiversity is poorly understood. However, this knowledge is essential for developing effective land use strategies, especially for grassland songbirds, which have experienced widespread declines due to land use changes. Habitat configuration may be particularly important to grassland songbirds as configuration of habitat affects the extent of edge effects on the landscape, which strongly influences habitat use by grassland birds.

Objectives

We examined the relative influence of grassland amount and a measure of grassland configuration per se (Landscape Shape Index; LSI) on the relative abundance and richness of grassland songbirds.

Methods

In 2013, 361 avian point counts were conducted across 47, 2.4 km radii landscapes in south-west Manitoba, Canada, selected to minimize the correlation between grassland amount and configuration. We used generalized linear mixed-effects models within a multi-model inference framework to determine the relative importance of grassland amount and configuration on songbird response variables.

Results

Effects of grassland amount and configuration were generally weak, but effects of configuration were greater than grassland amount for most species. Relative abundance and richness of obligate species, and Savannah sparrows, showed a strong negative response to LSI, while grasshopper sparrows responded positively to grassland amount.

Conclusion

Our results suggest that habitat configuration must be considered when managing landscapes for conservation of grassland songbirds. Maintaining large, intact tracts of grasslands and limiting development of roads that bisect grassland parcels may be an effective means of maintaining grassland songbird diversity and abundance in northern mixed-grass prairies.

     

Metapopulation dynamics and determinants of H5N1 highly pathogenic avian influenza outbreaks in Indonesian poultry

In 2008, the Indonesian Government implemented a revised village-level Participatory Disease Surveillance and Response (PDSR) program to gain a better understanding of both the magnitude and spatial distribution of H5N1 highly pathogenic avian influenza (HPAI) outbreaks in backyard poultry. To date, there has been considerable collection of data, but limited publically available analysis. This study utilizes data collected by the PDSR program between April 2008 and September 2010 for Java, Bali and the Lampung Province of Sumatra. The analysis employs hierarchical Bayesian occurrence models to quantify spatial and temporal dynamics in backyard HPAI infection reports at the District level in 90 day time periods, and relates the probability of HPAI occurrence to PDSR-reported village HPAI infection status and human and poultry density. The probability of infection in a District was assumed to be dependent on the status of the District in the previous 90 day time period, and described by either a colonization probability (the probability of HPAI infection in a District given there had not been infection in the previous 90 day time period) or a persistence probability (the probability of HPAI infection being maintained in the District from the previous to current 90 day period). Results suggest that the number of surveillance activities in a district had little relationship to outbreak occurrence probabilities, but human and poultry densities were found to have non-linear relationships to outbreak occurrence probabilities. We found significant spatial dependency among neighboring districts, indicating that there are latent spatial processes that are not captured by the covariates available for this study, but which nonetheless impact outbreak dynamics. The results of this work may help improve understanding of the seasonal nature of H5N1 in poultry and the potential role of poultry density in enabling endemicity to occur, as well as to assist the Government of Indonesia target scarce resources to regions and time periods when outbreaks of HPAI in poultry are most likely to occur.     

Distribution and prevalence of Cytauxzoon felis in bobcats (Lynx rufus), the natural reservoir, and other wild felids in thirteen states

Cytauxzoon felis, a protozoan parasite of wild and domestic felids, is the causative agent of cytauxzoonosis in domestic and some exotic felids in the United States. The bobcat (Lynx rufus) is the natural reservoir for this parasite, but other felids such as Florida panthers (Puma concolor coryii) and domestic cats may maintain long-term parasitemias and serve as reservoirs. Experimentally, two tick species, Dermacentor variabilis and Amblyomma americanum, have demonstrated the ability to transmit C. felis. These two tick species have overlapping distributions throughout much of the southeastern United States. The objective of the current study was to determine the distribution and prevalence of C. felis in free-ranging bobcat populations from 13 states including California, Colorado, Florida, Georgia, Kansas, Kentucky, Missouri, North Carolina, North Dakota, Ohio, Oklahoma, South Carolina, and West Virginia. These states were selected because of differential vector presence; D. variabilis is present in each of these states except for the region of Colorado sampled and A. americanum is currently known to be present only in a subset of these states. Blood or spleen samples from 696 bobcats were tested for C. felis infection by a polymerase chain reaction (PCR) assay which targeted the first ribosomal internal transcribed spacer region (ITS-1). Significantly higher prevalences of C. felis were detected from Missouri (79%, n=39), North Carolina (63%, n=8), Oklahoma (60%, n=20), South Carolina (57%, n=7), Kentucky (55%, n=74), Florida (44%, n=45), and Kansas (27%, n=41) compared with Georgia (9%, n=159), North Dakota (2.4%, n=124), Ohio (0%, n=19), West Virginia (0%, n=37), California (0%, n=26), and Colorado (0%, n=67). In addition to bobcats, seven cougars (Puma concolor) from Georgia, Louisiana, and North Dakota and one serval (Leptailurus serval) from Louisiana were tested for C. felis. Only one cougar from Louisiana was PCR positive, which represents the first report of an infected cougar outside of the Florida panther population. These data also indicate that C. felis is present in North Dakota where infection has not been reported in domestic cats. Based on a nonparametric analysis, prevalence rates were significantly higher in states where there are established populations of A. americanum, which supports recent data on the experimental transmission of C. felis by A. americanum and the fact that domestic cat clinical cases are temporally associated with A. americanum activity. Collectively, these data confirm that bobcats are a common reservoir for C. felis and that A. americanum is likely an epidemiologically important vector.     

Articulating beneficial rhizobacteria-mediated plant defenses through induced systemic resistance: A review

Induced systemic resistance (ISR) is a mechanism by which certain plant beneficial rhizobacteria and fungi produce immunity, which can stimulate crop growth and resilience against various phytopathogens, insects, and parasites. These beneficial rhizobacteria and fungi improve plant performance by regulating hormone signaling, including salicylic acid (SA), jasmonic acid (JA), prosystemin, pathogenesis-related gene 1, and ethylene (ET) pathways,which activate the gene expression of ISR, the synth...