Genome-enabled biotechnologies have the potential to accelerate breeding efforts in long-lived perennial crop species. Despite the transformative potential of molecular tools in pecan and other ...outcrossing tree species, highly heterozygous genomes, significant presence-absence gene content variation, and histories of interspecific hybridization have constrained breeding efforts. To overcome these challenges, here, we present diploid genome assemblies and annotations of four outbred pecan genotypes, including a PacBio HiFi chromosome-scale assembly of both haplotypes of the 'Pawnee' cultivar. Comparative analysis and pan-genome integration reveal substantial and likely adaptive interspecific genomic introgressions, including an over-retained haplotype introgressed from bitternut hickory into pecan breeding pedigrees. Further, by leveraging our pan-genome presence-absence and functional annotation database among genomes and within the two outbred haplotypes of the 'Lakota' genome, we identify candidate genes for pest and pathogen resistance. Combined, these analyses and resources highlight significant progress towards functional and quantitative genomics in highly diverse and outbred crops.
Pecan bacterial leaf scorch, caused by
subsp.
, is an economically significant disease of pecan with known detrimental effects on the yield of susceptible cultivars. In this study, endosperm was ...harvested from developing pecan seeds, and direct qPCR and sequencing were used to detect and confirm the presence of
. DNA was isolated from mature seeds originating from seven trees, revealing a positivity rate up to 90%, and transmission of
from infected seed to the germinated seedlings was found to be over 80%. Further epidemiological analyses were performed to determine where
localizes in mature seed and seedlings. The highest concentrations of
DNA were found in the hilum and outer integument of the seeds and the petioles, respectively. High-, medium-, and low-density seeds were harvested to determine the impact of the bacterium on seed density and seedling growth rate. The growth rate of seedlings originating from low-density seeds was significantly reduced compared to the medium- and high-density seeds. Despite the increased growth and germination rates, the high-density seed group had a greater proportion of samples that tested positive for the presence of
by qPCR. The results demonstrate the ability of
to colonize developing seeds and be efficiently transmitted from well-developed seeds to germinated seedlings. Continued research is needed to understand the plant-microbe interactions involved in the colonization of pecan seeds by
and to develop effective phytosanitary approaches to reduce the risks posed by seed transmission.
Abstract
Background
The clinical findings among children with postnatally acquired Zika virus disease are not well characterized. We describe and compare clinical signs and symptoms for children aged ...<18 years.
Methods
Zika virus disease cases were included if they met the national surveillance case definition, had illness onset in 2016 or 2017, resided in a participating state, and were reported to the Centers for Disease Control and Prevention. Pediatric cases were aged <18 years; congenital and perinatal infections were excluded. Pediatric cases were matched to adult cases (18‒49 years). Clinical information was compared between younger and older pediatric cases and between children and adults.
Results
A total of 141 pediatric Zika virus disease cases were identified; none experienced neurologic disease. Overall, 28 (20%) were treated in an emergency department, 1 (<1%) was hospitalized; none died. Of the 4 primary clinical signs and symptoms associated with Zika virus disease, 133 (94%) children had rash, 104 (74%) fever, 67 (48%) arthralgia, and 51 (36%) conjunctivitis. Fever, arthralgia, and myalgia were more common in older children (12‒17 years) than younger children (1‒11 years). Arthralgia, arthritis, edema, and myalgia were more common in adults compared to children.
Conclusions
This report supports previous findings that Zika virus disease is generally mild in children. The most common symptoms are similar to other childhood infections, and clinical findings and outcomes are similar to those in adults. Healthcare providers should consider a diagnosis of Zika virus infection in children with fever, rash, arthralgia, or conjunctivitis, who reside in or have traveled to an area where Zika virus transmission is occurring.
Zika virus disease in children is generally mild, and severe illnesses are unusual. The symptoms frequently reported among children with Zika virus disease are common to many childhood illnesses and are not notably different than those experienced by adults.
(Wangenh.) K.Koch production has expanded beyond the native distribution as the genetic diversity of the species, in part, has allowed the trees to grow under broad geographic and climatic ranges. ...Research in other plant species has demonstrated that the phytobiome enhances their ability to survive and thrive in specific environments and, conversely, is influenced by the prevailing environment and plant genetics, among other factors. We sought to analyze the microbiota of pecan seedlings from the controlled cross 'Lakota' × 'Oaxaca' that were made in Georgia and Texas, respectively, to determine if the maternal geographical origin influences the microbiome of the resulting progeny. No significant differences in bacterial communities were observed between the seeds obtained from the two different states (
= 0.081). However, seed origin did induce significant differences in leaf fungal composition (
= 0.012). Results suggest that, in addition to some environmental, epigenetics, or host genetic components, ecological processes, such as dispersal mechanisms of the host, differentially impact the pecan microbiome, which may have ramifications for the health of trees grown in different environments. Future studies on the role of the microbiome in plant health and productivity will aid in the development of sustainable agriculture for improved food security.
We report a fatal case of Lassa fever diagnosed in the United States in a Liberian traveler. We describe infection control protocols and public health response. One contact at high risk became ...symptomatic, but her samples tested negative for Lassa virus; no secondary cases occurred among health care, family, and community contacts.
Carya illinoinensis (pecan) trees are recognized as the largest hickory native to North America with the ability to grow under broad climatic and environmental conditions. Pecan production is on the ...rise and expanding worldwide. Thus, it is important to understand the influence that plant microbiomes and genetics have on plant adaptation to both abiotic and biotic stressors. The plant microbiome (composed of bacteria, fungi, and viruses) is a key player in the status of plant health and productivity. By elucidating the microbiome of pecan trees, pecan tree health and overall production may benefit in the future. In the studies presented here, we analyzed the microbiome of Carya illinoinensis (pecan) seedlings and the influence that deficit watering has on micropropagated pecan trees and their associated fungal communities.We analyzed the microbiome of pecan seedlings grown in controlled conditions in a quarantine greenhouse by comparing the microbial communities present in each tissue type (leaves, stems, and roots). As expected, findings revealed significant differences in bacterial and fungal communities between each tissue type. Alpha diversity was observed to increase from leaves, stems, to roots. Further studies analyzing the microbial composition of seedling from five different maternal genotypes indicated a core microbiome within pecan seedings. Significant differences in bacterial and fungal communities were also observed between the seedlings from each maternal genotype indicating a signature core microbiome per genotype. Further studies analyzing the influence that maternal orchard location has on the resulting seeds-to-seedlings, revealed no significant differences in bacterial communities between seedlings from a controlled cross located in two states. However, significant differences in fungal beta diversity were observed, presenting the possible carry over microbes from maternal location to offspring.Additional studies investigating the effects of drought stress on micropropagated pecan trees, revealed significant differences in fungal communities present between fully and 60% deficit watered trees. Conversely, a lack of differences was observed between the control and treated groups when the trees were slowly acclimated to water deficit treatment (from 70% to 60% of water). Pecan trees gradually exposed to water deficit treatment, exhibited acclimation as observed through their growth and other photosynthesis parameters measured. This study presents the foundational information for further study of pecan tree microbiomes.
Carya illinoinensis
(pecan) produce a high valued and desired nut crop; with production expanding worldwide. Important attributes of pecans and their ability to adapt to different environments aside ...from their native regions are currently being investigated. Microbial communities are known to play an important role in crop productivity and overall plant health. Studies in other plant species have shown that the plant microbiome may be influenced by both the environmental conditions and genetics of the plant. Microbiota research in pecan is in its early stages and here we report insights into the core microbiome of seedlings derived from five pecan cultivars located in an orchard from Las Cruces, New Mexico. Seeds from open-pollinated pecan cultivars (‘Burkett’, ‘Mandan’, ‘Pawnee’, ‘Western’, and ‘Wichita’) were collected and grown in a quarantine greenhouse under highly regulated conditions. DNA from the resulting seedlings were used for next generation sequencing (MiSeq) for 16S and ITS and microbiome analyses revealed significant differences in microbial composition and relative abundance (bacterial and fungal) between seedling organs, with roots having the highest alpha diversity followed by stems and leaves. Bacterial family
Chitinophagaceae
was identified to be most relatively abundant in the roots of seedlings compared to the bacterial families
Rhizobiaceae
and
Moraxellaceae
, which were found to be most relatively abundant in the stems and leaves, respectively. Analyses also indicated that there were several families (bacterial families:
Rhizobiaceae
,
Enterobacteriaceae
,
Chitinophagaceae
,
Burkholderiaceae
,
Sphingomonadaceae
,
Pseudomonadaceae
,
Moraxellaceae
,
Microscillaceae
,
Rubritaleaceae
,
Caulobacteraceae
; fungal families:
Serendipitaceae
,
Nectriaceae
,
Ophiostomataceae
,
Hypocreaceae
,
Aspergillaceae
, and
Cephalothecaceae
) that were found in all seedlings and these constitute a core microbiome for pecan. There were also differences in microbial composition (bacterial and fungal) between seedlings from different maternal pecan cultivars and these differences are proposed to constitute a signature microbiome for the maternal cultivar. As pecan trees continues to extend to other growing regions it is important to understand the role that these microbes play in pecan. By establishing the core microbiome of pecans, the selection of microbes for breeding and improving pecan production will become a possibility.
Pecan bacterial leaf scorch (PBLS), caused by
Xylella fastidiosa
has been reported in Georgia, Louisiana, Texas, New Mexico, Arizona, and California. Accurate methods are critical for the early ...detection of
X. fastidiosa
, but the validation of current diagnostic tools for pecan has yet to be investigated. Collected petioles, leaflets, and shoots from pecan and other
Carya
relatives in Texas, Indiana, and Georgia were used as tissue samples, and to isolate crude xylem sap and gDNA for side-by-side testing using immunological (ELISA) and molecular-based assays traditional PCR and real-time quantitative PCR (qPCR). Isolated crude sap was found to be the most reliable template for ELISA diagnostics.
X. fastidiosa
-specific genes were amplified with previously published PCR primer sets; however, they revealed non-specific binding. New
Xylella-
specific primers were subsequently generated and validated using infected tissue from pecan and related
Carya
species. Two new primer sets (NMU3 and 5) produced expected amplicons specific to
X. fastidiosa
but did not amplify any non-specific bands of the pecan gDNA. When compared to that of total gDNA as the template in PCR reactions, diluted crude sap was found to be an efficient way to detect
X. fastidiosa
in pecan petioles. A novel TaqMan qPCR assay was also developed for the detection of
X. fastidiosa.
The results of the qPCR experiments were equivalent to the traditional PCR amplification when crude sap was used as the template. Comparative PCR analysis confirms that the PCR protocol outlined in this study can be replicated across different laboratories.
The TeleCommunications Association's annual conference and exposition will be held October 3-7 at the San Diego Convention Center. In addition to the usual assortment of educational conferences and ...exhibitors, the show also will include The Solutions Center, a dedicated area on the show floor that will team a variety of vendors in technology demonstrations showing how new and existing technologies can be linked to help users improve performance, gain strategic advantages, or capitalize on new operational opportunities.
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