Southern Crop Protection and Food Research Center

London, Canada

Southern Crop Protection and Food Research Center

London, Canada
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Miller S.S.,Agriculture and Agri Food Canada | Jin Z.,Carleton University | Jin Z.,University of British Columbia | Schnell J.A.,Carleton University | And 4 more authors.
Annals of Botany | Year: 2010

Background and Aims Hourglass cells (HGCs) are prominent cells in the soybean seed coat, and have potential use as 'phytofactories' to produce specific proteins of interest. Previous studies have shown that HGCs initiate differentiation at about 9 d post-anthesis (dpa), assuming their characteristic morphology by 18 dpa. This study aims to document the structural changes in HGCs during this critical period, and to relate these changes to the concurrent development of a specific soybean peroxidase (SBP) encoded by the Ep gene. Methods Pods were collected from plants at specific growth stages. Fresh material was processed for analysis of Ep peroxidase activity. Tissues were processed for scanning and transmission electron microscopy, as well as extracted for western blotting. A null variety lacking expression of Ep peroxidase was grown as a control. Key Results and Conclusions At 9 dpa, HGCs are typical undifferentiated plant cells, but from 12-18 dpa they undergo rapid changes in their internal and external structure. By 18 dpa, they have assumed the characteristic hourglass shape with thick cell walls, intercellular air spaces and large central vacuoles. By 45 dpa, all organelles in HGCs have been degraded. Additional observations indicate that plasmodesmata connect all cell types. SBP activity and SBP protein are detectable in the HGC before they are fully differentiated (approx. 18 dpa). In very early stages, SBP activity appears localized in a vacuole as previously predicted. These results increase our understanding of the structure and development of the HGC and will be valuable for future studies aimed at protein targeting to components of the HGC endomembrane systems.

Wang Y.,Northwest University, China | Wang Y.,Southern Crop Protection and Food Research Center | Hua W.,Shaanxi Normal University | Hua W.,Shaanxi Institute of Education | And 4 more authors.
Molecular Genetics and Genomics | Year: 2013

Lotus corniculatus L. is used worldwide as a forage crop due to its abundance of secondary metabolites and its ability to grow in severe environments. Although the entire genome of L. corniculatus var. japonicus R. is being sequenced, the differences in morphology and production of secondary metabolites between these two related species have led us to investigate this variability at the genetic level, in particular the differences in flavonoid biosynthesis. Our goal is to use the resulting information to develop more valuable forage crops and medicinal materials. Here, we conducted Illumina/Solexa sequencing to profile the transcriptome of L. corniculatus. We produced 26,492,952 short reads that corresponded to 2.38 gigabytes of total nucleotides. These reads were then assembled into 45,698 unigenes, of which a large number associated with secondary metabolism were annotated. In addition, we identified 2,998 unigenes based on homology with L. japonicus transcription factors (TFs) and grouped them into 55 families. Meanwhile, a comparison of four tag-based digital gene expression libraries, built from the flowers, pods, leaves, and roots, revealed distinct patterns of spatial expression of candidate unigenes in flavonoid biosynthesis. Based on these results, we identified many key enzymes from L. corniculatus which were different from reference genes of L. japonicus, and five TFs that are potential enhancers in flavonoid biosynthesis. Our results provide initial genetics resources that will be valuable in efforts to manipulate the flavonoid metabolic pathway in plants. © 2013 Springer-Verlag Berlin Heidelberg.

Tian G.,Southern Crop Protection and Food Research Center | Tian G.,University of Western Ontario | Lu Q.,Southern Crop Protection and Food Research Center | Lu Q.,University of Guelph | And 4 more authors.
Plant Signaling and Behavior | Year: 2012

The 26S proteasome interacts with a number of different proteins, while the TREX-2 complex is an important component of the mRNA export machinery. In animals and yeast, members of the Ubiquitin C-terminal Hydrolase 37 (UCH37) family are found to associate with the 26S proteasome, but this has not been demonstrated in plants. The Arabidopsis UCH1 and UCH2 are orthologous to UCH37. Here, we show that UCH1 and UCH2 interact with the 26S proteasome lid subunits. In addition, the two UCHs also interact with TREX-2 components. Our data suggest that Arabidopsis UCHs may serve as a link between the 26S proteasome lid complex and the TREX-2 complex. © 2012 Landes Bioscience.

Chowda-Reddy R.V.,University of Greenwich | Chowda-Reddy R.V.,Southern Crop Protection and Food Research Center | Kirankumar M.,University of Agricultural Sciences, Bangalore | Seal S.E.,University of Greenwich | And 4 more authors.
Journal of Integrative Agriculture | Year: 2012

Bemisia tabaci adults from various host-plant species were collected from 31 regions across India. 266 B. tabaci samples were first screened by RAPD-PCR to examine molecular variability and to select individuals with different fingerprints. Host-plant and region of collection were then used to select 25 individuals for PCR amplification and sequencing of their partial mitochondrial cytochrome oxidase subunit one (mtCOI) genes. Pairwise comparisons with mtCOI consensus sequences showed that the majority of these samples had <3.5% sequence divergence from groups currently termed Asia I, Asia II-5, Asia II-7, and Asia II-8. The biotype-B B. tabaci from India clustered into the Middle East-Asia Minor 1 group. A new group of B. tabaci from Coimbatore, collected from pumpkin, was related most closely to the Asia I group (6.2% sequence divergence from the consensus Asia I sequence). To increase our understanding of the epidemiology of tomato leaf curl disease (ToLCD) and the key B. tabaci genetic groups involved in virus spread, the indigenous Asia I and the exotic biotype-B population from South India were used to carry out transmission experiments using Tomato leaf curl Bangalore virus (ToLCBV). The acquisition access periods (AAP), inoculation access periods (IAP), latent periods (LP), and ToLCBV transmission efficiencies of the two populations were compared and the biotype-B had the more efficient transmission characteristics. These results are discussed in relation to recent changes in the epidemiology of tomato leaf curl disease in South India. © 2012 Chinese Academy of Agricultural Sciences.

Wang A.,Southern Crop Protection and Food Research Center | Tian L.,Southern Crop Protection and Food Research Center | Brown D.C.W.,Southern Crop Protection and Food Research Center | Svircev A.M.,Southern Crop Protection and Food Research Center | And 2 more authors.
Acta Horticulturae | Year: 2015

Plum pox virus (PPV) is the causal agent of the devastating viral disease, known as sharka in Europe, on many stone fruit species. To engineer genetic resistance against PPV through the hairpin-mediated RNA silencing (RNAi) approach, previously two plant transformation vectors, pAWp1 and pAWcp were constructed by cloning two highly conserved regions of the PPV genome corresponding to portions of viral RNA coding for P1 and CP, respectively, into a Ti binary vector under the control of the double Cauliflower mosaic virus 35S promoter as inverted repeats spanned by an intron from the peach endo-polygalacturonase (endo-PG) genomic DNA. The resulting transgenic plants expressing hairpin RNAs either targeting the viral P1 or CP sequences showed resistance to PPV. Here we report construction of a new construct pAWp1-cp by cloning the P1 and CP hairpin sequences together into the Ti vector and the inserted DNA contains a triple-intron double-hairpin sequence simultaneously targeting the P1 and CP sequence of PPV. This vector was transformed into Nicotiana benthamiana and plum (Prunus domestica L.). Resistance assays showed the transgenic plants were efficiently resistant to PPV.

Kim W.-S.,Norgen Biotek Corporation | Haj-Ahmad Y.,Norgen Biotek Corporation | Stobbs L.W.,Southern Crop Protection and Food Research Center | Greig N.,Southern Crop Protection and Food Research Center
Canadian Journal of Plant Pathology | Year: 2015

Early viroid detection in chrysanthemum cultivars depends on both an efficient RNA extraction method as well as a sensitive detection assay. In this study, we evaluated RNA purification methods and optimized a one-step RT-qPCR assay for the detection of Chrysanthemum stunt viroid (CSVd). Three commercially available RNA extraction technologies (silica and silicon carbide spin column as well as the phenol/chloroform extraction) were compared for efficacy in CSVd detection sensitivity. We found a 10- to 50-fold improvement in CSVd detection sensitivity when using silicon carbide (SiC) spin columns to purify RNA compared with the silica-based column or the traditional phenol/chloroform extraction method. To optimize detection sensitivity and reduce detection time, a commercial CSVd end-point PCR primer set was adapted to a SYBR Green based one-step RT-qPCR assay. Standard curve analysis estimated that the limit of detection was about 54 CSVd copies and the specificity test against six related viroids showed no cross-reactivity. As a part of the validation, the one-step RT-qPCR detection system was compared with RT-PCR to detect CSVd in both randomly selected greenhouse plants and mechanically inoculated chrysanthemum varieties. Cultivars selected from a commercial greenhouse with >50% infection levels were tested for CSVd presence. Cultivars Pelee, Puma and Shamrock tested positive by both the one step RT-qPCR and RT-PCR but CSVd was not detected in Icecap and Snowball. In mechanical inoculation studies, CSVd was detected in 5 of 6 chrysanthemum cultivars - Chesapeake, Durango, Juneau, Pelee and Viron but not in Pueblo. No differences in detection were evident between the RT-qPCR and RT-PCR methods. © 2015 The Canadian Phytopathological Society.

Stobbs L.W.,Southern Crop Protection and Food Research Center | Greig N.,Southern Crop Protection and Food Research Center
Canadian Journal of Plant Pathology | Year: 2014

Greenhouse trials demonstrated the ability of bumblebees (Bombus impatiens Cresson) to transmit Pepino mosaic virus (PepMV) from infected tomato plants to perennial climbing nightshade (Solanum dulcamara L) in 2 of 3 trials (5.1% and 5.6% frequency, respectively). The efficiency of transmission was lower than that between tomato plants in previous studies (80%). Low rates of transmission were also seen in bee transmission from nightshade plants back to tomato (6.3%, 3.7% and 2.8%), and between nightshade plants (8.3% and 2.8%). Nightshade was easily infected by mechanical inoculation in controls. Bumblebees used by growers to pollinate tomatoes can move freely in and out of the production houses, and bees carrying virus inoculum from infected greenhouse tomatoes could establish and spread PepMV in nearby climbing nightshade populations. This overwintering reservoir could allow for ongoing virus introduction from the field through pollinating bees back into tomato production houses seasonally. The virus could also spread from infected climbing nightshade into tomato field plantings through similar bee activity. © 2014 The Canadian Phytopathological Society.

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