Articles

The use of enzyme linked immunosorbent assay (ELISA) for the detection of plant viruses is well documented. It proved to be a very valuable detection tools for the plant viruses. The efficiency of the ELISA technique was for practical purpose independent of the ratio of antibodies to antigen. This avoids the necessity of making specific enzyme conjugates for each antigen to be tested and eliminates the extreme specificity, thus allowing for quantitative evaluation of strain relationships. The advantages of indirect ELISA are sample. It needs only to be macerated and added to the plate. The crude antiserum could be used, although it should be cross absorbed before to prevent spurious host reaction. Single commercially available second antibody conjugate is utilized, thus eliminating the problems of preparing and storing many different conjugated antisera. Blotting technique has become widely used for specific identification of nucleic acid and proteins. This dot assay was modified to detect protein by spotting the antigen on a nitrocellulose membrane and incubating the membrane in test antibody followed by incubation in peroxidase-conjugated second antibody to the first antibody, and by development in 4-chloro-1-naphthol. The above procedure termed dot blot immunobinding assay (DBIA). The technique of tissue blotting on nitrocellulose membrane was described for detection of plant viruses in infected plants. Tissue blots were made by pressing with a firm and gentile force, the freshly cut tissue surface on nitrocellulose membranes. The possibility of using both sides of the nitrocellulose membrane (NCM) by tissue blot immuno assay (TBIA) for the detection plant viruses. In an effort to reduce the cost of virus assays, different types of regular paper were evaluated as possible replacements for the commonly used nitrocellulose membrane (NCM) as the solid phase in the tissue-blot immunoassay (TBIA) were used. Comparisons between different serological methods were demonstrated by many investigators Dot immunobinding was eight times more sensitive for detection of PVX and four times more sensitive for detection of PVS and PVY than DAS-ELISA.

Goosegrass (Eleusine indica L. Gaertn.) is a troublesome weed in turfgrass systems throughout the world. The development of herbicide resistant ecotypes has occurred to multiple modes of action. Goosegrass is a prolific seed producer (~50,000 per plant), fast growing and diverse weed. Such growing attributes make it essential to have a better understanding of the genetic diversity of various ecotypes. The objectives of this study were to determine if morphologically distinct goosegrass ecotypes collected in Florida were phenotypically distinct and genetically different. Phenotypically, the goosegrass ecotypes can be classified as follows; dwarf, intermediate 1 (int_I), intermediate 2 (int_II) and wild. The dwarf had the least seedheads followed by the wild ecotype; 5 and 17 respectively, while int_I and int_II had highest number of seedheads; 22 and 34 respectively. The dwarf ecotype had lowest height of 6 cm and the wild ecotype had highest height of 36 cm. Dwarf and int_II ecotypes had shortest internode length of 0.2 cm and 1 cm, respectively, while the wild ecotype had longest internode length of 7 cm. The dwarf ecotype had lowest number of racemes per plant of 1, while the wild ecotype had highest number of racemes per plant of 7. Total biomass was lowest for the dwarf and int_II ecotype; 0.7 g and 1.5 g, respectively, and total biomass was highest for the wild ecotype at 5 g. Gene sequencing of two rice (Oryza) gene sequences (accession AP014964 (gene A) and AP014965 (gene B)) and subsequent phylogenetic analysis suggest the ecotypes are genetically different. Three single nucleotide polymorphisms (SNP) of interest were discovered indicating allelic differences between ecotypes.

Cowpea plants naturally infected with cowpea mosaic comovirus (CPMV) showed different mosaic, mottle, dwarfing, and vain clearing symptoms. Diseased plants were ollected from certain locations of Alexandria and El-Beheira governorates during the growing seasons from 2011 to 2012. CPMV was detected in infected sap at 8 to 24 days after inoculation by DBIA, indirect ELISA and tissue blot immunoassay (TBIA). Chlorotic local lesions were observed on Chenopodium amaranticolor in infectivity test. By using indirect ELISA and DBIA, CPMV were detected in infected plant sap of serial dilutions up to 1: 400. The incidence of CPMV in 21 day old cowpea seedlings grown from infected seeds was determined by ELISA and positive detection of virus antigen reached 65%. Nitrocellulose membrane and canson paper could be used as solid carriers in TBIA and DBIA for detection of CPMV in infected plant tissues. Results revealed that both faces of nitrocellulose membrane and canson paper could be used as solid carriers in TBIA for detection of CPMV in infected plant tissues. According to reverse transcription polymerase chain reaction (RT-PCR) assay of CPMV infected plant; the amplified product was approximately 800bp of partial coat protein gene. The nucleotide sequences accession number were LN606585 and LN606586. The phylogenetic tree was generated using sequences of CPMV isolates with the other CPMV records from GenBank.

Abamectin and emamectin are members of avermectin family which categorized as very effective but in the same time are toxic naturally. Most of products in this family are utilized as pharmaceuticals in both humans & animals and for crop protection. Despite avermectins are having complex chemical structures, but they are produced via synthesis in large scales for commercial use. Plant parasitic nematodes (PPNs) cause severe damages in all parts of their host plants, in addition to yield losses. The available strategies to control PPN include use of insecticides/nematicides but these have proved detrimental to environment and human health. Therefore, this scenario gave an opportunity for the utilization of avermectins (abamectin and emamectin) to control plant parasitic nematodes because of their chemical and biological properties, as well as relative safety. Avermectins have short half-lives and their residues can be eliminated easily through different food processing methods. Both abamectin and emamectin were very effective nematicides which proved capability of reducing PPNs significantly in various crops.

Standardized method of seed treatment is of prime importance in the production of groundnut. The study was to carry out control trial using bark extract (aqueous and ethanol) and oil (seed) of mahogany (Khaya senegalensis) on seven (7) isolated fungi from two groundnut varieties (peruvian and valencia). The result shows that both mahogany bark and seed extracts are capable of inhibiting mycelial growth of all the isolates. There was no significant variation between the aqueous and ethanol bark extracts in-vitro, however the in-vivo test shows a significant difference between the aqueous and the ethanol bark extract in which the ethanol extract reduced growth of the pathogens more than the aqueous. For all the pathogens except Rhizopus stolonifer there was no growth between 50% to 100% concentration of the Khaya senegalensis oil in-vitro, however in-vivo control at 50% produced scanty to moderate growth for all the pathogens except Rhizopus stolonifer on peruvian, while there was full coverage on the seeds of valencia variety with Aspergillus niger and Rhizopus stolonifer having total coverage though Pseudaiiescheria boydii and Cylindrocarpon lichenicola were effectively inhibited and showed no growth at the 50% and 100%. Further research to focus on the quantifying the chemical constituents and formulation are suggested.

The calyces of Hibiscus sabdariffa have been used by many communities as herbal tea. Their anthocyanin contents have been reported as the key component in anti-obesity studies. This present work reported results of anthocyanin content of calyces in two varieties of H. sabdariffa collected from Sabak Bernam, Selangor, Malaysia. The samples have been authenticated in the Herbarium, Institute of Bioscience, University Putra Malaysia prior to the study. The samples were processed and the ground dry raw material and its aqueous extract were analyzed using Fourier Transform Infrared (FTIR) and Two-Dimensional Infrared (2DIR). The short hybrid calyces (FT11-15A) raw material spectrum showed more than 80% similarity with long wild variety calyces (FT11-15B) when using “Compare” in analysis. The differences of both samples were obviously shown in their aqueous extract spectra. The peak at 1672 cm-1 and 841 cm-1 showed that tri-substituted double bond in FT11-15B aqueous extract was not present in FT11-15A aqueous extract spectra, whereby a double peak was assigned at 1221 cm-1 referred to anti symmetry stretching of aromatic and vinyl =C-O-C- with other =C-O- and 1192 cm-1 is assigned In-plane δ C-H in FT11-15A aqueous extract. The peak at 1071 cm-1 assigned as bonding C-H in plane bending of phenyl of both samples was the only peak comparable with standard delphinidin and cyanidin which are used for qualification and quantification of sample content. Aqueous extract spectra of both samples showed higher number of peaks detected compared with raw material spectra, which was attributed to the higher solubility of anthocyanins in water. The 2DIR correlation spectroscopy is advantageous in enhancing the qualitative analysis of herbal products. The anthocyanin content in both varieties of H. sabdariffa in descending amount is delphinidin-3-O-sambubioside (DS), cyanidin-3-O-sambubioside (CS), delphenidin-3-O-glucoside (DG) and lastly cyanidin-3-O-glucoside (CG). FT11-15A has more content of DS and DG of raw material and CG of water extract plus TFA than FT11-15B, whereby, FT11-15B has more content of CS, CG of raw material and DS, DG, CS of water extract plus TFA than FT11-15A.

Pumpkins (Cucurbita pepo) are grown all around the world for a variety of reasons ranging from agricultural purposes to commercial and ornamental sales. The pathogens causing the rot of pumpkin in the world include fungi, bacteria, and viruses. The study was aim to identify fungal pathogens of pumpkin rot during storage, as well as control measures of the diseases using wood ash, mango leaf and rice chaff. Three hundred and sixty-six (366) fruits of pumpkins were studied in Pela, Gaya and Kulinyi districts of Hong Local Government Area of Adamawa State. The diseased samples (fruits) were randomly purchased. Of all the districts visited, Kulinyi has the highest percentage of disease samples (43.82%) while the least is Gaya district with 21.35%. Potato Dextrose Agar (PDA) was used for the isolation of pathogens and these gave Fusarium solani, Aspergillus niger, Aspergillus flavus, and Phytophthora capsici. All the fungal isolates exhibited different degree of pathogenic effect on the pumpkin fruits. The pathogens are susceptible to treatment both In-vitro and In-vivo control trials with wood ash and mango leaf at p ≤ 0.05. Inhibition improved with increased in concentration of the wood ash and mango leaf. Rice chaff treatment equally proved worthwhile with significant inhibition compared to the control at p ≤ 0.05.

The circadian clock is an endogenous molecular oscillator with a period of about 24 hours, which regulates the physiology and developmental processes of almost all higher plants. Pseudo-response regulators (PRRs) are an important part of the central clock oscillator, together with other clock genes, constituting interlinked transcriptional feedback loops, which partly influence plant growth and development. In this study, a circadian clock-related gene MsPRR7 was cloned from Medicago sativa (alfalfa) by homologous cloning. The full length MsPRR7 gene was 2648 bp in length, with an open reading frame of 2385 bp encoding a protein of 795amino acids. Phylogenetic analysis showed that the MsPRR7 was closely related to PRR7 from the PRR family of Arabidopsis thaliana. Subcellular localization analysis found that MsPRR7 was located in the nucleus. Quantitative reverse-transcription polymerase chain reactions (qRT-PCR) demonstrated that expression of MsPRR7 gene transcripts in leaves was affected by circadian rhythms, and that its expression level increased with an extension of illumination time, reaching a peak around 8–10 hours. These results will provide the experimental basis for further study of the regulation of PRR family genes in alfalfa.

Peaches, Prunus persica were planted as grafted saplings in an avocado orchard previously infested with Armillaria mellea (Vahl) P.Kumm. Trees were planted in large or small holes with or without fresh yardwaste chips added as an amendment and with or without a Trichoderma biocontrol product sprayed into the hole. Trees were monitored for six years -- growth and mortality was tabulated. Six years later 40% of the trees had died from the disease. Trees planted in a large hole were more likely to survive than in a smaller hole (P=0.07) and trees in large holes with fresh organic matter added were the most likely to survive (P=0.04). Trichoderma sprays in the planting hole did not increase survival rates. While growth was initially retarded by adding fresh yardwaste to the hole, in later years none of the treatments affected growth rates.

Although laurel wilt disease was first reported in the United States in 2002 from redbay trees (Persea borbonia) around Savannah, Georgia it has rapidly spread throughout the southeastern coastal plain including Georgia and Florida. In the current study, transects were used to assess the spread and impact of the disease on two native bay trees redbay (P. borbonia) and swampbay (P. palustris) from north Florida in a semi-naturalized ecological preserve. Although tree size and mortality rates have been reported previously, this study provides the first size-based static life tables for both species. While a significantly higher percent (76%) of swampbay trees exhibited signs of laurel wilt disease compared to redbay trees (62%); redbay had more of its canopy damaged by the disease (41% vs. 32% for redbay vs. swampbay respectively); this resulted in a significantly smaller stem diameter for P. borbonia compared to swampbay, both species are experiencing significant declines due to the disease. Both species exhibited a Type III survivorship curve in which the vast majority of individuals were in the smallest size class (average stem diameter was only 2.5 and 3.6 cm for redbay and swampbay respectively). Although traditionally, population age (or size) structure that is heavily biased toward younger or smaller size classes suggests that the population is likely to expand in the future, for these bay trees high mortality rate due to beetle/fungal infestation of larger size classes is responsible for this trend; the smallest size classes are largely free from beetle infestation and laurel wilt disease because the stem diameter is likely insufficient to support beetle development. Results from this study suggest that swampbay is also highly susceptible to laurel wilt disease and its populations are likely to exhibit a similar (albeit slower) decline in Florida’s wetland and mesic ecosystems.