Plant Pathology

The genus Diaporthe comprises pathogenic, endophytic and saprobic species with both temperate and tropical distributions. Cryptic diversification, phenotypic plasticity and extensive host associations have long complicated accurate identifications of species in this genus. The delimitation of the generic type species Diaporthe eres has been uncertain due to the lack of ex-type cultures. Species limits of D. eres and closely related species were evaluated using molecular phylogenetic analysis of eight genes including nuclear ribosomal internal transcribed spacer (ITS), partial sequences of actin (ACT), DNA-lyase (Apn2), translation elongation factor 1- α (EF1-α), beta-tubulin (TUB), calmodulin (CAL), 60s ribosomal protein L37 (FG1093) and histone-3 (HIS). The occurrence of sequence heterogeneity of ITS within D. eres is observed, which complicates the analysis and may lead to overestimation of the species diversity. The strict criteria of Genealogical Concordance Phylogenetic Species Recognition (GCPSR) were applied to resolve species boundaries based on individual and combined analyses of other seven genes except the ITS. We accept nine distinct phylogenetic species including Diaporthe alleghaniensis, D. alnea, D. bicincta, D. celastrina, D. eres, D. helicis, D. neilliae, D. pulla and D. vaccinii. Epitypes are designated for D. alnea, D. bicincta, D. celastrina, D. eres, D. helicis and D. pulla. Modern descriptions and illustrations are provided for these species. Newly designed primers are introduced to amplify and sequence the Apn2 (DNA- lyase) gene in Diaporthe. Based on phylogenetic informativeness profiles, EF1-α, Apn2 and HIS genes are recognised as the best markers for defining species in the D. eres complex.

Gerbera (Gerbera jamesonii) and Chrysanthemum (family Asteraceae) are two of the top 10 cut flowers of the world, with great commercial value. Since 1998, Venezuela began a floral industry to produce and export fresh cut gerbera and chrysanthemum, with 40% of nurseries concentrated in Altos Mirandinos (Miranda State, north central region of the country). For the past 2 years, greenhouse-grown gerbera and chrysanthemum have been observed displaying symptoms resembling those associated with tospoviruses. Symptomatic plants showed concentric rings, irregular chlorotic blotches, and deformation on leaves. Disease incidence was estimated at 30%. Mechanical inoculation with extracts of symptomatic leaves reproduced the typical concentric ring symptoms on indicator plants Arachis hypogaea L. cv. San Martín, Capsicum chinense, and G. jamesonii 6 to 15 days after inoculation. In initial tests, leaves from each 30 symptomatic gerbera and chrysanthemum species from several greenhouse facilities in Altos Mirandinos reacted positively when tested by DAS-ELISA with polyclonal antisera (ATCC, Rockville, MD) raised against Tomato spotted wilt virus (TSWV). Total RNA was extracted with the RNeasy Plant Mini kit (QIAGEN, Hilden, Germany) from two gerbera and two chrysanthemum ELISA-positive samples. The TSWV coat protein gene was amplified by conventional reverse transcription (RT)-PCR using primers CP1 TSWV (TTAACTTACAGCTGCTTT) and CP2 TSWV (CAAAGCATATAAGAACTT) (1). A single DNA product of ~823 bp was amplified from all samples. RT-PCR products were directly sequenced in both orientations and sequences were deposited in GenBank (Accession Nos. KF146700 and KF146701 derived from chrysanthemum, KF146702 and KF146703 derived from gerbera). The resulting sequences showed over 99% identity with each other. and were found to be closely related (over 99%) with TSWV isolates deposited in GenBank originating from different hosts from France (FR693058, FR693055), Montenegro (GU339506, GU339508, GU355940), Italy (HQ830187), New Zealand (KC494501), South Korea (KC261967), and the United States (AY744476). To our knowledge, this is the first confirmed report of TSWV infecting gerbera and chrysanthemum in Venezuela. The relatively widespread occurrence of TSWV in Miranda State underscores the need for systematic surveys to assess its incidence and impact on ornamental crops so that appropriate management tactics can be developed.

Reference: (1) R. A. Mumford et al. J. Virol. Methods 57:109, 1996.

Backgrounds: Food waste is commonly being dumped in landfills without undergo any treatment.
Food waste is one of the major wastes that contribute to landfills problems as it contains high
organic materials that will be broken down by microorganisms to form a liquid ‘leachate’ which
contains bacteria, rotting matter and maybe chemical contaminants from the landfill. This leachate
can present a serious hazard if it reaches a ground water or surface water. Digesting organic matter
in landfills also generates methane, which is a harmful greenhouse gas, in large quantity. One way
to turn the food waste to be useful and to reduce the volume of food waste in the landfills is through,
composting. However, composting process is generally takes a long time to produce compost and
the composting process also create bad odors. The application of Effective Microorganism (EM)
in composting has been observed to accelerate the process of decomposition.
Results: This paper provides an overview of the effective microorganism (EM) application in food
waste compost. It highlights the properties of EM, the process of EM in food waste composting
and the quality of compost with EM in terms of the nutrient and heavy metals concentration. (High
concentration of heavy metal in compost will be a toxic to soil, plant and will be consumed by
human as food and effect human health. In conclusion, EM has a great potential to be implemented
for food waste treatment as it can easily be produced, accelerate the composting process, and can
reduce the bad odors during decomposition of organic matter.
Keywords: Effective microorganisms, Food Waste, nutrient, heavy metals, composting