Search results for "Phytophthora spp"

Identification of Phytophthora species infecting citrus in Vietnam

2013

In a survey aimed at identifying Phytophthora species infecting fruit crops in Viet Nam, P. citrophthora and P. nicotianae were the species most commonly recovered from soil and trees in citrus plantations. P. nicotianae was prevalent in citrus groves in the Ben Tre and Tien Giang provinces (southern Viet Nam). Interestingly, both A1 and A2 mating types of the latter species were found, while in other citrus-growing areas of the world, such as the Mediterranean region, South Africa, Australia and the Americas, A1 is the only mating type occurring in citrus groves, suggesting southern-east Asia could be a centre of origin of this Phytophthora species. Mixed infections of three Phytophthora s…

MOLECULAR ANALYSIS OF PHYTOPHTHORA DIVERSITY IN ORNAMENTAL NURSERIES.

2013

A molecular approach based on the use of genus-specific nested-PCR primers (Scibetta et al., 2012; J. Microbiol. Meth. 88: 356-368) was utilized to detect Phytophthora species in soil and root samples of potted ornamentals, collected across Apulia and Calabria, Southern Italy. Analyzed samples comprised many plant species with different levels of symptoms of decline on the canopy and root rots. Extraction protocols were optimized to obtain DNA samples of appropriate quality from soil and roots. The analysis of sequences after cloning of nested-PCR amplicons enabled the identification of different Phytophthora species including P. nicotianae, P. cinnamomi, P. cryptogea, P. palmivora and P. n…

METAGENOMIC ANALYSIS OF PHYTOPHTHORA DIVERSITY IN NURSERIES OF POTTED ORNAMENTAL SPECIES.

2015

The genetic diversity of Phytophthora was investigated in soil and root samples of potted ornamental and fruit tree plants collected in nurseries located in Apulia and Calabria (Southern Italy) using metagenomic approaches based on Phytophthora genus specific primers. PCR amplicons containing the ITS1 region of the rDNA were sequenced using both a conventional cloning and Sanger sequencing approach and a 454 pyrosequencing protocol. All sequences were accurately analyzed with an appropriate software and used as barcode for species identification utilizing a validated ITS database. The cloning/Sanger sequencing approach enabled the identification of nine different Phytophthora taxa (P. nicot…

Whither the species? Phytophthora taxa, MOTUs and barcodes in the world of metagenomics

2015

The study of ecosystem diversity is being transformed by high throughput sequencing technology that allows an unparalleled depth of sampling of DNA barcode sequences. The opportunities are great at this fascinating interface of pathology, ecology, taxonomy and molecular biology but there are pitfalls. It is important to consider the potential for bias at all steps in the process from sampling through to data analysis. Increasingly Phytophthora diversity is being examined by metabarcoding of the PCR amplified rDNA ITS regions from soil, water or plant sample DNA. We have applied baiting and isolation, cloning and Sanger sequencing and Illumina MiSeq analysis to a time-series of filtered wate…

Root and crown rot of olive caused by Phytophthora spp

2011

Metagenomic strategies to assess genetic diversity in Phytophthora species

A molecular method to assess Phytophthora diversity in environmental samples

2012

Current molecular detection methods for the genus Phytophthora are specific to a few key species rather than the whole genus and this is a recognized weakness of protocols for ecological studies and international plant health legislation. In the present study a molecular approach was developed to detect Phytophthora species in soil and water samples using novel sets of genus-specific primers designed against the internal transcribed spacer (ITS) regions. Two different rDNA primer sets were tested: one assay amplified a long product including the ITS1, 5.8S and ITS2 regions (LP) and the other a shorter product including the ITS1 only (SP). Both assays specifically amplified products from Phy…

Molecular analysis ofPhytophthoradiversity in nursery-grown ornamental and fruit plants

2015

The genetic diversity of Phytophthora spp. was investigated in potted ornamental and fruit tree species. A metabarcoding approach was used, based on a semi-nested PCR with Phytophthora genus-specific primers targeting the ITS1 region of the rDNA. More than 50 ITS1 sequence types representing at least 15 distinct Phytophthora taxa were detected. Nine had ITS sequences that grouped them in defined taxonomic groups (P. nicotianae, P. citrophthora, P. meadii, P. taxon Pgchlamydo, P. cinnamomi, P. parvispora, P. cambivora, P. niederhauserii and P. lateralis) whereas three phylotypes were associated to two or more taxa (P. citricola taxon E or III; P. pseudosyringae, P. ilicis or P. nemorosa; and…