Entity

Time filter

Source Type


Rao G.,Indian Agricultural Research Institute | Mall S.,Sugarcane Research Station Kunraghat | Raj S.,National Botanical Research Institute | Snehi S.,National Botanical Research Institute
Acta Phytopathologica et Entomologica Hungarica | Year: 2011

In India recent evidences showed that phytoplasma associated with plants including crops, fruits, trees, ornamental, sugarcane, grasses and weeds increasing at alarming rate. Phytoplasma cause diseases in several plant species and resulted in serious threat as a source of alternative natural host for the spread of phytoplasma pathogen to other economically important plants and thereby chances of causing severe losses. In earlier days very few phytoplasma diseases were identified in India merely on the basis of bright-field, fluorescence, electron microscope observations, tetracycline treatment and to a lesser extent by serological assays. Among these, microscopic methods do not attain pathogen identification, and all of them are not always sufficiently sensitive to detect phytoplasma infections in low-titer hosts. Today detection of phytoplasma based on molecular genetic methods including PCR assays are efficiently carried out in India and on that basis several plant species are reported to have phytoplasma infections. So far more than 37 plant species have been reported to be associated with phytoplasma infections from all over India. The "Candidatus Phytoplasma asteris", "Candidatus Phytoplasma aurantifolia", "Candidatus Phytoplasma trifolii" and "Candidatus Phytoplasma cynodontis" belong to 16SrI, 16SrII, 16SrVI and 16SrXIV group of phytoplasmas are the major groups associated with different species reported to be infected with phytoplasma throughout India. In this paper, we have discussed overall progress on phytoplasma disease on plant species in India in terms of taxonomy, symptomatology, economic significance, transmission and characterization. Source


Chaturvedi Y.,Sugarcane Research Station Kunraghat | Rao G.,Sugarcane Research Station Kunraghat | Tiwari A.,Sugarcane Research Station Kunraghat | Duduk B.,Serbian Institute of Pesticides and Environmental Protection | Bertaccini A.,University of Bologna
Acta Phytopathologica et Entomologica Hungarica | Year: 2010

During recent years, increasing attention has been devoted to the development of field floriculture, particularly for benefit of small farming businesses that produce seedlings of perennial ornamental plants for the domestic market and for export to neighboring countries. Like other segments of agricultural economies, this industry is threatened by plant diseases, including those associated to phytoplasma infection. Phytoplasmas cause diseases in several commercial cut flower and ornamental plant causing serious economic losses all around the world. Therefore, phytoplasma diseases are the major constraints in profitable ornamental plants production and lowers its quantum and quality gaining international importance because of unspecific symptoms, various losses and diverse epidemiology throughout the world. Epidemics of these diseases have compelled withdrawal of many floriculture plant varieties from cultivation such as gladiolus, lily, chrysanthemum and rose. Symptoms of general yellowing and stunting of plants, proliferation of shoots, phyllody, virescence, reduced size of flowers and reddening of leaves were observed in diverse ornamental plants in botanical gardens and various floriculture farms. Knowledge of the diversity of phytoplasmas has been expanded by recent studies as well as the availability of molecular tools for pathogen identification. The diversity of the potential reservoir of disease has been increased with the discovery of new phytoplasmas hosts. Ornamental plant phytoplasmas showed wide geographical distribution. The ' Ca . P. asteris' belonging to 16SrI group is the major group associated with ornamentals worldwide, so far more than 42 ornamental plant species were reported as phytoplasma infected. Basing on the sequences retrieved from GenBank identified phytoplasmas mainly belong to 16SrI, 16SrII, 16SrIII, 16SrV, 16SrVI, 16SrVII, 16SrIX, 16SrX, 16SrXII, 16SrXIII and 16SrXV groups. In this review, detailed information on occurrence, symptomatology, molecular characterization, transmission, taxonomy, genetic diversity and management approaches on phytoplasma infecting ornamental plants have been discussed. Source


Tiwari A.K.,Sugarcane Research Station Kunraghat | Snehi S.K.,Plant Molecular Virology Laboratory | Singh R.,Plant Molecular Virology Laboratory | Raj S.K.,Plant Molecular Virology Laboratory | And 2 more authors.
Archives of Phytopathology and Plant Protection | Year: 2012

Begomoviruses cause a number of serious diseases of cultivated crops and are considered as the major constraint for the cultivation of several crops all over the world. During a survey in the years 2007 and 2008, the typical symptoms of Begomovirus (yellow mosaic and yellow vein) were observed on six cucurbitaceous crops, viz. bitter gourd (Momordica charantia L.), pointed gourd (Trichosanthes dioica), pumpkin (Cucurbita pepo), pumpkin (Cucurbita maxima), sponge gourd (Luffa cylindrica) and ridged gourd (Luffa acutangula) being cultivated in northern India. Begomovirus infection was suspected due to significant infestation of whiteflies (Bemisia tabaci, the known vector of Begomoviruses) on these species. The presence of Begomovirus was detected from the total DNA extracted from six infected leaf samples of these species by polymerase chain reaction using the specific primers of a well-characterised Begomovirus. The ~800 bp amplicons of these isolates were cloned, sequenced and the data obtained were compared with each other and with sequence database available in GenBank for best sequence identities and phylogenetic relationships. Based on highest 97-99% sequence identities and closest phylogenetic relationships, four representative Begomovirus species were identified as Ageratum enation virus (from T. dioica), Squash leaf curl China virus (from C. maxima), Tomato leaf curl New Delhi virus (from M. charantia, L. cylindrica and L. acutangula) and Tomato leaf curl Palampur virus (from C. pepo). These results suggested the existence of a high genetic diversity among Begomoviruses infecting cucurbitaceous crops. © 2012 Copyright Taylor and Francis Group, LLC. Source


Raj S.K.,National Botanical Research Institute | Snehi S.K.,National Botanical Research Institute | Khan M.S.,National Botanical Research Institute | Tiwari A.K.,Sugarcane Research Station Kunraghat | Rao G.P.,Sugarcane Research Station Kunraghat
Australasian Plant Disease Notes | Year: 2010

A severe yellow mosaic disease with a significant disease incidence was observed on bitter gourd (Momordica charantia L.) during a survey of different locations around Gorakhpur, Uttar Pradesh, India in 2008. Polymerase chain reaction (PCR) was carried out using total DNA isolated from infected leaf samples and a pair of begomovirus-specific primers. The expected size (∼1300bp) amplicon was detected from all four symptomatic samples but not from samples of healthy plants, indicating the presence of a begomovirus infection. A PCR amplicon was cloned and sequenced (GenBank Accession reference EU888908). Basic local alignment search tool analysis revealed the newly derived sequence had the highest identities (9997%) with Pepper leaf curl Bangladesh virus (PepLCBV) sequences. The phylogenetic analysis of the virus sequences with selected begomovirus sequences also revealed the closest relationship with PepLCBV. These results suggest an association of PepLCBV with yellow mosaic disease of bitter gourd; PepLCBV on bitter gourd (M. charantia) is a new record in India. © Australasian Plant Pathology Society 2010. Source

Discover hidden collaborations