Complete nucleotide sequence of a new geminivirus isolated from Vitis vinifera in India: a symptomless host of Grapevine red blotch virus.

Symptomless grape plants (Vitis vinifera) cultivated in Jind, Punjab, have been found to carry a Grapevine red blotch virus (GRBV). Evaluation of full length DNA sequence (3204 bp) of the virus (KU522121) has revealed similarity with mastrevirus, begomovirus, and other Grapevine red blotch viruses reported in the US and Canada. Similar to naturally growing plants, agroinfiltrated model plants with infectious clone of GRBV do not show any visible disease warning sign. To the best of our knowledge, this is the first report of a symptomless host Vitis vinifera from Indian vineyards harbouring a Grapevine geminivirus.

In vitro reporter assays for screening of chemicals that disrupt androgen signaling.

Endocrine disruptive chemicals (EDCs) modulate hormone signaling and cause developmental and reproductive anomalies. Today, there is a global concern regarding endocrine disruption effects, particularly those mediated by the androgen receptor (AR). Androgen or male hormones are critical for the development and maintenance of male characteristics and numerous EDCs exist in the environment with the potential to disrupt androgen action. The threat is more during critical developmental windows when there is increased sensitivity to these compounds. Timely screening and detection of the EDCs is essential to minimize deleterious effects produced by these toxic chemicals. As a first line of screening, in vitro transcription assays are very useful due to their speed, convenience, and cost effectiveness. In this paper, recent in vitro reporter assays for detecting androgenic or antiandrogenic activity of EDCs have been reviewed. Two important cell systems used for this purpose, namely, the mammalian or yeast cell systems, have been discussed. Use of reporter genes such as bacterial luciferase (lux) and green fluorescent protein (gfp) has significantly improved speed and sensitivity of detection. Also, many of the current reporter assay systems can be used in a high throughput format allowing speedy evaluation of multiple potential EDCs at a lower price.

Multiple displacement amplification as a pre-polymerase chain reaction (pre-PCR) to detect ultra low population of Ralstonia solanacearum (Smith 1896) Yabuchi et al. (1996).

AIMS: To develop a reliable and sensitive protocol for detection of Ralstonia solanacearum using MDA-PCR (Multiple displacement amplification-PCR amplification). METHODS AND RESULTS: MDA-PCR technique was performed on pure cell lysates as well as soil samples. Pure cell lysate as well as that of soil DNA was used as template in MDA reaction. MDA of template DNA was carried out in the presence of sample buffer, reaction buffer and enzyme mix (Phi 29 DNA polymerase and random hexamers). The MDA amplified DNA was used for PCR amplification using R. solanacearum -specific PCR primers. MDA-PCR could detect as low as 1 colony forming unit (CFU ml(-1)) of bacteria within 8 h including DNA isolation. CONCLUSION: MDA followed by standard PCR facilitated the detection of pathogen from very low count samples. The method is of great importance in managing the brown rot disease of potato. SIGNIFICANCE AND IMPACT OF STUDY: The ultrasensitive detection technique developed in the present study is sensitive and speedy enough to be included into integrated wilt disease control programmes.

Antiviral activity in plants of a mycoviral double-strained RNA from Trichothecium roseum.

Hexagonal virus-like particles (VLPs) measuring 45 nm across were detected in mycelial extracts from Trichothecium roseum Himachal strain, the source fungus for the production of T-poly (Trichothecium polysaccharide), a known inhibitor of plant viruses. VLPs were found to contain double-stranded RNA (ds RNA) and the purified ds RNA was capable of inhibiting tobacco mosaic virus infection in Nicotiana glutinosa plants. Active preparations of T-poly were found to contain traces of ds RNA, probably of mycoviral origin.