A Study of Virus Infecting Clerodendrum inerme L Gaertn Exhibiting Mosaic Symptoms in Agra Region

Abstract

Objectives of the present research work included: disease prevalence of Clerodendrum inerme yellow mosaic in Agra region; effect of virus on host physiology; control measures through botanicals; physical properties; biological characterization; isolation; transmission electron microscopic studies and molecular characterization of virus. During the course of study three successive surveys (2014/15-2015/16-2016/17) were conducted and it was reported that the disease incidence increased gradually from 70.01% to 93.79% and disease severity from 80.55% to 84.4% from year 2014-17. Physiological studies on assay host i.e., cowpea revealed decrease in carbohydrates and pigment contents whereas total nitrogen, proteins, free amino acids and enzymatic activity increased when compared with control. Same observations were revealed in healthy and diseased garden quinine plants. To minimize the disease incidence, root extracts of Boerhaavia diffusa (53.76%), were found to be more effective against C. inerme mosaic virus. The virus in crude sap remained infective up to 10-4 in successive mechanical inoculation. TIP was found to be (62±1°C) and LIV was found to be 4 days at room temperature and 5 days at (4±1°C) for the present virus. Mechanical inoculation test confirmed its viral nature as symptoms of diseased garden quinine were transmissible through sap. Graft and whitefly transmission was also successful for virus transmission. Attempts were made to isolate virus particles and geminate isometric virus particles alongwith single monomer with a size of about 18 X 20 nm and 32nm in length, observed through electron microscopy. Nucleic acid was found to be single stranded DNA, 1.4kb molecular weight, confirmed as begomovirus through PCR. SDS-PAGE band profiling of total soluble proteins from diseased Garden quinine and cowpea leaves revealed bands of 135, 100, 63, 35 and 25 kDa. Analysis of full length sequence DNA and#946; of Clerodendrum inerme mosaic virus with other begomovirus showed the closest identity of 97.76% with Clerodendron golden mosaic virus isolate Jankipuram: Lucknow. The sequences were submitted to Genbank, and accession no.-MT186259 provided for the Agra isolate under the name, Clerodendrum mosaic virus, Agra isolate. newline