Survival of Xiphinema index in Vineyard Soil and Retention of Grapevine fanleaf virus Over Extended Time in the Absence of Host Plants

Abstract

Grapevine fanleaf virus (GFLV) is transmitted specifically from grapevine to grapevine by the ectoparasitic root-feeding nematode Xiphinema index. Limited information is available on the survival of X. index in vineyard soil and on the retention of GFLV by X. index over extended periods of time. We addressed these two issues by quantifying the numbers of living X. index recovered from soil samples that were collected in three naturally GFLV-infected vineyards in France and subsequently stored at 7 or 20 degrees C in the absence of host plants. Our data indicated a two- to eightfold decrease in X. index numbers but the recovery of 8 to 10 living fourth-stage juveniles (J4) and adults per kilogram of soil after 4 years of storage regardless of temperature. In addition, GFLV was detected readily in all groups of 20 isolated X. index adults and J4 (except for J4 that were kept 4 years at 20 degrees C) by reverse transcription-polymerase chain reaction using total nematode RNAs and a primer set located in conserved regions at the 3' end of viral genomic RNA 2. Our findings on the long-term survival of viruliferous X. index under adverse conditions emphasize the need for new control strategies against GFLV.

Molecular detection of Grapevine fanleaf Virus by the isolation of ssRNA and dsRNA from Xiphinema index

“…An efficient transmission of GFLV isolates by different populations of X. index has previously been reported (Catalano et al, 1989;1991;1992). X. index can retain GFLV for at least 4 years (Demangeat et al, 2005). Based on Demangeat et al (2010) findings with seven X. index lines from diverse geographical locations, it is reasonable to expect that most, if not all, X. index populations are able to transmit natural GFLV isolates.…”

Survival of Xiphinema index in clay loam soil

“…• C for periods from two up to four years (Demangeat et al 2005). The X. index populations from Crete, in the study presented here, have been subjected to higher temperature and drying stress, as they had been stored in small bags and kept in a cupboard at room temperature which in winter dropped to 13…”

“…However, the nematode is able to survive in fields after uprooting the vineyards, for periods up to 4.5 years (Raski et al 1965). Also a four year survival period of the nematode, with a concomitant retention of the GFLV, was recorded when kept in vineyard soil stored in the lab (Demangeat et al 2005).…”

Simple and Portable Magnetic Immunoassay for Rapid Detection and Sensitive Quantification of Plant Viruses

“…The fluidMAG-streptavidin beads had a superparamagnetic magnetite core covered with a hydrophilic polymer functionalized with covalently coupled streptavidin, allowing the binding of biotinylated molecules. Hence, biotinylated mAbFL 6 antibodies were coupled to the streptavidin-coated magnetic beads before injection into the immunofil-tration columns. Biotinylation of mAbFL 6 was achieved using an EZ-Link biotinylation kit (Thermo Fisher Scientific, Waltham, MA, USA), with the conditions being adjusted according to the manufacturer's recommendations so that the number of biotin molecules could be statistically limited to 2 to 4 molecules per antibody.…”

“…It belongs to subgroup A of the genus Nepovirus in the subfamily Comovirinae (5). GFLV is predominantly transmitted by nematodes in infected vineyard soils, where the virus can remain dormant for many years without any need for host plants (6). Furthermore, GFLV can be transmitted by grafting or the propagation of infected grapevine plants.…”