Viruses associated with chlorotic rosette and green rosette diseases of groundnut in Nigeria*

Abstract

SUMMARY Groundnut (Arachis hypogaea) plants from Nigeria with chlorotic rosette disease contained a manually transmissible virus, considered to be a strain of groundnut rosette virus (GRV(C)). GRV(C) infected nine out of 32 species in three out of nine families. It caused local lesions without systemic infection in Chenopodium amaranticolor, C. murale and C. quinoa, and systemic symptoms in Glycine max, Nicotiana benthamiana, N. clevelandii and Phaseolus vulgaris as well as in groundnut. Some ‘rosette‐resistant’ groundnut lines were also infected. GRV(C) was transmitted by Aphis craccivora, but only from groundnut plants that were also infected with an aphid‐transmissible second virus, which was not manually transmissible and was considered to be groundnut rosette assistor virus (GRAV). Plants infected with GRAV contained isometric particles c. 25 nm in diameter which were detectable by immunosorbent electron microscopy on grids coated with antisera to several luteoviruses, especially with antisera to bean leaf roll, potato leafroll and beet western yellows viruses. No virus‐like particles were observed in extracts from plants infected with GRV(C) alone. A single groundnut plant obtained from Nigeria with symptoms of green rosette contained luteovirus particles, presumed to be of GRAV, and yielded a manually transmissible virus that induced symptoms similar to those of GRV(C) in C. amaranticolor but gave only mild or symptomless infection of N. benthamiana and N. clevelandii. It was considered to be a strain of GRV and designated GRV(G).

Groundnut Rossette: A Virus Disease Affecting Groundnut Production in Sub-Saharan Africa

“…One or more of these 142 plant species could be the source of the rosette complex. However, although host plants for GRAV and/or GRV and sat RNA have been identified under experimental conditions (3,25,36,44,59), groundnut is the only known natural host for the entire rosette complex. The development of the specific diagnostic techniques described earlier has enhanced the chances of identifying such alternative hosts and of understanding their role in the perpetuation of the disease.…”

A Satellite RNA of Groundnut Rosette Virus that Is Largely Responsible for Symptoms of Groundnut Rosette Disease

“…Isolates GRV(C) and GRV(G), from Nigeria, were those of Reddy et al (1985a), and were from plants with chlorotic and green forms of rosette respectively (Hayes, 1932;Hull & Adams, 1968). Additional Nigerian isolates of the same type were called GRV(C2) and GRV(G2).…”

“…Isolate GRAV(C) was that of Rajeshwari & Murant (1988) and was propagated in groundnut by graft inoculation. Procedures for raising test plants and for manual and aphid transmission were as described by Reddy et al (1985a).…”

“…Affected plants contain groundnut rosette virus (GRV), which is transmitted by Aphis craccivora only from plants that also contain groundnut rosette assistor virus (GRAV) (Okusanya & Watson, 1966: Hull & Adams, 1968Dubern, 1980;Reddy et al, 1985a). A. craccivora transmits the virus complex in the persistent (circulative) manner (Storey & Ryland, 1955).…”

“…GRV is manually transmissible but GRAV is not. GRAV is a luteovirus (Casper et al, 1983;Reddy et al, 1985a;Rajeshwari et al, 1987;Rajeshwari & Murant, 1988) with isometric particles approx. 28 nm in diameter.…”