Cucurbit Genetics Cooperative Report 7:43-44 (article
Interaction of Zucchini Yellow Mosaic Virus Strains and Muskmelon
Lecoq, H. and M. Pitrat
I.N.R.A., Centre de Recherches Agronomiques d'Avignon, B.P. 94,
84140 Montfavet, France
Zucchini yellow mosaic virus (ZYMV), a recently described member
of the potyvirus group (3), is now commonly found infecting
cucurbits in various parts of the world (2). It induces severe
symptoms including mosaic, leaf deformations, plant stunting,
necrosis and fruit alterations.
In muskmelon, two pathotypes were distinguished on 'Doublon' (1).
One is pathotype F which causes a rapid wilting of the plant and
subsequent general necrosis (WN). The second is pathotype NF
which causes vein clearing, yellowing, mosaic and leaf
deformations (VcY). Both pathotypes induce VcY symptoms in
'Vedrantais' muskmelon. The WN reaction of 'Doublon' has been
attributed to the action of the semidominant Flaccida necrosis gene, symbolized (Fn) (5).
Muskmelon plant introduction (PI) 414723 is partially resistant
to ZYMV (4). Most plants of PI 414723 remain symptomless when
inoculated with strain E15 (pathotype NF) or with strain 1318
(pathotype F) and the virus does not become systemic. This
resistance is controlled by the dominant gene Zucchini Yellow
Mosaic, symbolized (Zym) (4). Some plants may,
however, develop systemic, chloronecrotic lesions from which the
virus may be recovered.
Some ZYMV strains, such as the ZYMV type strain from Italy (3)
(pathotype NF) and strain E9 (pathotype F), induce systemic,
chloronecrotic lesions on all inoculated PI 414723 plants. The
virus can be recovered from the apex of plants infected with
these strains. From such plants, we have selected in the
laboratory ZYMV strains that completely overcome the resistance
of PI 414723 and induce on this line typical VcY symptoms.
These results suggest another classification of ZYMV strains
based on the symptoms of PI 414723 and 'Doublon' (Table 1).
Table 1. Classification of 6 ZYMV strains according to the
reaction of PI 414723 and 'Doublon' muskmelon lines.
Vein clearing yellowing (Pathotype NF)
Wilt necrosis (Pathotype F)
Symptomless (Pathotype 0)
Systemic, chloronecrotic lesions (Pathotype 1)
ZYMV type, Italy
Vein clearing yellowing (Pathotype 2)
It appears that the ability of a ZYMV isolate to induce the
wilting reaction in 'Doublon' is independent of its virulence in
PI 414723. The observed variability in the pathogenicity of ZYMV
is important, and emphasizes the need for other sources of
resistance to ZYMV even though pathotype 2 has not yet been found
in the field.
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et caractérisation d'un potyvirus provoquant la maladie du
rabougrissement Jaune du Melon. Agronomie 1:827-834.
- Lecoq, H., V. Lisa and G. Dellavalle. 1983. Serological
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