Etiology of Leaf Chlorosis and Deterioration of the Fruit Interior of Watermelon Plants

Abstract

A severe disease with combined symptomatology affecting only grafted watermelon plants appeared in several regions of northern and central Greece during the summers of 1999 and 2000. Disease symptoms included chlorotic mottling followed by pedicel necrosis at a later more mature fruit stage, and finally decomposition of fruit interior. Electron microscopy, double antibody sandwich enzyme-linked immunosorbent assay tests and reverse transcriptase-polymerase chain reaction assays identified Cucumber green mottle mosaic virus (CGMMV) as the causal agent. Our studies indicated that the CGMMV isolates from watermelon are closely related to the Israeli variant of CGMMV (CGMMV-Is). However, bioassays revealed that the Greek isolates elicit symptoms of higher severity and have a wider host range, compared with other described CGMMV isolates. Nucleotide sequence comparison of the movement protein gene of the Greek isolates showed a 97-99% identity with other CGMMV strains. This paper reports the presence of the virus in arable weeds such as Amaranthus blitoides, Amaranthus retroflexus, Heliotropium europaeum, Portulaca oleracea and Solanum nigrum.U. S.

Grafting for Disease Resistance

“…It is also possible that certain diseases affecting the scion may become more prevalent with the use of grafting. Boubourakas et al (2004) detected cucumber green mottle mosaic virus on grafted watermelon, whereas nongrafted watermelon were unaffected by the disease. Although this association has not been repeated, it highlights the necessity for monitoring for new disease developments when production practices change dramatically, as would be the case if farming practices shift extensively to grafted plants.…”

Biological and Molecular Characterization of Cucumber green mottle mosaic virus Affecting Bottle Gourd and Watermelon Plants in Saudi Arabia

“…Serological testing by ELISA of a large number of fruits exhibiting systemic mosaic and mild to severe yellow mottling symptoms, confirmed the presence of CGMMV. Differences were observed among CGMMV isolates in their response to differential hosts (Boubourakas et al, 2004). Serological and molecular variability has also been reported between European and Asian isolates.…”

Control of Cucurbit Viruses

“…Also, infected seeds of Lagenaria sp. and other watermelon rootstocks have introduced Cucumber green mottle mosaic virus (CGMMV) in many countries causing serious yield losses (Boubourakas, Hatziloukas, Antignus, & Katis, 2004). This emphasizes the need to check the sanitary status of both the rootstock and the cultivar/hybrid seeds.…”

“…Grafting on resistant rootstock (Lagenaria siceraria, various Cucurbita sp. including interspecific crosses between C. moschata and C. maxima and resistant melons) are now commonly used to prevent soil-borne infection by MNSV or CGMMV (Boubourakas et al, 2004;Choi, 2001 …”