Search Results

You are looking at 1 - 10 of 67 items for :

  • virus-resistant papayas x
Clear All

The disease resistance of a transgenic line expressing the coat protein (CP) gene of the mild strain of the papaya ringspot virus (PRSV) from Hawaii was further analyzed against PRSV isolates from Hawaii and other geographical regions. Line 63-1 originated from the same transformation experiment that resulted in line 55-1 from which the transgenic commercial cultivars, `Rainbow' and `SunUp', were derived. Plants of line 63-1 used in this study consisted of a population from a self pollinated R0 bisexual plant. ELISA and PCR tests provided evidence that there are at least two segregating CP loci. To allow for comparison with reactions of the previously reported line 55-1, virus isolates from Hawaii, Brazil, Thailand, and Jamaica were used to challenge seedlings of 63-1. Unlike line 55-1, a significant percentage of inoculated transgenic plants were susceptible to isolates from Hawaii. However, a proportion of plants were resistant to the non-Hawaiian isolates. In contrast, previous work showed that all plants of the hemizygous line 55-1 were susceptible to PRSV isolates from Brazil, Thailand, and Jamaica. Line 63-1, therefore, presents Hawaii with PRSV-resistant transgenic germplasm that could be used as a source of transgenes for resistance to PRSV isolates within and outside of Hawaii.

Free access

PI 414723 has received much attention from melon (Cucumis melo L.) breeders, pathologists, and entomologists for resistances to zucchini yellow mosaic and watermelon mosaic viruses, including resistances to virus multiplication and subsequent transmission by the melon aphid, powdery mildew resistance, and melon aphid (Aphis gossypii Glover). PI 414723 was derived from PI 371795, which was a contaminant in cucumber (Cucumis sativus L.) PI 175111 collected in 1948 by Walter N. Koelz in Mussoorie, Uttar Pradesh, India (altitude 1829 m). Its fruit, which have soft flesh and rind that split at maturity, are used in soups and stews, and the seeds are roasted and eaten. PI 414723, PI 371795, and the related Ames 20219 and progeny 92528a were resistant to California and Florida isolates of papaya ringspot virus watermelon strain (PRSV-W). Plants were either symptomless, or they exhibited local lesions, systemic necrosis, or systemic spots. Resistance to PRSV-W is conditioned by a single dominant gene. Allelism with Prv1 (PI 180280, Rajkot, Gujarat, India), Prv2 (PI 180283, Bhavnagar, Gujarat, India), Nm (`Vedrantais, Fance), and a recently described gene for PRSV-W resistance in PI 124112 (Calcutta, India) is yet to be determined.

Free access
Authors: and

Plant viruses are extremely difficult to manage in vegetable crops, particularly those viruses transmitted by aphids (Aphididae) in a nonpersistent manner. Viruses in the genus Potyvirus [e.g., papaya ringspot virus (PRSV), watermelon mosaic virus

Free access

.F. Chen, J.H. Chen, Y.W. Yeh, S.D. 2011 Generation of transgenic watermelon resistant to Zucchini yellow mosaic virus and Papaya ringspot virus type W Plant Cell Rep. 30 359 371

Free access

., 2009 ; Ling et al., 2009 ). Fig. 1. Leaves of the Papaya ringspot virus (PRSV)-resistant Citrullus colocynthis Plant Introduction (PI) 537277 (upper) vs. distorted leaves of the susceptible C. colocynthis PI 549161 (lower) following inoculation

Free access

), watermelon mosaic virus (WMV), and papaya ringspot virus (PRSV) from ‘Marketmore 88’ ( Fig. 1 ). Description and Performance The fruit of ‘Marketmore 76’ and ‘Marketmore 97’ are nearly identical in length, diameter, weight, and appearance ( Table 1

Free access

development of virus symptoms due to PRSV and ZYMV in susceptible and resistant genotypes of tropical pumpkin from inoculation in the greenhouse to mature plants in the field, 2) to determine whether greenhouse evaluations of PRSV and ZYMV are predictive of a

Open Access

Abstract

Greenflesh Honeydew (GFHD) musk-melon (Cucumis melo L.) is an erratic performer in the varied environments of Arizona, California (Imperial Valley and San Joaquin Valley), and Texas. The vines are susceptible to powdery mildew caused by Sphaero-theca fuliginea (Schlecht. ex. Fr.) Poll, and the cucurbit mosaic viruses including papaya ringspot virus (watermelon mosaic virus, see ref. 3), watermelon mosaic virus 2, and zucchini yellow mosaic virus. Common quality defects of the fruit include traces of net, nonuniform shapes and sizes, low soluble solids, thin flesh, the cavity becoming watery prior to best edibility, and poor flavor. This report describes PMR Honeydew, a recently released powdery mildew resistant honeydew breeding line.

Open Access

Resistance to watermelon mosaic virus (WMV) was transferred by successive backcrossing with selection from Cucumis melo PI 414723 to three melon varieties. Levels of resistance to virus accumulation in leaf tissue were evaluated using enzyme-linked immunosorbent assay, and procedures are described to select resistant individuals efficiently and accurately in segregating populations. Resistance is controlled by a single dominant. gene designated Wmr. Plants that carry this gene initially develop mosaic symptoms on inoculated leaves, but eventually recover from symptoms, and low or no virus can be detected in the youngest leaves. In contrast, susceptible plants show similar symptoms initially, but remain stunted and symptomatic with reduced fruit yield and fruit quality. Co-infection with other cucurbit viruses, specifically cucumber mosaic virus, papaya ringspot virus, and zucchini yellow mosaic virus, did not overcome resistance to WMV conferred by Wmr.

Free access

Potyviruses cause severe loss in cucurbit crops. Inbred lines derived from the Chinese cucumber cultivar, Taichung Mau Gua (TMG), have been identified to be resistant to several potyviruses including zucchini yellow mosaic virus (ZYMV), zucchini yellow fleck virus, watermelon mosaic virus, and the watermelon strain of papaya ringspot virus. Recently, an additional virus that infects cucurbits, the Moroccan watermelon mosaic virus (MWMV), has been identified to be a distinct member of the potyvirus group. In this study, we sought to determine if TMG-1 is resistant to MWMV and, if so, examine whether a relationship exists between resistance to MWMV and resistance to ZYMV. Progeny analyses show that TMG-1 is resistant to MWMV and, like resistance to ZYMV, MWMV resistance is conferred by a single recessive gene. Sequential inoculation of progeny possessing resistance to ZYMV followed by MWMV (or MWMV followed by ZYMV) suggests that both resistances are conferred by the same gene, or two tightly linked genes. Additionally, all F3 families derived from F2 individuals selected for resistance to ZYMV, were resistant to MWMV. A second source of resistance to ZYMV, allelic to the TMG-1 source, has been incorporated into the Dutch hybrid Dina. Progeny analyses show Dina to posses a single recessive gene for MWMV resistance. As with TMG-1, no segregation of resistances was observed when ZYMV resistant progeny were inoculated with MWMV (or MWMV followed by ZYMV). Collectively, these results suggest that a single gene, or two tightly linked genes, control resistance to the potyviruses ZYMV and MWMV.

Free access