The Genetic Basis of High Resistance to Rice Yellow Mottle Virus (RYMV) in Cultivars of Two Cultivated Rice Species

Abstract

Ndjiondjop, M. N., Albar, L., Fargette, D., Fauquet, C., and Ghesquière, A. 1999. The genetic basis of high resistance to rice yellow mottle virus (RYMV) in cultivars of two cultivated rice species. Plant Dis. 83:931-935.Three cultivars of Oryza sativa (IR64, Azucena, and Gigante) and four cultivars of O. glaberrima (Tog5681, Tog5673, CG14, and SG329) were evaluated for their resistance to two isolates of rice yellow mottle virus (RYMV) by enzyme-linked immunosorbent assay (ELISA) and symptomatology. Cultivars Tog5681 and Gigante were highly resistant, and no symptoms were observed when either virus isolate was inoculated at 10 or 20 days postgermination and assayed by ELISA at 7, 14, 22, 35, 50, or 64 days postinoculation. Azucena showed a partial resistance, whereas the other cultivars were susceptible. Symptom appearance was associated with increase in ELISA absorbance in the systemically infected leaves. The best discrimination among the cultivars occurred when the plants were inoculated at 10 days postgermination. Crosses were made between the highly resistant (Gigante and Tog5681) and the susceptible (IR64) cultivars to determine the genetic basis of resistance to RYMV. Evaluation of F1 hybrids and interspecific progenies, as well as the segregation of resistance in F2 and F3 lines of the IR64 × Gigante cross, provided results consistent with the presence of a single recessive resistance gene common to Tog5681 and Gigante.

Yield Potential and Physiological and Morphological Characteristics Related to Yield Performance inOryza glaberrimaSteud.

“…Since this species is inherently low yielding compared to O. sativa, its cultivation area has decreased (Linares, 2002). However, O. glaberrima can be a source of resistance to various indigenous biotic constraints such as rice yellow mottle virus (Abo et al, 1998;Ndjiondjop et al, 1999Ndjiondjop et al, , 2001Deless et al, 2010;Maji et al, 2010), African rice gall midge Williams et al, 1999;Nwilene et al, 2009), weeds Dingkuhn et al, 1999;Fofana and Rauber, 2000), and nematodes (Coyne et al, 1995Plowright et al, 1999;Soriano et al, 1999;Lorieux et al, 2003), and to abiotic stresses such as drought (Jones et al, 1997a(Jones et al, , 1997bMaji et al, 2010;Ndjiondjop et al, 2010), submergence (Futakuchi et al, 2001;Kawano et al, 2008), iron toxicity (Sahrawat and Sika, 2002) and low phosphorus availability in acid soils (Tobita et al, 2003). Thus, this species is highly adaptable to the local rice cultivation conditions in Africa.…”

Pathogenic Variation and Occurrence of Multiple Resistance-Breaking <i>Rice yellow mottle virus</i> Strains in Tanzania

“…Insect vector control and prophylactic measures such as high surveillance of seedbeds, fields and weed reservoirs are also used for management of RYMV despite time-consuming and variable efficiency [1] [2]. The resistance of rice plants to RYMV is controlled by the recessive gene RYMV1 [3], located on chromosome 4 [4] and encodes the isoform of the eukaryotic translation initiation factor 4G (eIF (iso) 4G1) [5] but RYMV is able to evolve fast. Generally, most of resistance sources to RYMV obtained from Oryza glaberrima.…”

“…Generally, most of resistance sources to RYMV obtained from Oryza glaberrima. Several highly resistant varieties with known genes of resistant to RYMV have been identified that include rice cultivars Gigante (rymv1-2) [3], Tog12387 (rymv1-3) [6], Tog5681 (rymv1-3) [4], Tog5438 (rymv1.4), Tog5672 (rymv1-4+rymv2) and Tog5674 (rymv1-5) [7]. Resistance conferred by RYMV2 and RYMV3 genes have currently been identified on Oryza glaberrima Tog7291 and Tog5307, respectively [2] [8].…”

Relative resistance to Rice yellow mottle virus in rice

“…Azucena and a few other cultivars of Oryza sativa subsp. japonica (Ndjiondjop et al 1999). High resistance is conferred by a single recessive gene Rymv 1 which has been identified in the rice cv.…”