To Tomato Yellow Leaf Curl Virus Research Articles

Screening Common Bean (Phaseolus vulgaris) for Resistance to Tomato yellow leaf curl virus.

Commercial cultivars of common bean (Phaseolus vulgaris) were screened for resistance to Tomato yellow leaf curl virus (TYLCV). Fourteen-day-old bean plants were inoculated with TYLCV by means of the whitefly vector (Bemisia tabaci). Following inoculation, plants were sprayed with an insecticide, kept in an insect-proof greenhouse for 4 weeks, and monitored for disease symptom development. The presence of viral DNA in the inoculated plants was assayed by dot blot hybridization and by polymerase chain reaction. Out of the 42 cultivars that were tested, 24 were found to be susceptible: the plants exhibited severe symptoms and accumulated high levels of viral DNA. In all, 18 cultivars were found to be resistant to the virus: 1 cultivar showed mild symptoms while the other 17 showed no symptoms following inoculation. From the 17 symptomless cultivars, plants of 3 cultivars contained viral DNA while no viral DNA was detected in the plants of the other 14 cultivars. When the effect of bean plant age on viral inoculation by whiteflies was assayed, it was found that the success rate of TYLCV infection was highly dependent on bean plant age. When 14-day-old susceptible bean plants were inoculated, nearly 100% infection was achieved but, when 26- or 12-day-old plants of the same cultivar were inoculated, the infection rates were only 34 and 40%, respectively.

Agroinoculation of Tomato Yellow Leaf Curl Virus (TYLCV) Overcomes the Virus Resistance of Wild Lycopersicon Species

AbstractAccessions of the wild tomato species Lycopersicon chilense LA 1969 and L. hirsutum LA 1777 which are resistant to tomato yellow leaf curl virus (TYLCV) in field‐ and in whitefly‐mediated transmission tests were agroinoculated with a tandem repeat of the TYLCV genome. Large amounts of viral DNA started to accumulate in the agroinoculated L. chilense and L. hirsutum plants about 10 days after the agroinoculation. Yellowing and narrowing of the upper leaves were observed in the L. chilense plants but no curling as in susceptible L. esculentum cultivars. The agroinoculated L. hirsutum plants showed typical yellowing and curling of young leaves. These findings indicate that TYLCV introduced by means of agroinoculation leads to the breakdown of natural resistance mechanisms which prevent the replication, spread and expression of symptoms in resistant tomato genotypes.

Genetics of resistant to tomato yellow leaf curl virus in tomato

The genetics of resistance to tomato yellow leaf curl virus (TYLCV) were studied in TYLCV-resistant lines developed by crossing wild species of Lycopersicon pimpinellifolium, L. hirsutum and L. peruvianum resistant to TYLCV with susceptible L. esculentum cv. Special Back. Crosses between TYLCV-resistant lines derived from the same wild species produced progenies similar to their parents in their level of resistance. However, progenies from interspecific crosses showed greater resistance than either parent suggesting that the genes for TYLCV resistance contributed by different wild species are probably not the same (non-allelic). The gene action for TYLCV resistance also varied with the source of resistance. Analysis of F1, F2 and BC populations for lines derived from L. pimpinellifolium showed that resistance to TYLCV in these lines is a quantitative trait with some dominance.

Accumulation of Tomato Yellow Leaf Curl Virus DNA in Tolerant and Susceptible Tomato Lines

Four tomato lines (M-60, M-54, 1970, and 2950), an F 1 hybrid (TY-20) tolerant to tomato yellow leaf curl virus (TYLCV), and the susceptible cultivars 1651, 1630, 614-1, and 199-2 were compared for accumulation of viral DNA in TYLCV-infected plants. DNA was analyzed by either alkaline transfer or dot spot hybridization using a cloned viral DNA as a probe. Results obtained with either procedure indicated that in all tested lines viral DNA accumulation peaked at 12-15 days after inoculation. At this time, accumulation of viral DNA in the tolerant genotypes was 10-50% lower than in the susceptible ones. Viral DNA then decreased up to 50% in both the tolerant and the susceptible lines, and it remained at that level (.)

Sources of resistance to tomato-yellow-leaf-curl-virus (TYLCV) in Lycopersicon species

Sources of resistance to tomato-yellow-leaf-curl-virus (TYLCV) were investigated in 16 accessions of three Lycopersicon species and 55 commercial tomato hybrids and cultivars. All commercial hybrids and cultivars were highly susceptible. Accessions of L. hirsutum, L. hirsutum f. glabaratum and L. pimpinellifolium showed a wide range of reactions. Those of L. peruvianum, LA 385 of L. peruvianum f. humifusum exhibited very high levels of resistance indicating their potential use in local breeding programs. In contrast to earlier findings, back indexing showed that all symptomless genotypes in this investigation were carriers of the TYLCV.

Inheritance of Resistance to Tomato Yellow Leaf Curl Virus Derived from Lycopersicon cheesmanii and Lycopersicon hirsutum

Abstract Inheritance of resistance to tomato yellow leaf curl virus (TYLCV) was studied in the interspecific crosses Lycopersicon escutentum Mill. cv. UC 82 x Lycopersicon cheesmanii ssp. minor (Hook) C.H. Mill. LA 1401, and Lycopersicon esculentum cv. VF 145-B-7879 x Lycopersicon hirsutum Humb. and Bonpl. LA 386. Genetic populations were artificially inoculated with TYLCV prior to transplanting, and were later evaluated under field conditions. Reaction of parents, F2 and F3 plants, and backcrosses of resistant F2 plants to UC 82, indicated that resistance derived from L. cheesmanii seems to be recessive. Narrow sense heritability (NSH) was 0.44. Reaction of parental F1, F2, and backcross plants indicated that resistance derived from L. hirsutum is dominant and controlled by more than one gene.