Fluctuations of Prunus Necrotic Ringspot Virus (PNRSV) at Various Phenological Stages in Peach Cultivars

Abstract

Fluctuations in Prunus necrotic ringspot virus (PNRSV) concentration were researched in single plants of six peach (Prunus persicae) cultivars—Kurakata, Red Haven, Nectar Red, Start Delicious, Meadowlark, and Loadel—by double antibody sandwich-enzyme-linked immunosorbent assay (DAS-ELISA) of dormant buds (May, June), flowers (September), new sprouts (November), and mature leaves (January) (Southern Hemisphere). The optimum extract dilution (sample weight per buffer volume) to detect the virus was also quantified. The average absorbance patterns of the six cultivars show a steady increase in virus concentration, ranging from A 405nm 0.61 in May to A 405nm 0.86 in July for dormant buds, to A 405nm 1.22 in September in flowers, to 1.53 in November in new sprouts, where the highest concentration was found. Virus concentrations in mature leaves drop to values similar to those of noninfected plants in January ( A405nm 0.12). The yearly average (six noninfected peach trees) ranged from A405nm 0.04 to A405nm 0.08. This drop coincides with an increase in summer temperature and attenuates foliation symptoms caused by PNRSV. Analysis of dormants buds, flowers, or new sprouts with 5-cm-long leaves was reliable to differentiate infected from noninfected plants. Cluster analysis of absorbance profiles for single plants of cvs. Loadel and Meadowlark, however, showed a comparatively low profile, with a drop at flowering time (A405nm 0.20 in September) close to the average of healthy controls. The difference between infected and healthy plants did not become apparent in all cultivars from the analysis of plants at a given phenological stage, for example by the analysis of flower only, the material most preferred to diagnose the virus. Therefore, plants should be analyzed during flowering and sprouting or flowering and dormancy (dormant buds).

Recent Advances on Detection and Characterization of Fruit Tree Viruses Using High-Throughput Sequencing Technologies

“…Some of these pathogens are causing diseases adversely affecting yield and/or decreasing the fruit quality [ 1 ]. The identification, detection, and characterization of the causal agents of such diseases are challenging, due to the low titer and irregular within-plant distribution of viruses in perennial plants, the occurrence of both inter- and intra-species mixed-infections in single trees, the frequent symptomless infections or fluctuation of symptom intensity during the season, and the complex and heterogeneous nature of viral populations [ 3 , 4 , 5 , 6 , 7 , 8 , 9 ].…”

Genetic diversity of the movement and coat protein genes of South American isolates of Prunus necrotic ringspot virus

“…PNRSV has been detected in many South American countries and in different host species. The prevalence of the virus in stone fruit trees in the central zone of Chile is 9.7% [28], while it reaches up to 25% in temperate zones in Argentina [14]. In Brazil, PNRSV has been detected in Rio Grande do Sul with a prevalence of 17% [16], while in Uruguay its prevalence is even higher, 48% [35].…”

Seasonal variation in Blueberry scorch virus concentration in highbush blueberry and implications for disease monitoring and management

“…If leaf tissue is sampled, our results suggest that studies of temporal variation in BlScV concentration are needed for each of the principal cultivars in a production area to determine optimal timing. The results of Dal Zotto et al (1999), Torrance and Dolby (1984) and Varveri et al (1997) corroborate this view for different virus-host plant systems.…”

“…Nothing is known of the seasonal variation in BlScV concentration but, given the importance of aphid numbers, the synchrony between aphid population dynamics and temporal changes in BlScV concentration may affect the epidemiology. Fluctuations in concentration of other viruses at different stages of crop development have been reported in garlic (Dovas et al 2002), red spruce (Bachand and Castello 1998), and peach (Dal Zotto et al 1999;Polák 1995Polák , 1998.…”