Sources of resistance to the erineum strain of Colomerus vitis (Acari: Eriophyidae) in grapevine cultivars

The erineum strain of Colomerus vitis (GEM) is the most destructive pest of vineyards in western Iran and sometimes causes considerable damages to the grapevine. Little information is available on the susceptibility of the grapevine to this pest and its knowledge can be useful for a sustainable management of GEM. The present study was aimed at evaluating the responses of the plants to the infestation of GEM in order to compare the resistance/susceptibility of some native cultivars to this pest. Also, the profiling of JA, SA and IAA in leaves of infested plants of Sezdang was studied. The experiment was carried out on eighteen native cultivars and the non-native Muscat Gordo which were selected amongst the most common in southern and western Iran. Potted plants were cultivated under greenhouse conditions at a temperature of 32 ± 3.8°C, 75 ± 5% R.H. and a photoperiod of L16: D8 h. The impact of GEM was evaluated on the basis of the leaf area and weight, number and size of the erinea, and percentage of leaves with erinea three months after the infestation. The cane length was measured, too. Mite density on galled leaves (three months after the infestation) and in buds (at the bud breaking) was assessed.        Cluster analysis based on the leaf damage index induced by GEM allowed to distinguish highly affected (Sezdang, Khalili, Ghalati and Rishbaba), moderately affected (Neyshaboori, Gazne, Muscat, Lale, Shahani Sefid, Ahmad, Monagha and Sia) and scarcely affected (Yaghuti, Rotabi, White Thompson, Atabaki, Koladari and Sahebi and Shahani Gerd) cultivars. The mite density into the buds and on the galled leaves was higher in the medium-late (Rishbaba and Khalili) and late ripening (Sezdang and Ghalati) cultivars rather than in the early (Sahebi and Shahani Gerd) and early-medium (Atabaki) ripening ones. The leaf damaged area, the leaf weight, the shoot length and the erineum development were correlated to the mite density and were the highest on Sezdang, Khalili, Ghalati and Rishbaba and the lowest on Atabaki, Koladari, Sahebi and Shahani Gerd. The highest density of the overwintering population was detected in proximal buds of all treated cultivars.        The plant responses and the mite density were investigated also in the second and third year after the first mite infestation on highly affected (Sezdang, Khalili, Ghalati, Rishbaba), a few of the moderately affected (Neyshaboori, Gazne, Muscat) and the scarcely affected cultivars (White Thompson, Atabaki, Koladari, Sahebi, Shahani Gerd). The leaf damaged area, the percentage of galled leaves, the percentage of cane length reduction and the mite density strongly decreased during all three years of observations on the highly affected Sezdang, Khalili and Gazne. On the contrary, Ghalati and Rishbaba displayed an increase of the leaf damaged area, leaf damaged index and mite density on galled leaves during the same period in comparison to the first year of observation. The percentage of the leaves with erinea, the leaf damaged area and the mite density of Sezdang were highly and positively correlated with IAA while a negative correlation was found between the leaf damaged area and the mite density with SA and JA in the assayed years. Almost all data currently collected allowed a recognition of White Thompson, Atabaki, Koladari, Sahebi and Shahani Gerd as the least affected cultivars.</jats:p

Study of defense-related gene expression in grapevine infested by Colomerus vitis (Acari: Eriophyidae)

Real-time quantitative polymerase chain reaction was used to study the expression of some marker genes involved in the interaction between grape (Vitis vinifera L.) and the erineum mite Colomerus vitis Pagenstecher (Acari: Eriophyidae). Potted vines of cultivars Atabaki (resistant to C. vitis), Ghalati (susceptible to C. vitis) and Muscat Gordo (moderately resistant to C. vitis) were infested at the six-leaf stage. The expression of protease inhibitor (PIN), beta-1,3-glucanase (GLU), polygalacturonase inhibitor (PGIP), Vitis vinifera proline-rich protein 1 (PRP1), stilbene synthase (STS), and lipoxygenase (LOX) genes was assessed on young leaves collected 96, 120 and 144&nbsp;h after mite infestation (hami). As a control, non-infested leaves collected 24&nbsp;h before mite infestations were used. Differences were detected in expression of the selected genes during the C. vitis–grapevine interaction. The resistant cultivar Atabaki increased the expression of LOX, STS, GLU, PGIP and PRP1 genes during the first 120 hami. On the contrary, in the susceptible Ghalati, all selected genes showed an expression level similar or lower than non-infested leaves. Muscat Gordo increased the expression of all selected genes in comparison with non-infested leaves, but it was lower than in Atabaki. Significant transcript accumulation of PIN gene was detected for Muscat Gordo whereas it was slightly up-regulated in Ghalati and Atabaki. LOX, STS, PIN, GLU, PGIP and PRP1 genes were clearly expressed in response to C. vitis infestation. We therefore infer that expression of PGIP, PIN and PRP1 genes could represent a defense strategy against C. vitis infestations in grapevine leaves

Impact of the erineum strain of Colomerus vitis (Acari: Eriophyidae) on the development of plants of grapevine cultivars of Iran

The present experiment was aimed at determining the influence of the grape erineum strain of Colomerus vitis (GEM) (Acari: Eriophyidae) on responses of local grapevine cultivars. GEM was applied at five density levels to each of five cultivars, i.e. Shahani, Sahebi Uroomie, Khalili Bovanat, Rishbaba and Sezdang Ghalat (listed from early to late grape ripening). The experiment was performed in a full factorial design (12 replicates each) and effects of the mite on the relative content of leaf chlorophyll, internode and cane length, leaf area and weight, number and size of the erinea, and percentage of leaves with erinea were investigated. Also mite density on leaves and in buds was assessed. Data were analyzed with a two-way ANOVA followed by Tukey’s test to separate means among treatment levels and cultivars. The relative content of chlorophyll (expressed in Spad units) in infested leaves was reduced along with an increase in mite density and it was shown to be highly significant at the two higher mite density levels for Khalili Bovanat, Rishbaba and Sezdang Ghalat; Shahani and Sahebi Uroomie leaves appeared to be less affected by mite infestation. The highest mite density treatment displayed a strong correlation with weight (positive correlation) and size (negative correlation) of the leaves of four cultivars; leaves of Sahebi Uroomie appeared to be less affected. The reduced internode length was weak in infested plants. Most infested plants produced shorter canes and their lengths appeared to have a strong negative correlation with the highest mite density in four cultivars; canes of Sahebi Uroomie did not appear affected. At the highest mite density, canes of Khalili Bovanat and Sahebi Uroomie displayed the most and the least shortening effects, respectively. The percentage of leaves with erinea, as well as the number of erinea per leaves and the diameter of erinea increased along with the mite population density. The mite densities in buds (April 2014) and on leaves with erinea (in November 2013) were higher at the highest treatment level in the medium-late (Rishbaba) and late ripening (Sezdang Ghalat) cultivars, than in the early and early-medium ripening ones. Almost all data collected in the current experiment allowed the conclusion that Sahebi Uroomie and Shahani were less affected than the other cultivars (Khalili Bovanat, Rishbaba and Sezdang Ghalat)

Resistance of grapevine to the erineum strain of Colomerus vitis (Acari: Eriophyidae) in western Iran and its correlation with plant features.

Trisetacus juniperinus (Nalepa) sensu Keifer (Acari: Eriophyoidea: Phytoptidae) causes irregular development of buds, shoot deformations and stunted growth of trees, resulting in a serious threat to nurseries and young stands of Cupressus sempervirens L. (Mediterranean cypress). Recently, some cypress clones selected for their resistance to the fungal canker agent Seiridium cardinale (Wag.) have shown high susceptibility to the mite. Considering its tiny body, its hidden lifestyle inside the buds and the probable occurrence of other species (the vagrant Epitrimerus cupressi (Keifer) is common on the Mediterranean cypress in Italy), detection and monitoring of T. juniperinus require taxonomic expertise and are often time-consuming and challenging before serious damage is discernible. In the present study, a rapid, cost-effective PCR-based method was developed and validated to detect T. juniperinus on cypresses. The cytochrome c oxidase subunit I gene was amplified with degenerate and specific primers, but the latter were the only ones able to discriminate between T. juniperinus and E. cupressi. PCR products distinguished the two species both in a pool of individuals in a mixed population of both species and in single individuals, indicating the sensitivity of the detection method. PCR–RFLP (restriction fragment length polymorphism) by means of XmnI and XbaI endonucleases separated the two species. Furthermore, a washing-sieving protocol was used to make mite collection from the tree sample faster and simpler; this procedure did not interfere with the molecular detection of the species. The possibility of the routine use of this assay to monitor quarantine eriophyoids infesting plant material is discussed

Study of defense-related gene expression in grapevine infested by Colomerus vitis (Acari: Eriophyidae)

Real-time quantitative polymerase chain reaction was used to study the expression of some marker genes involved in the interaction between grape (Vitis vinifera L.) and the erineum mite Colomerus vitis Pagenstecher (Acari: Eriophyidae). Potted vines of cultivars Atabaki (resistant to C. vitis), Ghalati (susceptible to C. vitis) and Muscat Gordo (moderately resistant to C. vitis) were infested at the six-leaf stage. The expression of protease inhibitor (PIN), beta-1,3-glucanase (GLU), polygalacturonase inhibitor (PGIP), Vitis vinifera proline-rich protein 1 (PRP1), stilbene synthase (STS), and lipoxygenase (LOX) genes was assessed on young leaves collected 96, 120 and 144&nbsp;h after mite infestation (hami). As a control, non-infested leaves collected 24&nbsp;h before mite infestations were used. Differences were detected in expression of the selected genes during the C. vitis–grapevine interaction. The resistant cultivar Atabaki increased the expression of LOX, STS, GLU, PGIP and PRP1 genes during the first 120 hami. On the contrary, in the susceptible Ghalati, all selected genes showed an expression level similar or lower than non-infested leaves. Muscat Gordo increased the expression of all selected genes in comparison with non-infested leaves, but it was lower than in Atabaki. Significant transcript accumulation of PIN gene was detected for Muscat Gordo whereas it was slightly up-regulated in Ghalati and Atabaki. LOX, STS, PIN, GLU, PGIP and PRP1 genes were clearly expressed in response to C. vitis infestation. We therefore infer that expression of PGIP, PIN and PRP1 genes could represent a defense strategy against C. vitis infestations in grapevine leaves

Influence of the erineum strain of Colomerus vitis (Acari: Eriophyidae) on grape (Vitis vinifera) defense mechanisms

Grape (Vitis vinifera) is commonly affected by the erineum strain of Colomerus vitis (GEM) in Iran and the susceptibility of grape cultivars to GEM is poorly understood. In order to evaluate the impact of GEM on grape and its defense mechanisms against the mite, an exploratory study was carried out on 19 cultivars (18 Iranian and the non-native Muscat Gordo). The differential susceptibility of cultivars to GEM was compared on the basis of the area of leaf damage induced by GEM. The cultivars White Thompson seedless of Bovanat, Atabaki Zarghan, Koladari Ghoochan and Sahebi Uroomie were less susceptible to GEM, whereas Ghalati Dodaj, Rishbaba, Muscat Gordo and Neyshaboori Birjand appeared to be the most affected by the mite. In a no-choice setup, plants of selected cultivars of these two groups were infested by GEM and assayed for 10 biomarkers usually related to plant stress mechanisms against plant feeders: the activity of defense enzymes—peroxidase (POX), polyphenol oxidase (PPO), superoxide dismutase (SOD), phenylalanine ammonia-lyase (PAL), catalase (CAT), the amount of total polyphenolics, total flavonoids, total soluble carbohydrates, hydrogen peroxide (H2O2), and malondialdehyde (MDA) expressing lipid peroxidation. The biomarkers were assessed in grape leaves 7 days before releasing the mites, as well as 7, 14 and 28 days after infestation (DAI). The activity of the enzymes and the amount of the compounds usually increased in percentage after mite infestation. A significant negative correlation was found between the area of leaf damage and PPO, POX, SOD, MDA and H2O2for all sampling dates. The area of leaf damage showed a significant positive correlation with total soluble carbohydrates at 28 DAI, and significant negative correlations with CAT (at 14 and 28 DAI), PAL and total flavonoids (at 7 DAI). No correlation was observed between area of leaf damage and total polyphenolics. The biomarkers PPO, SOD, CAT activity and H2O2provided the best explanation for the response of grape cultivars to GEM infestation