Molecular investigation of proteinase inhibitor (PI) gene in tomato plants induced by Meloidogyne species

Background The plant parasitic nematode genus Meloidogyne parasitize almost all flowering crops. Plants respond with a variety of morphological and molecular mechanisms to reduce the effects of pathogens. Proteinase inhibitors (PI), a special group of plant proteins which are small proteins, involve in protective role in the plants attacked by microorganisms. Still, the plant response using PI against nematodes has not been well understood. Therefore, this study was aimed to determine the expression of proteinase inhibitor I (PI-I) gene subsequent the infection of M. incognita, M. javanica, and M. chitwoodi in tomato plants post nematode infections. Molecular methods were used to determine the PI gene expressions at different days post nematode infections in host tissues. Results Results revealed that the population of M. incognita species reached the highest level of nematode population followed by M. javanica and M. chitwoodi, respectively. All Meloidogyne species induced expression of PI-I gene reached at the utmost level at 3 days post infection (dpi) in host tissues. Relative gene expression level was sharply dropped at 7 dpi, 14 dpi, and 21 dpi in M. incognita induced gene expression in host tissues. Similar results were observed in host tissues after infection of M. javanica and M. chitwoodi. Conclusions The commonalities of plant response across a diverse Meloidogyne species interaction and the expression of PI gene may be related to plant defense system. Increased level of PI gene expressions in early infection days in host tissues induced by parasitic nematodes may share resemblances to the mechanisms of resistance on biotrophic interactions.

Reaction of grapevine rootstocks and cultivars to Meloidogyne incognita, M. arenaria and M. hapla

This study aimed to evaluate the reaction of six grapevine rootstocks (MGT 101-14, Ritcher 110, Paulsen 1103, K 5BB, SO4, Salt creek) and two cultivars (Quebranta and Torontel) to three species of the root-knot nematode (Meloidogyne incognita, M. arenaria and M.hapla). The experiment was performed as a completely randomized design with an 8 × 3 factorial scheme and six replicates per treatment. The experimental unit in each replicate comprised a grapevine cutting planted in 3 kg bags with sterilized soil. Cuttings were inoculated with 5000 eggs + juveniles (J2) of M. incognita, M. arenaria and M. hapla. Six months after inoculation, plants were removed from the bags, and the reaction was determined by evaluating the number of galls (NG), number of nematodes per gram of root (NNGR), and reproduction factor (RF). The evaluated rootstocks, MGT 101-14, Ritcher 110, Paulsen 1103, K 5BB, SO4 and Salt Creek, were resistant to M. incognita, M. arenaria and M. hapla, except for Salt creek, which was susceptible to the latter. The Quebranta and Torontel cultivars were susceptible to the Meloidogyne species under study.

Meloidogynidae: Meloidogyne species.

This chapter includes information on: authentic identification; geographical distribution; risk of introduction; host ranges; symptoms; biology and ecology; planting material liable to carry the nematode; chance of establishment; likely impact; phytosanitary measures; and a detailed account of diagnosis procedures, such as sampling, isolation/detection and identification with morphological and molecular characterization, of invasive plant-parasitic Meloidogyne species.

Distribution of Meloidogyne species in carrot in Brazil

ABSTRACT: Root-knot nematodes (RKN - Meloidogyne spp.) are one of the most serious threats to carrot production worldwide. In Brazil, carrots are grown throughout the year, and economic losses due to RKN are reported. Since little is known on the distribution of RKN species in carrot fields in Brazil, we collected plant and soil samples from 35 fields across six states. Based on the morphology of perineal patterns, esterase phenotypes and species-specific PCR, three Meloidogyne species were identified: 60% of the fields were infested with Meloidogyne incognita, M. javanica was reported in 42.9% of the areas, whereas M. hapla was detected in 17.1% of carrot fields. Mixed populations were reported in 20% of the areas with a predominance of M. incognita + M. javanica. The combination of morphological, biochemical, and molecular techniques is a useful approach to identify RKN species.

The Use of Essential Oil and Hydrosol Extracted from Cuminum cyminum Seeds for the Control of Meloidogyne incognita and Meloidogyne javanica

The essential oil (EO) and hydrosol (HL) isolated from Cuminum cyminum (cumin) seeds were evaluated against the root-knot nematodes Meloidogyne incognita and M. javanica. The efficacy of extracts on the motility, hatching, and survival in soil of second-stage juveniles (J2s), and the activity on egg differentiation were tested. All J2s were paralyzed after immersion in the EO at 62.5 μL/L concentration for 96 h. Encouraging results were recorded using HL equal to or higher than 10% concentration for both Meloidogyne species tested. More than 70% paralyzed J2s were recorded after immersion for 48 h, while the percentage was increased to higher than 90% after 96 h of immersion. A clear effect on egg differentiation was observed after immersion in EO or HL. A significant decrease in egg differentiation was revealed at even low concentrations of EO while an evident decrease in egg differentiation was recorded after immersion of eggs in 50% HL dilution. Decreased hatching of M. incognita and M. javanica J2s was observed with the increase in concentration. The lowest numbers of hatched J2s were recorded when EO was used at 1000 and 2000 μL/L concentrations. A constant reduction in root-knot nematode J2 hatching was observed upon increasing the concentration of HL from 5% to 50%. The EO of C. cyminum is characterized by the presence of γ-terpinene-7-al (34.95%), cumin aldehydes (26.48), and α-terpinene-7-al (12.77%). The above constituents were observed in HL following the same order as that observed in EO. The components γ-terpinene (11.09%) and ο-cymene (6.56%) were also recorded in EO while they were absent in HL.