scholarly journals IDENTIFICATION AND DISTRIBUTION OF ROOT-KNOT NEMATODE SPECIES IN POMEGRANATE ORCHARDS OF EASTERN IRAN

2021 ◽  
Vol 33 (2) ◽  
pp. 293-297
Author(s):  
Nafiseh Katooli ◽  
Esmat M. Moghadam ◽  
Reza Aghnum

2005 ◽  
Vol 95 (2) ◽  
pp. 158-165 ◽  
Author(s):  
A. Pegard ◽  
G. Brizzard ◽  
A. Fazari ◽  
O. Soucaze ◽  
P. Abad ◽  
...  

In the pepper Capsicum annuum CM334, which is used by breeders as a source of resistance to Phytophthora spp. and potyviruses, a resistance gene entirely suppresses reproduction of the root-knot nematode (Meloidogyne spp.). The current study compared the histological responses of this resistant line and a susceptible cultivar to infection with the three most damaging root-knot nematodes: M. arenaria, M. incognita, or M. javanica. Resistance of CM334 to root-knot nematodes was associated with unidentified factors that limited nematode penetration and with post-penetration biochemical responses, including the hypersensitive response, which apparently blocked nematode migration and thereby prevented juvenile development and reproduction. High-performance liquid chromatography analysis suggested that phenolic compounds, especially chlorogenic acid, may be involved in CM334 resistance. The response to infection in the resistant line varied with root-knot nematode species and was correlated with nematode behavior and pathogenicity in the susceptible cultivar: nematode species that quickly reached the vascular cylinder and initiated feeding sites in the susceptible cultivar were quickly recognized in CM334 and stopped in the epidermis or cortex. After comparing our data with those from other resistant pepper lines, we suggest that timing of the resistance response and the mechanism of resistance vary with plant genotype, resistance gene, and root-knot nematode species.


Nematology ◽  
2021 ◽  
pp. 1-9
Author(s):  
Hung X. Bui ◽  
Johan A. Desaeger

Summary Cover crops can be a useful tool for managing plant-parasitic nematodes provided they are poor or non-hosts for the target nematode species. A glasshouse experiment was done to determine the host status of four common cover crops in Florida, sunn hemp, cowpea, sorghum sudangrass and sunflower, to pure populations of four common tropical root-knot nematode (RKN) species Meloidogyne javanica (Mj), M. incognita (Mi), M. enterolobii (Me) and M. arenaria (Ma). Tomato was included as a susceptible control. Eight weeks after nematode inoculation (WAI), tomato showed the highest root gall damage for all tested RKN species, with gall indices (GI) between 7 (Ma) and 8.5 (Me) and reproduction factor (RF) ranging from 20 (Ma) to 50 (Mj). No visible root galls were observed for any of the RKN species on sunn hemp and sorghum sudangrass at 8 WAI. However, Mj and Mi were able to reproduce slightly on sorghum sudangrass (RF = 0.02 and 0.79, respectively). Sunflower and cowpea were infected by all four tested RKN species, but host suitability varied. Sunflower root galling ranged from 1.1 (Me) to 4.5 (Mj) and RF = 3.2 (Me) to 28.7 (Mj), while cowpea root galling ranged from 0.6 (Mi) to 5.1 (Me) and RF = 0.8 (Mi) to 67.3 (Mj). Sunn hemp and, to a lesser extent, sorghum sudangrass were poor hosts to all four tested RKN species. Sunflower was a good host to all RKN species, but root gall damage and RF were lowest for Me. Cowpea was a good host to Mj, Me and Ma, but a poor host to Mi. Our results confirm and stress the importance of RKN species identification when selecting cover crops as an RKN management strategy.


Nematology ◽  
2001 ◽  
Vol 3 (2) ◽  
pp. 129-139 ◽  
Author(s):  
Jaap Bakker ◽  
Fred Gommers ◽  
Geert Smant ◽  
Pierre Abad ◽  
Marie-Noëlle Rosso ◽  
...  

AbstractExpressed sequence tags (EST) have been widely used to assist in gene discovery in various organisms (e.g., Arabidopsis thaliana, Caenorhabditis elegans, Mus musculus, and Homo sapiens). In this paper we describe an EST project, which aims to investigate gene expression in Meloidogyne incognita at the onset of parasitism. Approximately 1000 5′-end sequence tags were produced from a cDNA library made of freshly hatched preparasitic second stage juveniles (J2). The EST were identified in the primary transformants of the cDNA library, and assigned to nine different functional groups, including (candidate) parasitism genes. A large fraction of the EST (45%) did not have a putative homologue in public databases. Sixty five percent of the EST that could be clustered into a functional group had putative homologues in other nematode species. EST were found for virtually all parasitism related genes that have been cloned from M. incognita to date. In addition, several novel genes were tagged, including a xylanase and a chitinase gene. The efficiency of EST projects, which produce sequence data for thousands of genes in months time without any difficult pre-selections of mRNA pools, makes random sequencing cDNA libraries a superior method to identify candidates for parasitism related genes in plant-parasitic nematodes. The sequences in this paper are retrievable from Genbank with the accession numbers BE191640 to BE191741, BE217592 to BE217720, BE225324 to BE225598, BE238852 to BE239221, and BE240829 to BE240865.


HortScience ◽  
2004 ◽  
Vol 39 (1) ◽  
pp. 120-123 ◽  
Author(s):  
Martin Schochow ◽  
Steven A. Tjosvold ◽  
Antoon T. Ploeg

Lisianthus [Eustoma grandiflorum (Raf.) Shinn.] plants were grown in soil infested with increasing densities of Meloidogyne hapla Chitwood, M. incognita (Kofoid & White) Chitwood, or M. javanica (Treub) Chitwood, root-knot nematodes. Compared to tomato plants grown in soil with the same nematode numbers and species, lisianthus had less severe root symptoms, suffered less damage, and resulted in lower nematode multiplication rates. Lisianthus was a better host for M. javanica than for M. incognita, and a poor host for M. hapla. Lisianthus shoot weights were significantly reduced after inoculation with M. javanica or M. hapla, but not after M. incognita inoculation. The number of flowers produced per lisianthus plant was reduced by all three nematode species. The results show that the root-knot nematode species that are most common in California may cause significant damage in the cut-flower production of lisianthus.


2018 ◽  
Vol 22 (1) ◽  
pp. 58
Author(s):  
Hishar Mirsam ◽  
Fitrianingrum Kurniawati

Root Knot Nematode (RKN) is one of the most important cosmopolite parasitic nematode species. Reports on RKN associated with rice root in Indonesia are still limited in West Java and Yogyakarta. This study aimed to identify the RKN associated with rice root in Sub-district of Bola, District of Wajo, South Sulawesi, based on morphological and molecular characters. Sampling was carried out by purposive method based on specific criteria of sample, i.e. root knot. Identification of root knot nematode (RKN) infestation in field was done by observing the primary and secondary symptoms. Morphological identification was carried out based on characters of juvenile 2 and the female perineal pattern. Molecular identification was based on amplification of r-DNA by polymerase chain reaction technique using primers rDNA2 and rDNA 1.58s. RKN were detected associated with the incidence of root knot in rice plant. RKN was identified as Meloidogyne graminicola based on morphological characters of juvenile 2 and the female perineal pattern. PCR using primer rDNA 2 / rDNA 1.58s successfully amplified a DNA band of RKN of ± 500 bp. Nucleotide sequence analysis showed that RKN isolated from Wajo was closely related to M. graminicola isolated from Nepal, China, India, Madagascar, and USA with homology of 98.1–100.00%. IntisariNematoda puru akar (NPA) merupakan salah satu jenis nematoda parasit penting yang bersifat kosmopolit. Laporan NPA yang berasosiasi dengan akar tanaman padi di Indonesia masih terbatas di Jawa Barat dan Yogyakarta. Penelitian ini bertujuan mengidentifikasi NPA yang berasosiasi dengan akar tanaman padi di Kabupaten Wajo, Sulawesi Selatan berdasarkan karakter morfologi dan molekuler. Pengambilan sampel dilakukan secara purposif dengan memilih sampel berdasarkan pada kriteria gejala spesifik penyakit puru akar. Identifikasi serangan dilakukan dengan mengamati gejala primer dan gejala sekunder. Identifikasi morfologi dilakukan dengan pengamatan karakter morfologi juvenil 2 dan pola perineal NPA betina.Identifikasi molekuler dilakukan dengan teknik polymerase chain reaction (PCR) untuk mengamplifikasi wilayah internal transcribed spacer (ITS) ribosomal DNA (rDNA) menggunakan pasangan primer rDNA2 dan rDNA1.58s. NPA ditemukan berasosiasi dengan akar tanaman padi yang memperlihatkan gejala puru akar. NPA diidentifikasi sebagai Meloidogyne graminicola berdasarkan karakter morfologi juvenil 2 dan pola perineal NPA betina. PCR menggunakan primer rDNA2/ rDNA1.58s berhasil mengamplifikasi pita DNA NPA dengan ukuran sekitar 500 bp. Analisis runutan nukleotida menunjukkan isolat NPA asal Wajo-Indonesia memiliki tingkat kekerabatan yang sangat dekat dengan isolat M. graminicola asal Nepal, Cina, India, Madagaskar, dan Amerika Serikat dengan nilai homologi berkisar 98,1–100,0%.


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