scholarly journals Planting Material of Enset (Ensete ventricosum), a Key Food Security Crop in Southwest Ethiopia, Is a Key Element in the Dissemination of Plant-Parasitic Nematode Infection

2021 ◽  
Vol 12 ◽  
Author(s):  
Selamawit A. Kidane ◽  
Solveig Haukeland ◽  
Beira H. Meressa ◽  
Anne Kathrine Hvoslef-Eide ◽  
Danny L. Coyne
Keyword(s):  
Food Security ◽  
Nematode Infection ◽  
Parasitic Nematodes ◽  
Herbaceous Plant ◽  
Root Lesion Nematode ◽  
Plant Parasitic Nematodes ◽  
Ensete Ventricosum ◽  
Planting Material ◽  
Lesion Nematode ◽  
Plant Parasitic

Enset (Ensete ventricosum), is a perennial herbaceous plant belonging to the family Musaceae, along with banana and plantain. Despite wild populations occurring in eastern, central and southern Africa, it is only in Ethiopia that the crop has been domesticated, where it is culturally and agriculturally symbolic as a food security crop. Although an under-researched orphan crop, enset serves as a staple food for about 20% of the Ethiopian population, comprising more than 20 million people, demonstrating its value in the country. Similar to banana and plantain, enset is heavily affected by plant-parasitic nematodes, with recent studies indicating record levels of infection by the root lesion nematode Pratylenchus goodeyi. Enset is propagated vegetatively using suckers that are purposely initiated from the mother corm. However, while banana and plantain suckers have proven to be a key source of nematode infection and spread, knowledge on the infection levels and role of enset suckers in nematode dissemination is lacking. Given the high levels of plant-parasitic nematodes reported in previous surveys, it is therefore speculated that planting material may act as a key source of nematode dissemination. To address this lack of information, we assessed enset planting material in four key enset growing zones in Ethiopia. A total of 340 enset sucker samples were collected from farmers and markets and analyzed for the presence of nematodes. Nematodes were extracted using a modified Baermann method over a period of 48 h. The root lesion nematode P. goodeyi was present in 100% of the samples, at various levels of infection. These conclusive results show that planting material is indeed a key source of nematode infection in enset, hence measures taken to ensure clean suckers for planting will certainly mitigate nematode infection and spread. The effect of nematode infection on yield and quality on enset remains to be investigated and would be a way forward to complement the nematode/disease studies conducted so far and add valuable knowledge to the current poorly known impact of pests and diseases.

THE ROOT-LESION NEMATODE, PRATYLENCHUS PENETRANS (COBB, 1917) FILIP. & STEK., 1941, IN STRAWBERRY IN THE NIAGARA PENINSULA AND NORFOLK COUNTY IN ONTARIO

1962 ◽  
Vol 42 (4) ◽  
pp. 728-736 ◽  
Author(s):  
J. L. Townshend
Keyword(s):  
Nematode Population ◽  
Parasitic Nematodes ◽  
Pratylenchus Penetrans ◽  
Root Lesion Nematode ◽  
Plant Parasitic Nematodes ◽  
Controlled Conditions ◽  
Large Numbers ◽  
Lesion Nematode ◽  
Plant Parasitic

Pratylenchus penetrans (Cobb, 1917) Filip. & Stek., 1941, and Paratylenchus projectus Jenkins, 1956, were the predominant plant parasitic nematodes associated with strawberry in the Niagara Peninsula and Norfolk County in Ontario from 1956 to 1960. However, P. penetrans was the only nematode whose occurrence could be correlated with a specific type of root lesion and with stunting. The lesions it caused on the roots were elliptical and amber to dark brown. All strawberry varieties examined were infected with P. penetrans. Under controlled conditions large numbers of P. penetrans were required to produce stunting. The amount of growth was inversely proportional to the density of the initial nematode population.

scholarly journals Occurrence of plant-parasitic nematodes on enset (Ensete ventricosum) in Ethiopia with focus on Pratylenchus goodeyi as a key species of the crop

Nematology ◽  
2020 ◽  
pp. 1-13
Author(s):  
Selamawit A. Kidane ◽  
Beira H. Meressa ◽  
Solveig Haukeland ◽  
Trine Hvoslef-Eide ◽  
Christer Magnusson ◽  
...  
Keyword(s):  
Population Density ◽  
Molecular Data ◽  
Parasitic Nematodes ◽  
Plant Parasitic Nematodes ◽  
Ensete Ventricosum ◽  
Mountainous Regions ◽  
Southwestern Ethiopia ◽  
Key Species ◽  
Lesion Nematode ◽  
Plant Parasitic

Summary Enset (Ensete ventricosum) is an important starch staple crop, cultivated primarily in south and southwestern Ethiopia. Enset is the main crop of a sustainable indigenous African system that ensures food security in a country that is food deficient. Related to the banana family, enset is similarly affected by plant-parasitic nematodes. Plant-parasitic nematodes impose a huge constraint on agriculture. The distribution, population density and incidence of plant-parasitic nematodes of enset was determined during August 2018. A total of 308 fields were sampled from major enset-growing zones of Ethiopia. Eleven plant-parasitic nematode taxa were identified, with Pratylenchus (lesion nematode) being the most prominent genus present with a prominence value of 1460. It was present in each sample, with a highest mean population density per growing zone of 16 050 (10 g root)−1, although densities as high as 25 000 were observed in fields at higher altitudes in Guraghe (2200-3000 m a.s.l.). This lesion nematode is found in abundance in the cooler mountainous regions. Visible damage on the roots and corms was manifested as dark purple lesions. Using a combination of morphometric and molecular data, all populations were identified as P. goodeyi and similar to populations from Kenya, Uganda and Spain (Tenerife). Differences in population densities amongst cultivars indicate possible resistance of enset to P. goodeyi.

scholarly journals A new esophageal gland transcriptome reveals signatures of large scale de novo effector birth in the root lesion nematode Pratylenchus penetrans

BMC Genomics ◽  
2020 ◽  
Vol 21 (1) ◽  
Author(s):  
Paulo Vieira ◽  
Jonathan Shao ◽  
Paramasivan Vijayapalani ◽  
Thomas R. Maier ◽  
Clement Pellegrin ◽  
...  
Keyword(s):  
Large Scale ◽  
Molecular Mechanisms ◽  
Parasitic Nematodes ◽  
Gene Gain ◽  
Pratylenchus Penetrans ◽  
Root Lesion Nematode ◽  
Plant Parasitic Nematodes ◽  
Depth Analysis ◽  
Lesion Nematode ◽  
Plant Parasitic

Abstract Background The root lesion nematode Pratylenchus penetrans is a migratory plant-parasitic nematode responsible for economically important losses in a wide number of crops. Despite the importance of P. penetrans, the molecular mechanisms employed by this nematode to promote virulence remain largely unknown. Results Here we generated a new and comprehensive esophageal glands-specific transcriptome library for P. penetrans. In-depth analysis of this transcriptome enabled a robust identification of a catalogue of 30 new candidate effector genes, which were experimentally validated in the esophageal glands by in situ hybridization. We further validated the expression of a multifaceted network of candidate effectors during the interaction with different plants. To advance our understanding of the “effectorome” of P. penetrans, we adopted a phylogenetic approach and compared the expanded effector repertoire of P. penetrans to the genome/transcriptome of other nematode species with similar or contrasting parasitism strategies. Our data allowed us to infer plausible evolutionary histories that shaped the effector repertoire of P. penetrans, as well as other close and distant plant-parasitic nematodes. Two remarkable trends were apparent: 1) large scale effector birth in the Pratylenchidae in general and P. penetrans in particular, and 2) large scale effector death in sedentary (endo) plant-parasitic nematodes. Conclusions Our study doubles the number of validated Pratylenchus penetrans effectors reported in the literature. The dramatic effector gene gain in P. penetrans could be related to the remarkable ability of this nematode to parasitize a large number of plants. Our data provide valuable insights into nematode parasitism and contribute towards basic understating of the adaptation of P. penetrans and other root lesion nematodes to specific host plants.

Testing for Plant-parasitic Nematodes that Feed on Corn in Iowa 2000-2010

2011 ◽  
Vol 12 (1) ◽  
pp. 2 ◽  
Author(s):  
Gregory L. Tylka ◽  
Adam J. Sisson ◽  
Laura C. Jesse ◽  
John Kennicker ◽  
Christopher C. Marett
Keyword(s):  
Sampling Time ◽  
Parasitic Nematodes ◽  
State University ◽  
Root Lesion Nematode ◽  
Plant Parasitic Nematodes ◽  
Iowa State University ◽  
Population Densities ◽  
The Past ◽  
Lesion Nematode ◽  
Plant Parasitic

The Iowa State University Plant and Insect Diagnostic Clinic analyzes soil and root samples for plant-parasitic nematodes. The results of samples associated with corn that were submitted from 2000 through 2010 were summarized. One or more genera of plant-parasitic nematodes were found in 92% of the samples. Spiral nematode and root-lesion nematode were most commonly found. Other nematodes recovered were dagger, lance, needle, pin, ring, and stunt nematodes. Nematodes recovered at damaging population densities were dagger, needle, ring, and spiral nematodes. An average of 15 samples were submitted per year from 2000 to 2004. Sample numbers increased nearly threefold since 2005, but overall sample numbers were low every year from 2000 through 2010. Samples were received from 53 of the 99 Iowa counties, and most samples were received in June and July, which is the recommended sampling time. Nematodes that have been associated with corn in Iowa in the past that were not recovered from the samples were sheath, sting, and stubby-root nematodes. The methods used to extract the nematodes from soil and roots and how the samples were handled during collection and processing may have affected the species and population densities recovered. Much more frequent and widespread sampling is needed in Iowa for plant-parasitic nematodes that feed on corn. Accepted for publication 28 October 2011. Published 5 December 2011.

Plant parasitic nematodes in white clover and soil from white clover pastures in Australia

1997 ◽  
Vol 37 (1) ◽  
pp. 75 ◽  
Author(s):  
L. J. McLeish ◽  
G. N. Berg ◽  
J. M. Hinch ◽  
L. V. Nambiar ◽  
M. R. Norton
Keyword(s):  
White Clover ◽  
Parasitic Nematode ◽  
Cyst Nematode ◽  
Parasitic Nematodes ◽  
Root Lesion Nematode ◽  
Plant Parasitic Nematodes ◽  
Meloidogyne Spp ◽  
Trifolium Repens L ◽  
Lesion Nematode ◽  
Plant Parasitic

Summary. Seventeen sites, including locations in all the major white clover growing regions of Australia, were surveyed for the presence of plant parasitic nematodes in autumn and spring 1993. Trifolium repens L. cvv. Haifa and Irrigation, plus 1 other cultivar, were sampled at each site and nematodes extracted from roots, stems and soil. Thirteen genera of plant parasitic nematodes were detected. The clover cyst nematode, Heterodera trifolii, and root knot nematodes, Meloidogyne spp., were each recorded at over 75% of the sites. The most common genera of plant parasitic nematodes detected were Tylenchus, which was present at all sites, and Pratylenchus (root lesion nematode), which was present at all but 1 site. Other plant parasitic nematode genera found included Ditylenchus, Helicotylenchus and Paratylenchus. The widespread presence of nematodes in white clover pastures, and the high populations at some sites, suggest that they may be economically important to the Australian dairy industry.

scholarly journals Toward genetic modification of plant-parasitic nematodes: delivery of macromolecules to adults and expression of exogenous mRNA in second stage juveniles

2021 ◽  
Vol 11 (2) ◽  
Author(s):  
Olaf Kranse ◽  
Helen Beasley ◽  
Sally Adams ◽  
Andre Pires-daSilva ◽  
Christopher Bell ◽  
...  
Keyword(s):  
Food Security ◽  
Genetic Modification ◽  
The Body ◽  
Forward Genetics ◽  
Heterodera Schachtii ◽  
Parasitic Nematodes ◽  
Plant Parasitic Nematodes ◽  
Root Knot Nematode ◽  
Cyst Nematodes ◽  
Plant Parasitic

Abstract Plant-parasitic nematodes are a continuing threat to food security, causing an estimated 100 billion USD in crop losses each year. The most problematic are the obligate sedentary endoparasites (primarily root knot nematodes and cyst nematodes). Progress in understanding their biology is held back by a lack of tools for functional genetics: forward genetics is largely restricted to studies of natural variation in populations and reverse genetics is entirely reliant on RNA interference. There is an expectation that the development of functional genetic tools would accelerate the progress of research on plant-parasitic nematodes, and hence the development of novel control solutions. Here, we develop some of the foundational biology required to deliver a functional genetic tool kit in plant-parasitic nematodes. We characterize the gonads of male Heterodera schachtii and Meloidogyne hapla in the context of spermatogenesis. We test and optimize various methods for the delivery, expression, and/or detection of exogenous nucleic acids in plant-parasitic nematodes. We demonstrate that delivery of macromolecules to cyst and root knot nematode male germlines is difficult, but possible. Similarly, we demonstrate the delivery of oligonucleotides to root knot nematode gametes. Finally, we develop a transient expression system in plant-parasitic nematodes by demonstrating the delivery and expression of exogenous mRNA encoding various reporter genes throughout the body of H. schachtii juveniles using lipofectamine-based transfection. We anticipate these developments to be independently useful, will expedite the development of genetic modification tools for plant-parasitic nematodes, and ultimately catalyze research on a group of nematodes that threaten global food security.

The role of plant-parasitic nematodes in reducing yield of sugarcane in fine-textured soils in Queensland, Australia

2007 ◽  
Vol 47 (5) ◽  
pp. 620 ◽  
Author(s):  
B. L. Blair ◽  
G. R. Stirling
Keyword(s):  
Growth And Yield ◽  
Parasitic Nematodes ◽  
Plant Parasitic Nematodes ◽  
Root Knot Nematode ◽  
Population Densities ◽  
Lesion Nematode ◽  
Yield Responses ◽  
The Impact ◽  
Stalk Length ◽  
Plant Parasitic

Damage to sugarcane caused by root-knot nematode (Meloidogyne spp.) is well documented in infertile coarse-textured soils, but crop losses have never been assessed in the fine-textured soils on which more than 95% of Australia’s sugarcane is grown. The impact of nematodes in these more fertile soils was assessed by repeatedly applying nematicides (aldicarb and fenamiphos) to plant and ratoon crops in 16 fields, and measuring their effects on nematode populations, sugarcane growth and yield. In untreated plant crops, mid-season population densities of lesion nematode (Pratylenchus zeae), root-knot nematode (M. javanica), stunt nematode (Tylenchorhynchus annulatus), spiral nematode (Helicotylenchus dihystera) and stubby-root nematode (Paratrichodorus minor) averaged 1065, 214, 535, 217 and 103 nematodes/200 mL soil, respectively. Lower mean nematode population densities were recorded in the first ratoon, particularly for root-knot nematode. Nematicides reduced populations of lesion nematode by 66–99% in both plant and ratoon crops, but control of root-knot nematode was inconsistent, particularly in ratoons. Nematicide treatment had a greater impact on shoot and stalk length than on shoot and stalk number. The entire community of pest nematodes appeared to be contributing to lost productivity, but stalk length and final yield responses correlated most consistently with the number of lesion nematodes controlled. Fine roots in nematicide-treated plots were healthier and more numerous than in untreated plots, and this was indicative of the reduced impact of lesion nematode. Yield responses averaged 15.3% in plant crops and 11.6% in ratoons, indicating that nematodes are subtle but significant pests of sugarcane in fine-textured soils. On the basis of these results, plant-parasitic nematodes are conservatively estimated to cost the Australian sugar industry about AU$82 million/annum.

scholarly journals First Report of the Spiral Nematode Scutellonema brachyurum on Lilyturf in the United States

Plant Disease ◽  
2011 ◽  
Vol 95 (1) ◽  
pp. 74-74 ◽  
Author(s):  
P. Agudelo ◽  
D. Harshman
Keyword(s):  
United States ◽  
Population Density ◽  
The United States ◽  
Parasitic Nematodes ◽  
Initial Population ◽  
Herbaceous Plant ◽  
Plant Parasitic Nematodes ◽  
Essential Information ◽  
First Report ◽  
Plant Parasitic

Lilyturf (Liriope muscari (Decne.) L.H. Bailey), an herbaceous plant, is commonly used in landscaping including borders (along sidewalks, driveways, and trees) and mass plantings as groundcover in the southeastern United States. In December of 2009, a soil sample was submitted to our lab for diagnosis of plant-parasitic nematodes from an area planted with lilyturf located on the Clemson University main campus. A high population density (1,220 individuals/100 cm3 of soil) of spiral nematodes (Scutellonema brachyurum (Steiner, 1938) Andrássy, 1958) was found by routine extraction by sugar centrifugal flotation (3). Other plant-parasitic nematodes, mainly ring nematodes (10 individuals/100 cm3) and stubby root nematodes (10 individuals/100 cm3), were present. To verify if high numbers of spiral nematodes were consistently associated with lilyturf, 20 additional soil and root samples were collected from different places on the campus. In all cases, S. brachyurum was found in densities ranging from 680 to 1,600 individuals/100 cm3 of soil (average of 1,210 individuals/100 cm3). The species was identified by morphological characters of females, including well developed stylet (26 to 30 μm long), no spermatheca, no sperm in uterus, tail broadly rounded with 8 to 12 annules between anus and tail, and scutella at anus level. As is commonly the case for this species, no males were found in any of the samples collected. Examination of the roots revealed numerous, small, reddish brown, necrotic lesions, apparently caused by the feeding and penetration of S. brachyurum. Host plant suitability and pathogenicity of the nematode were tested in the greenhouse. Ten nematode-free lilyturf plants grown individually in 15-cm-diameter plastic pots with pasteurized soil were inoculated with 1,000 spiral nematodes each. Ten uninoculated plants were kept under identical conditions as controls. Three months after inoculation, soil population densities were measured and reproduction factors were calculated to be between 2.8 and 5.4 (final population density divided by initial population density) for the 10 plants. Characteristic lesions previously described were observed in the roots of all inoculated plants, along with slight chlorosis of foliage. These symptoms were not observed on control plants. Spiral nematodes may attack the roots and stolons of lilyturf as ectoparasites or they may enter them and feed in the cortex as endoparasites. Although root lesions were common on affected plants, root injury in general was not severe and generalized root decay was not observed on either the collected plants or those from the greenhouse study. Reports on the pathogenicity of S. brachyurum are variable. Moderate damage was recorded on amaryllis and other ornamentals (4), while measurable damage was observed on tobacco (2), with approximately 100 individuals/100 cm3 of soil, and severe damage on Aloe vera ((L.) Burm. f.), with approximately 500 individuals/100 cm3 (1). To our knowledge, this is the first report of S. brachyurum causing visible symptoms on lilyturf. As the interstate and international movement of perennial plants continues to grow, awareness of the host status of potentially harmful nematodes becomes essential information. References: (1) R. P. Esser et al. Nematropica 16:65, 1986. (2) T. W. Graham. Phytopathology (Abstr.) 45:347, 1955. (3) W. R. Jenkins. Plant Dis. Rep. 48:692, 1964. (4) L. Nong and G. F. Weber. (Abstr.) Phytopathology 54:902, 1964.

Handbook of invasive plant-parasitic nematodes

2021 ◽  
Keyword(s):  
Invasive Plant ◽  
Global Perspective ◽  
Parasitic Nematodes ◽  
Plant Parasitic Nematodes ◽  
Government Officials ◽  
Potential Threat ◽  
Planting Material ◽  
Detection And Identification ◽  
Phytosanitary Measures ◽  
Plant Parasitic

Abstract This volume compiles and updates information on invasive plant-parasitic nematodes and their looming threat in different countries. It offers a global perspective on invasive nematodes by presenting 17 chapters with information on more than 100 nematodes and their potential threat in different countries. Each nematode entry includes information on: authentic identification; geographical distribution; risk of introduction; host ranges; symptoms; biology and ecology; planting material liable to carry the nematode(s) and its vector, if any; 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. The aim of the book is to provide basic and advanced knowledge on invasive nematodes with a global perspective, and it targets practitioners, professionals, scientists, researchers, students and government officials working on plant quarantine and biosecurity with regard to plant-parasitic nematodes.

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