The aim of this review was to undertake a survey of researchers working with plant-parasitic nematodes in order to determine a ‘top 10’ list of these pathogens based on scientific and economic importance. Any such list will not be definitive as economic importance will vary depending on the region of the world in which a researcher is based. However, care was taken to include researchers from as many parts of the world as possible when carrying out the survey. The top 10 list emerging from the survey is composed of: (1) root-knot nematodes (Meloidogyne spp.); (2) cyst nematodes (Heterodera and Globodera spp.); (3) root lesion nematodes (Pratylenchus spp.); (4) the burrowing nematode Radopholus similis; (5) Ditylenchus dipsaci; (6) the pine wilt nematode Bursaphelenchus xylophilus; (7) the reniform nematode Rotylenchulus reniformis; (8) Xiphinema index (the only virus vector nematode to make the list); (9) Nacobbus aberrans; and (10) Aphelenchoides besseyi. The biology of each nematode (or nematode group) is reviewed briefly.

/pdf/top-10-plant-parasitic-nematodes-in-molecular-plant-22vrx0hc6m.pdf

Top 10 plant-parasitic nematodes in molecular plant pathology

Top 10 plant parasitic nematodes in molecular plant pathology in (Abstracts from the 6th International Congress of Nematology, Cape Town, South Africa, 4-9 May 2014)

Oomycetes form a deep lineage of eukaryotic organisms that includes a large number of plant pathogens which threaten natural and managed ecosystems. We undertook a survey to query the community for their ranking of plant-pathogenic oomycete species based on scientific and economic importance. In total, we received 263 votes from 62 scientists in 15 countries for a total of 33 species. The Top 10 species and their ranking are: (1) Phytophthora infestans; (2, tied) Hyaloperonospora arabidopsidis; (2, tied) Phytophthora ramorum; (4) Phytophthora sojae; (5) Phytophthora capsici; (6) Plasmopara viticola; (7) Phytophthora cinnamomi; (8, tied) Phytophthora parasitica; (8, tied) Pythium ultimum; and (10) Albugo candida. This article provides an introduction to these 10 taxa and a snapshot of current research. We hope that the list will serve as a benchmark for future trends in oomycete research.

/pdf/the-top-10-oomycete-pathogens-in-molecular-plant-pathology-3gxpkolrjj.pdf

The Top 10 oomycete pathogens in molecular plant pathology

https://espace.library.uq.edu.au/view/UQ:705404/UQ705404_OA.pdf

Emerging microbial biocontrol strategies for plant pathogens.

Parasitic nematodes (roundworms) and platyhelminths (flatworms) cause debilitating chronic infections of humans and animals, decimate crop production and are a major impediment to socioeconomic development. Here we report the broadest comparative study to date of the genomes of parasitic and non-parasitic worms, involving 81. We have identified gene family births and hundreds of expanded gene families at key nodes in the phylogeny that are relevant to parasitism. Examples include gene families that modulate host immune responses, enable parasite migration though host tissues or allow the parasite to feed. We reveal extensive lineage-specific differences in core metabolism and protein families historically targeted for drug development. From an in silico screen, we have identified and prioritised new potential drug targets and compounds for testing. This comparative genomics resource provides a much needed boost for the research community to understand and combat parasitic worms.

/pdf/comparative-genomics-of-the-major-parasitic-worms-4kdqf5ty69.pdf

Comparative genomics of the major parasitic worms

The nematophagous fungus Pochonia chlamydosporia var. chlamydosporia is one of the most studied biological control agents against plant (semi-) endo-parasitic nematodes of the genera Globodera, Heterodera, Meloidogyne, Nacobbus and, more recently, Rotylenchulus. In this paper we present highlights from more than three decades of worldwide research on this biological control agent. We cover different aspects and key components of the complex plant-fungus-nematode tri-trophic interaction, an interaction that needs to be addressed to ensure the efficient use of P. chlamydosporia as a biopesticide as part of an integrated pest management approach.

Pochonia chlamydosporia: Advances and Challenges to Improve Its Performance as a Biological Control Agent of Sedentary Endo-parasitic Nematodes.

Identification, morphology and biology of plant parasitic nematodes.

The two known species of Nacobbus, N. aberrans and N. dorsalis, are sedentary root endoparasites that occur in the Americas. The parasitic habits of these two so-called "false root-knot nematode" species include similarities to both root lesion and root-knot nematodes. The migratory and vermiform juveniles and immature adults behave like lesion nematodes, causing cavities and lesions inside the root tissues, whereas the mature females are sedentary and obese and induce root galls and specialized feeding sites as do true root-knot nematodes. Limited information is available on the less wellknown species N. dorsalis, which is present only in California where it has negligible economic importance and parasitizes only a few non-cultivated plants without evidence of attack on agricultural crops. In contrast, many studies have examined the biology, economic impact, and management of the more economically important N. aberrans, which occurs in temperate and subtropical latitudes of North and South America. This false root-knot (or potato rosary) nematode has a wide host range, which includes at least 84 plant species. Many common weeds are good hosts. The results of host and field studies conducted in North and South America indicate that N. aberrans populations can be separated into bean, potato and sugarbeet groups. The populations of each group have distinct host preferences and do not reproduce on graminaceous species or on leguminous species of the genera Medicago and Lupinus. The yield losses reported on staple and industrial crops infected by N. aberrans average 65% for potato in the Andean region of Latin America, 55% and 36% for tomato and bean in Mexico, respectively, and 10-20% for sugarbeet in the United States (Nebraska). Different levels of resistance, varying according to the nematode population, have been found in bean, chilli pepper, potato, and tomato. Most research on crop rotation, mixed cropping, and chemical and non-chemical strategies for management of N. aberrans has been conducted on bean, chilli pepper, and tomato in Mexico, potato in Argentina, Bolivia and Peru, and sugarbeet in the United States.

/pdf/the-genus-nacobbus-thorne-allen-1944-nematoda-pratylenchidae-4tseh8jw7h.pdf

Rosa H. Manzanilla-López

Papers

Top 10 plant-parasitic nematodes in molecular plant pathology

Top 10 plant parasitic nematodes in molecular plant pathology in (Abstracts from the 6th International Congress of Nematology, Cape Town, South Africa, 4-9 May 2014)

Pochonia chlamydosporia: Advances and Challenges to Improve Its Performance as a Biological Control Agent of Sedentary Endo-parasitic Nematodes.

Identification, morphology and biology of plant parasitic nematodes.

The genus nacobbus thorne & allen, 1944 (nematoda: pratylenchidae): systematics, distribution, biology and management