Serendipitous identification of Pratylenchus curvicauda from the grainbelt of Western Australia

Abstract

A Pratylenchus species identified during a survey of Pratylenchus quasitereoides incidence at four locations of the grainbelt of Western Australia is described. Morphological and morphometric features indicated the previously undescribed morphotypes in nematode mixtures encountered were conspecific to P. curvicauda, and were clearly distinguishable from nine common Pratylenchus spp. Typical features of P. curvicauda were its body length (415-540 µm), which was curved to a c-shaped with a maximum body diameter of 20 µm, and the nature of its tail; 34 µm long, 2.8 µm wide at the anus and a typical ventrally arcuate with a round terminus. Sequenced for the first time, the sequences of the partial 18S-ITS1-5.8S-ITS2-partial 28S (80 clones, 14 individual nematodes) and the 28S-D3 (17 clones) regions of the rDNA of P. curvicauda had overall mean distances of 0.013 and 0.085, respectively. Phylogenetic analyses with sequences of both segments of the rDNA clearly showed the P. curvicauda isolates as monophyletic, distinct from ca 40 Pratylenchus species. Notably, it was distinct from Pratylenchus species present in Australia including P. quasitereoides and a Western Australia isolate of P. thornei. Further research into the biology of P. curvicauda is needed to facilitate development of strategies for its management, if it is an important pest.

Assessment of the pest status of Pratylenchus curvicauda and ultrastructural changes in roots of infected wheat and barley

“…The population of P. curvicauda used in this study was obtained from soil collected from a wheat field in Pingelly, Western Australia (32°32′02.4″S, 117°05′09.6″E). A misting apparatus (Tan et al, 2013) was used to extract plant-parasitic nematodes from the field soil followed by isolation of P. curvicauda from the nematode mixtures using morphological and morphometric features, and PCR-based characterization using the differences in the DNA sequences of the partial 18S-ITS1-5.8S-ITS2-partial 28S of the rDNA and part of the 28S-D3 expansion region as described by Begum et al (2019). The misting apparatus sprayed a mist of water on the soil samples (100 g batches) for 10 s every 10 min for 72 hr, and nematodes were collected in 50 ml syringes through silicone rubber tubing tied at the end with a spring clip (Tan et al, 2013).…”

“…Calingiri), and barley (cv. Hamelin) was assessed using field soil from Pingelly, naturally and predominantly infested with P. curvicauda (Begum et al, 2019). The nematodes were identified using morphological and morphometric features, and PCRbased characterization using the differences in the DNA sequences of the partial 18S-ITS1-5.8S-ITS2-partial 28S of the rDNA and part of the 28S-D3 expansion region as described by Begum et al (2019).…”

“…Twelve economically important Pratylenchus species have been reported so far in Australia (Hodda and Nobbs, 2008;Begum et al, 2019). The most recent addition in field crops is P. curvicauda, identified in field soil from four grain-growing areas of Western Australia, namely Pingelly, Katanning, Arthur River, and Williams in 2018 (Begum et al, 2019).…”

“…Twelve economically important Pratylenchus species have been reported so far in Australia (Hodda and Nobbs, 2008;Begum et al, 2019). The most recent addition in field crops is P. curvicauda, identified in field soil from four grain-growing areas of Western Australia, namely Pingelly, Katanning, Arthur River, and Williams in 2018 (Begum et al, 2019). Although P. curvicauda was first reported in metropolitan Perth in 1991 (Siddiqi et al, 1991), it was only recently identified in field soils where wheat and barley were grown (Begum et al, 2019).…”

“…The most recent addition in field crops is P. curvicauda, identified in field soil from four grain-growing areas of Western Australia, namely Pingelly, Katanning, Arthur River, and Williams in 2018 (Begum et al, 2019). Although P. curvicauda was first reported in metropolitan Perth in 1991 (Siddiqi et al, 1991), it was only recently identified in field soils where wheat and barley were grown (Begum et al, 2019). The economic importance, biology, and host relationships of most established root-lesion nematodes in Australians soils, namely P. neglectus, P. penetrans, P. quasitereoides, P. thornei, and P. zeae, have been studied to various extents.…”