Histopathology and histochemistry of lesions caused by<i>Pratylenchus penetrans</i>in roots of forage legumes

Townshend, J. L.; Stobbs, L. W.

doi:10.1080/07060668109501931

Cited by 15 publications

(20 citation statements)

References 14 publications

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“…The number of TLDs that accumulated within the cortical root cells in each cultivar was different: deposition of TLDs in the resistant cultivar MNGRN-16 was especially massive, both in control plants, and particularly after infection with P. penetrans . Increase in numbers of TLDs in alfalfa root cells during infection with P. penetrans and their potential implication in host defenses against RLN were reported as early as 1981 (Townshend and Stobbs, 1981), and later confirmed in 1989 (Townshend et al, 1989). Both studies, however, used alfalfa cultivar Du Puits, that appeared to be susceptible to P. penetrans (Olthof, 1982), and did not perform any comparative analyses with alfalfa resistant cultivars.…”

Section: Discussionmentioning

confidence: 96%

Cellular and Transcriptional Responses of Resistant and Susceptible Cultivars of Alfalfa to the Root Lesion Nematode, Pratylenchus penetrans

et al. 2019

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The root lesion nematode (RLN), Pratylenchus penetrans , is a migratory species that attacks a broad range of crops, including alfalfa. High levels of infection can reduce alfalfa forage yields and lead to decreased cold tolerance. Currently, there are no commercially certified varieties with RLN resistance. Little information on molecular interactions between alfalfa and P. penetrans , that would shed light on mechanisms of alfalfa resistance to RLN, is available. To advance our understanding of the host–pathogen interactions and to gain biological insights into the genetics and genomics of host resistance to RLN, we performed a comprehensive assessment of resistant and susceptible interactions of alfalfa with P. penetrans that included root penetration studies, ultrastructural observations, and global gene expression profiling of host plants and the nematode. Several gene-candidates associated with alfalfa resistance to P. penetrans and nematode parasitism genes encoding nematode effector proteins were identified for potential use in alfalfa breeding programs or development of new nematicides. We propose that preformed or constitutive defenses, such as significant accumulation of tannin-like deposits in root cells of the resistant cultivar, could be a key to nematode resistance, at least for the specific case of alfalfa- P. penetrans interaction.

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Section: Discussionmentioning

confidence: 96%

Cellular and Transcriptional Responses of Resistant and Susceptible Cultivars of Alfalfa to the Root Lesion Nematode, Pratylenchus penetrans

et al. 2019

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“…The damage to cells upon which the nematode has fed, and to cells adjacent to the pathway of nematode migration, might result from both physical and biochemical factors, as reported for other Pratylenchus spp. (Acedo & Rohde, 1971;Townshend & Stobbs, 1981;Townshend et al, 1989). Although damage to endodermal cells occurred in some cultivars, P. thornei was not found feeding on endodermal cells, even in the most susceptible genotypes.…”

Section: Discussionmentioning

confidence: 99%

Pathogenicity and histopathology of Pratylenchus thornei populations on selected chickpea genotypes

1998

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Four populations of Pratylenchus thornei from different locations were tested for reproductive fitness in axenic carrot disc cultures and for pathogenicity to chickpea cultivars JG 62 and UC 27 and lines K 850 and ILC 1929. Parasitism and histopathology on selected chickpea genotypes (JG 62, UC 27 and lines ILC 482, ICC 11324 and ICC 12237) were also investigated. Reproductive fitness, assessed as the ratio of the final number of nematodes per carrot disc to the number of nematodes inoculated, was similar among the populations tested and the four populations reproduced to a similar extent in a given chickpea genotype. However, the extent of reproduction was significantly affected by the chickpea genotype, JG 62 and UC 27 being the best and poorest hosts, respectively. Pathogenicity to chickpea genotypes was assessed by the difference in fresh root and dry shoot weights between infected and uninfected plants 90 days after inoculation. Plant growth was significantly reduced by the four nematode populations in all chickpea genotypes, with the exception of cv. JG 62, which was tolerant of P. thornei. Severity of root necrosis caused by nematode infection was similar for all populations. Histopathological studies of chickpea genotypes infected by P. thornei showed that all were suitable hosts according to nematode reproduction and host reaction. P. thornei always migrated through epidermal and cortical cells by breaking down cell walls along the nematode pathway. In the most susceptible lines (ILC 482 and JG 62), damage to endodermal cells adjacent to nematode feeding sites was occasionally observed.

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“…In a study using mixed inoculum, Oyekan et al (1972) reported that males were more likely to exit lesioned areas in pea roots, resulting in a 5:1 infection ratio of females to males. Townshend (1978) demonstrated that female P. penetrans penetrated roots at a broader range of temperature than males. Wixted and MacGuidwin (1990) observed roots occupied only by males had less apparent discoloration than roots with females, but no study tested the hypothesis that males and females were equal for the ability to induce lesions.…”

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confidence: 98%

Difference in lesion formation by male and female Pratylenchus penetrans

Saikai

MacGuidwin

2020

Journal of Nematology

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Pratylenchus penetrans induce necrotic lesions, the hallmark symptom for the genus, soon after infection. The objective of our study was to characterize and quantify gender differences in lesion development. Independent experiments were conducted in vitro for three hosts; pea (Pisum sativum L. cv. Early Alaskan), dill (Anethum graveolens cv. Long Island Mammoth), and alfalfa (Medicago sativa cv. Vernal). Each experimental unit was an excised radical placed on water agar in a Petri dish and inoculated with either 40 adult males or 40 fourth-stage juvenile females. Length, size, and number of lesions were recorded during the experiment and the radicals were harvested 14 days after introducing nematodes. Lesions were first observed on pea after two days for female-inoculated roots, and 24 hr after introducing both genders to dill and alfalfa. Lesions expanded either by multiple lesions coalescing or individual lesions expanding over time. Males made fewer, smaller lesions with less discoloration for all three hosts. There was no difference among genders for the total number of nematodes recovered per Petri dish or the number of endoparasitic nematodes after 14 days. The survival rate of males and females at harvest was not different, indicating that the difference in lesion formation was not related to nematode population densities. This study verified and quantified the observation that lesions induced by males are less extensive and in smaller numbers than lesions by females.

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Histopathology and histochemistry of lesions caused byPratylenchus penetransin roots of forage legumes

Cited by 15 publications

References 14 publications

Cellular and Transcriptional Responses of Resistant and Susceptible Cultivars of Alfalfa to the Root Lesion Nematode, Pratylenchus penetrans

Cellular and Transcriptional Responses of Resistant and Susceptible Cultivars of Alfalfa to the Root Lesion Nematode, Pratylenchus penetrans

Pathogenicity and histopathology of Pratylenchus thornei populations on selected chickpea genotypes

Difference in lesion formation by male and female Pratylenchus penetrans

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