The plant cell inhibitor KRP6 is involved in multinucleation and cytokinesis disruption in giant-feeding cells induced by root-knot nematodes.
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ABSTRACT:
SUBMITTER: Vieira P
PROVIDER: S-EPMC4622652 | biostudies-other | 2015
REPOSITORIES: biostudies-other
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Project description:Biotrophic plant pathogens have evolved sophisticated strategies to manipulate their host. They derive all of their nutrients from living plant tissues, by making intimate contact with their host while avoiding a resistance response. Rice is one of the most important crop plants worldwide and an excellent model system for studying monocotyledonous plants. Estimates of annual yield losses due to plant-parasitic nematodes on this crop range from 10 to 25% worldwide. One of the agronomically most important nematodes attacking rice is the rice root knot nematode Meloidogyne graminicola. Attack of plant roots by sedentary plant parasitic nematodes, like the root knot nematodes (RKN; Meloidogyne spp.) involves the development of specialized feeding cells in the vascular tissue. The second stage juvenile of the RKN punctures selected vascular cells with its stylet, injects pharyngeal secretions, and this ultimately leads to the reorganisation of these cells into typical feeding structures called giant cells (GCs), from which the nematode feeds for the remainder of its sedentary life cycle (Gheysen & Mitchum, 2011). Morphological and physiological reprogramming of the initial feeding cell leads to nucleus enlargement, proliferation of mitochondria and plastids, metabolic activation, cell cycle alterations and cell wall changes (Gheysen and Mitchum, 2011). The hyperplasia and hypertrophy of the surrounding cells leads to the formation of a root gall, which is typically formed at the root tips in the case of the rice RKN M. graminicola. In comparison with other RKN, M. graminicola has a very fast life cycle, with swelling of the root tips observed as early as 1 day after infection (dai). At 3 dai, terminal hook-like galls are clearly visible (Bridge et al., 2005). After 3 moults the nematodes are mature, around 10 dai. The M. graminicola females lay their eggs inside the galls, while most other RKN deposit egg masses at the gall surface, and hatched juveniles can reinfect the same or adjacent roots. In well-drained soil at 22-29ºC the life cycle of M. graminicola is completed in 19 days.
2013-08-07 | GSE43577 | GEO
Project description:Biotrophic plant pathogens have evolved sophisticated strategies to manipulate their host. They derive all of their nutrients from living plant tissues, by making intimate contact with their host while avoiding a resistance response. Rice is one of the most important crop plants worldwide and an excellent model system for studying monocotyledonous plants. Estimates of annual yield losses due to plant-parasitic nematodes on this crop range from 10 to 25% worldwide. One of the agronomically most important nematodes attacking rice is the rice root knot nematode Meloidogyne graminicola. Attack of plant roots by sedentary plant parasitic nematodes, like the root knot nematodes (RKN; Meloidogyne spp.) involves the development of specialized feeding cells in the vascular tissue. The second stage juvenile of the RKN punctures selected vascular cells with its stylet, injects pharyngeal secretions, and this ultimately leads to the reorganisation of these cells into typical feeding structures called giant cells (GCs), from which the nematode feeds for the remainder of its sedentary life cycle (Gheysen & Mitchum, 2011). Morphological and physiological reprogramming of the initial feeding cell leads to nucleus enlargement, proliferation of mitochondria and plastids, metabolic activation, cell cycle alterations and cell wall changes (Gheysen and Mitchum, 2011). The hyperplasia and hypertrophy of the surrounding cells leads to the formation of a root gall, which is typically formed at the root tips in the case of the rice RKN M. graminicola. In comparison with other RKN, M. graminicola has a very fast life cycle, with swelling of the root tips observed as early as 1 day after infection (dai). At 3 dai, terminal hook-like galls are clearly visible (Bridge et al., 2005). After 3 moults the nematodes are mature, around 10 dai. The M. graminicola females lay their eggs inside the galls, while most other RKN deposit egg masses at the gall surface, and hatched juveniles can reinfect the same or adjacent roots. In well-drained soil at 22-29 degrees C the life cycle of M. graminicola is completed in 19 days. 2 biological replicates of nematode infected giant cells and control vascular cells were sampled at two time points: 7 and 14 dai
2013-08-07 | E-GEOD-43577 | biostudies-arrayexpress
Project description:Galls induced by Meloidogyne spp. in plant roots are a complex organ formed by heterogeneous tissues; within them there are 5-8 giant cells (GCs) that root-knot nematodes use for their own nurturing. Subtle regulatory mechanisms likely mediate the massive gene repression described at early infection stages in galls, particularly in giant cells. Some of these mechanisms are mediated by microRNAs (miRNAs); hence we describe a reliable protocol to detect miRNAs abundance within the gall tissues induced by Meloidogyne spp. Some methods are available to determine the abundance of specific miRNAs in different plant parts; however, galls are complex organs formed by different tissues. Therefore, detection of miRNAs at the cellular level is particularly important to understand specific regulatory mechanisms operating within the GCs. In situ hybridization (ISH) is a classical, robust and accurate method that allows the localization of specific RNAs directly on plant tissues. We present for the first time an adapted and standardized ISH protocol to detect miRNAs in GCs induced by nematodes based on tissue embedded in paraffin and on-slide ISH of miRNAs. It can be adapted to any laboratory with no more requirements than a microtome and an optical microscope and it takes 10 days to perform once plant material has been collected. It showed to be very valuable for a quick detection of miRNAs expression pattern in tomato. We tested the protocol for miR390, as massive sequencing analysis showed that miR390 was induced at 3 dpi (days post-infection) in Arabidopsis galls and miR390 is 100% conserved between Arabidopsis and tomato. Successful localization of miR390 in tomato GCs constitutes a validation of this method that could be easily extended to other crops and/or syncytia induced by cyst nematodes. Finally, the protocol also includes guidance on troubleshooting.
| S-EPMC4936241 | biostudies-literature
Project description:Plant-parasitic nematodes and especially the root-knot nematodes are ubiquitous pathogens. Eggs of root-knot nematodes (Meloidogyne javanica) were extracted from greenhouse cultures and second-stage juveniles (J2) were hatched in tap, sterile water on 30 µm sieves. Solanum tubersum cv. Desiree explants, i.e., stem including an axillary bud, were sectioned, under sterile conditions from in vitro growing seedlings and transferred to Magenta boxes containing Gamborg's media. Seedlings, 4 weeks post transferring to Gamborg's media were planted in pots containing autoclaved quartz sand. Three weeks later the plants were infected with 3000 M. javanica infective juveniles, applied to the soil in tap, sterile water. Control uninfected plants were mock-inoculated with tap, sterile water. Roots from 6 infected and 6 mock-inoculated plants were collected at a series of time points, including 5, 10 and 15 days post nematode infection/mock inoculation. Roots were observed under the microscope, and nematode feeding sites were selectively dissected, from young lateral roots. To control for the effect of tissue sectioning on gene expression, young lateral roots of the mock inoculated roots were dissected similarly to the infected roots, and collected. Dissected roots were snapped-freeze in liquid nitrogen and immediately stored in -80 C freezer. Total RNA was extracted using Qiagen RNAEasy kit. The experiment for each time point was duplicated, each duplicate derived from independent biological repeat. All RNA samples were amplified using the Ambion kit Message Amp catalog no. 1750, using as starting material 2.5 to 5 µg of total RNA. Keywords: Reference design
2007-09-01 | GSE8209 | GEO
Project description:Beneficial microorganisms are generally known to activate plant defense against biotic challenges. However, the molecular mechanisms by which activated plants react more rapidly and actively to pests remain still largely unclear. Tomato plants pre-treated with a mixture of beneficial bio-control agents (BCAs), as soil-drenches, were less sensitive to infection of the root-knot nematode (RKN) Meloidogyne incognita. To unravel the molecular mechanisms of this induced resistance against RKNs, we used qRT-PCR to monitor the expression, in tomato roots and leaves, of 6 key defense genes. Gene transcripts were detected until the 12th day after BCA treatment(3, 7, 8, 12 dpt) and3 and 7 days after nematode inoculation of pre-treated plants. Early after BCA treatment, the salicylic acid (SA)-dependent pathogenesis related gene (PR-gene), PR-1b, marker of the systemic acquired resistance (SAR), was systemically over-expressed. Another PR-gene, PR-5, was over-expressed at later stages of BCA-plant interaction, and only in roots. Activation of defense against RKNs was attested by the early up-regulation of 4 genes (PR-1, PR-3, PR-5, ACO) in pre-treated plants after inoculation. Conversely, the expression of the JA/ET-dependent gene JERF3 did not increase after nematode inoculation in primed plants. A catalase gene (CAT)was highly over-expressed by nematode infection, however, this over-expression was annulled at the earliest stages or limited at the later stages of infection toBCA-treated roots. Enzyme activities, such as glucanase and endochitinase, were enhanced in roots of pre-treated inoculated plants with respect to plants left not inoculated as a control. These findings indicate that BCA interaction with roots primes plants against RKNs. BCA-mediated immunity seems to rely on SA-mediated SAR and to be associated with both the activation of chitinase and glucanase enzyme activities and the inhibition of the plant antioxidant enzyme system. Immunity is triggered at the penetration and movements inside the roots of the invading nematode juveniles but probably acts at the feeding site building stage of nematode infection.
| S-EPMC6890175 | biostudies-literature
Project description:Commercial biocontrol of microbial plant diseases and plant pests, such as nematodes, requires field-effective formulations. The isolate Pseudomonas chlororaphis O6 is a Gram-negative bacterium that controls microbial plant pathogens both directly and indirectly. This bacterium also has nematocidal activity. In this study, we report on the efficacy of a wettable powder-type formulation of P. chlororaphis O6. Culturable bacteria in the formulated product were retained at above 1 × 108 colony forming units/g after storage of the powder at 25 °C for six months. Foliar application of the diluted formulated product controlled leaf blight and gray mold in tomato. The product also displayed preventative and curative controls for root-knot nematode (Meloidogyne spp.) in tomato. Under laboratory conditions and for commercially grown melon, the control was at levels comparable to that of a standard commercial chemical nematicide. The results indicated that the wettable powder formulation product of P. chlororaphis O6 can be used for control of plant microbial pathogens and root-knot nematodes.
| S-EPMC5985650 | biostudies-literature
Project description:Understanding the interactions of plant-parasitic nematodes with antagonistic soil microbes could provide opportunities for novel crop protection strategies. Three arable soils were investigated for their suppressiveness against the root knot nematode Meloidogyne hapla. For all three soils, M. hapla developed significantly fewer galls, egg masses, and eggs on tomato plants in unsterilized than in sterilized infested soil. Egg numbers were reduced by up to 93%. This suggested suppression by soil microbial communities. The soils significantly differed in the composition of microbial communities and in the suppressiveness to M. hapla. To identify microorganisms interacting with M. hapla in soil, second-stage juveniles (J2) baited in the test soil were cultivation independently analyzed for attached microbes. PCR-denaturing gradient gel electrophoresis of fungal ITS or 16S rRNA genes of bacteria and bacterial groups from nematode and soil samples was performed, and DNA sequences from J2-associated bands were determined. The fingerprints showed many species that were abundant on J2 but not in the surrounding soil, especially in fungal profiles. Fungi associated with J2 from all three soils were related to the genera Davidiella and Rhizophydium, while the genera Eurotium, Ganoderma, and Cylindrocarpon were specific for the most suppressive soil. Among the 20 highly abundant operational taxonomic units of bacteria specific for J2 in suppressive soil, six were closely related to infectious species such as Shigella spp., whereas the most abundant were Malikia spinosa and Rothia amarae, as determined by 16S rRNA amplicon pyrosequencing. In conclusion, a diverse microflora specifically adhered to J2 of M. hapla in soil and presumably affected female fecundity.
| S-EPMC3993313 | biostudies-literature
Project description:Strigolactones (SLs) are carotenoid-derived phytohormones that are known to influence various aspects of plant growth and development. As root-derived signals, SLs can enhance symbiosis between plants and arbuscular mycorrhizal fungi (AMF). However, little is known about the roles of SLs in plant defense against soil-borne pathogens. Here, we determined that infection with root-knot nematodes (RKNs; Meloidogyne incognita) induced SL biosynthesis in roots of tomato (Solanum lycopersicum). Silencing of SL biosynthesis genes compromised plant defense against RKNs, whilst application of the SL analog racGR24 enhanced it. Accumulation of endogenous jasmonic acid (JA) and abscisic acid (ABA) in the roots in response to RKN infection was enhanced by silencing of SL biosynthetic genes and was suppressed by application of racGR24. Genetic evidence showed that JA was a positive regulator of defense against RKNs while ABA was a negative regulator. In addition, racGR24 enhanced the defense against nematode in a JA-deficient mutant but not in an ABA-deficient mutant. Silencing of SL biosynthetic genes resulted in up-regulation of MYC2, which negatively regulated defense against RKNs. Our results demonstrate that SLs play a positive role in nematode defense in tomato and that MYC2 negatively regulates this defense, potentially by mediating hormone crosstalk among SLs, ABA and JA.
| S-EPMC6382333 | biostudies-literature
Project description:Dactylellina haptotyla is a typical nematode-trapping fungus that has garnered the attention of many scholars for its highly effective lethal potential for nematodes. Secondary metabolites play an important role in D. haptotyla-nematode interactions, but which metabolites perform which function remains unclear. We report the metabolic functions based on high-quality, chromosome-level genome assembly of wild D. haptotyla YMF1.03409. The results indicate that a large variety of secondary metabolites and their biosynthetic genes were significantly upregulated during the nematode-trapping stage. In parallel, we identified that 2-furoic acid was specifically produced during nematode trapping by D. haptotyla YMF1.03409 and isolated it from fermentation production. 2-Furoic acid demonstrated strong nematicidal activity with an LD50 value of 55.05 µg/mL against Meloidogyne incognita at 48 h. Furthermore, the pot experiment showed that the number of galls of tomato root was significantly reduced in the experimental group treated with 2-furoic acid. The considerable increase in the 2-furoic acid content during the infection process and its virulent nematicidal activity revealed an essential synergistic effect during the process of nematode-trapping fungal infection. IMPORTANCE Dactylellina haptotyla have significant application potential in nematode biocontrol. In this study, we determined the chromosome-level genome sequence of D. haptotyla YMF1.03409 by long-read sequencing technology. Comparative genomic analysis identified a series of pathogenesis-related genes and revealed significant gene family contraction events during the evolution of D. haptotyla YMF1.03409. Combining transcriptomic and metabolomic data as well as in vitro activity test results, a compound with important application potential in nematode biocontrol, 2-furoic acid, was identified. Our result expanded the genetic resource of D. haptotyla and identified a previously unreported nematicidal small molecule, which provides new options for the development of plant biocontrol agents.
| S-EPMC10580851 | biostudies-literature
Project description:Root-knot nematodes (RKNs; Meloidogyne spp.) are obligate endoparasites that infect many crops and cause severe yield losses. In this research, we studied the effect of Welsh onion, grown as a companion plant, on the resistance of cucumber plants to RKN infection and analyzed the most abundant components of Welsh onion root exudates. The results showed that, when grown with Welsh onion as a companion plant, cucumber roots had 77.0% fewer root knots and egg masses than the control cucumber roots. Welsh onion root exudates were collected and extracted with chloroform, ethyl ether, n-butanol and ethyl acetate. High concentrations of the extracts from the Welsh onion root exudates decreased the hatchability of RKN eggs. In particular, the inhibitory effect of the n-butanol extract was significant and the hatchability of RKN eggs did not exceed 10%. Gas chromatographic-mass spectrometric analysis revealed that the most abundant component in the n-butanol extract was 4-hydroxy-benzeneethanol. Treatment with 1.2 mM 4-hydroxy-benzeneethanol decreased egg hatchability to 40%, whereas treatment with 9.6 mM or a higher concentration of 4-hydroxy-benzeneethanol decreased egg hatchability to less than 10%. In addition, 1.2 mM or a higher concentration of 4-hydroxy-benzeneethanol decreased the activity of the second-stage juvenile (J2). Higher 4-hydroxy-benzeneethanol concentrations (9.8 and 19.2 mM) were lethal to RKNs to some extent, with death rates greater than 50% at 48 h of treatment. The present results suggest that cultivation with Welsh onion as a companion plant may represent an alternative to the application of synthetic nematicides, with fewer side effects. We confirmed that 4-hydroxy-benzeneethanol is a natural effective nematicide.
| S-EPMC6066241 | biostudies-literature