scholarly journals SlWRKY45 Interacts with Jasmonate-ZIM Domain Proteins to Negatively Regulate Defense Against Root Knot Nematode Meloidogyne incognita in Tomato

Author(s):  
Huang Huang ◽  
Wenchao Zhao ◽  
Hui Qiao ◽  
Chonghua Li ◽  
Xuechun Ma ◽  
...  

Root knot nematode (RKN), a kind of plant parasitic nematodes, leads to large reduction of crop yield, and seriously damages the agricultural production. The phytohormone jasmonates (JAs) act as important signals to regulate resistance against multiple abiotic and biotic stresses. However, little is known about the mechanism of JA-mediated defense responses against RKN in tomato. In this study, we found that the WRKY transcription factor SlWRKY45 interacts with most of the Jasmonate-ZIM domain proteins (JAZs) in yeast and plant. Overexpression of SlWRKY45 decreased plant resistance to RKN Meloidogyne incognita with increased gall index. We further generated slwrky45 mutants using the CRISPR/Cas9 technology, and discovered that the gall index and the number of nematodes and females in slwrky45 mutants are significantly reduced compared with wild type, as inoculated with RKN Meloidogyne incognita. Moreover, the contents of jasmonic acid and JA-isoleucine (JA-Ile) were highly increased in slwrky45 mutants with RKN Meloidogyne incognita infection compared with wild type. Furthermore, EMSA, and Dual-LUC assays demonstrated that SlWRKY45 directly binds and represses jasmonate biosynthesis gene ALLENE OXIDE CYCLASE ( AOC). Overall, our findings reveled that JAZ-interaction protein SlWRKY45 negatively controls plant defense against RKN Meloidogyne incognita by the regulation of JA biosynthesis in tomato.

Nematology ◽  
2005 ◽  
Vol 7 (1) ◽  
pp. 125-132 ◽  
Author(s):  
Rong De Jin ◽  
Joo Won Suh ◽  
Ro Dong Park ◽  
Yong Woong Kim ◽  
Hari B. Krishnan ◽  
...  

Abstract Plant-parasitic nematodes are distributed worldwide and affect a broad range of important agronomic plant species. Chitinolytic bacteria were evaluated as potential biological control agents of the root-knot nematode, Meloidogyne incognita, on tomato. After transplantation of seedlings into pots containing soil amended with chitin compost, chitin broth, or respective controls, soil was inoculated with nematode eggs and infective second-stage juveniles (J2). Samples taken at 4, 6 and 8 weeks after inoculation indicated that fresh weights of plants did not vary between treatments or between treatments and controls. The gall index was lower in the plants grown in the chitin-amended soil at each time point. Activities of soil chitinase and β-1,3-glucanase were greater in those soils amended with chitin compost and chitin broth. Gall index of tomato root was negatively correlated with soil chitinase activity. Activities of tomato root chitinase and β-1,3-glucanase were higher in plants growing in non-chitin-amended soil at 6 and 8 weeks after nematode infestation. Chitinase activity in tomato root was positively correlated with the gall index of tomato root. The results indicate the potential of chitinase producing bacteria to alleviate nematode parasitism in important vegetable crops.


Nematology ◽  
2001 ◽  
Vol 3 (2) ◽  
pp. 129-139 ◽  
Author(s):  
Jaap Bakker ◽  
Fred Gommers ◽  
Geert Smant ◽  
Pierre Abad ◽  
Marie-Noëlle Rosso ◽  
...  

AbstractExpressed sequence tags (EST) have been widely used to assist in gene discovery in various organisms (e.g., Arabidopsis thaliana, Caenorhabditis elegans, Mus musculus, and Homo sapiens). In this paper we describe an EST project, which aims to investigate gene expression in Meloidogyne incognita at the onset of parasitism. Approximately 1000 5′-end sequence tags were produced from a cDNA library made of freshly hatched preparasitic second stage juveniles (J2). The EST were identified in the primary transformants of the cDNA library, and assigned to nine different functional groups, including (candidate) parasitism genes. A large fraction of the EST (45%) did not have a putative homologue in public databases. Sixty five percent of the EST that could be clustered into a functional group had putative homologues in other nematode species. EST were found for virtually all parasitism related genes that have been cloned from M. incognita to date. In addition, several novel genes were tagged, including a xylanase and a chitinase gene. The efficiency of EST projects, which produce sequence data for thousands of genes in months time without any difficult pre-selections of mRNA pools, makes random sequencing cDNA libraries a superior method to identify candidates for parasitism related genes in plant-parasitic nematodes. The sequences in this paper are retrievable from Genbank with the accession numbers BE191640 to BE191741, BE217592 to BE217720, BE225324 to BE225598, BE238852 to BE239221, and BE240829 to BE240865.


2015 ◽  
Vol 28 (4) ◽  
pp. 398-407 ◽  
Author(s):  
Taketo Fujimoto ◽  
Takayuki Mizukubo ◽  
Hiroshi Abe ◽  
Shigemi Seo

The root-knot nematode (RKN) is one of the most devastating parasitic nematodes of plants. Although some secondary metabolites released by the host plant play roles as defense substances against parasitic nematodes, the mechanism underlying the induction of such defense responses is not fully understood. We found that sclareol, a natural diterpene known as an antimicrobial and defense-related molecule, inhibited RKN penetration of tomato and Arabidopsis roots. Sclareol induced genes related to ethylene (ET) biosynthesis and signaling and phenylpropanoid metabolism in Arabidopsis roots. In roots of ein2-1, an ET-insensitive mutant line, both sclareol-induced inhibition of RKN penetration and sclareol-induced enhancement of lignin accumulation were abolished. A mutant defective in lignin accumulation did not exhibit such inhibition. Sclareol also activated MPK3 and MPK6, Arabidopsis mitogen-activated protein kinases whose activation is required for triggering ET biosynthesis. Sclareol-induced inhibition of RKN penetration was exhibited by mutants of neither MPK3 nor MPK6. Treatment with a biosynthetic precursor of ET was insufficient compared with sclareol treatment to inhibit RKN penetration, suggesting the existence of an ET-independent signaling pathway leading to RKN resistance. These results suggested that sclareol induced resistance to RKN penetration partially through ET-dependent accumulation of lignin in roots.


2021 ◽  
Author(s):  
Mao-Yan Liu ◽  
De-Liang Peng ◽  
Wen Su ◽  
Chao Xiang ◽  
Jin-Zhuo Jian ◽  
...  

Abstract Background Potassium (K), an important nutrient element, can improve the stress resistance/tolerance of crops. The application of K in resisting plant parasitic nematodes shows that the K treatment can effectively reduce the occurrence of nematode diseases and increase crop yield. However, data on K2SO4 induced rice resistance to Meloidogyne graminicola are still lacking. To evaluate rice resistance against M. graminicola induced by K2SO4 and to further clarify its mechanism is essential for the rational use of K fertilizer to ensure the safety of rice production.Results In this work, K2SO4 treatment effectively reduced the numbers of both galls and nematodes in rice roots, and delayed the development of nematodes to the adult stage. Rather than by affecting the attractiveness of roots to nematodes and the morphological phenotype of giant cells at feeding sites, such effect was achieved by rapidly stimulating hydrogen peroxide (H2O2) accumulation, increasing callose deposition. Meanwhile, such induced resistance required the active participation of the potassium channel OsAKT1 and the potassium transporter OsHAK5. The numbers of both galls and nematodes were higher in both gene deficient plants than that in the wild-type plants, and the K2SO4-induced resistance showed weaker in the defective plants than in the wild-type plants.Conclusions K2SO4 treatment effectively induces rice resistance to root-knot nematode M. graminicola. The mechanism of inducing resistance is to prime the basic defense of rice, up-regulating the expression of resistance-related genes and with the involvement of K+ channel and transporter. These laid a foundation for further study on the mechanism of rice to defense against root-knot nematodes and the effective use of potassium fertilizer to improve rice resistance against nematodes in the field.


Author(s):  
Yadom Y. F. R. Kouakou ◽  
Kouamé Daniel Kra ◽  
Hortense Atta Diallo

Agricultural activities such as watering crops with nematode-infested water from wells and boreholes, and using infected plant debris as manure or mulch increase root-knot nematode infection. So, this study aims at assessing the influence of the inoculation method and inoculum level of Meloidogyne incognita on the development of root galls on okra plants. Two M. incognita inoculation methods (suspension of individuals and galled root explants) and six inoculum levels (0, 10, 100, 500, 1000 and 2000 second-stage larvae/plant) were studied. The gall index, total numbers and reproductive factor of M. incognita were used to assess the effect of treatments on root gall development. Unlike the reproductive factor, gall index and the total numbers of M. incognita increased with their inoculum level. The pathogenic activities of M. incognita were most significant when crop soils were infested with galled root explants. However, an inverse relationship was found between the inoculum levels of M. incognita and the okra plant’s development. It is reflected by negative correlation coefficients ranging from -0.90 to -0.62. It is therefore important to burn roots infected with root-knot nematodes left in fields so that they do not act as an inoculum for crops.


2019 ◽  
Vol 18 (4) ◽  
pp. 62-69
Author(s):  
Phong V. Nguyen

Effectors have been identified to play a very important role in the parasitism of plant-parasitic nematode. To cope with this type of pathogen, many approaches of silencing genes encoding for effectors have been studied and promise to be an effective tool to create plant varieties resistant to plant-parasitic nematodes. In this study, the Minc16281 gene encoding a pioneer effector with unknown function was determined and cloned from a Meloidogyne incognita population isolated from soybean field (ID: MH315945.1). The nucleotide sequence of this gene showed 97% identity to its homolog in GenBank (ID: JK287445.1) used as the control strain in our research. To generate host-induced gene silencing constructs which can potentially silence the expression of Minc16281 gene, two artificial microRNAs were synthesized based on the miR319a structure of Arabidopsis thaliana and inserted into an expression vector in soybean. These microRNAs can be introduced into soybean to investigate the function of Minc16281 on parasitism of root-knot nematode.


2021 ◽  
Author(s):  
Rahim Hassanaly-Goulamhoussen ◽  
Ronaldo De Carvalho Augusto ◽  
Nathalie Marteu-Garello ◽  
Arthur Péré ◽  
Bruno Favery ◽  
...  

In model organisms, epigenome dynamics underlies a plethora of biological processes. The role of epigenetic modifications in development and parasitism in nematode pests remains unknown. The root-knot nematode Meloidogyne incognita adapts rapidly to unfavorable conditions, despite its asexual reproduction. However, the mechanisms underlying this remarkable plasticity and their potential impact on gene expression remain unknown. This study provides the first insight into contribution of epigenetic mechanisms to this plasticity, by studying histone modifications in M. incognita. The distribution of five histone modifications revealed the existence of strong epigenetic signatures, similar to those found in the model nematode Caenorhabditis elegans. We investigated their impact on chromatin structure and their distribution relative to transposable elements (TE) loci. We assessed the influence of the chromatin landscape on gene expression at two developmental stages: eggs, and pre-parasitic juveniles. H3K4me3 histone modification was strongly correlated with high levels of expression for protein-coding genes implicated in stage-specific processes during M. incognita development. We provided new insights in the dynamic regulation of parasitism genes kept under histone modifications silencing. In this pioneering study, we establish a comprehensive framework for the importance of epigenetic mechanisms in the regulation of the genome expression and its stability in plant-parasitic nematodes.


Plant Disease ◽  
2018 ◽  
Vol 102 (5) ◽  
pp. 977-982 ◽  
Author(s):  
Manzoor Hussain ◽  
Miloslav Zouhar ◽  
Pavel Ryšánek

The entomopathogenic fungus Lecanicillium muscarium (Petch) Zare and Gams is currently being developed as a biocontrol agent against insect pests, as well as some plant-pathogenic fungi and bacteria. Data about its activity against plant-parasitic nematodes exist, but are relatively limited. To expand this understanding, we investigated the biocontrol efficiency of three isolates of L. muscarium (Lm) against the root knot nematode, Meloidogyne incognita, in both in vitro and in vivo conditions. In our experiments, the maximum number of nematode eggs, juveniles (J2s), females, and egg masses that were parasitized were quantified after a 72-h exposure to the fungus. The isolate Lm1 was designated as the best biocontrol agent against nematode eggs as well as J2s. It showed the highest colonization of eggs and significantly decreased egg hatching events. The results from two additional isolates, Lm2 and Lm3, were also significant (P = 0.05) but less pronounced than those observed with Lm1. L. muscarium treatments had significant (P = 0.05) positive effects on plant shoot and root growth compared with the growth of control plants. These results suggest the effectiveness of the fungus may be due to either the infection of eggs and J2s, or the production of secondary metabolites that induced plant defense mechanisms and lead to systemic resistance. Our study demonstrates that L. muscarium could be used as a potential biocontrol agent against root knot nematodes.


1970 ◽  
Vol 36 (3) ◽  
pp. 477-486 ◽  
Author(s):  
MI Faruk ◽  
MI Rahman ◽  
MR Ali ◽  
MM Rahman ◽  
MMH Mustafa

A field experiment was conducted in two consecutive years to find out the efficacy of poultry refuse (PR), mustard oilcake (MOC), and Furadan 5G for the management of root-knot disease (Meloidogyne incognita) of tomato. Soil was treated with PR @ 3 and 5 t/ha, MOC @ 0.3 and 0.6 t/ha 3 weeks before transplanting and Furadan 5G @ 40 kg/ha on the day of transplanting of tomato seedlings. PR @ 3 t/ha and MOC @0.3 t/ha were applied alone and also mixed with Furadan 5G @ 20 kg/ha. The soils of the experimental plots were inoculated with chopped severely galled (M incognita) roots of tomato at the time of treatment application. In both the years, considerable reduction in rootknot disease and increase in plant growth and fruit yield were achieved with different treatments with two organic materials applied alone or mixed with Furadan 5G. The most effective treatment was PR @ 3 t/ha + Furadan 5G @ 20 kg/ha followed by PR alone @ 5 t/ha. Efficacy of PR @ 3 t/ha and MOC @ 0.6 1/ha were also appreciable. In first year and second year, gall index values were 6.50 and 6.27 under control, respectively. The severity was reduced to 2.27-4.00 in first year and 1.73-4.07 in second year due to application of the four treatments. On the other hand, fruit yield under control was 50.9 t/ha at first year and 47.6 t/ha in second year. The highly effective four treatments increased fruit yield to 71.1-82.5 t/ha in first year and 60.8-82.0 t/ha in second year. The fruit yield of tomato was directly and linearly correlated with gall indices in tomato gall. Based on findings of the study PR @ 3 t/ha + Furadan @20 kg/ha and PR alone @ 5 t/ha were noted as effective treatment to manage root-knot disease of tomato. Keywords: Poultry refuse; mustard oilcake; Furadan; Meloidogjyne incognita; tomato. DOI: http://dx.doi.org/10.3329/bjar.v36i3.9275 BJAR 2011; 36(3): 477-486


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