Effect of chitin compost and broth on biological control of Meloidogyne incognita on tomato (Lycopersicon esculentum Mill.)

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.

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.


2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Haiyan Fan ◽  
Meiling Yao ◽  
Haiming Wang ◽  
Di Zhao ◽  
Xiaofeng Zhu ◽  
...  

Abstract Background Root-knot nematode is one of the most significant diseases of vegetable crops in the world. Biological control with microbial antagonists has been emerged as a promising and eco-friendly treatment to control pathogens. The aim of this study was to screen and identify novel biocontrol agents against root-knot nematode, Meloidogyne incognita. Results A total of 890 fungal isolates were obtained from rhizosphere soil of different crops and screened by nematicidal activity assays. Snef1910 strain showed high virulence against second stage juveniles (J2s) of M. incognita and identified as Trichoderma citrinoviride by morphology analysis and biomolecular assay. Furthermore, T. citrinoviride Snef1910 significantly inhibited egg hatching with the hatching inhibition percentages of 90.27, 77.50, and 67.06% at 48, 72, and 96 h after the treatment, respectively. The results of pot experiment showed that the metabolites of T. citrinoviride Snef1910 significantly decreased the number of root galls, J2s, and nematode egg masses and J2s population density in soil and significantly promoted the growth of tomato plants. In the field experiment, the biocontrol application showed that the control efficacy of T. citrinoviride Snef1910 against root-knot nematode was more than 50%. Meanwhile, T. citrinoviride Snef1910 increased the tomato plant biomass. Conclusions T. citrinoviride strain Snef1910 could be used as a potential biological control agent against root-knot nematode, M. incognita.


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.


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.


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