# First reppport and additional information of meloidogyne konaensis parasiting different crops in Brazil

J. Monteiro, J. E. Cares, A. C. M. M. Gomes, V. R. Correa, M. F. A. Santos, M. D. G. Carneiro, G. Gomez, C. D. G. Santos, Philippe Castagnone-Sereno, R. M. D. G. Carneiro

► To cite this version:

J. Monteiro, J. E. Cares, A. C. M. M. Gomes, V. R. Correa, M. F. A. Santos, et al. First reppport and additional information of meloidogyne konaensis parasiting different crops in Brazil. Joint Meeting of the Society of Nematologists and the Organization of Nematologists of Tropical America (ONTA), 2016, Jul 2016, Montréal, Canada. 387 p. hal-01594530

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determine drenching frequency of VCT to suppress RKN in a cucumber (*Cucumis sativus*) agroecosystem. Cucumber plants were drenched at 1-, 2- or 4-week intervals and compared to a water control. In both trials, drenching VCT at 1-week intervals suppressed (*P* ≤ 0.05) RKN but not reniform (*Rotylenchulus reniformis*) nematodes. VCT could induce host-plant resistance, consequently two split-root experiments were conducted in the greenhouse. Cucumber root penetration by of *M. incognita* was reduced by VCT drenching. Quantitative real time PCR was used to detect the expression of the defense related genes *CHIT-1* and *PAL-1* encoding chitinase and phenylalanine ammonia-lyase, respectively. Cucumbers were drenched with VCT from uncured vermicompost 2 days prior to *M. incognita* inoculation. Gene expression levels in leaves were determined at 0 hr, 1, 2, 5 and 8 days post nematode inoculation. Plants drenched with VCT showed an increased expression of *CHIT-1* at 2 days after *M. incognita* inoculation, and increased expression of *PAL-1* at 0, 1, 2 and 8 days after *M. incognita* inoculation. Additional assays were conducted to study the expression of *β*-1,3-*Glucanase*, *LOX-1* and *PR-1* encoding glucanase, lipoxygenase, and pathogenesis-related protein 1 respectively. These experiments suggested that VCT prepared from uncured vermicompost has the potential to induce host-plant resistance against RKN. Although this induction was short in duration, drenching VCT at a weekly interval provided significant and consistent suppression of root-knot nematodes throughout a cucumber crop. Thus, use of VCT prepared from an uncured vermicompost is a viable post-plant nematode management tool against RKN. Future work could include applying VCT through fertigation and modifying feed stock of vermicompost to achieve reniform nematode suppression by VCT.

PHLOROGLUCINOL (1,3,5-TRIHYDROXYBENZENE) ENHANCED THE AMELIORATES STRESS RESISTANCE AND REDUCED β-AMYLOID TOXICITY IN *CAENORHABDITIS ELEGANS*. Mohankumar, A¹., G. Shanmugam¹, P. Sundararaj¹, S.L. Hafez² and Nivitha Sundararaj³. ¹Unit of Nematology, Department of Zoology, Bharathiar University, Coimbatore; ²U of I Parma REC, 29603 U of I Lane, Parma, ID 83660, USA ³Kumaraguru College of Technology, Coimbatore, India.

Phloroglucinol (PG), found in brown algae (Phaeophyceae), is a monomeric unit of phlorotannins with antioxidant, anti-inflammatory, anti-diabetic, antimicrobial, anti-allergic and anti-viral properties. An attempt has been made to study the effect of PG on the lifespan, health, β-Amyloid toxicity and oxidative stress tolerance on the nematode model *Caenorhabditis elegans*. Various concentrations of PG viz, 10µM, 50µM, 100µM, 200µM, 400µM, 800µM, 1000µM were prepared using DMSO (final concentration to be maintained at 0.2%) and treated on *C. elegans*. For lifespan assay, *C. elegans* eggs were transferred to the NGM plates previously treated with or without PG and *E. coli* OP50 and maintained at 20 °C. Synchronization was performed at L4 larvae stage, and young L4 larvae were transferred to fresh plates with different PG concentrations (40 worms per plate with a total of 3 plates per treatment). Worms were observed daily for survival and transferred to fresh treatment plates until the last worms dead. At 400 µM PG, the mean lifespan of wild type N2 and mev-1 *C. elegans* increased while there was no increase in longevity of daf-16 mutant worms. Exposure of wild *C. elegans* to PG at 400 µM did not induce any changes in body length, morphology, brood size, locomotion or mortality while there was a significant decrease in lipofuscin accumulation. Pre-treated *C. elegans* with PG suppressed the damage due to heat stress and oxidative stress induced by an ROS generator, Juglone (500µM). PG treated worms had increased fluorescence intensity of HSP-16.2 and SOD-3 proteins compared to untreated control strains of CL2070 and CF1553 respectively. PG delayed the amyloid-β induced paralysis up to 25.4% compared to control worms in transgenic *C. elegans* strain CL4176 expressing human Amyloid β₁-₄₂. Thus, the results suggest that the insulin/IGF-1 signalling and their downstream and mitochondrial respiratory chain pathways are involved in the mechanism of life extension and stress tolerance mediated by PG.

FIRST REPORT AND ADDITIONAL INFORMATION OF *MELOIDOGYNE KONAENSIS* PARASITIZING DIFFERENT CROPS IN BRAZIL. Monteiro, J.¹, J.E. Cares¹, A.C.M.M. Gomes², V.R. Correa², M. F. A. Santos², M.D.G. Carneiro², G. Gomez², C.D.G. Santos³, and P. Castagnone-Sereno⁴, and R.M.D.G. Carneiro². ¹Departamento de Fitopatologia, Universidade de Brasília, Brasília DF 70910-900, Brazil, ²EMBRAPA- Recursos Genéticos e Biotecnologia, CP.02372 Brasília DF 70849-970, Brazil, ³Departamento de Fitopatologia, Universidade Federal do Ceará, Fortaleza CE 60020-181, ⁴INRA, Univ. Nice Sophia Antipolis, CNRS, UMR 1355-7254, Institut Sophia Agrobiotech, 06900 Sophia Antipolis, France.

In a survey for *Meloidogyne* spp. in different crops from eleven regions at Ceará State, Brazil using esterase isozyme electrophoresis as a specific identification method, four atypical populations were characterized from cabbage, papaya, noni and canapum plants, which showed an esterase profile different from those previously detected in Brazil. Morphological studies showed typical characteristics of the specie *Meloidogyne konaensis*. Perineal patterns of females were variable, similar to *M. arenaria* and *M. incognita*, stylet length 14-20 µm, the knobs gradually merging with the shaft and the dorsal esophageal gland orifice (DEGO) ranging from 4-7 µm, are some characteristics of females. Although males are not frequently found, the stylet morphology provides the most useful source of diagnostic character for the specie, with 6-12 large projections protruding from the shaft. The esterase pattern K3 is unique and species-specific with three major bands Rm 1.0, 1.17, 1.27 and a secondary band Rm 1.10. Some confusion about the true identity of this species was clarified in this study including the differentiation from *M. paranaensis*. A species-specific SCAR marker developed for *M. paranaensis* was
tested and no amplification products were observed. In Neighbour-Joining analyses of ITS and D2-D3 rRNA sequences, *M. konaensis* from Brazil appeared clearly separated from *M. paranaensis*. Pathological tests indicated that coffee is not a host of *M. konaensis* as previously reported in the original description of this species.

FIRST REPORT OF ENDOTOKIA MATRICIDA IN *MELOIDOGYNE HAPLA*: A STUDY CASE. Monteiro, T.S.A.¹, J.A. Brito², S.J.S. Vau⁴, W. Yuan², J.A. LaMondia³, and D.W. Dickson⁴. ¹Plant Path. Dept., Univ. of Vicoso, Vicoso, MG, 36570-900, Brazil, ²Div. of Plant Industry, FDACS, Gainesville, FL 32614-7100; ³Connecticut Agri. Exp. Sta., Windsor, CT 06095, ⁴Entomology and Nematology Dept., Univ. of Florida, Gainesville, FL 32611-0620.

Endotokia matricida is a phenomenon known to occur when embryogenesis and egg hatching takes place within the nematode uterus. This phenomenon is known to occur within the Rhabidita, but it is very uncommon among plant- parasitic nematodes. This phenomenon was observed in a population of *Meloidogyne hapla*, originally collected in Connecticut, USA and reared on tomato 'Rutgers' maintained at 24°C for 60 days in a growth room. Out of 974 females examined, only 14 showed this phenomenon or 1.44%. Eggs at different stages of development, including first-stage juveniles within the egg and second-stage juveniles (J2) were observed inside of the female body cavity. The highest number of J2 and eggs observed per female showing endotokia matricida was 57 and 350, respectively. However, the average number of J2/female was 13, whereas the average number of eggs/female was 90. These findings suggest that this phenomenon is not common in the population of *M. hapla* used in this study. To the best of our knowledge this is the first report of endotokia matricida in *M. hapla*.

VIRAL INFECTION IN NEMATHOPHAGOUS FUNGUS *POCHONIA CHLAMYDOSPORIA*. Monteiro, T.S.A.¹, A.P. Oliveira², A.S. Xavier¹, P. Alfenas-Zerbini² and L.G. Freitas¹. ¹Plant Pathology Dept., University of Viçosa, Viçosa, MG, 36570-900, Brazil, ²Microbiology Dept., University of Viçosa, Viçosa, MG, 36570-900, Brazil.

*Pochonia chlamydosporia* is a nematophagous fungus which has been widely studied because of its ability to reduce nematode populations and to promote plant growth. The differences in the virulence against nematodes, common among isolates of *P. chlamydosporia*, may be due to the genetic constitution or to the interactions with other microorganisms or the environment. The mycoviruses cause cryptic infections and may be responsible for alterations in the fungus aggressiveness (hypo/hypervirulence). The *P. chlamydosporia* isolate PCM4 was the only infected out of 12 investigated. The virus found has a standard complex dsRNAs, multisegmented or a mixed infection. In a greenhouse experiment, this strain failed to reduce the population of the root-knot nematode, *Meloidogyne javanica*. These findings infer the importance of indexing when screening isolates for biological control of nematodes. Future trials using a virus-free line of PCM4 would help to understand if the low nematode antagonism in this isolate is the result of the viral infection or not. This is the first report of a mycovirus infecting *P. chlamydosporia*.

HOW LOCAL SCALE VARIATION INFLUENCES NEMATODE COMMUNITY STRUCTURE IN THE FYNBOS MEDITERRANEAN HEATHLAND OF SOUTH AFRICA. Moroenyane, I.¹, K. Dong², S.B.M. Chimphango³, D. Singh⁴, and J.M. Adams². ¹Institut National de la Recherche Scientifique, Centre INRS-Institut Armand-Frappier, 531 Boulevard de Prairies, Laval, Québec, H7V 1B7, ²Department of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul 151-742, South Korea,³Department of Biological Sciences, University of Cape Town, Cape Town, South Africa, 7700, ⁴Environmental Genomics Division, CSIR-NEERI, Nehru Marg, Nagpur (MH), 440020, India.

The Fynbos biome of South Africa is renowned for its high levels of plant diversity, endemism, and heterogeneous soils. Studies have elucidated the broad taxonomic classification and diversity patterns of soil nematodes in Fynbos. However, majority of these studies have only looked at the diversity of plant feeding nematode, and none have compared the community of free-living nematodes from different Fynbos types. We used a novel metagenetic approach to investigate variation in nematode community structure in the Fynbos vegetation. We compared 23 samples of soil nematode communities from five different Fynbos vegetation types. Nematode DNA was 454- pyrosequenced for the 18S rRNA gene. Here we show that soils from Fynbos sites (Alluvial, Sand, Limestone, Shale, and Sandstone) have distinct properties and how these influence the nematode community structure and diversity. Previous studies of free-living nematode, revealed great diversity and differentiation of nematode community structure along an environmental gradient. We found that the diversity (Shannon and Simpson index) was overall significant, but there was no difference between sites and there was no environmental gradient that seemed to delimit this diversity. Similarly, the relative abundance of dominant nematode families did not vary across sites, with the exception of *Tylenchidae*. The relative abundance of feeding guilds also did not vary across sites; interestingly, only plant feeding nematodes significantly varied and were negatively correlated with NH₄. Furthermore, the nematode community based on Bray Curtis distance did not cluster by Fynbos vegetation type and was significantly influenced by potassium (K) and sulphate (SO₄). However, the phylogenetic signal detected that closely related taxa in Fynbos tend to co-occur more often than expected by chance. Unifrac analyses also did not cluster by vegetation type, but was influenced by geographical distance. It seems that in the Fynbos there has been very little phylogenetic divergence (ecological and genetic drift) of nematode lineages. Furthermore, at local scale the ses.NTI (nearest taxon index) was significantly higher than null expectations, indicating that co-occurrence of related nematode lineages is determined by the differences in environmental