Biovar Differentiation and Variation in Virulence of Ralstonia solanacearum Isolates Infecting Solanaceous Vegetables

Bacterial wilt caused by Ralstonia solanacearum E.F. Smith is one of the destructive diseases of solanaceous vegetables specially tomato (Lycopersicon esculentum L.) and eggplant (Solanum melongena L.). Experiments were conducted to determine biovar types existing among the strains or isolates of Nepal and variation in virulence in some vegetables belonging to solanaceae family. A total of 39 isolates infecting tomato, eggplant, chilli and potato collected from different parts of Nepal were analyzed for biovar types on the basis of 3 disaccharides and 3 hexose alcohols oxidation test. Experiments were conducted to determine variation in virulence or aggressiveness of some of the isolates under screen house conditions using three host differentials such as Pusa Ruby (susceptible), Bishesh (moderately resistant) and Srijana (resistant) tomato cultivars. Of the 39 isolates, 23 were biovar III, three biovar II, three biovar IV, and one was biovar I. Nine isolates could not be differentiated into any of the five biovars. For breeding and epidemiological purposes it is very important to analyze the variability of aggressiveness. A total of 5 isolates collected from different places were included in the test. Isolates from Bhaktapur was found the most virulent causing wilt in the variety Bishesh (moderately resistant). Other isolates had the negative impact with zero wilt on the differentials used. Isolates from Jungekhola of Dhading district did not induce wilt even on susceptible variety (Pusa Ruby), but exhibited only senescence reaction. The result indicated that there is some slight variation among the isolates tested. Some effective management tactics might be needed in those locations where highly aggressive or virulent strain of bacterial wilt is prevalent, because resistant variety may not be stable in such locations.

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Screening Cultivated Eggplant and Wild Relatives for Resistance to Bacterial Wilt (Ralstonia solanacearum)

Agriculture ◽

10.3390/agriculture9070157 ◽

2019 ◽

Vol 9 (7) ◽

pp. 157 ◽

Cited By ~ 3

Author(s):

Namisy ◽

Chen ◽

Prohens ◽

Metwally ◽

Elmahrouk ◽

...

Keyword(s):

High Temperatures ◽

Resistance Genes ◽

Bacterial Wilt ◽

Ralstonia Solanacearum ◽

Solanum Melongena ◽

Wild Relatives ◽

Sources Of Resistance ◽

Race 1 ◽

Moderately Resistant ◽

Phylotype I

Bacterial wilt, caused by Ralstonia solanacearum, is highly diverse and the identification of new sources of resistance for the incorporation of multiple and complementary resistance genes in the same cultivar is the best strategy for durable and stable resistance. The objective of this study was to screen seven accessions of cultivated eggplant (Solanum melongena L.) and 40 accessions from 12 wild relatives for resistance to two virulent R. solanacearum strains (Pss97 and Pss2016; phylotype I, race 1, biovar 3). The resistant or moderately resistant accessions were further evaluated with Pss97 in a second trial under high temperatures (and also with Pss2016 for S. anguivi accession VI050346). The resistant control EG203 was resistant to Pss97, but only moderately resistant to Pss2016. One accession of S. sisymbriifolium (SIS1) and two accessions of S. torvum (TOR2 and TOR3) were resistant or moderately resistant to Pss97 in both trials. Solanum anguivi VI050346, S. incanum accession MM577, and S. sisymbriifolium (SIS1 and SIS2) were resistant to Pss2016 in the first trial. However, S. anguivi VI050346 was susceptible in the second trial. These results are important for breeding resistant rootstocks and cultivars that can be used to manage this endemic disease.

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Whole Root Transcriptomic Analysis Suggests a Role for Auxin Pathways in Resistance to Ralstonia solanacearum in Tomato

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi-08-17-0209-r ◽

2018 ◽

Vol 31 (4) ◽

pp. 432-444 ◽

Cited By ~ 15

Author(s):

Elizabeth French ◽

Bong-Suk Kim ◽

Katherine Rivera-Zuluaga ◽

Anjali S. Iyer-Pascuzzi

Keyword(s):

Bacterial Wilt ◽

Ralstonia Solanacearum ◽

Transcriptional Response ◽

Resistant Variety ◽

Auxin Signaling ◽

Transport Pathways ◽

Solanum Lycopersicum L ◽

Genome Wide ◽

Transcriptomic Changes ◽

Solanaceae Family

The soilborne pathogen Ralstonia solanacearum is the causal agent of bacterial wilt and causes significant crop loss in the Solanaceae family. The pathogen first infects roots, which are a critical source of resistance in tomato (Solanum lycopersicum L.). Roots of both resistant and susceptible plants are colonized by the pathogen, yet rootstocks can provide significant levels of resistance. Currently, mechanisms of this ‘root-mediated resistance’ remain largely unknown. To identify the molecular basis of this resistance, we analyzed the genome-wide transcriptional response of roots of resistant ‘Hawaii 7996’ and susceptible ‘West Virginia 700’ (WV) tomatoes at multiple timepoints after inoculation with R. solanacearum. We found that defense pathways in roots of the resistant Hawaii 7996 are activated earlier and more strongly than roots of susceptible WV. Further, auxin signaling and transport pathways are suppressed in roots of the resistant variety. Functional analysis of an auxin transport mutant in tomato revealed a role for auxin pathways in bacterial wilt. Together, our results suggest that roots mediate resistance to R. solanacearum through genome-wide transcriptomic changes that result in strong activation of defense genes and alteration of auxin pathways.

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Identification of Ralstonia solanacearum resistant rootstocks for tomato grafting

Journal of Animal & Plant Sciences ◽

10.35759/janmplsci.v43-3.1 ◽

2020 ◽

Vol 43.3 ◽

pp. 7452-7457

Author(s):

Kanyua Stella ◽

Mwangi Maina ◽

Mbaka Jesca

Keyword(s):

Bacterial Wilt ◽

Ralstonia Solanacearum ◽

Solanum Melongena ◽

Tomato Cultivar ◽

Solanum Lycopersicum L ◽

Management Measures ◽

Tomato Cultivars ◽

Sodom Apple ◽

Solanaceae Family ◽

Susceptible Tomato

Bacterial wilt, caused by Ralstonia solanacearum, causes severe losses to tomato (Solanum lycopersicum L). Current management measures are not fully effective. Grafting with resistant rootstocks may be an effective strategy for managing the disease. However, R. solanacearum populations maintain considerable diversity, and little information is known regarding the efficacy of available rootstocks for use in grafting to reduce bacterial wilt incidence and subsequent crop loss. Tomato belongs to family Solanaceae which includes other well-known species, such as eggplant (aubergine), peppers, tobacco and potato. The objective of this study was to identify bacterial wilt resistant germplasm that can be used as rootstocks in tomato grafting. The potential candidates for the study included species that belong to solanaceae family. Rootstocks included tomato cultivar Mt56, Eggplant (Solanum melongena), Capsicum and Sodom apple (Solanum incarnum). Tomato cultivars Anna F1 and Cal J were used as sources of scions. Diseased plants were collected from farmers’ fields and bacterial inoculum isolated using CPG Medium with TZC used to identify distinct colonies of R.solanacearum. The inoculum was applied on the test plants by injecting into the soil planted with tomatoes. Disease severity data was recorded using 0 to 5 scoring scale. Data was subjected to ANOVA using Genstat version 15 and significantly different treatment means separated using LSD at P < 0.05. Solanum melongena, Solanum incarnum and tomato cultivar (Mt56) did not develop infection while tomato cultivar Anna F1 and Cal J (used as positive controls) and Capsicum developed infection. It was concluded that resistant germplasm to bacterial wilt exists and can be utilized to graft susceptible tomato cultivars and contribute to management of bacterial wilt.

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Resistance Response of Maize Germplasm to Downy Mildew [Peronosclerospora philipinensis]

Buletin Plasma Nutfah ◽

10.21082/blpn.v24n1.2018.p43-52 ◽

2018 ◽

Vol 24 (1) ◽

pp. 43

Author(s):

Syahrir Pakki ◽

Mappaganggang Mappaganggang

Keyword(s):

Downy Mildew ◽

Block Design ◽

Susceptible Variety ◽

Resistant Variety ◽

Average Intensity ◽

Standard Score ◽

Resistance Response ◽

Maize Germplasm ◽

Randomized Block Design ◽

Moderately Resistant

Two experiments to study responses of resistance of maize germplasm to downy mildew (Peronosclerospora philipinensis) have been conducted. Both experiments were arranged in randomized block design with two replication. The treatments in each experiment (2014 and 2016) were 70 maize accessions. The accessions were planted in planting distant of 75 cm × 20 cm, in 5 m rows, resulting in 20 plants per row. In every 10 rows, two check varieties were planted, i.e. one susceptible and one resistant variety. Ten days prior to planting, the soil was fertilized with mixed fertilizers consisted of urea, ZA, SP36, and KCl at a dose of 100, 100, 100, and 100 kg/ha, respectively. Fertilization II and III was given at 30 days after planting, and 45 days after planting with a dose of 100 kg urea/ha. As a source of inoculum downy mildew, around the repeated plot was planted with varieties Anoman variety (susceptible variety) that was inoculated with a suspension of downy mildew pathogen. Observation was conducted at 25, 35, and 55 days after planting, with the standard score of resistant to downy mildew, followed: 0–10% = resistant, 11–25% = moderately resistant, 26–50% = moderately susceptible, >50% = susceptible. The result of the experiments showed that there were 5 accessions resistant to downy mildew (P. philipinensis), i.e. CML 440×MR4-9-30-3, 664, 60, 572, and 554 with the intensity of downy mildew infection ranged from 5 to 10%. Twelve other accessions were classified as moderately resistant, i.e. CML 440×MR4-9-98-2, 440×MR4-9-98-4 CML, CML 440×MR4-9-124-1, 66, 71, 319, 108, 73, 48, 105, 554, and 682 with intensity of infection ranged from 13 to 25%. At the same experiments, the average intensity of downy mildew infection on susceptible check varieties reached 100 percent.

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Pseudomonads: major antagonistic endophytic bacteria to suppress bacterial wilt pathogen, Ralstonia solanacearum in the eggplant (Solanum melongena L.)

World Journal of Microbiology and Biotechnology ◽

10.1007/s11274-008-9859-3 ◽

2008 ◽

Vol 25 (1) ◽

pp. 47-55 ◽

Cited By ~ 85

Author(s):

R. Ramesh ◽

A. A. Joshi ◽

M. P. Ghanekar

Keyword(s):

Bacterial Wilt ◽

Ralstonia Solanacearum ◽

Endophytic Bacteria ◽

Solanum Melongena

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Bacterial Wilt of Solanaceae Caused by Ralstonia solanacearum Race 1 Biovar 3 in Mali

Plant Disease ◽

10.1094/pdis-94-3-0372b ◽

2010 ◽

Vol 94 (3) ◽

pp. 372-372 ◽

Cited By ~ 4

Author(s):

A. T. Thera ◽

B. J. Jacobsen ◽

O. T. Neher

Keyword(s):

Surface Water ◽

Bacterial Wilt ◽

Ralstonia Solanacearum ◽

Solanum Tuberosum L ◽

Solanum Melongena ◽

Potato Seed ◽

Relative Distribution ◽

Tetrazolium Chloride ◽

Wide Range ◽

Race 1

Ralstonia solanacearum (Smith) Yabuuchi et al. causes bacterial wilt worldwide on a wide range of plant species. In Mali, the disease is commonly found on potato (Solanum tuberosum L.), tomato (Lycopersicon esculentum var. esculentum L.), pepper (Capsicum annuum L.), eggplant (Solanum melongena L.), tobacco (Nicotiana tabacum L.), and peanut (Arachis hypogaea L.). Determination of race and biovar is critical for development of potato seed certification programs for management of the disease. Isolates (25) of R. solanacearum were obtained from wilting potato, pepper, eggplant, tobacco, and tomato plants collected from fields near Baguineda, Sonityeni, Sotuba, Sikasso, and Kolikoro. Isolations were made from bacterial streaming by dilution plating on triphenyl tetrazolium chloride medium (TZC) (2). Characteristic colonies were selected and identified by ELISA or Immunostrips (Pathoscreen Rs, Agdia Inc., Elkhart, IN). These isolates were used in host range studies and hypersensitivity (HR) tests on tobacco (cv. xanthi) (3) and tested for their ability to produce acids on Ayers basal media amended with disaccharide and hexose alcohol carbon sources (1). These isolates caused characteristic wilt 40 days postinoculation on greenhouse-grown tobacco (cv. Xanthi), peanut (cv. 4610), and tomato (cv. Roma VF) plants when stems of five plants of each host were syringe inoculated with 0.1 ml of a 1 × 109 CFU/ml of bacteria. Plants inoculated with sterile distilled water remained symptomless and R. solanacearum was reisolated from infected plants on TZC and identified with Immunostrips. All HR tests were negative. Infection of peanut, tobacco, and tomato and the results of the HR tests indicated that all isolates were Race 1 and no significant variation was noted between isolates. Acid was produced from the hexose alcohols: mannitol, sorbitol, and dulcitol; and the disaccharides: cellobiose, lactose, and maltose. This indicated that all isolates were biovar 3, the same as a known Race 1 strain from tobacco (MSU Plant Pathology teaching collection) (1). To assess relative distribution of R. solanacearum, 20 soil samples collected from potato fields in the vicinity of Baguineda, Kati, Koulikoro, and Sikasso were placed in pots (30 × 25 cm) under shade cloth at the IER Station in Sotuba and planted with 30-day-old tobacco plants. After 90 days, infected plants (35 to 100% infection) were found in all soils. Infected plants exhibited classical wilt symptoms and tested positive for R. solanacearum infections as confirmed by Immunostrip tests. Six of nine surface water samples taken near potato fields in Baguineda, Sikasso, Mopti, and Koulikoro tested positive for the presence of R. solanacearum by an Agdia Inc. enrichment kit and ELISA. A weed, Commelina forskalaei (Vahl), collected by Farako creek near Sikasso tested positive in the Immunostrip test even though no symptoms were obvious. No attempt was made to characterize the race, biovar, or phylotype of the soil, water, and weed isolates. To our knowledge, this is the first time that the race and biovar of R. solanacearum from Mali has been reported and the wide distribution of this pathogen in Malian soils and surface water has been demonstrated. It is significant that we did not detect Race 3 biovar 2, which is subject to quarantine and biosecurity regulations. References: (1) A. C. Hayward. J. Bacteriol. 27:265, 1964. (2) A. Kelman. Phytopathology 44:693, 1954. (3) J. Lozano and L. Sequeira. Phytopathology 60:833, 1970.

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Induced ligno-suberin vascular coating and tyramine-derived hydroxycinnamic acid amides restrict Ralstonia solanacearum colonization in resistant tomato roots

10.1101/2021.06.15.448549 ◽

2021 ◽

Author(s):

Anurag Kashyap ◽

Montserrat Capellades ◽

Weiqi Zhang ◽

Sumithra Srinivasan ◽

Anna Laromaine ◽

...

Keyword(s):

Bacterial Wilt ◽

Ralstonia Solanacearum ◽

Structural Changes ◽

De Novo ◽

Susceptible Variety ◽

Hydroxycinnamic Acid ◽

Physico Chemical ◽

Tomato Roots ◽

Hydroxycinnamic Acid Amides ◽

Susceptible Tomato

The soil borne pathogen Ralstonia solanacearum is the causing agent of bacterial wilt, a devastating disease affecting major agricultural crops. R. solanacearum enters plants through the roots and reaches the vasculature, causing rapid wilting. We recently showed that tomato varieties resistant to bacterial wilt restrict bacterial movement in the plant. In the present work we go a step forward by identifying the physico-chemical nature of the barriers induced in resistant tomato roots in response to R. solanacearum. We describe that resistant tomato specifically responds to infection by assembling de novo a structural barrier at the vasculature formed by a ligno-suberin coating and tyramine-derived hydroxycinnamic acid amides (HCAAs). On the contrary, susceptible tomato does not form these reinforcements in response to the pathogen but instead displays lignin structural changes compatible with its degradation. Further, we show that overexpressing genes of the ligno-suberin pathway in a commercial susceptible variety of tomato restricts R. solanacearum movement inside the plant and slows disease progression, enhancing resistance to the pathogen. We thus propose that the induced barrier in resistant plants does not only restrict the movement of the pathogen, but may also prevent cell wall degradation by the pathogen and confer anti-microbial properties.

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Occurrence and Biovar Classification of Bacterial Wilt Caused by Ralstonia solanacearum in Eggplant (Solanum melongena)

Research in Plant Disease ◽

10.5423/rpd.2008.14.1.010 ◽

2008 ◽

Vol 14 (1) ◽

pp. 10-14 ◽

Cited By ~ 5

Author(s):

Yang-Sook Lim ◽

Mun-Jung Lee ◽

Jong-Do Cheung ◽

Young-Hyun Rew ◽

Byung-Soo Kim

Keyword(s):

Bacterial Wilt ◽

Ralstonia Solanacearum ◽

Solanum Melongena

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SKRINING KETAHANAN SOMAKLON NILAM TERHADAPP PENYAKIT LAYU BAKTERI (Ralstonia solanacearum)

Jurnal Penelitian Tanaman Industri ◽

10.21082/littri.v21n3.2015.131-138 ◽

2016 ◽

Vol 21 (3) ◽

pp. 131

Author(s):

S. Y. HARTATI ◽

E. HADIPOENTYANTI ◽

AMALIA AMALIA ◽

NURSALAM NURSALAM

Keyword(s):

Bacterial Wilt ◽

Ralstonia Solanacearum ◽

Screening Method ◽

Wilt Disease ◽

Resistance Screening ◽

Bacterial Wilt Disease ◽

House Condition ◽

Moderately Resistant

ABSTRAKLayu bakteri yang disebabkan oleh Ralstonia solanacearum merupakan salah satu penyakit penting pada tanaman nilam. Perakitan varietas nilam tahan terhadap penyakit tersebut yang dilakukan melalui induksi keragaman somaklonal telah menghasilkan beberapa somaklon yang tahan terhadap R. solanacearum secara in-vitro. Tujuan penelitian adalah menguji tingkat ketahanan somaklon tersebut terhadap penyakit layu pada kondisi rumah kaca (in-vivo). Penelitian disusun dalam Rancangan Acak Lengkap dengan 27 perlakuan, 3 ulangan, dan 10 tanaman/ulangan. Sebagian akar dari somaklon nilam dilukai (dipotong), selanjutnya diinokulasi (disiram) dengan suspensi R. solanacearum dengan berbagai konsentrasi 105, 107, dan 109 cfu/ml, sebanyak 50 ml/tanaman. Hasil penelitian menunjukkan, bahwa somaklon yang diinokulasi dengan konsentrasi 105 cfu/ml, 50 ml/tanaman semuanya tidak menunjukkan gejala layu. Somaklon yang diinokulasi dengan konsentrasi 107 dan 109cfu/ml, 50 ml/tanaman, sebagian layu dan mati. Dari somaklon yang7diinokulasi dengan konsentrasi 10 cfu/ml, 50 ml/tanaman, 8 di antaranyamenunjukkan respon sangat tahan, 4 tahan, dan 5 agak tahan. Ke 17 somaklon tersebut mempunyai intensitas penyakit <50% dan semua lebih tahan dari pada varietas Sidikalang (agak toleran). Dari 17 somaklon yang diinokulasi dengan konsentrasi 109 cfu/ml, 50 ml/tanaman, 2 di antaranya sangat tahan dan 7 somaklon tahan. Teknik skrining ini dapat digunakan sebagai metode standar untuk pengujian ketahanan nilam terhadap penyakit layu.Kata kunci: Skrining ketahanan, somaklon, nilam, penyakit layu, R. solanacearum. ABSTRACTResistance-Screening of Patchouli Somaclones on Bacterial Wilt Disease (Ralstonia solanacearum) Bacterial wilt caused by Ralstonia solanacearum is one of the most important diseases on patchouli. The developing patchouli resistance varieties against wilt disease conducted through the induction of somaclonal variation produced resistant patchouli somaclones against R. solanacearum (in-vitro). The aim of this research was to screen the resistance of those patchouli somaclones against wilt disease under a glass house condition (in-vivo). The research was conducted in a Randomized Completely Design with 27 treatments, 3 replicates, and 10 plants/ replicate. Some roots of the patchouli somaclones were wounded (cut), then inoculated (drenched) with R. solanacearum suspension in concentration of 105, 107, and 109 cfu/ml; 50 ml/plant. The result showed, that all the patchouli somaclones inoculated with R. solanacearum 105 cfu/ml, 50 ml/plant were not show any wilt sympthom. Whereas, some somaclones inoculated with the higher concentration 107 and 109 cfu/ml, 50 ml/plant were wilted and died. Among the somaclones inoculated with the concentration of 107 cfu/ml, 50 ml/plant, 8 of them were highly resistant, 4 were resistant, and 5 were moderately resistant. The disease intencity of those 17 somaclones were <50% and they were more resistant than the Sidikalang variety (moderately tolerant). Among those 17 somaclones inoculated with the concentration of 109 cfu/ml, 50 ml/plant, 2 of them were highly resistant and 7 were resistant. This screening method could be used as a standard protocol for patchouli resistance screening against wilt disease.Kata kunci: Screening resistance, somaclone, patchouli, wilt disease, R. solanacearum.

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