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Cucumis Melo, Cucumis Sativus, Cucurbita Moschata, and Anthurium Spp, New Hosts of Ralstonia Solanacearum in Martinique (French West Indies)

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Cucumis Melo, Cucumis Sativus, Cucurbita Moschata, and Anthurium Spp, New Hosts of Ralstonia Solanacearum in Martinique (French West Indies) http://ibws.nexenservices.com Cucumis melo, Cucumis sativus, Cucurbita moschata, and Anthurium spp, New Hosts of Ralstonia solanacearum in Martinique (French West Indies) Emmanuel WICKER 1, Laurence GRASSART 2, Danielle MIAN 3, Régine CORANSON-BEAUDU 3, Denise DUFEAL 3, Caroline GUILBAUD 4 and Philippe PRIOR 4 1CIRAD-FLHOR, BP 153, 97202, Fort de France Cedex, Martinique, FWI, 2 Service de la Protection des Végétaux, BP 438, La Pointe des Sables, 97205, Fort de France Cedex, Martinique, FWI, 3 Fédération régionale de défense contre les organismes nuisibles (FREDON), BP 550 – La Pointe des Sables, 97205 Fort de France Cedex, Martinique, FWI, 4INRA, Unité de Pathologie Végétale, Domaine St Maurice, BP 94, 84140, Montfavet, France. Corresponding author : [email protected] In the French West Indies (FWI), endemic wilt. A section of the pseudo-stem showed cucumber (C. sativus, cv. Gemini), pumpkin bacterial wilt caused by lowland tropical brown-reddish discoloration within and along (Cucurbita moschata, cv. Phoenix), Anthurium strains of Ralstonia solanacearum is known to vascular elements. Bacterial wilt on cucurbit andreanum (cv. Amigo), and Cavendish be a devastating disease to major solanaceous plot began in foci. At that stage, symptoms banana (Musa acuminata) cv. Grande naine. food and cash-crops like potato, tomato, developed quite late (fruit setting) on Inoculation was by infiltrating a bacterial eggplant and pepper (Prior & Steva, 1990). cantaloupe and pumpkin. When established in suspension (107 cfu.ml-1) into the stem or Since 1999, hybrid and local anthurium the plot, bacterial wilt may destroy the entire pseudo-stem, or by pouring 10 ml of inoculum (Anthurium sp.) productions which have crop only 2-3 weeks after planting. Disease is (108 cfu.ml-1) onto the pot surface after developed in the wetter and elevated areas of typically soilborne and develops rapidly from wounding of roots. One or two weeks after Martinique (Centre-North Atlantic) were older to youngest leaves which may wilt or inoculation, these tests reproduced symptoms dramatically affected by an unknown bacterial not. Leaves turn yellow with necrotic lesions observed in natural conditions : wilting and disease. The disease was not bacterial spot between or along major veins (same as for necrosis to cucurbit leaves, water-soaking and (Acidovorax anthurii) nor bacterial blight anthurium). The whole plant collapses and blackening to anthurium leaves and R. (Xanthomonas axonopodis pv. dies, while there are no apparent symptoms on solanacearum was successfully recovered dieffenbachiae), but bacterial wilt due to novel mature fruits. Such bacterial wilt development from these symptoms. All strains were and unexpected strains of R. solanacearum. is very fast on zucchini compared to avirulent on banana (encoded NPB) as no Late in 2001 R. solanacearum was isolated for cantaloupe and pumpkin. symptom were observed 45 days after the first time from wilted native heliconia inoculations. However, R. solanacearum was (Heliconia caribaea, Strelitziaceae) Characterization. consistently recovered from these established in the same area. Simultaneously, Bacteria were isolated from oozing stems of asymptomatic plants. massive wilt damage due to bacterial wilt was rotted rhizomes and surface-disinfected leaves also noted for the first time on cantaloupe of anthurium, and from stems of wilted Discussion (Cucumis melo), zucchini (Cucurbita pepo), cucurbits. The culture medium used was From our knowledge, this is the first record pumpkin (Cucurbita moschata) and cucumber Kelman’s triphenyltetrazolium chloride of cantaloupe and pumpkin as hosts of R. (Cucumis sativus). These outbreaks were medium (TZC). Individual bacterial colonies solanacearum. In the literature, bacterial wilt caused by the same new pathotypes of R. were selected and assessed for purity after 48 h caused by biovar 1 strains was reported on solanacearum. incubation at 28±1°C. Representative isolates summer squash, zucchini summer squash and were mucoid, with pink-reddish swirling egg- cucumber from Brazil (Oliveira and Moura, Symptoms (colour plate, back-cover). shaped pigmentation pattern characteristic of 1994; Sinigaglia et al., 2001). Natural Bacterial wilt on anthurium resulted in a R. solanacearum (Kelman, 1954). All strains occurrence of bacterial wilt on anthurium was definitive decline of many plantation and the tested were oxidase positive, strictly aerobic, reported to be caused by biovar 3 strains in disease extended rapidly in Martinique. nitrate and citrate positive, and induced a Singapore (Yik et al., 1994), Reunion Island Characteristic symptoms consist of greasy, hypersensitive reaction on tobacco leaves (cv. (Poussier et al., 2000) and Mauritius Island water-soaked lesions (lower face) which turn Xanthi) within 24 h. Strains from anthurium, (Dookun et al., 2001), or by biovar 4 strains in necrotic with greasy margins (upper face). pumpkin, zucchini and cantaloupe were tested Taïwan (Su and Leu, 1995). Unlike regular When the disease becomes systemic, these for biovar determination using a modified biovar 3 (phylotype I) strains pathogenic to lesions, generally originating from the version of the procedures of Hayward (1964), anthurium which developed as focus under the insertion point of the leaf on the petiole, and were metabolically classified as biovar 1. shade-house, behaviour of strains falling in develop following the main and secondary PCR amplification, using the R. solanacearum phylotype II seems to be dramatically active veins in a full or partial glove-shape. External species-specific primers set 759 and 760 with regard to major epidemiological traits like infection (disseminated by water) may (Opina et al. 1997) generated the expected fast spreading, rapid disease onset and developed from any natural opening such as 280bp amplicon (internal control for the acquisition of new hosts. This is the first time hydatodes. Regardless of the way the infection following multiplex-PCR) with all isolates that biovar 1 strains are found to cause so occurs, R. solanacearum establishes itself by tested. In terms of genetic diversity, typing much damage in anthurium fields. These novel flooding into parenchyma tissue, resulting in was assayed using multiplex PCRs for strains had also the unique feature of being colonization of the vascular system until most subspecies: phylotype- and Musa-specific genotypically indistinguishable from Moko of the leaves or the whole plant collapse. primers (Fegan and Prior 2002, Prior and strains, while being not pathogenic to banana. Leaves may turn yellow or not depending on Fegan 2002). Our results clearly demonstrate Recently, biovar 1 strains infecting anthurium the severity of the systemic invasion, and the that these anthurium and cucurbit strains are pots were reported from Florida, but these stem, a rhizome structure (formally named not distinguishable from reference strains strains were reported pathogenic to banana ‘caudex’) may rot with abundant bacterial ANT307 and 11212 (Prior and Fegan 2002), (Norman and Yuen, 1999). At present we ooze. Major characteristic bacterial wilt falling in the phylotype II, sequevar 4 (or don’t know if they also belong to phylotype II, symptoms on native heliconia, surrounding MLG25) cluster, unifying strains (ecotype sequevar 4. heavily infested and abandoned anthurium SFR/A) that induce the insect-transmitted form Using the hierarchical classification from plantations, as browning and rotting of the of the Moko disease (banana bacterial wilt). Fegan and Prior (2002) and relevant molecular cigar, which is the youngest rolled-up Pathogenicity tests were performed on tests, these cucurbitaceous and anthurium NPB emerging leaf. Fully expanded leaves may also cantaloupe (Cucumis melo, cv. Charentais), strains fall in phylotype II, sequevar 4 and 20 http://ibws.nexenservices.com more specifically in the NPB sub-group of common biovar 1 or biovar 3 strains may be primers for identifying Burkholderia Musa’s sequevar 4. Whereas, they are by-passed by these strains. From an solanacearum (formerly Pseudomonas pathogenic to different botanical families and agronomical point of view, these strains solanacearum). Asia Pacific Journal of were simultaneously isolated from distinct remain a major threat for banana industry and Molecular Biology and Biotechnology 5:19- geographic and climatic areas (North and provide a unique model to explore genetic 30. Center hills for anthurium strains, Windward determinism for host specificity within R. Poussier, S., D. Trigalet Demery, P. South border for cucurbitaceous strains). In the solanacearum complex species. Vandewalle, B. Goffinet, J. Luisetti, and A. FWI, bacterial wilt has only been known to Trigalet. 2000. Genetic diversity of affect solanaceous crops, being caused by Literature cited Ralstonia solanacearum as assessed by biovar 1 (phylotype II, sequevar 5) and biovar Dookun, A., S. Saumtally, and S. Seal. 2001. PCR-RFLP of the hrp gene region, AFLP 3 (phylotype I) strains (Prior and Steva 1990; Genetic diversity in Ralstonia solanacearum and 16S rRNA sequence analysis, and Fegan and Prior, 2002). In Martinique, the strains from Mauritius using restriction identification of an African subdivision. phylogenetic position of a large collection of fragment length polymorphisms. Journal of Microbiol 146 (pt.7):1679-1692. R. solanacearum strains was predicted using Phytopathology-Phytopathologische Prior, P., and M. Fegan. 2002. Diversity and multiplex-PCRs tools developed by Fegan and
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