ABSTRACT
The genus Dendrothripoides was originally described by Bagnall (1923) from India and is currently represented by five species (ThripsWiki 2020). Dendrothripoides innoxius (Karny) is widely distributed in the Oriental and Pacific regions; D. microchaetus Okajima is from the Philippines and Indonesian archipelago; D. nakaharai Reyes known only from the Philippines, D. poni Kudo from Thailand, and D. venustus Faure from Rhodesia [Zimbabwe] and South Africa (Faure 1941; Kudo 1977; Bournier 2000). Little is known about the biology of these species because collections often have samples with few specimens. D. innoxius is considered a minor pest on Ipomoea crops (Watson Mound 2020) but adults have been taken on the leaves of plants in numerous families (Asteraceae, Convolvulaceae, Dioscoreaceae, Musaceae, Poaceae). Dendrothripoides was classified within the Panchaetothripinae by Priesner (1957) for having a reticulate body surface. However, Ananthakrishnan (1963) indicated that the similarities are superficial, and that this genus should be classified in the Aptinothripina of the Thripinae because the pronotum lacks long setae. The genus is now not included in the Anaphothrips genus-group (Masumoto Okajima 2017), but the systematic position is unclear with a recent morphological phylogenetic analysis indicating a position near the Panchaetothripinae that may be due to superficial resemblance (Zhang et al. 2019).
Subject(s)
Thysanoptera , Animals , Madagascar , PhylogenyABSTRACT
The Ralstonia solanacearum species complex (RSSC), composed of three species and four phylotypes, are globally distributed soil-borne bacteria with a very broad host range. In 2009, a devastating potato bacterial wilt outbreak was declared in the central highlands of Madagascar, which reduced the production of vegetable crops including potato, eggplant, tomato and pepper. A molecular epidemiology study of Malagasy RSSC strains carried out between 2013 and 2017 identified R. pseudosolanacearum (phylotypes I and III) and R. solanacearum (phylotype II). A previously published population biology analysis of phylotypes II and III using two MultiLocus Variable Number of Tandem Repeats Analysis (MLVA) schemes revealed an emergent epidemic phylotype II (sequevar 1) group and endemic phylotype III isolates. We developed an optimized MLVA scheme (RS1-MLVA14) to characterize phylotype I strains in Madagascar to understand their genetic diversity and structure. The collection included isolates from 16 fields of different Solanaceae species sampled in Analamanga and Itasy regions (highlands) in 2013 (123 strains) and in Atsinanana region (lowlands) in 2006 (25 strains). Thirty-one haplotypes were identified, two of them being particularly prevalent: MT007 (30.14%) and MT004 (16.44%) (sequevar 18). Genetic diversity analysis revealed a significant contrasting level of diversity according to elevation and sampling region. More diverse at low altitude than at high altitude, the Malagasy phylotype I isolates were structured in two clusters, probably resulting from different historical introductions. Interestingly, the most prevalent Malagasy phylotype I isolates were genetically distant from regional and worldwide isolates. In this work, we demonstrated that the RS1-MLVA14 scheme can resolve differences from regional to field scales and is thus suited for deciphering the epidemiology of phylotype I populations.
Subject(s)
Bacterial Typing Techniques , Genetic Variation , Multilocus Sequence Typing , Phylogeny , Ralstonia/classification , Ralstonia/genetics , Tandem Repeat Sequences/genetics , GenotypeABSTRACT
The genus Thrips comprises 296 species (ThripsWiki 2019) and is the largest of all Terebrantian genera. The only other Thysanopteran genera comparable in size are the phlaeothripids Haplothrips and Liothrips. Species of Thrips can be found in flowers and on leaves of a wide variety of plants from grasses to trees. Most of them are beneficial pollinators (Garcia-Fayos Goldarazena 2008; Eliyahu et al. 2015), while others are pests and cause significant economic damage (Mound Marullo 1996). Some of them are polyphagous and widespread, while others are rarely seen and restricted to one species of plant (Palmer 1992).
