Identification of candidate type 3 effectors that determine host specificity associated with emerging Ralstonia pseudosolanacearum strains

AbstractRalstonia pseudosolanacearum (Rps), previously known as R. solanacearum phylotypes I and III is one of the causal agents of bacterial wilt, a devastating disease that affects more than 250 plant species. Emerging Rps strains were identified infecting new hosts. P824 Rps strain was isolated from blueberry in Florida. Rps strains including PD7123 were isolated from hybrid tea roses in several countries through Europe. P781 is a representative strain of Rps commonly found on mandevilla in Florida. UW757 is a strain isolated from osteospermum plants originating in Guatemala. These strains are phylogenetically closely related and of economic importance on their respective hosts. The objective of this study is to associate the Type 3 Effectors (T3Es) repertoire of these four strains with host specificity. Candidate T3E associated with host specificity to blueberry, tea rose, osteospermum, and mandevilla were identified by sequence homology. Pathogenicity assays on 8 hosts including, blueberry, mandevilla, osteospermum and tea rose with the 4 strains showed that both P824 and PD7123 are pathogenic to blueberry and tea rose. P781 is the only strain pathogenic to mandevilla and P824 is the only strain non-pathogenic to osteospermum. Hypotheses based on correlation of T3E presence/absence and pathogenicity profiles identified 3 candidate virulence and 3 avirulence T3E for host specificity to blueberry and tea rose. Two candidate avirulence T3E were identified for mandevilla, and one candidate virulence for osteospermum. The strategy applied here can be used to reduce the number of host specificity candidate genes in closely related strains with different hosts.

Download Full-text

Low Temperature Induces Infectious Nonresuscitatable VBNC Cells in Ralstonia Pseudosolanacearum

10.21203/rs.3.rs-312710/v1 ◽

2021 ◽

Author(s):

Neha Faridi ◽

Merwyn Packia raj Samuel ◽

Shalini Bhatt ◽

Ankur Agrawal ◽

Veena Pande ◽

...

Keyword(s):

Low Temperature ◽

Bacterial Wilt ◽

Ralstonia Solanacearum ◽

Species Complex ◽

Economic Importance ◽

Bacterial Genus ◽

Window Period ◽

Ralstonia Pseudosolanacearum ◽

Uv C

Abstract Ralstonia pseudosolanacearum and other members of Ralstonia solanacearum species complex (RSSC) causes the disease bacterial wilt in many crops of economic importance. The organism is known to form Viable But Non Culturable cells (VBNC). VBNCs resuscitate invitro during the “resuscitation window” period and are infectious Previous studies have identified nonresuscitatable VBNCs in various bacterial genus including RSSC, however their infectivity was not elucidated and described. In this work, VBNCs of two Ralstonia pseudosolanacearum strains were generated by exposing the microcosms to psychrophilic stress, UV-C radiation and 70% isopropanol. Both resuscitatable and nonresuscitatable VBNCs were observed in psychrophilic and UV-C stressed microcosms. The nonresuscitatable VBNCs generated at psychrophilic temperature were found infective. Based on resuscitation properties, nonresuscitatable VBNCs can be considered as a different VBNC type from resuscitatable VBNCs.

Download Full-text

Different Sequevars of Ralstonia pseudosolanacearum Causing Bacterial Wilt of Bidens pilosa in China

Plant Disease ◽

10.1094/pdis-12-19-2738-sc ◽

2020 ◽

Vol 104 (11) ◽

pp. 2768-2773

Author(s):

Yonglin He ◽

Yixue Mo ◽

Dehong Zheng ◽

Qiqin Li ◽

Wei Lin ◽

...

Keyword(s):

Arachis Hypogaea ◽

Bacterial Wilt ◽

Geographical Origin ◽

Bidens Pilosa ◽

Invasive Weed ◽

High Virulence ◽

Race 1 ◽

Ralstonia Pseudosolanacearum ◽

Phylotype I

Bidens pilosa is an invasive weed that threatens the growth of crops and biodiversity in China. In 2017, suspected bacterial wilt of B. pilosa was discovered in Qinzhou and Beihai, Guangxi, China. A variety of weeds are considered as reservoirs harboring bacterial wilt pathogens, but most do not show obvious symptoms in the field. Identifying the classification status of the B. pilosa bacterial wilt pathogen and exploring its geographical origin might be helpful for clarifying the role of weeds in the circulation of the disease. Phylotyping, sequevar analysis, and cross inoculation of pathogens isolated from B. pilosa and nearby peanut (Arachis hypogaea), balsam gourd (Momordica charantia), and eucalyptus (Eucalyptus robusta) plants were carried out. Three isolates of B. pilosa (Bp01, Bp02, and Bp03) were identified as Ralstonia pseudosolanacearum, race 1, biovar 3, and phylotype I, and belonged to sequevars 17 and 44, and an unknown sequevar. The sequevars isolated from B. pilosa were not completely consistent with those of the nearby hosts, and the virulence of these isolates differed when cross inoculated. The Bp03 sequevar was different from peanut isolate sequevars in the same field and was not identical to any previously designated sequevars. The isolates from B. pilosa and other nearby hosts displayed low or no virulence toward their cross hosts (with wilt incidences less than 33.33%). An exception to this was the isolates from B. pilosa, which displayed high virulence toward eucalyptus (with a wilt incidence of 70.00 to 100.00%). This is the first report of different sequevars of R. pseudosolanacearum causing typical bacterial wilt symptoms in B. pilosa in the field.

Download Full-text

Spider mites (Acari: Tetranychidae) in protected natural areas of Serbia

Systematic and Applied Acarology ◽

10.11158/saa.23.10.12 ◽

2018 ◽

Vol 23 (10) ◽

pp. 2033

Author(s):

Ivana Marić ◽

Irena Međo ◽

Slobodan Jovanović ◽

Radmila Petanović ◽

Dejan Marčić

Keyword(s):

Plant Species ◽

Host Plants ◽

Spider Mite ◽

Spider Mites ◽

Mite Species ◽

Southeast Europe ◽

Natural Areas ◽

Relict Species ◽

Protected Natural Areas ◽

New Hosts

Despite economic importance of Tetranychidae, knowledge regarding diversity of spider mites in the Balkan Peninsula and Southeast Europe is incomplete, especially in protected natural areas. This study presents diversity of spider mites (Acari: Tetranychidae) collected over five growing seasons at 296 locations in 38 protected natural areas of Serbia. A total of 31 spider mite species were found, 10 from Bryobiinae and 21 from Tetranychinae. The species Eotetranychus fagi Zacher was recorded as new to Serbia and this record was also the first one for Southeast Europe. Spider mites were found on host plants in five basic types as well as many subtypes of terrestrial habitats, with woodland as the most dominant one. A total of 151 plant species from 44 families were recorded as hosts for spider mites including new world records: 60 new hosts for family Tetranychidae and 41 new hosts for 21 spider mite species. Host plants from Rosaceae family harbored the highest number of spider mite species (16). A considerable number of species was found on host plants from the families Betulaceae (11), Asteraceae (10) and Sapindaceae (10). Two cosmopolitan spider mites, Tetranychus urticae Koch and Tetranychus turkestani Ugarov & Nikolskii, were clearly distinguished with 67 (7 new) and 43 (13 new) recorded host species, respectively; among newly recorded hosts for Tetranychidae family, these two mite species were found on 27 and 12 hosts, respectively. After the two most common species, the most striking was the presence of Bryobia praetiosa Koch with 24 (4 new) recorded host plants, followed by Amphitetranychus viennensis (Zacher), Eotetranychus carpini (Oudemans) and Bryobia rubrioculus (Scheuten), with 21 (7 new), 20 (6 new) and 16 (2 new) hosts, respectively. The remaining tetranychids were found on 1–9 host plant species. This study provided the first insight into diversity of tetranychids in Serbian protected areas. Further research in this field should focus on mites from host plants representative of specific areas and habitats, including endangered, endemic and relict species.

Download Full-text

COMPARATIVE ANATOMY AND HISTOCHEMISTRY OF FRUITS OF FOUR VARIETIES OF Hancornia speciosa GOMES (APOCYNACEAE)

DESAFIOS Revista Interdisciplinar da Universidade Federal do Tocantins ◽

10.20873/uftv8-10593 ◽

2021 ◽

Vol 8 (2) ◽

pp. 31-41

Author(s):

Dayana Figueiredo Abdalla ◽

Indiara Nunes Mesquita Ferreira ◽

Moemy Gomes de Moraes ◽

Eli Regina Barboza de Souza

Keyword(s):

Secondary Metabolites ◽

Plant Species ◽

Comparative Anatomy ◽

Economic Importance ◽

Taxonomic Identification ◽

Anatomical Characteristics ◽

Isolated Organs ◽

The Family ◽

Hancornia Speciosa ◽

Botanical Varieties

Hancornia speciosa Gomes, known as mangaba or mangabeira, is a plant species of the family Apocynaceae with botanical varieties occurring in several regions of Brazil. The species is of considerable ecological and economic importance in the food, timber, latex and medicinal industries. Four different varieties of H. speciosa occur in Cerrado. Anatomical characteristics contribute to the taxonomic identification of plants, including those of isolated organs such as leaves, roots, stems, fruits and seeds. Thus, the present work investigated the anatomical characteristics and the location of the main classes of secondary metabolites of the fruits of H. speciosa var. pubescens, H. speciosa var. gardneri, H. speciosa var. speciosa and H. speciosa var. cuyabensis to assist in distinguishing the varieties. Fruits were collected, preserved and fixed following usual methods for anatomical and histochemical analyses. All varieties under study showed similarities in anatomical characteristics and in the distribution of metabolites in the fruits, with the exception of the anatomy of the exocarp, where the occurrence of trichomes differed among the varieties of H. speciosa.

Download Full-text

An Ethnobotanical Study of Medicinal Plants of Billawar Region, Jammu and Kashmir, India

Journal of Mountain Research ◽

10.51220/jmr.v16i1.22 ◽

2021 ◽

Vol 16 (1) ◽

Author(s):

Rakesh Kumar ◽

Vikas Sharma ◽

Sudesh Kumar ◽

Vikrant Jaryan

Keyword(s):

Medicinal Plants ◽

Plant Species ◽

Field Survey ◽

Local Communities ◽

Economic Importance ◽

Local People ◽

Ethnobotanical Study ◽

Efficient Utilization ◽

Jammu And Kashmir ◽

Union Territory

The present study was carried out in some interior regions of Billawar in Jammu and Kashmir Union Territory to collect the information of traditionally used and ethno-botanically important medicinal plants by the local communities. Proper identification of the plant species and their importance to the local people can provide useful information and play a pivotal role in efficient utilization of natural wealth. So, it is important to scientifically identify and document this natural wealth before they are lost forever. The field survey was conducted at different sites namely, Dewal, Billawar, Bhaddu, Sukrala, Koti Marhoon and Kishanpur of Kathua district from December 2019 to June 2020. During this study, a total of 64species of medicinal plants (including trees, shrubs herbs, and grasses) belonging to 40 families and 43 genera were identified and were commonly used by the local people to cure different diseases. Each recorded plant was identified for their economic importance and medicinal values for the treatment of diseases like headache, toothache, epilepsy, gastric problem, skin disorders earache, pneumonia, jaundice, etc. Therefore, the present work was an attempt to document and compute which includes the collection and compilation of different plant species of the region.

Download Full-text

Bacterial wilt of ginger (Zingiber officinale Rosc.) incited by Ralstonia pseudosolanacearum - A review based on pathogen diversity, diagnostics and management

Journal of Plant Pathology ◽

10.1007/s42161-020-00487-5 ◽

2020 ◽

Vol 102 (3) ◽

pp. 709-719

Author(s):

Thekkan Puthiyaveedu Prameela ◽

Rajamma Suseela Bhai

Keyword(s):

Bacterial Wilt ◽

Zingiber Officinale ◽

Pathogen Diversity ◽

Ralstonia Pseudosolanacearum

Download Full-text

First Report of Bacterial Wilt of Tomato Caused by Ralstonia pseudosolanacearum (Ralstonia solanacearum phylotype I) in Cambodia

Plant Disease ◽

10.1094/pdis-09-19-1823-pdn ◽

2020 ◽

Vol 104 (3) ◽

pp. 969-969

Author(s):

T. L. Klass ◽

M. M. Hayes ◽

K. H. Seng ◽

C. An ◽

F. Rotondo ◽

...

Keyword(s):

Bacterial Wilt ◽

Ralstonia Solanacearum ◽

First Report ◽

Ralstonia Pseudosolanacearum ◽

Phylotype I

Download Full-text

Host specificity of insect herbivores in tropical forests

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2004.3023 ◽

2005 ◽

Vol 272 (1568) ◽

pp. 1083-1090 ◽

Cited By ~ 208

Author(s):

Vojtech Novotny ◽

Yves Basset

Keyword(s):

Host Specificity ◽

Tropical Forests ◽

Plant Species ◽

Field Studies ◽

Tropical Species ◽

Distribution Data ◽

Insect Herbivores ◽

Leaf Miners ◽

Experimental Conditions ◽

Plant Phylogeny

Studies of host specificity in tropical insect herbivores are evolving from a focus on insect distribution data obtained by canopy fogging and other mass collecting methods, to a focus on obtaining data on insect rearing and experimentally verified feeding patterns. We review this transition and identify persisting methodological problems. Replicated quantitative surveys of plant–herbivore food webs, based on sampling efforts of an order of magnitude greater than is customary at present, may be cost-effectively achieved by small research teams supported by local assistants. Survey designs that separate historical and ecological determinants of host specificity by studying herbivores feeding on the same plant species exposed to different environmental or experimental conditions are rare. Further, we advocate the use of host‐specificity measures based on plant phylogeny. Existing data suggest that a minority of species in herbivore communities feed on a single plant species when alternative congeneric hosts are available. Thus, host plant range limits tend to coincide with those of plant genera, rather than species or suprageneric taxa. Host specificity among tropical herbivore guilds decreases in the sequence: granivores>leaf-miners>fructivores>leaf-chewers=sap-suckers>xylophages>root-feeders, thus paralleling patterns observed in temperate forests. Differences in host specificity between temperate and tropical forests are difficult to assess since data on tropical herbivores originate from recent field studies, whereas their temperate counterparts derive from regional host species lists, assembled over many years. No major increase in host specificity from temperate to tropical communities is evident. This conclusion, together with the recent downward revisions of extremely high estimates of tropical species richness, suggest that tropical ecosystems may not be as biodiverse as previously thought.

Download Full-text