scholarly journals Diversity of Ralstonia pseudosolanacearum, the causal agent of bacterial wilt on Eucalyptus pellita in Indonesia

2021 ◽  
Vol 22 (6) ◽  
Author(s):  
Bayo Alhusaeri Siregar ◽  
Giyanto Giyanto ◽  
Sri Hendrastuti Hidayat ◽  
Iskandar Zulkarnain Siregar ◽  
Budi Tjahjono

Abstract. Siregar BA, Giyanto, Hidayat SH, Siregar IZ, Tjahjono B. 2021. Diversity of Ralstonia pseudosolanacearum, the causal agent of bacterial wilt on Eucalyptus pellita in Indonesia. Biodiversitas 22: 2538-2545. The Ralstonia species complex was initially classified into five races and five biovars but the classification could not accommodate the isolates' phylogenetic history or geographic origins. A phylotype and sequevar system is based on the geographic distribution and characteristics of endoglucanase (egl) and hypersensitive response and pathogenicity (hrp) gene sequences. This study aims to describe pathogen diversity of the causal agent of bacterial wilt on Eucalyptus pellita F. Muell. Pathogens were isolated from wilting seedlings and trees in several Eucalyptus plantations. The phenotypic diversity analysis included biovar, exopolysaccharide quantification and virulence tests, while genotypic diversity included phylotypes and sequevar determination based on egl gene sequences. A total of 35 strains were isolated from the field and nurseries of Eucalyptus in various locations. All isolates were confirmed as Ralstonia species complex based on morphological characteristics and molecular studies using species-specific primers. These isolates were dominantly classified as biovar 3 and 4 and had a high variation on virulence and EPS production. Based on the egl sequence's alignment, 29 strains of Phylotype I are grouped into four sequevar references (sequevars 14, 17, 18, 30) and new a sequevar 58. This study shows that strains of R. pseudosolanacearum causing bacterial wilt on E. pellita in Indonesia have high phenotypic and genotypic diversities.

2021 ◽  
Author(s):  
Neha Faridi ◽  
Merwyn Packia raj Samuel ◽  
Shalini Bhatt ◽  
Ankur Agrawal ◽  
Veena Pande ◽  
...  

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.


2020 ◽  
Vol 3 (1) ◽  
pp. 94
Author(s):  
Bayo A. Siregar ◽  
Abdul Gafur ◽  
Pranita Nuri ◽  
H. Halimah ◽  
Budi Tjahjono ◽  
...  

Bacterial wilt is one of major threats to eucalyptus plantations which may cause significant losses. Until now, study about bacterial wilt on Eucalyptus pellita in Indonesia has been very limited, especially about the presence of the pathogen on or in the seeds. This study aims to provide evidence of the existence of the R. solanacearum bacterium on or in E. pellita seeds. Detection of seed-borne bacteria is determined by several approaches such as (i) direct detection using universal and selective media in the laboratory, (ii) the nursery test, and (iii) species-specific molecular detection. The results of our study indicate that R. solanacearum can be detected from eucalyptus seeds using universal and selective media in the laboratory, nursery test, and molecular-based detection using the Enrichment PCR method. The bacterial inoculum is also proven to exist both on the surface of and inside the eucalyptus seeds. This is the first report that R. solanacearum is a seed-borne pathogen in E. pellita seeds. Previous studies in different agricultural systems show that the effective method used to control the pathogen is through seed treatments using biological, physical, and chemical approaches.


PLoS ONE ◽  
2014 ◽  
Vol 9 (8) ◽  
pp. e104195 ◽  
Author(s):  
Zhenyue Lin ◽  
Shiqiang Xu ◽  
Youxiong Que ◽  
Jihua Wang ◽  
Jack C. Comstock ◽  
...  

Plant Disease ◽  
2017 ◽  
Vol 101 (6) ◽  
pp. 1022-1028 ◽  
Author(s):  
Yingjuan Chen ◽  
Wenjun Qiao ◽  
Liang Zeng ◽  
Dahang Shen ◽  
Zhi Liu ◽  
...  

Brown blight disease caused by Colletotrichum species is a common and serious foliar disease of tea (Camellia sinensis). Fungal isolates from several tea plantations causing typical brown blight symptoms were identified as belonging to the Colletotrichum acutatum species complex and the Colletotrichum gloeosporioides species complex based on morphological characteristics as well as DNA analysis of the internal transcribed spacer (ITS) and glyceraldehyde 3-phosphate dehydrogenase (GAPDH). Colletotrichum acutatum, a new causal agent associated with C. sinensis, showed high phenotypic and genotypic diversity compared with the more commonly reported C. gloeosporioides. Phylogenetic analysis derived from individual and combined ITS and GAPDH sequences clearly clustered C. acutatum and C. gloeosporioides into separate species. Pathogenicity tests validated that both species were causal agents of tea brown blight disease and were highly pathogenic to tea leaves. However, the two groups of C. gloeosporioides with low levels of variability within their ITS and GAPDH regions differed in their virulence. This study reports for the first time the characterization of C. acutatum and C. gloeosporioides causing brown blight disease on tea (Camellia sinensis (L.) O. Kuntze) in China.


2014 ◽  
Vol 64 (Pt_9) ◽  
pp. 3087-3103 ◽  
Author(s):  
Irda Safni ◽  
Ilse Cleenwerck ◽  
Paul De Vos ◽  
Mark Fegan ◽  
Lindsay Sly ◽  
...  

The Ralstonia solanacearum species complex has long been recognized as a group of phenotypically diverse strains that can be subdivided into four phylotypes. Using a polyphasic taxonomic approach on an extensive set of strains, this study provides evidence for a taxonomic and nomenclatural revision of members of this complex. Data obtained from phylogenetic analysis of 16S-23S rRNA ITS gene sequences, 16S–23S rRNA intergenic spacer (ITS) region sequences and partial endoglucanase (egl) gene sequences and DNA–DNA hybridizations demonstrate that the R. solanacearum species complex comprises three genospecies. One of these includes the type strain of Ralstonia solanacearum and consists of strains of R. solanacearum phylotype II only. The second genospecies includes the type strain of Ralstonia syzygii and contains only phylotype IV strains. This genospecies is subdivided into three distinct groups, namely R. syzygii , the causal agent of Sumatra disease on clove trees in Indonesia, R. solanacearum phylotype IV strains isolated from different host plants mostly from Indonesia, and strains of the blood disease bacterium (BDB), the causal agent of the banana blood disease, a bacterial wilt disease in Indonesia that affects bananas and plantains. The last genospecies is composed of R. solanacearum strains that belong to phylotypes I and III. As these genospecies are also supported by phenotypic data that allow the differentiation of the three genospecies, the following taxonomic proposals are made: emendation of the descriptions of Ralstonia solanacearum and Ralstonia syzygii and descriptions of Ralstonia syzygii subsp. nov. (type strain R 001T = LMG 10661T = DSM 7385T) for the current R. syzygii strains, Ralstonia syzygii subsp. indonesiensis subsp. nov. (type strain UQRS 464T = LMG 27703T = DSM 27478T) for the current R. solanacearum phylotype IV strains, Ralstonia syzygii subsp. celebesensis subsp. nov. (type strain UQRS 627T = LMG 27706T = DSM 27477T) for the BDB strains and Ralstonia pseudosolanacearum sp. nov. (type strain UQRS 461T = LMG 9673T = NCPPB 1029T) for the strains of R. solanacearum phylotypes I and III.


Author(s):  
A. Muntala ◽  
P. M. Norshie ◽  
K. G. Santo ◽  
C. K. S. Saba

A survey was conducted in twenty-five cashew (Anacardium occidentale) orchards in five communities in the Dormaa-Central Municipality of Bono Region of Ghana to assess the incidence and severity of anthracnose, gummosis and die-back diseases on cashew. Cashew diseased samples of leaves, stem, inflorescences, twigs, flowers, nuts and apples showing symptoms (e. g. small, water-soaked, circular or irregular yellow, dark or brown spots or lesions on leaves, fruits and flowers, sunken surface, especially on the apples, blight, gum exudates) were collected for isolation of presumptive causative organism. The pathogen was isolated after disinfecting the excised diseased pieces in 70% ethanol, plated on potato dextrose agar (PDA) and incubated at 28 oC for 3 to 7 days. The identity of the putative pathogen was morphologically and culturally confirmed as belonging to Colletotrichum gloeosporioides species complex using standard mycological identification protocols. The pathogen had varied conidia sizes of between 9-15 up to 20 μm in length and diameter of 3-6 μm. The conidia were straight and cylindrically shaped with rounded or obtuse ends. The septate mycelium was whitish-grey, velvety and cotton-like in appearance from the top. The results confirmed the presence of the pathogen in the orchards with incidence ranging from 6.9% and 14.0% for gummosis and averaged 22.9% for anthracnose infected orchards. The result of the pathogenicity test confirmed the isolates to be pathogenic on inoculated cashew seedlings and were consistently re-isolated, thereby establishing the pathogen as the true causal agent of the said diseases in cashew trees and thus completed the Koch’s postulate.


Plant Disease ◽  
2020 ◽  
Vol 104 (11) ◽  
pp. 2768-2773
Author(s):  
Yonglin He ◽  
Yixue Mo ◽  
Dehong Zheng ◽  
Qiqin Li ◽  
Wei Lin ◽  
...  

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.


Plant Disease ◽  
2013 ◽  
Vol 97 (4) ◽  
pp. 485-490 ◽  
Author(s):  
Sylvana Soto-Alvear ◽  
Mauricio Lolas ◽  
Inés M. Rosales ◽  
Eduardo R. Chávez ◽  
Bernardo A. Latorre

Apple fruit in Chile are primarily produced for export to Asia, Europe, and the United States, which typically requires 15 to 40 days of maritime transportation. Therefore, Chilean apple production must fulfill the sanitization requirements imposed by the receiving countries. Under these circumstances, it was important to clarify the etiology of bull's eye rot that can severely affect ‘Cripps Pink’ apple and other late-harvest cultivars in Chile. Based on morphological characteristics and the partial sequence analysis of the internal transcribed spacer sequences and β-tubulin genes, Neofabraea alba was identified as the causal agent of the bull's eye rot of Chilean apple. These results were further corroborated using species-specific primers. The incidence of bull's eye rot varied considerably; for instance, in 2009, 0.0 to 58.7% in 38 Cripps Pink orchards surveyed in the relatively arid and humid apple-growing areas of Chile, respectively. There was no evidence for the presence of N. malicorticis or N. perennans, which are commonly identified as causal agents of bull's eye rot in other apple-producing countries. Altogether, these data suggest that N. alba might represent the predominant and possibly the only cause of bull's-eye rot of Chilean apple.


2019 ◽  
Vol 30 (1) ◽  
pp. 25-33
Author(s):  
E.A. Rossi ◽  
M. Ruiz ◽  
M. Di Renzo ◽  
N.C. Bonamico

CIMMYT maize inbred lines (CMLs) are freely distributed to breeding programs around the world. Better information on phenotypic and genotypic diversity may provide guidance to breeders on how to use more efficiently the CMLs in their breeding programs. In this study a group of 291 CIMMYT maize inbred lines, was phenotyped by nine agro-morphological traits in south Córdoba, Argentina and genotyped using 18,082 SNPs. Based on the geographic information and the environmental adaptation, 291 CMLs were classified into eight subgroups. Anthesis-silking interval (IAE) was the trait with higher phenotypic diversity. A 40% of maize inbred lines, with IAE less than five days, show a good adaptation to growing conditions in south Córdoba, Argentina. The low phenotypic variation explained by environmental adaptation subgroups indicates that population structure is only a minor factor contributing to phenotypic diversity in this panel. Principal component analysis (ACP) allowed us to obtain phenotypic and genotypic orderings. Generalized procrustes analysis (APG) indicated a 60% consensus between both data type from the total panel of maize lines. In each environmental adaptation subgroup, the APG consensus was higher. This result, which might indicate linkage disequilibrium between SNPs markers and the genes controlling these agro-morphological traits, is promising and could be used as an initial tool in the identification of Quantitative Trait Loci (QTL). Information on genetic diversity, population structure and phenotypic diversity in local environments will help maize breeders to better understand how to use the current CIMMYT maize inbred lines group. Key words: broad-sense heritability, multivariate analysis, SNPs, agro-morphological traits.


Agronomy ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1955
Author(s):  
Anysia Hedy Ujat ◽  
Ganesan Vadamalai ◽  
Yukako Hattori ◽  
Chiharu Nakashima ◽  
Clement Kiing Fook Wong ◽  
...  

The re-emergence of the Fusarium wilt caused by Fusarium odoratissimum (F. odoratissimum) causes global banana production loss. Thirty-eight isolates of Fusarium species (Fusarium spp.) were examined for morphological characteristics on different media, showing the typical Fusarium spp. The phylogenetic trees of Fusarium isolates were generated using the sequences of histone gene (H3) and translation elongation factor gene (TEF-1α). Specific primers were used to confirm the presence of F. odoratissimum. The phylogenetic trees showed the rich diversity of the genus Fusarium related to Fusarium wilt, which consists of F. odoratissimum, Fusarium grosmichelii, Fusarium sacchari, and an unknown species of the Fusarium oxysporum species complex. By using Foc-TR4 specific primers, 27 isolates were confirmed as F. odoratissimum. A pathogenicity test was conducted for 30 days on five different local cultivars including, Musa acuminata (AAA, AA) and Musa paradisiaca (AAB, ABB). Although foliar symptoms showed different severity of those disease progression, vascular symptoms of the inoculated plantlet showed that infection was uniformly severe. Therefore, it can be concluded that the Fusarium oxysporum species complex related to Fusarium wilt of banana in Malaysia is rich in diversity, and F. odoratissimum has pathogenicity to local banana cultivars in Malaysia regardless of the genotype of the banana plants.


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