scholarly journals Analysis of Genetic Diversity of Fusarium tupiense, the Main Causal Agent of Mango Malformation Disease in Southern Spain

Plant Disease ◽  
2016 ◽  
Vol 100 (2) ◽  
pp. 276-286 ◽  
Author(s):  
M. Crespo ◽  
F. M. Cazorla ◽  
A. de Vicente ◽  
E. Arrebola ◽  
J. A. Torés ◽  
...  

Mango malformation disease (MMD) has become an important global disease affecting this crop. The aim of this study was to identify the main causal agents of MMD in the Axarquía region of southern Spain and determine their genetic diversity. Fusarium mangiferae was previously described in the Axarquía region but it represented only one-third of the fusaria recovered from malformed trees. In the present work, fusaria associated with MMD were analyzed by arbitrary primed polymerase chain reaction (ap-PCR), random amplified polymorphic DNA (RAPD), vegetative compatibility grouping (VCG), a PCR screen for mating type idiomorph, and phylogenetic analyses of multilocus DNA sequence data to identify and characterize the genetic diversity of the MMD pathogens. These analyses confirmed that 92 of the isolates were F. tupiense, which was previously only known from Brazil and Senegal. In addition, two isolates of a putatively novel MMD pathogen were discovered, nested within the African clade of the Fusarium fujikuroi species complex. The F. tupiense isolates all belonged to VCG I, which was first described in Brazil, and the 11 isolates tested showed pathogenicity on mango seedlings. Including the prior discovery of F. mangiferae, three exotic MMD pathogenic species have been found in southern Spain, which suggests multiple independent introductions of MMD pathogens in the Axarquía region.

2010 ◽  
Vol 100 (11) ◽  
pp. 1176-1184 ◽  
Author(s):  
Gabriel Otero-Colina ◽  
Gerardo Rodríguez-Alvarado ◽  
Sylvia Fernández-Pavía ◽  
Marcel Maymon ◽  
Randy C. Ploetz ◽  
...  

The primary objective of this study was to characterize Fusarium spp. associated with the economically devastating mango malformation disease (MMD) in Mexico. In all, 142 Fusarium strains were isolated from symptomatic mango inflorescences and vegetative tissues in eight geographically diverse Mexican states from 2002 through 2007. Initially, all the Mexican isolates were screened for genetic diversity using appolymerase chain reaction and random amplified polymorphic DNA markers and were grouped into seven distinct genotypes. Based on results of these analyses, evolutionary relationships and species limits of the genetically diverse MMD-associated Fusarium spp. were investigated using multilocus DNA sequence data and phylogenetic species recognition. Maximum parsimony analyses of a five-locus data set comprising 5.8 kb of aligned DNA sequence data indicated that at least nine phylogenetically distinct Fusarium spp. within the Gibberella fujikuroi species complex are associated with MMD, including one species within the African clade (Fusarium pseudocircinatum), two species within the Asian clade (F. mangiferae and F. proliferatum), and at least six species within the American clade (F. sterilihyphosum and five undescribed Fusarium spp.). Molecular phylogenetic analyses indicate that a novel genealogically exclusive lineage within the American clade was the predominant MMD associate in Mexico. This new Fusarium sp. caused MMD and could be distinguished from all other known species morphologically by the production of mostly sterile, coiled hyphae which are typically associated with sporodochial conidiophores together with unbranched or sparsely branched aerial conidiophores. Koch's postulates were completed for isolates of the new species on nucellar seedlings of mango cv. Ataulfo. This pathogen is formally described herein as F. mexicanum.


2021 ◽  
Vol 9 (3) ◽  
pp. 666
Author(s):  
Niccolò Forin ◽  
Alfredo Vizzini ◽  
Federico Fainelli ◽  
Enrico Ercole ◽  
Barbara Baldan

In a recent monograph on the genus Rosellinia, type specimens worldwide were revised and re-classified using a morphological approach. Among them, some came from Pier Andrea Saccardo’s fungarium stored in the Herbarium of the Padova Botanical Garden. In this work, we taxonomically re-examine via a morphological and molecular approach nine different Roselliniasensu Saccardo types. ITS1 and/or ITS2 sequences were successfully obtained applying Illumina MiSeq technology and phylogenetic analyses were carried out in order to elucidate their current taxonomic position. Only the ITS1 sequence was recovered for Rosellinia areolata, while for R. geophila, only the ITS2 sequence was recovered. We proposed here new combinations for Rosellinia chordicola, R. geophila and R. horridula, while for R. ambigua, R. areolata, R. australis, R. romana and R. somala, we did not suggest taxonomic changes compared to the current ones. The name Rosellinia subsimilis Sacc. is invalid, as it is a later homonym of R. subsimilis P. Karst. & Starbäck. Therefore, we introduced Coniochaeta dakotensis as a nomen novum for R. subsimilis Sacc. This is the first time that these types have been subjected to a molecular study. Our results demonstrate that old types are an important source of DNA sequence data for taxonomic re-examinations.


Plant Disease ◽  
2003 ◽  
Vol 87 (11) ◽  
pp. 1329-1332 ◽  
Author(s):  
J. Roux ◽  
H. Myburg ◽  
B. D. Wingfield ◽  
M. J. Wingfield

Cryphonectria cubensis is an economically important pathogen of commercial Eucalyptus spp. Differences have been reported for disease symptoms associated with Cryphonectria canker in South Africa and other parts of the world, and recent DNA-based comparisons have confirmed that the fungus in South Africa is different from that in South America and Australasia. During a disease survey in the Republic of Congo, Cryphonectria canker was identified as an important disease on Eucalyptus grandis and E. urophylla. In this study, we compared Congolese and South African isolates of C. cubensis using DNA sequence data and pathogenicity under greenhouse conditions. The β-tubulin and internal transcribed spacer (ITS) region sequences show that C. cubensis in Congo is different from the fungus in South Africa and that Congolese isolates group most closely with South American isolates. Furthermore, pathogenicity tests showed that a South African isolate was more aggressive than two Congolese isolates. We conclude that two distinct Cryphonectria spp. occur in Africa and hypothesize that the fungus in the Congo probably was introduced into Africa from South America. Both fungi are important pathogens causing disease and death of economically important plantation trees. However, they apparently have different origins and must be treated separately in terms of disease management and quarantine considerations.


2017 ◽  
Vol 31 (6) ◽  
pp. 781 ◽  
Author(s):  
Savel R. Daniels ◽  
Megan Dreyer ◽  
Prashant P. Sharma

During the present study, we examined the phylogeography and systematics of two species of velvet worm (Peripatopsis Pocock, 1894) in the forested region of the southern Cape of South Africa. A total of 89 P. moseleyi (Wood-Mason, 1879) and 65 P. sedgwicki (Purcell, 1899) specimens were collected and sequenced for the cytochrome c oxidase subunit I mtDNA (COI). In addition, a single P. sedgwicki specimen per sample locality was sequenced for the 18S rRNA locus. Furthermore, morphological variation among P. sedgwicki sample localities were explored using traditional alpha taxonomic characters. DNA sequence data were subjected to phylogenetic analyses using Bayesian inference and population genetic analyses using haplotype networks and analyses of molecular variance (AMOVAs). Phylogenetic results revealed the presence of four and three clades within P. moseleyi and P. sedgwicki respectively. Haplotype networks were characterised by the absence of shared haplotypes between clades, suggesting genetic isolation, a result corroborated by the AMOVA and highly significant FST values. Specimens from Fort Fordyce Nature Reserve were both genetically and morphologically distinct from the two remaining P. sedgwicki clades. The latter result suggests the presence of a novel lineage nested within P. sedgwicki and suggests that species boundaries within this taxon require re-examination.


Phytotaxa ◽  
2021 ◽  
Vol 480 (1) ◽  
pp. 29-44
Author(s):  
GUO-CHENG ZHANG ◽  
HUA-FENG HONG ◽  
GE-HONG CHEN ◽  
SHU-GANG LU ◽  
YAN-FEN CHANG

The Hymenasplenium obliquissimum group contains the widespread H. obliquissimum and several geographically restricted species, including H. retusulum, H. wuliangshanense, H. latidens, H. changputungense, H. quercicola, H. szechuanense, H. furfuraceum, H. adiantifrons, and H. filipes. However, the taxonomy of this group is still unclear and needs to be revised because some entities were treated infraspecifically or as synonyms and the validation of some species still needs to be assessed. To formulate a natural classification and investigate the relationships in this group, we collected and studied specimens of species related to the H. obliquissimum group and obtained specimens of species described by Ching at their locus classicus in southwestern China. An integrative taxonomic approach was taken to delimit species in the group using cytological, morphological, and DNA sequence data. Specifically, in the phylogenetic analyses, the H. obliquissimum group was recovered as a monophyletic group, comprising five principal chloroplast lineages. Based on our inferences, we provided taxonomic implications of chloroplast lineages discovered in this study and suggested possible reticulate evolution in the H. obliquissimum group which was interpreted by the incongruence of chloroplast and nuclear phylogenies. Further studies to strengthen the taxonomic of taxa especially those with the co-existence of different ploidy levels are still warranted.


Phytotaxa ◽  
2014 ◽  
Vol 161 (2) ◽  
pp. 157 ◽  
Author(s):  
Sinang Hongsanan ◽  
Putarak Chomnunti ◽  
Pedro W. Crous ◽  
Ekachai Chukeatirote ◽  
Kevin D. Hyde

The order Microthyriales comprises foliar biotrophs, epiphytes, pathogens or saprobes that occur on plant leaves and stems. The order is relatively poorly known due to limited sampling and few in-depth studies. There is also a lack of phylogenetic data for these fungi, which form small black spots on plant host surfaces, but rarely cause any damage to the host. A "Microthyriaceae"-like fungus collected in central Thailand is described as a new genus, Chaetothyriothecium (type species Chaetothyriothecium elegans sp. nov.). Phylogenetic analyses of LSU gene data showed this species to cluster with other members of Microthyriales, where it is related to Microthyrium microscopicum the type of the order. The description of the new species is supplemented by DNA sequence data, which resolves its placement in the order. Little molecular data is available for this order, stressing the need for further collections and molecular data.


2014 ◽  
Vol 62 (3) ◽  
pp. 235 ◽  
Author(s):  
S. Safaei Chaei Kar ◽  
F. Ghanavati ◽  
M. R. Naghavi ◽  
H. Amirabadi-zade ◽  
R. Rabiee

Onobrychis, comprising more than 130 species, is a genus of the family Fabaceae. At this time, the interspecies relationship of this biologically important genus is still a subject of great discussion and debate. To help resolve this disagreement, we used molecular phylogeny to analyse internal transcribed spacer (ITS) and trnL–trnF sequences of 76 species of Onobrychis. Bayesian interference, maximum parsimony and maximum likelihood analyses of nuclear ITS and plastid trnL–trnF DNA sequence data generated trees with strong posterior probability for two groups: Onobrychis subgen. Sisyrosema (including: Heliobrychis, Hymenobrychis, Afghanicae and Anthyllium sections) along with Laxiflorae section in Group I and Onobrychis subgen. Onobrychis (except Laxiflorae section) in the other (Group II). The Laxiflorae section roots back to the ancestral node for Sisyrosema subgen. O. viciifolia (cultivated species), which is closely associated with O. cyri var. cyri, suggesting that the latter may be a wild progenitor of O. viciifolia. The present study supported the paraphyly of subgenera Onobrychis and Sisyrosema. The study proposed the paraphyletic nature of the sections Onobrychis, Dendrobrychis, Heliobrychis and Hymenobrychis. Together with our molecular phylogenetic analyses we present a review of Onobrychis morphology and discuss and compare our results with those of earlier morphological and molecular phylogenetic analyses.


2020 ◽  
Vol 86 (1) ◽  
pp. 64-71
Author(s):  
Leila Carmona

ABSTRACT The aeolid species Facelina bostoniensis (Couthouy, 1838) was originally described from Massachusetts and was later reported from the Eastern Atlantic Ocean and the Mediterranean Sea. So far, no molecular systematic study of its amphiatlantic status has been carried out. Phylogenetic analyses (maximum likelihood and Bayesian) of DNA sequence data for the mitochondrial cytochrome c oxidase subunit I and 16S rRNA genes confirm the amphiatlantic status of F. bostoniensis. My findings show that this species is restricted to the Atlantic realm and that the species recorded from the Mediterranean is not F. bostoniensis but F. vicina (Bergh, 1882). It is hypothesized that previous records of F. bostoniensis from the Mediterranean Sea were actually misidentifications of F. vicina.


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