scholarly journals Phylogenetic, Morphological, and Pathogenic Characterization of Alternaria Species Associated with Fruit Rot of Blueberry in California

2015 ◽  
Vol 105 (12) ◽  
pp. 1555-1567 ◽  
Author(s):  
X. Q. Zhu ◽  
C. L. Xiao

Fruit rot caused by Alternaria spp. is one of the most important factors affecting the postharvest quality and shelf life of blueberry fruit. The aims of this study were to characterize Alternaria isolates using morphological and molecular approaches and test their pathogenicity to blueberry fruit. Alternaria spp. isolates were collected from decayed blueberry fruit in the Central Valley of California during 2012 and 2013. In total, 283 isolates were obtained and five species of Alternaria, including Alternaria alternata, A. tenuissima, A. arborescens, A. infectoria, and A. rosae, were identified based on DNA sequences of the plasma membrane ATPase, Alt a1 and Calmodulin gene regions in combination with morphological characters of the culture and sporulation. Of the 283 isolates, 61.5% were identified as A. alternata, 32.9% were A. arborescens, 5.0% were A. tenuissima, and only one isolate of A. infectoria and one isolate of A. rosae were found. These fungi were able to grow at temperatures from 0 to 35°C, and mycelial growth was arrested at 40°C. Optimal radial growth occurred between 20 to 30°C. Pathogenicity tests showed that all five Alternaria spp. were pathogenic on blueberry fruit at 0, 4, and 20°C, with A. alternata, A. arborescens, and A. tenuissima being the most virulent species, followed by A. infectoria and A. rosae. Previously A. tenuissima has been reported to be the primary cause of Alternaria fruit rot of blueberry worldwide. Our results indicated that the species composition of Alternaria responsible for Alternaria fruit rot in blueberry can be dependent on geographical region. A. alternata, A. arborescens, A. infectoria, and A. rosae are reported for the first time on blueberry in California. This is also the first report of A. infectoria and A. rosae infecting blueberry fruit.

Plant Disease ◽  
2020 ◽  
Author(s):  
Fei Wang ◽  
Seiya Saito ◽  
Themis Michailides ◽  
Chang-Lin Xiao

Alternaria rot caused by Alternaria species is one of the major postharvest diseases of mandarin fruit in California. The aims of this study were to identify these Alternaria species using phylogenetic analyses and morphological characteristics and test their pathogenicity to mandarin. Decayed mandarin fruit exhibiting Alternaria rot symptoms were collected from three citrus fruit packinghouses in the Central Valley of California. In total, 177 Alternaria isolates were obtained from decayed fruit and preliminarily separated into three groups representing three species (A. alternata, A. tenuissima and A. arborescens) based on the colony characterization and sporulation patterns. To further identify these isolates, phylogenetic analysis was conducted based on DNA sequences of the second largest subunit of RNA polymerase II (RPB2), plasma membrane ATPase (ATPase) and Calmodulin gene regions in combination with morphological characters. Of the 177 isolates, 124 isolates (70.1%) were identified as A. alternata and 53 isolates (29.9 %) were A. arborescens. The isolates initially identified as A. tenuissima based on the morphological characteristics could not be separated from those of A. alternata in phylogenetic analysis and thus considered A. alternata. Pathogenicity tests showed that both Alternaria species were pathogenic on mandarin fruit at both 5°C and 20°C. Our results indicated that two Alternaria species, A. alternata and A. arborescens, were responsible for Alternaria rot of mandarin fruit in California with A. arborescens causing fruit rot on mandarin being reported for the first time.


Plant Disease ◽  
2021 ◽  
Author(s):  
Danae Riquelme ◽  
Carolina Zúñiga ◽  
Eduardo Tapia

During the last two seasons, an unusual fruit rot was observed in four orchards of sweet Japanese plum (Prunus salicina) cultivars located in the Chilean Central Valley (30°00ʼS, 70°42ʼW). The incidence was 5% in Black Majesty, 4% in Red Lyon, and 6% in Sweet Mary cultivars in 2020. Fruits in the field showed a firm, dehydrated, and slightly sunken rot on the blossom end, along with rough and irregular epidermis in the affected area. Internally, the fruit flesh appeared light to dark-brown or olive-green. Symptomatic fruits (n=119) were superficially disinfected (75% ethanol) and, pieces of the pericarp (3 x 3 mm) were removed and placed on potato dextrose agar (PDA). Isolates of Alternaria spp. were obtained and 9 of these were selected for identification. Colonies were dark olive to gray-brown with white margins, small, catenulate and muriform conidia, produced in single or branched conidiophores. Isolates produced brown to golden-brown, ovoid, ellipsoidal to obclavate conidia with dimensions of 19.7 to 26.7 × 10.0 to 11.9 μm with two to four transverse and zero to three longitudinal septa on 0.05× PDA (Pryor and Michailides 2002) after 7 d at 20°C under 10/14 h light/dark cycles. A molecular analysis was performed by sequencing the nuclear genes RNA polymerase II subunit (RPB2), plasma membrane ATPase (ATP), and the calmodulin (Cal) gene using primers RPB2-5F2/fRPB2-7cR, ATPDF1/ATPDR1, and CALDF1/CALDR1, respectively (Lawrence et al. 2013; Woudenberg et al. 2013). A BLAST search revealed the presence of Alternaria spp. with a 99% to 100% identity with the reference sequences of A. alternata (JQ905182, JQ671874, JQ646208), A. arborescens (JQ646487, JQ671880, JQ646214), and A. tenuissima (JQ811961, JQ811989, JQ646209). Maximum parsimony phylogenetic analysis confirmed the identifications. Sequences were deposited in GenBank as numbers MW514249 to MW514257, MT872324 to MT872332, and MT872314 to MT872322 for RPB2, ATP, and Cal sequences, respectively. All these Alternaria isolates were deposited in the Colección Chilena de Recursos Genéticos Microbianos – INIA, Chillán Chile (RGM3069 to RGM3077). Pathogenicity of A. alternata (n=4), A. arborescens (n=3) and, A. tenuissima (n=2) was tested in Red Lyon plum fruits. Plums were disinfected in 1% sodium hypochlorite for 2 min, rinsed in sterile distilled water for 1 min and dried on absorbent towels in a laminar flow hood. Then, the plums were wounded on the blossom end with a sterile needle (1 x 0.5 mm), inoculated with 10 µl of a conidial suspension (106 conidia/ml), wrapped with Parafilm and maintained in a humid chamber (>95% relative humidity). An equal number of fruits wounded and inoculated with sterile water were used as a control. After 7 days at 20°C, all inoculated fruits developed a dark-brown firm rot with lesion lengths of 24.4 (±3.0) mm, 19.6 (±0.7) mm, and 16.8 (±2.4) mm for A. alternata, A. arborescens and A. tenuissima, respectively. A. alternata was the most aggressive species (P < 0.001). Control fruits remained asymptomatic. Koch’s postulates were fulfilled after the re-isolating the causal agent from the border of the lesions. Leaf spots and fruit rots caused by Alternaria isolates have been reported in stone fruits, including plums (Kim et al. 2005; Long et al. 2021; Moosa et al., 2019; Yang et al. 2014). To our knowledge, this is the first report of A. alternata, A. arborescens, and A. tenuissima associated with fruit rot in sweet Japanese plum cultivars in the field, in Chile.


2009 ◽  
Vol 2 (1) ◽  
pp. 92-97 ◽  
Author(s):  
John D. Gerlach ◽  
B. Shaun Bushman ◽  
John K. McKay ◽  
Harald Meimberg

AbstractChloroplast DNA sequences and recently established morphological characters were used to confirm the widespread invasion of California's vernal pools by European low mannagrass. Morphological similarities between low mannagrass and western mannagrass have led to different taxonomic treatments, depending on the geographical extent of a particular flora. When California's flora was last revised, the two species were combined as western mannagrass, which was then considered to be a native species. Unfortunately, the revised flora was published just as low mannagrass began to rapidly expand its range within the state and, because it was considered to be a native species in the new flora, no actions were initiated to limit the invasion. Our data show that low mannagrass was present at all localities in the Central Valley of California that were investigated, indicating a widespread and undetected invasion. The invasion has led to a degradation of the vernal pool ecosystems, which are the habitat of many federal and state protected endangered and threatened species.


2019 ◽  
Vol 104 (1) ◽  
pp. 33-48 ◽  
Author(s):  
Alejandro Zuluaga ◽  
Martin Llano ◽  
Ken Cameron

The subfamily Monsteroideae (Araceae) is the third richest clade in the family, with ca. 369 described species and ca. 700 estimated. It comprises mostly hemiepiphytic or epiphytic plants restricted to the tropics, with three intercontinental disjunctions. Using a dataset representing all 12 genera in Monsteroideae (126 taxa), and five plastid and two nuclear markers, we studied the systematics and historical biogeography of the group. We found high support for the monophyly of the three major clades (Spathiphylleae sister to Heteropsis Kunth and Rhaphidophora Hassk. clades), and for six of the genera within Monsteroideae. However, we found low rates of variation in the DNA sequences used and a lack of molecular markers suitable for species-level phylogenies in the group. We also performed ancestral state reconstruction of some morphological characters traditionally used for genera delimitation. Only seed shape and size, number of seeds, number of locules, and presence of endosperm showed utility in the classification of genera in Monsteroideae. We estimated ancestral ranges using a dispersal-extinction-cladogenesis model as implemented in the R package BioGeoBEARS and found evidence for a Gondwanan origin of the clade. One tropical disjunction (Monstera Adans. sister to Amydrium Schott–Epipremnum Schott) was found to be the product of a previous Boreotropical distribution. Two other disjunctions are more recent and likely due to long-distance dispersal: Spathiphyllum Schott (with Holochlamys Engl. nested within) represents a dispersal from South America to the Pacific Islands in Southeast Asia, and Rhaphidophora represents a dispersal from Asia to Africa. Future studies based on stronger phylogenetic reconstructions and complete morphological datasets are needed to explore the details of speciation and migration within and among areas in Asia.


Plant Disease ◽  
2021 ◽  
pp. PDIS-06-20-1290
Author(s):  
Juliana S. Baggio ◽  
Bruna B. Forcelini ◽  
Nan-Yi Wang ◽  
Rafaela G. Ruschel ◽  
James C. Mertely ◽  
...  

Pestalotiopsis-like species have been reported affecting strawberry worldwide. Recently, severe and unprecedented outbreaks have been reported in Florida commercial fields where leaf, fruit, petiole, crown, and root symptoms were observed, and yield was severely affected. The taxonomic status of the fungus is confusing because it has gone through multiple reclassifications over the years. Morphological characteristics, phylogenetic analyses, and pathogenicity tests were evaluated for strawberry isolates recovered from diseased plants in Florida. Phylogenetic analyses derived from the combined internal transcribed spacer, β-tub, and tef1 regions demonstrated that although there was low genetic diversity among the strawberry isolates, there was a clear separation of the isolates in two groups. The first group included isolates recovered over a period of several years, which was identified as Neopestalotiopsis rosae. Most isolates recovered during the recent outbreaks were genetically different and may belong to a new species. On potato dextrose agar, both groups produced white, circular, and cottony colonies. From the bottom, colonies were white to pale yellow for Neopestalotiopsis sp. and pale luteous to orange for N. rosae. Spores for both groups were five-celled with three median versicolored cells. Mycelial growth and spore production were higher for the new Neopestalotiopsis sp. isolates. Isolates from both groups were pathogenic to strawberry roots and crowns. However, the new Neopestalotiopsis sp. proved more aggressive in fruit and leaf inoculation tests, confirming observations from the recent outbreaks in commercial strawberry fields in Florida.


Author(s):  
Dirk Erpenbeck ◽  
Merrick Ekins ◽  
Nicole Enghuber ◽  
John N.A. Hooper ◽  
Helmut Lehnert ◽  
...  

Sponge species are infamously difficult to identify for non-experts due to their high morphological plasticity and the paucity of informative morphological characters. The use of molecular techniques certainly helps with species identification, but unfortunately it requires prior reference sequences. Holotypes constitute the best reference material for species identification, however their usage in molecular systematics and taxonomy is scarce and frequently not even attempted, mostly due to their antiquity and preservation history. Here we provide case studies in which we demonstrate the importance of using holotype material to answer phylogenetic and taxonomic questions. We also demonstrate the possibility of sequencing DNA fragments out of century-old holotypes. Furthermore we propose the deposition of DNA sequences in conjunction with new species descriptions.


Phytotaxa ◽  
2014 ◽  
Vol 186 (4) ◽  
pp. 188 ◽  
Author(s):  
Ying-Ying Zhou ◽  
HONG-WEI ZHANG ◽  
JIANG-QIN HU ◽  
Xiao-Feng Jin

Sinalliaria is described here as a new genus of the family Brassicaceae from eastern China, based on the morphological characters and molecular sequences. Sinalliaria differs from the related genus Orychophragmus in having basal leaves petiolate, simple or rarely with 1‒3 lateral lobes (not pinnatisect); cauline leaves petiolate, cordate at base (not sessile, auriculate or amplexicaul at base); petals obovate to narrowly obovate, claw inconspicuous (not broadly obovate, with a claw as along as sepal); siliques truncate (not long-beaked) at apex. The microscopic characters of seed testa also show significant differences between Sinalliaria and Orychophragmus. Phylogenetic evidence from DNA sequences of nuclear ribosomal ITS and plastid region trnL-trnF indicates that Sinalliaria is a distinct group related to Orychophragmus and Raphanus, but these three genera do not form a clade. The new genus Sinalliaria is endemic to eastern China and has only one species and one variety. The new combinations, S. limprichtiana (Pax) X. F. Jin, Y. Y. Zhou & H. W. Zhang and S. limprichtiana var. grandifolia (Z. X. An) X. F. Jin, Y. Y. Zhou & H. W. Zhang are proposed here.


Zootaxa ◽  
2021 ◽  
Vol 4926 (3) ◽  
pp. 401-416
Author(s):  
MOHAMMAD HUSSAIN FALAHZADAH ◽  
EBRAHIM SHOKOOHI ◽  
GHOLAM HOSSEIN MORAVEJ ◽  
PHATU WILLIAM MASHELA ◽  
ABDUL KHALID MADADI ◽  
...  

Several soil samples from different habitats in Badakhshan province of Afghanistan were collected to isolate and characterize bacteria feeding nematodes. The Galleria mellonella-baiting method was used for the isolation of the Afghan insect-associated nematodes. The nematodes were studied using morphological and morphometric data. The Oscheius specimen was characterized by a longer body (630–820 µm) and shorter pharynx (125–145 µm), whereas other morphological characters were not unusual. The Diploscapter specimen had an annulated cuticle, with lip region width 1.5 times shorter than the stoma, and had separated pharyngeal corpus from the isthmus and vulva located in the middle of the body. The molecular data were derived using three loci; 18S, 28S (D2/D3 segment), and ITS rRNA region, which were utilized to measure the genetic distance. The phylogenetic analysis was conducted to reconstruct the relationship tree. Both morphological and molecular approaches confirmed the identity of nematode isolates as Oscheius tipulae and Diploscapter coronatus. This is the first report of insect-associated nematodes from the soil of Afghanistan. Both species were capable of infecting and killing G. mellonella larvae in less than 96 h. 


2010 ◽  
Vol 100 (12) ◽  
pp. 1340-1351 ◽  
Author(s):  
Juan Moral ◽  
Concepción Muñoz-Díez ◽  
Nazaret González ◽  
Antonio Trapero ◽  
Themis J. Michailides

Species in the family Botryosphaeriaceae are common pathogens causing fruit rot and dieback of many woody plants. In this study, 150 Botryosphaeriaceae isolates were collected from olive and other hosts in Spain and California. Representative isolates of each type were characterized based on morphological features and comparisons of DNA sequence data of three regions: internal transcribed spacer 5.8S, β-tubulin, and elongation factor. Three main species were identified as Neofusicoccum mediterraneum, causing dieback of branches of olive and pistachio; Diplodia seriata, causing decay of ripe fruit and dieback of olive branches; and Botryosphaeria dothidea, causing dalmatian disease on unripe olive fruit in Spain. Moreover, the sexual stage of this last species was also found attacking olive branches in California. In pathogenicity tests using unripe fruit and branches of olive, D. seriata isolates were the least aggressive on the fruit and branches while N. mediterraneum isolates were the most aggressive on both tissues. Isolates of B. dothidea which cause dalmatian disease on fruit were not pathogenic on branches and only weakly aggressive on fruit. These results, together with the close association between the presence of dalmatian disease symptoms and the wound created by the olive fly (Bactrocera oleae), suggest that the fly is essential for the initiation of the disease on fruit. Isolates recovered from dalmatian disease symptoms had an optimum of 26°C for mycelial growth and 30°C for conidial germination, suggesting that the pathogen is well adapted to high summer temperatures. In contrast, the range of water activity in the medium for growth of dalmatian isolates was 0.93 to 1 MPa, which was similar to that for the majority of fungi. This study resolved long-standing questions of identity and pathogenicity of species within the family Botryosphaeriaceae attacking olive trees in Spain and California.


Zootaxa ◽  
2017 ◽  
Vol 4311 (3) ◽  
pp. 301 ◽  
Author(s):  
FERNANDA AZEVEDO ◽  
ANDRÉ PADUA ◽  
FERNANDO MORAES ◽  
ANDRÉ ROSSI ◽  
GUILHERME MURICY ◽  
...  

Despite the enormous economic, scientific and strategic value of the Brazilian oceanic and mid-shelf islands (BOMIs), the biological communities of these islands are still poorly known. An example is their fauna of calcareous sponges (Porifera: Calcarea), with only six species described up to date. In the present study, we analysed the Calcinean sponges from the mid-shelf Abrolhos Archipelago and four of the five Brazilian oceanic islands (São Pedro e São Paulo Archipelago, Fernando de Noronha Archipelago, Rocas Atoll, and Trindade Island), using both morphological and molecular approaches for taxonomy. Fourteen species were found, of which 12 are new to science: Arturia trindadensis sp. nov., Borojevia tenuispinata sp. nov., B. trispinata sp. nov., Clathrina insularis sp. nov., C. lutea sp. nov., C. mutabilis sp. nov., C. zelinhae sp. nov., Ernstia citrea sp. nov., E. multispiculata sp. nov., E. rocasensis sp. nov., E. sanctipauli sp. nov., and E. solaris sp. nov. These results raised in 63% the species richness of calcareous sponges from the BOMIs. Clathrina aurea and Leucetta floridana were recollected and the former had its geographical distribution expanded. The molecular tree obtained confirmed the morphological identifications and allowed a discussion about the evolution of morphological characters, and the usefulness of some of those characters in the taxonomy of Calcinea. 


Sign in / Sign up

Export Citation Format

Share Document