Pseudopestalotiopsis

Pseudopestalotiopsis Maharachch., K.D. Hyde & Crous (2014), in Marachchikumbura et al., in Maharachchikumbura et al., Stud. Mycol. 79:180(2014)

The genus was introduced by Maharachchikumbura et al. (2014b) with Pseudopestalotiopsis theae (Sawada) Maharachch., K.D. Hyde & Crous as the type species. Species of Pseudopestalotiopsis are appendage-bearing phenotypically diverse coelomycetes in the family Sporocadaceae and are commonly found in tropical and subtropical ecosystems (Jaklitsch et al. 2016; Maharachchikumbura et al. 2016b). Pseudopestalotiopsis is characterized by brown to dark brown or olivaceous median cells and knobbed or not knobbed apical appendages (Maharachchikumbura et al. 2014b, 2016b). The epitype of Pseudopestalotiopsis theae (Sawada) Steyaert was designated from fresh leaves of Camellia sinensis collected in Thailand (Maharachchikumbura et al. 2013). Pseudopestalotiopsis has been studied for the production of various secondary metabolites with diverse structural features, with antitumor, antifungal, antimicrobial and other activities (Ding et al. 2008; Maharachchikumbura et al. 2011, 2016b).

Pseudopestalotiopsis theae is economically significant as it has been identified as a pathogen in major tea-growing areas in the world (Maharachchikumbura et al. 2016b). Pseudopestalotiopsis theae causes grey blight of tea and reduces yield (Maharachchikumbura et al. 2011, 2013, 2016b). Pseudopestalotiopsis theae was also isolated as an endophyte from different hosts (Camellia nitidissima, C. sinensis, Holarrhena antidysenterica, Podocarpus macrophyllus, Terminalia arjuna) or as a saprobe (seeds of Diospyros crassiflora) (Maharachchikumbura et al. 2011, 2013, 2016b).

ClassificationSordariomycetes, Xylariomycetidae, Amphisphaeriales, Sporocadaceae

Type speciesPseudopestalotiopsis theae (Sawada) Maharachch., in Maharachchikumbura et al., Stud. Mycol. 79:183 (2014)

Distribution – China, India, Indonesia, Malaysia, Thailand (Maharachchikumbura et al. 2016b)

Disease symptomsPseudopestalotiopsis theae causes grey blight in major tea growing areas in the world (Horikawa 1986, Maharachchikumbura et al. 2013, 2016b). The pathogen develops circular to irregular leaf spots initially and grey, brown margins when mature, covering up to half of the leaf with acervuli (Maharachchikumbura et al. 2016b). Pseudopestalotiopsis ixorae and P. taiwanensis cause a leaf spot that initially develops small, circular, ash-colored spots which later turn into brown spots (Tsai et al. 2018).

 

Hosts Averrhoa carambola, Camellia sp., Cinnamomum sp., Cocos nucifera, Diospyros crassiflora, Fragaria sp., Hibiscus rosa-sinensis, Holarrhena antidysenterica, Ixora sp., Kandelia obovate, Macaranga sp., Pandanus odoratissimus, Podocarpus macrophyllus, Prunus sp., Terminalia arjuna and Thea sinensis

 

Morphological based identification and diversity

There are 14 species recorded in Index Fungorum (2019). Pseudopestalotiopsis can be distinguished from Neopestalotiopsis and Pestalotiopsis by dark concolorous median cells with indistinct conidiophores (Maharachchikumbura et al. 2014b, 2016b). However, there could be a wide host range for Pseudopestalotiopsis species and the actual number of species could be much higher than presently known (Maharachchikumbura et al. 2011, 2016b).

Conidial morphology is widely used in taxonomy in pestalotioid fungi (Steyaert 1949; Guba 1961; Nag Raj 1993; Maharachchikumbura et al. 2011, 2012, 2014b). Species delimitation based on morphological characters is limited as these characters are plastic and vary between hosts and environments (Maharachchikumbura et al. 2011, 2016a). Therefore, phylogenetic species recognition is an effective method to identify different pestalotioid species (Maharachchikumbura et al. 2016a).

 

Molecular based identification and diversity

ITS sequence data alone is not sufficient for species delimitation of Pseudopestalotiopsis. Therefore, Maharachchikumbura et al. (2012) suggested a phylogenetic analysis of combined ITS, TUB2 and tef1 genes provide better resolution as compared to single-gene phylogeny (Fig. 22).

 

Recommended genetic markers (genus level) – LSU (as outlined in Maharachchikumbura et al. 2012)

Recommended genetic markers (species level) – ITS, TUB2 and tef1 (as outlined in Maharachchikumbura et al. 2012)

The accepted number of species: 20 species

References: Maharachchukumbura 2013, 2014b, 2016b (morphology, phylogeny)

 

 

 

 

Table Details of the Pseudopestalotiopsis isolates used in the phylogenetic analyses. Ex-type (ex-epitype) strains are in bold and marked with an asterisk* and voucher strains are in bold.

Species Isolates ITS TUB2 tef1
Pseudopestalotiopsis ampullacea LC6618* KX895025 KX895358 KX895244
P. avucenniae MFLUCC 17-0434* MK764287 MK764353 MK764331
P. camelliae-sinensis LC3490* KX894985 KX895316 KX895202
P. chinensis LC3011* KX894937 KX895269 KX895154
P. cocos CBS 272.29* KM199378 KM199467 KM199553
P. dawaina MM14-F0015* LC324750 LC324751 LC324752
P. curvatispora MFLUCC 17-1722* MK764288 MK764354 MK764332
P. ignota NN 42909* KU500020 KU500016
P. indica CBS 459.78* KM199381 KM199470 KM199560
P. ixorae NTUCC 17-001.1* MG816316 MG816326 MG816336.
P. jiangxiensis LC 4479* KX895034 KX895343 KX895229
P. kawthaungina MM14-F0083 LC324753 LC324754 LC324755
P. kubahensis UMAS KUB-P20* KT006749
P. myanmarina NBRC 112264* LC114025 LC114045 LC114065
P. rhizophorae MFLUCC 17-1560* MK764291 MK764357 MK764335
P. smitheae MFLUCC 12-0121* KJ503812 KJ503815 KJ503818
P. thailandica MFLUCC 17-1724* MK764292 MK764358 MK764336
P. taiwanensis NTUCC 17-002.1* MG816319 MG816329 MG816339
P. theae MFLUCC 12-0055* JQ683727 JQ683711 JQ683743
P. vietnamensis NBRC 112252* LC114034 LC114054 LC114074

Fig. Phylogram generated from maximum likelihood analysis based on combined ITS, TUB2 and tef1 sequence data of Pseudopestalotiopsis species. Related sequences were obtained from GenBank. Twenty-five strains are included in the combined sequence analyses, which comprise 1404 characters with gaps. Neopestalotiopsis natalensis (CBS 138.41) was used as the outgroup taxa. The best scoring RAxML tree with a final likelihood value of -4028.799660 is presented. The matrix had 274 distinct alignment patterns, with 6.34% of undetermined characters or gaps. Estimated base frequencies were as follows; A = 0.235765, C = 0.270775, G = 0.213073, T = 0.280387; substitution rates AC = 1.242401, AG = 3.217138, AT = 1.272343, CG = 0.837226, CT = 4.463116, GT = 1.000000; gamma distribution shape parameter α = 0.229606. The maximum parsimonious dataset consisted of 1122 constant, 79 parsimony-informative and 203 parsimony-uninformative characters. The parsimony analysis of the data matrix resulted in the maximum of four equally most parsimonious trees with a length of 386 steps (CI = 0.832, RI = 0.737, RC = 0.613, HI = 0.168) in the first tree. RAxML and maximum parsimony bootstrap support value ≥ 50% are shown respectively near the nodes. Bayesian posterior probabilities ≥0.95 (BYPP) indicated as thickened black branches. Ex-type strains are in bold.

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