Phylogenetic relationship of mycosphaerellaceae found in Northern Thailand

Abstract

The current study of fungal diversity of cercosporoid fungi from Northern Thailand investigates cercosporoid leafspots in a wide range of hosts. The diseased leaves with symptoms and visible fungal structures were collected from all provinces representing Northern Thailand. The provinces are Chiang Mai, Chiang Rai, Lampang, Lamphun, Mae Hong Son, Nan and Phayao provinces. The collection was performed from September 2019 to October 2021. Specimen with disease symptoms were examined and fungi were isolated using the single spore isolation technique. A total of 87 isolates representing Cercospora, Clarohilum, Coremiopassalora, Phaeocercospora, Pluripassalora, Pseudopantospora, Pseudocercospora, Septoria and Zasmidium were obtained. The fungi were isolated from a wide range of plant hosts in 24 families, 52 species, and two unidentified plant species. The morphology of each fungus was observed and described with illustrations herein. However, due to the overlapping morphologies of cercosporoid fungi, molecular characterization is necessary for the proper identification of those fungi. The phylogenetic relationships of the isolates were analyzed using concatenated internal transcribed spacers (ITS1, 5.8S nrDNA, ITS2), 28S nrDNA (LSU) regions, RNA polymerase II gene (rpb2), actin gene (actA), and translation elongation factor 1 alpha 1 (tef1) sequence data. Based on morphology and molecular phylogeny, two isolates of Pseudocercospora mangiferae sp. nov. from Mangifera indica (Anacardiaceae), 18 Cercospora species: Cercospora arecacearum on Areca catechu (Arecaceae), Cercospora beticola on Apium graveolens (Apiaceae), two isolates of Cercospora canescens on Psophocarpus tetragonolobus (Fabaceae) and 3 isolates on Vigna unguiculata (Fabaceae), Cercospora coffeicola on Coffea arabica (Rubiaceae), Cercospora cf. flagellaris on Cocus nucifera (Arecaceae), Cercospora fuligena on Lycopersicon esculentum (Solanaceae), Cercospora eupatorii on Eupatorium odoratum (Asteraceae), Cercospora lactucae-sativae on Lactuca sativa (Asteraceae), Cercospora longipes on Saccharum officinarum (Poaceae), two isolates of Cercospora momordicae on Momordica charantia (Cucurbitaceae), Cercospora morina on Morus alba (Moraceae), Cercospora nicotianae on Nicotiana tabacum (Solanaceae), Cercospora physalidis on Capsicum annuum (Solanaceae), Cercospora rodmanii on Lablab purpureus (Fabaceae), Cercospora sojina on Brassica oleracea var. alboglabra (Brassicaceae) and Crotalaria juncea (Fabaceae), Cercospora sorghi on Sorghum bicolor (Poaceae), and two isolates of Cercospora violae on Clitoria ternatea (Fabaceae) were identified. Further, Cercospora sp. was described from Zinnia violacea (Asteraceae), three isolates on Coccinia grandis (Cucurbitaceae), two isolates on Phaseolus vulgaris (Fabaceae), and four isolates on Zea mays (Poaceae). Two isolates of Clarohilum henninggsii on Manihot esculenta (Euphorbiaceae), 11 isolates of Mycosphaerella eumusae on Musa eumusae (Musaceae). Eight Pseudocercospora species: three isolates of Pseudocercospora centrosematicola on Centrosema pubescens (Fabaceae), three isolates of Pseudocercospora eumusae on Musa eumusae (Musaceae), Pseudocercospora mori on Morus alba (Moraceae), Pseudocercospora nephrolepidigena on Nephrolepis sp. (Lomariopsidaceae), Pseudocercospora nymphaeacea on Nymphaea lotus (Nymphaeaceae), Pseudocercospora punicae on Punica granatum (Lythraceae), Pseudocercospora rosae on Rosa hybrida (Rosaceae). Further, Pseudocercospora sp. on Gymnema inodorum (Asclepiadaceae), Ipomoea aquatica (Convolvulaceae), two isolates on Vigna unguiculata (Fabaceae), Ocimum basilicum var. citratum (Labiatae), two isolates on Abelmoschus esculentus (Malvaceae) and on Poaceae were described. Septoria steviae on Stevia rebaudiana (Asteraceae) was described. Coremiopassalora sp. on Bougainvillea hybrid (Nyctaginaceae) and Malus domestica (Rosaceae), Pluripassalora sp. on Passiflora edulis (Passifloraceae), Phaeocercospora sp. on Lansium domesticum (Meliaceae) and Pseudopantoapora sp. on Gliricidia sepium (Fabaceae) are described as novel host records. Cercospora cf. flagellaris on Cocos nucifera (Arecaceae), Cercospora sp. on Zea mays (Poaceae), Pseudocercospora nymphaeacea on Nymphaea lotus (Nymphaeaceae), Pseudocercospora sp. on Abelmoschus esculentus (Malvaceae), Ipomoea aquatica (Convolvulaceae) and Ocimum basilicum var. citratum (Labiatae) are described as new geographical records for Thailand. Current study provides novel hosts for the cercosporoid fungi: Cercospora rodmanii on Lablab purpureus (Fabaceae), Cercospora sojina on Brassica oleracea var. alboglabra (Brassicaceae) and Crotalaria juncea (Fabaceae), Cercospora sorghicola on Sorghum bicolor (Poaceae) and Cercospora violae on Clitoria ternatea (Fabaceae). In this study, passalora-like genera: Coremiopassalora, Phaeocercospora, Pluripassalora, Pseudopantospora and Zasmidium were identified. However, species in these genera show polyphyly based on multigene phylogeny. Hence this study shows that species previously identified as passalora-like species based on morphology show polyphyly across Mycosphaerellaceae with multigene phylogeny. Further in this study, multi-gene phylogeny was used as a tool to build up the sexual morph and asexual morph interconnection for Mycosphaerella eumusae (isolate MTI) on Banana leaf sport.