Molecular and Morphological Assessment of Septoria Species Associated with Ornamental Plants in Yunnan Province, China.

Yuan-Yan An,Yong Wang,Xiang-Yu Zeng,Monika C Dayarathne,Alan J L Phillips,Kevin D Hyde

doi:10.3390/jof7060483

Abstract

The Karst landform is the main geographic characteristic in South China. Such areas are rich in vegetation and especially suitable for growth of shrubs and herbaceous plants. In this study, 11 Septoria strains were obtained from different plants’ leaves collected in the Kunming Botanical Garden, Yunnan Province, China. Based on single-gene and multi-gene analyses of five gene loci (tef1, rpb2, tub2, ITS, and LSU) and four gene regions (without LSU), these strains were found to belong to three independent phylogenetic lineages representing five species, including four novel taxa, and one new record for China. Five single gene trees were also provided to evaluate the effectiveness of each gene for discriminating the species, as a result of which tub2 was found to have the most suitable DNA barcode for rapid identification. Morphological descriptions, illustrations, and comparisons are provided for a more comprehensive assessment. Genealogical Concordance Phylogenetic Species Recognition (GCPSR) with a pairwise homoplasy index (PHI) test was used to evaluate the conclusions of the phylogenetic analyses.

Highlights

We found that Septoria pileicola can be distinguished from S. sanguisorbigena by its wider conidia, and from S. posoniensis and S. exotica by its shorter conidia with obviously fewer septa [36,37]
The species concept was to produce pycnidial, ostiolate conidiomata; conidiophores reduced to conidiogenous cells that proliferate sympodially; and hyaline, filiform conidia with transverse eusepta that fit the original concept of [4]
After comparing the topologies of five single-gene and two multi-gene trees (Figures 1 and 2 and Supplementary Figures S1–S5), we showed that Septoria forms two branches (Branch 1 and Branch 2), mainly because only the phylogenetic trees based on the LSU region and five DNA fragments supported three branches, whereas the conserved LSU sequences included the least parsimonious characters (31/799)