Leveillula, G. Arnaud, 1921

Khodaparast, Seyed Akbar, Takamatsu, Susumu, Shadlou, Adel, Damadi, Mohsen, Pirnia, Mahdi & Jahani, Mahdi, 2016, Notes on the genus Leveillula (Erysiphaceae): a new unrecorded species and notes on Leveillula infecting Ficus, Cucurbita and Tropaeolum in Iran, Phytotaxa 260 (3), pp. 267-275 : 270-271

Leveillula on Tropaeolum majus L.

Recently published taxonomic manual of the Erysiphales by Braun and Cook (2012) assigned Leveillula on Tropaeolum as Leveillula tropaeolicola T.Z. Liu & U. Braun. We examined one new collection and one specimen deposited at Herbarium of IRAN (Iranian Research Institute of Plant Protection, Tehran). According to our observation morphology of this fungus is different from what described by Braun and Cook (2012) for L. tropaeolicola . Phylogenetic analysis based on ITS rDNA ( Fig. 1 ) showed that this fungus belongs to an already described phylogenetic group including Leveillula on Medicago sativa . More interestingly primary conidium morphology of this fungus more or less agreed with Medicago fungus. In both fungi primary conidia are subcylindrical with parallel side which pointed at apex ( Fig. 4 ). ITS rDNA sequence was 100% identical to the ITS rDNA sequences obtained from Medicago powdery mildew from Iran ( Khodaparast et al. 2012). Hence, we conclude that powdery mildew on Tropaeolum in Iran differs from species described by Braun and Cook (2012) on this host plant. The occurrence of more than one morphologically or molecularly distinguished species on a single host is not uncommon as shown for Helianthus and Eryngium ( Khodaparast et al. 2012) . On the other hand, morphology of L. tropaeolicola is very close to L. taurica . Hence, we suggest that L. tropaeolicola may belong or closely related to a polyphagus race of L. taurica occurring on several unrelated plant species and our new collections belong to a different species.

Specimen examined. IRAN, East azarbaijan Province, Tabriz, on Tropaeolum majus L., 26 Aug 2009, M. Damadi

(GUM 681); IRAN, Alborz Province, Karaj, on T. majus ,?, Shahidi ( IRAN 2272 F) .

Figures

FIGURE 1. A minimum-evolution (ME) tree (length = 0.28600863) based on ITS data for 38 Leveillula and one outgroup taxa. The tree is drawn to scale, with branch lengths in the same units as those of the evolutionary distances used to infer the phylogenetic tree. The evolutionary distances were computed using the Kimura 2-parameter method and are in the units of the number of base substitutions per site. The ME tree was searched using the Close-Neighbor-Interchange (CNI) algorithm at a search level of 1 (level = 1). The Neighborjoining algorithm was used to generate the initial tree.All ambiguous positions were removed for each sequence pair. The numbers above the branches represent branch support using 1000 bootstrap replications (Bootstrap values below 50 % are not shown). GenBank database accession numbers of the nucleotide sequence data are shown after each taxon name.

FIGURE 4. Leveillula sp. On Tropaeolum majus (A) primary conidia (B) secondary conidia. Scale bare =10 μm.