Puccinia tuberosa Jing X. Ji & Kakish., 2021

Ji, Jingxin, Zhang, Yunfeng, Fan, Yongshan, Li, Zhuang, Li, Yu & Kakishima, Makoto, 2021, Puccinia tuberosa, a new species of rust fungus on Allium tuberosum in Asia, Phytotaxa 525 (3), pp. 243-246 : 244

Puccinia tuberosa Jing X. Ji & Kakish. , sp. nov. ( Fig. 1 )

MycoBank No.: MB841349

Diagnosis: —Morphologically differs from P. allii complex and U. japonicus on Allium species by having smaller urediniospores with thicker walls. Phylogenetically distinct from Puccinia allii complex and Uromyces japonicus .

Type: — CHINA. Jilin Province: Changchun , uredinia on Allium tuberosum Rottler ex Spreng. , October 2018, leg. Jing-Xin Ji ( HMJAU8955 , holotype, GenBank no. 28S: OK489427 , ITS: OK489435 ) .

Etymology: —Named after species name of host plant.

Description: —Uredinia amphigenous, subepidermal, erumpent, pale yellow. Urediniospores ellipsoid to oval, 20–26.5 × 17.5–22.5 μm (av. 23.0 × 20.0 µm). Wall hyaline, echinulate, 2.0–4.0 μm thick, germ pores obscure.

Known host and distribution: —On Allium tuberosum , China, Philippines, Thailand ( McTaggart et al. 2016).

In the phylogenetic analysis, U. japonicus on A. ochotense Prokh. and A. victorialis L. lies in a separate monophyletic clade from other rust species in the P. allii complex on Allium species ( Fig. 2 ). However, U. japonicus should be transferred to Puccinia because it is phylogenetically included with a cluster of Puccinia species ( McTaggart et al. 2016, Tanaka & Ono 2018). Although it is morphologically different from Puccinia species in having single-celled teliospores, it is common for rust fungi on Allium species to have a mixture of single-celled and 2-celled teliospores. Because P. japonica Dietel is preoccupied, we propose a new name, P. japonensis , as a replacement for U. japonicus .

Figures

FIGURE 1. Puccinia tuberosa on Allium tuberosum. A. Uredinia on the leaf. B. Vertical section of a uredinium. C, D. Urediniospores. E. Urediniospore observed by SEM. F. Uredinium observed by SEM. Scale bars: B = 40 μm, C, D = 25 μm, E = 5 μm, F = 50 μm.

FIGURE 2. A phylogenetic tree of ITS+28S sequences of selected rust species constructed by MP method. Bootstrap values greater than 60% are shown along the nodes in the topology (MP/ML). Sample data are shown with voucher specimen number or GenBank accession number, and host plant. Sequence data newly generated in this study are shown in bold face. Scale bar indicates the number of substitutions per site.