Fusarium houttuyniae Y. K. He, Yong Wang

He, Yu-Ke, Jayawardena, Ruvishika S., Kakumyan, Pattana & Wang, Yong, 2023, Taxonomy and phylogeny of Fusarium houttuyniae and F. liriopes spp. nov. (Hypocreales, Nectriaceae) from China, Phytotaxa 603 (3), pp. 260-270 : 264-265

Fusarium houttuyniae Y. K. He, Yong Wang bis, sp. nov. Fig. 2 .

Mycobank: MB846236; FOF number: 14109

Etymology:— houttuyniae refers to the host genus Houttuynia , which the holotype was isolated.

Holotype:— CHINA, Guangxi Province, Nanning City, Guang Xi Medicinal Botanical Garden , 108°19’ E, 22°51’ N, leaf of Houttuynia cordata , November 2017, collected by Qian Zhang (Collection number: HGUP 10007 , culture number: GUCC 21004 ).

Additional specimens examined:— CHINA, Guangxi Province, Nanning City, Guang Xi Medicinal Botanical Garden , 108°19’ E, 22°51’ N, leaf of Houttuynia cordata , November 2017, collected by Qian Zhang (Collection number: HGUP 10007 , culture number: GUCC 21008 ) .

Description: Colonies on PDA media with an average radial growth rate of 2.1‒3.0 mm/d at 24℃. The colony was white with abundant and flocculent aerial hyphae, but later turned light purple, odour absent. Colony margins regularly. Conidiophores unbranched or sparingly branched, aerial phialides subulate to subcylindrical, straight, thin- and smooth- walled. Microconidia hyaline, ellipsoidal to falcate, smooth- and thin-walled, 0‒1 septate; 0-septate, 4‒10 × 1‒5 (av. 6.4 ± 1.53 × 3.2 ± 1.08) µm or 1-septate, 9‒17 × 2‒6 (av. 13.9 ± 2.11 × 4.3 ± 1.21) µm. Macroconidia formed on aerial mycelium, falcate, curved dorsiventrally with almost parallel sides tapering slightly towards both ends, with a blunt to papillate, curved apical cell and a blunt to foot-like basal cell, hyaline, smooth- and thin-walled, 1‒3 septate; 1-septate conidia: 12‒20 × 2‒5 (av. 16.5 ± 2.1 × 3.5 ± 0.65) µm; 2-septate conidia: 15‒22 × 2‒4 (av. 18.15 ± 1.92 × 3 ± 0.44) µm; 3-septate conidia: 28‒45 × 3‒6 (av. 38.5 ± 3.18 × 4.71 ± 0.7) µm. Chlamydospores globose to sub globose, 4.5‒9 (av. 6.92 ± 1.06) µm diam.

Notes: Phylogenetically, F. houttuyniae (GUCC 21004) formed a well-supported, distinct clade sister to F. liriopes (GUCC 21005), and F. nirenbergiae (CBS 129.24) ( Fig. 1 ). Between F. houttuyniae and F. liriopes , there are 6/606 character differences in cmdA, 1/876 character in rpb2, 1/621 character in tef1, and 10/534 characters in tub2. Between F. houttuyniae and F. nirenbergiae , there are 4/606 characters in cmdA, 2/876 characters in rpb2, 7/621 characters in tef1 and 12/534 characters in tub2 ( Table 2 ). This species (conidia 1‒3-septate) can be distinguished from F. nirenbergiae (0‒5-septate; ( Zhao et al. 2020)) based on the septation of the macroconidia. Fusarium houttuyniae differs from F. liriopes by having bigger conidia ( F. houttuyniae : 1-septate conidia: 12‒20 × 2‒5 µm; 2-septate conidia: 15‒22 × 2‒4 µm; 3-septate conidia: 28‒45 × 3‒6 µm. vs. F. liriopes : 1-septate conidia: 11‒15 × 2‒3 µm; 2-septate conidia: 14‒22 × 2‒4 µm; 3-septate conidia: 18‒28 × 3‒5 µm.). Thus, we propose F. houttuyniae as a novel species.

Figures

FIGURE 1. The most parsimonious trees obtained from a heuristic search of combined cmdA, rpb2, tef1 and tub2, sequence data for the Fusarium oxysporum complex (FOSC) group. Fusarium udum (CBS 177. 31) is used as the outgroup taxon. The MP bootstrap values ≥ 50%, ML bootstraps ≥ 70%, and Bayesian posterior probabilities ≥ 0.90 (MPBS/MLBS/BYPP) are given at the nodes. New collections obtained in this study are in red.

FIGURE 2. Fusarium houttuyniae (Specimen code: HGUP 10007) a, b. Colony on PDA; a. Surface of colony on PDA after 21 days at 24 °C under continuous white light; b. Reverse of colony on PDA; c, d. Mycelium on PDA; e, f. Conidiophores and phialides on aerial mycelium; g. Chlamydospores; h, o. Aerial conidia (microconidia); p, t. Sporodochial conidia (macroconidia). Scale bars: a, b = 10 mm; c, d = 1 mm; f = 20 μm; e, g, p, t = 15 µm; h, o = 5 µm.