Diaporthe rhodomyrti C.M. Tian & Q. Yang, 2022

Cao, Lingxue, Luo, Dun, Lin, Wu, Yang, Qin & Deng, Xiaojun, 2022, Four new species of Diaporthe (Diaporthaceae, Diaporthales) from forest plants in China, MycoKeys 91, pp. 25-47 : 25

Diaporthe rhodomyrti C.M. Tian & Q. Yang sp. nov.

Fig. 6

Diagnosis.

Distinguished from the phylogenetically closely-related species, D. hongkongensis , in narrower beta conidia.

Etymology.

Named after the host genus on which it was collected, Rhodomyrtus .

Description.

On PNA: Conidiomata pycnidial, 500-850 μm diam, globose or rostrate, black, erumpent in tissue, erumpent at maturity, often with translucent conidial drops exuding from ostioles. Conidiophores reduced to conidiogenous cells. Conidiogenous cells (14.5-)15.5-23(-25.5) × 1.5-2 μm (n = 30), L/W = 8.5-13, cylindrical, hyaline, unbranched, septate, straight, tapering towards the apex. Alpha conidia abundant in culture, hyaline, aseptate, ellipsoidal, biguttulate, 6-7(-8.5) × 2-2.5(-3) μm (n = 30), L/W = 2.8-3.3. Beta conidia hyaline, aseptate, filiform, straight to sinuous, eguttulate, (15-)16.5-21.5(-23) × 1-1.5 µm (n = 30), L/W = 15.5-16.5.

Culture characters.

Colony entirely white at surface, reverse with pale brown pigmentation, white, fluffy aerial mycelium.

Specimens examined.

China. Jiangxi Province: Ganzhou City , on leaves of Rhodomyrtus tomentosa , 10 May 2018, Q. Yang & Y.M. Liang (holotype BJFC-S1660; ex-type living culture: CFCC 53101; living culture: CFCC 53102) .

Notes.

This new species is introduced as molecular data, and shows it to be a distinct clade with high support (ML/BI = 100/1) and appears closely related to Diaporthe hongkongensis . Diaporthe rhodomyrti can be distinguished based on ITS, cal, his3, tef-1α, and tub2 loci from D. hongkongensis (2/463 in ITS, 26/441 in cal, 11/434 in his3, 10/327 in tef-1α, and 2/420 in tub2). Morphologically, D. rhodomyrti can be distinguished from D. hongkongensis by its longer conidiogenous cells (15.5-23 vs. 5-12 μm) and narrower beta conidia (1-1.5 vs. 1.5-2 μm) ( Gomes et al. 2013). This is the first time that Diaporthe species has been discovered from infected leaves on Rhodomyrtus tomentosa and demonstrate it as a new species based on phylogeny and morphology.

Figures

Figure 6. Diaporthe rhodomyrti (BJFC-S 1660) a conidioma formed on PNA b conidiogenous cells c alpha and beta conidia. Scale bars: 500 μm (a); 10 μm (b, c).