Diaporthe caryae C.M. Tian & Q. Yang, MycoKeys

Lu, Qing-Tao, Zhang, Jing-Yi, Sun, Ya-Ru, Tang, Xia, Lu, Yong-Zhong & Zhang, Zhen, 2022, Diaporthe orixae sp. nov., an endophytic species isolated from Orixa japonica in southern China, Phytotaxa 544 (1), pp. 37-51 : 46-48

Diaporthe caryae C.M. Tian & Q. Yang, MycoKeys 39, 97–149 (2018) FIGURE 3

Index Fungorum number: IF824706, MycoBank: MB824706

Etymology: Named after the host genus on which it was collected, Carya

Holotype: BJFC-S1476

Endophytic in the stem of Orixa japonica . Sexual morph: Undetermined. Asexual morph: Conidiomata pycnidial, sporulating poorly on MEA, immersed in the medium, aggregated, globose, multilocular, black, erumpent. Conidiophores hyaline, smooth, 1–3-septate, branched, densely aggregated, cylindrical, straight to sinuous, 6.0–16 (–21.0) × 1.7–3.0 μm (x̅ = 11.5 × 2.5 μm, n = 15). Alpha conidia 3.5–6.5 × 1.5–2.5 μm (x̅ = 5.3 × 2.2 μm, n = 30), aseptate, hyaline, smooth, guttulate, ellipsoidal or fusiform, tapering towards ends or obtuse at both ends. Beta conidia hyaline, aseptate, filiform, straight or hamate, slightly tapering towards both ends, eguttulate, base subtruncate, 15.0– 24.5 × 1.0–2.0 μm (x̅ = 20.7 × 1.4 μm, n = 30).

Culture characters: Cultures incubated on MEA at 25 °C. Colony entirely white at surface, reverse with pale brown pigmentation, white, fluffy aerial mycelium, the sporulation distributed in the media randomly.

Known distribution: CHINA ( Yang et al. 2018, Guo et al. 2020, Wang et al. 2021, this study)

Known hosts: On symptomatic twigs of Carya illinoensis (Juglandaceae) , pear shoot canker, Rosa roxburghii , Prunus persica and health stems of Orixa japonica (Rutaceae) ( Yang et al. 2018, Guo et al. 2020, Wang et al. 2021, this study).

Material examined: CHINA, Guizhou Province, Qingzhen city, from the healthy stems of Orixa japonica , 14 Sep 2020, Hong-Bo Wang, JJ 9 (GZAAS 21–0393, dried culture; living culture: GZCC 21–1086 ), JJ17 (GZAAS 21–0394, dried culture; living culture: GZCC21–1087 ) .

Notes: Diaporthe sackstonii was introduced by Thompson et al. (2015) with only producing alpha conidia. The strain (GZCC 19–0129) which was reported by Dissanayake et al. (2020a) without any morphological description was clustered together with taxa of D. caryae in our study ( FIGURE 1 ). A comparison of nucleotide base pairs of ITS, tef1-α, and β-tub between the strain (GZCC 19–0129) and the type species of D. sackstonii and D. caryae were done based on BLASTn algorithms for aligning two sequences in NCBI. In ITS, D. sackstonii (GZCC 19–0129) differs from the type species of D. sackstonii (BRIP 54669b) and D. caryae (CFCC 52563) in 1/469 bp (0.21%), 3/452 bp (0.66%), respectively. In tef1-α, they are different in 13/311 bp (4.18%), 1/311 bp (0.32%), respectively. In β-tub, they are different in 25/701 bp (0.036%) and 10/400 bp (2.5%), respectively. We therefore suggested that the identification of the strain ( D. sackstonii GZCC 19–0129) may need to re-evaluate.

Diaporthe caryae was firstly described from symptomatic twigs of Carya illinoensis by Yang et al. (2018). Morphologically, the two new collections (GZCC 21–1086, GZCC 21–1087) are similar to the holotype of D. caryae in conidiophores and conidia. Phylogenetically, GZCC 21–1086 and GZCC 21–1087 are grouped with D. sackstonii (GZCC 19–0129) and D. caryae (CFCC 52563, CFCC 52564) in the phylogenetic tree with good support. Furthermore, we compared the new collections with the holotype of D. caryae (CFCC 52563) using single gene data, and they are 100%, 1.8% (5/273), 0.7% (5/699) similar in ITS, tef1-α, and β-tub, respectively. Based on the morphology and molecular data analyses, the two new collections (GZCC 21–1086, GZCC 21–1087) are considered as D. caryae . This is the first report of D. caryae on O. japonica in China.

Figures

FIGURE 1. Maximum likelihood tree generated by RAxML based on the combined ITS, tef1-α, β-tub, cal, and his3. Bootstrap support values for ML and MP equal to or greater than 70% and Bayesian posterior probabilities equal to or greater than 0.95 are given near nodes as ML/PP/MP, respectively. The tree was rooted with Diaporthella corylina (CBS 121124) and Diaporthella cryptica (CBS 140348). The newly generated strains are shown in red and the ex-type strains are in bold.

FIGURE 3. Diaporthe caryae (GZAAS 21–0393, new host record) a, b Colonies on MEA. c Immersed conidiomata. d Peridium. e Alpha and beta conidia f–i Conidiogenous cells. j, k Alpha conidia. l–n Beta conidia. Scale bars: d, e, l–n = 10 µm, f–k = 5 µm.