Diaporthe citri (H.S. Fawc.) F.A. Wolf, J. Agric. Res., Washington 33(7): 625, 1926.

Yang, Qin, Jiang, Ning & Tian, Cheng-Ming, 2021, New species and records of Diaporthe from Jiangxi Province, China, MycoKeys 77, pp. 41-64 : 41

Diaporthe citri (H.S. Fawc.) F.A. Wolf, J. Agric. Res., Washington 33(7): 625, 1926. Figure 4

Description.

Leaf spots subcircular to irregular, pale brown, with dark brown at margin. Pycnidia solitary, scattered on the leaf surface. Pycnidial conidiomata in culture, globose, erumpent, single or clustered in groups of 3-5 pycnidia, coated with hyphae, cream to yellowish translucent conidial droplets exuded from ostioles. Conidiophores reduced to conidiogenous cells. Conidiogenous cells hyaline, unbranched, septate, straight, slightly tapering towards the apex, 14.5-25 × 2-3 μm. Alpha conidia hyaline, aseptate, rounded at one end, apex at the other end, usually with two large guttulate, (9.5-)10.5-12 × 3.5-4.5 μm. Beta conidia not observed.

Culture characters.

Colony originally flat with white fluffy aerial mycelium, becoming greyish mycelium with age, with yellowish-cream conidial drops exuding from the ostioles.

Specimens examined.

China. Jiangxi Province: Ganzhou City, on leaves of Citrus sinensis , 24°59'44"N, 115°31'01"E, 13 May 2018, Q. Yang, Y. Liu & Y.M. Liang (BJFC-S1658; living culture: CFCC 53079 and CFCC 53080); 24°59'45"N, 115°31'02"E, 13 May 2018, Q. Yang, Y. Liu & Y.M. Liang (BJFC-S1659; living culture: CFCC 53081 and CFCC 53082).

Notes.

Diaporthe citri is a widely distributed species in citrus-growing regions. In the present study, four isolates (CFCC 53079, CFCC 53080, CFCC 53081 and CFCC 53082) from symptomatic leaves of Citrus sinensis were congruent with D. citri , based on DNA sequence and morphological data (Fig. 1 ). The clade was, therefore, confirmed to be D. citri .

Figures

Figure 1. Phylogram of Diaporthe from a Maximum Likelihood analysis based on combined ITS, cal, his 3, tef 1 and tub 2. Values above the branches indicate Maximum Likelihood bootstrap (left, ML BP ≥ 50 %) and Bayesian probabilities (right, BI PP ≥ 0.90). The tree is rooted with Diaporthella corylina. Strains in current study are in blue font and the ex-type cultures are in bold font.

Figure 4. Diaporthe citri on Citrus sinensis (BJFC-S 1658) a, b symptoms on leaves of host plant c culture on PDA (30 d) d conidiomata e alpha conidia f conidiophores and alpha conidia. Scale bars: 10 μm (e, f).