First report of Gilbertella persicaria causing soft rot in eggplant fruit in China

Abstract

In August 2018, eggplant fruits (Solanum melongena) were collected with circular, light brown and slightly sunken lesions at the apex containing little white mycelium (infection incidence was 1-2%) from a local market in the Haidian district, Beijing, China. Purified fungal isolates initially produced white colonies; later individual colonies covered the entire PDA plate surface (90 mm diam) within 3 days. Sporangiophores were smooth walled, simple to branched, erect and curved below the sporangium. Sporangia were globose to subglobose, 36.5-247.5 × 37.4-250.5 μm, columella (ovoid, pyriform or subglobose), 21.5-108.2 × 24.5-135.6 μm. Sporangiospores were globose to ellipsoid, hyaline, smooth, one-celled, 7.8-13 × 5.2-10.4 μm. Based on the morphological characteristics the fungus was identified as Gilbertella persicaria (Hesseltine 1960). Fungal DNA of eight isolates were amplified for partial ITS regions using ITS1/IT4 primers and sequenced. Obtained sequences showed a 100% similarity with various ITS sequences of G. persicaria (KR076759, KR076758, KT213049). The ITS sequence (MH753636) of a representative isolate (YC-IK2) was submitted in GenBank and showed 9 9 . 8 3 % s i m i l a r i t y w i t h t h e e x -t y p e s e q u e n c e NR_111692. Koch's postulates were fulfilled by inocul a t i n g t h r e e a s y m p t o m a t i c e g g p l a n t f r u i t s . A sporangiospores suspension (1 × 10 5 sporangiospores/ml) was sprayed on punctured sites on each fruit, kept in plastic boxes and placed in a moist chamber at 25°C for 5 days. Sterile distilled water was sprayed on a set of three eggplant fruits for control. Inoculated fruits showed symptoms (circular, light brown spots) after 48 h of inoculation and sporangiophores evolved into rotted lesion after 5 days. The re-isolated and identified fungus from infected fruits corresponded to G. persicaria. Recently, G. persicaria has been reported to cause soft rot on dragon fruits (Hylocereus spp.) in China and Taiwan (Guo et al. 2012;Lin et al. 2014). To our knowledge, this is the first report of G. persicaria soft rot in eggplant fruit in mainland China.

Morphological and molecular studies of a rare mucoralean species causing flower rot in Hylocereus polyrhizus

“…Gilbertella persicaria is the only species in this genus (Benny, 1991;Hoffmann et al, 2013;Walther et al, 2013) with diverse colony morphology and mycelial development (Papp et al, 2001). G. persicaria reportedly affects papaya fruit grown in Colima (Cruz-Lachica et al, 2016) and also causes rot disease in eggplant in China, with an incidence of 1%-2% as observed in a local market (Khokhar et al, 2019).…”