Storage Rot of Dragon Fruit Caused by Gilbertella persicaria

Abstract

In October 2011, a new disease of dragon fruit (Hylocereus costaricensis) was discovered in a fruit market in Yuanjiang, Yunnan Province, China. Small, light brown, water-soaked spots appeared initially and then coalesced, extending to the entire fruit in 6 days. Hyaline hyphae and light brown sporangia were observed over the entire surface of the infected fruit. On potato sucrose agar (PSA) the fungus produced a white, appressed colony that covered a 9-cm diameter petri dish in less than 5 days at 25°C. The sporangiophores were hyaline, light brown to grayish, 44.71 to 143.14 (average = 85.10) μm long, and arose directly from the non-septate substrate hyphae. The sporangia were spherical, single, and terminal and yellow-brown to brown when young turning to dark brown or black at maturity. Both the sporangiophores and sporangia were covered with calcium oxalate crystals. When mounted in a drop of water, the sporangium immediately broke longitudinally into two halves, releasing the spores and exposing a large pyriform columella at the tip of the sporangiophore. The spores were mostly globose to ellipsoid, aseptate, and 5.15 (3.71 to 7.86) × 6.30 (4.08 to 9.19) μm (n = 300). Two to three slender, hyaline appendages were attached to the ends of the spores. The cardinal growth temperatures of the pathogen were 10, 30, and 40°C and it grew faster in the dark than under 12-h alternating light-dark cycles. The fungus was identified as Gilbertella persicaria (1). To confirm the identification, the internal transcribed spacer region of the nuclear rDNA of one isolate was amplified using the fungal primers ITS1 and ITS4. The nucleotide sequence (Accession No. JQ951601) showed 98% homology with G. persicaria in GenBank (HM999958). Pathogenicity tests were carried out on two species of dragon fruit, H. costaricensis and H. undatus, by placing a 6-mm diameter young mycelial PSA agar disc on the surface of an asymptomatic fruit, either unwounded or wounded with a sterile needle. As the control, a plain PSA disc was used. Each inoculated fruit was placed in a moist chamber and incubated at 25°C. Three fruits were used per treatment and the experiment was repeated twice. The fruits rotted in 2 to 3 days, and the disease was especially serious on wounded fruits and on H. costaricensis. The fungus was reisolated from infected fruits. The controls did not show any disease symptoms. Inoculation studies were also made on other fruits but rot was produced only on peach, pear, and wounded tomato. To our knowledge, this is the first record of dragon fruit rot caused by G. persicaria. The fungus had been reported in China but caused no diseases (2). In India, it caused fruit rot of pear, tomato, and peach (3). To minimize the disease, dragon fruit should be stored at low temperature and in uncovered containers. References: (1) G. L. Benny. Mycologia 83:150, 1991. (2) J. Y. Cheng and H. Y. Mei. Acta Phytotax. Sin. 10:105, 1965. (3) M. D. Mehrotra. Mycopath. Mycol. Appl. 29:151, 1966.

Identificación de hongos mucorales causantes de la pudrición blanda en frutos de papaya (Carica papaya L.) en México

“…The morphology of G. persicaria structures is similar to that reported by diverse authors (Benny, 1991;Guo et al, 2012;Pinho et al, 2014). It is considered a monotypic species in its genus, which is located in the subfamily Gilbertelloideae and the family Choanephoraceae (Hyde et al, 2014).…”

“…Morphotype 1 (petaloid colonies, brown sporangia) was observed in 31% of the isolates, while the rest of the isolates presented morphotype 2 (69%). G. persicaria is a common pathogen in tropical and subtropical regions, causing the soft rot of tomato, pear, peach, pitahaya, jambolan (Ginting et al, 1996;Guo et al, 2012;Pinho et al, 2014) and recently, it was reported to have infected papaya fruits in the state of Colima, Mexico (Cruz-Lachica et al, 2016). This study reports the presence of this species in the states of Oaxaca and Veracruz, showing that it is present in other papaya producing regions and its distribution should be considered important.…”

“…La morfología de las estructuras de G. persicaria es similar a la reportada por diversos autores (Benny, 1991;Guo et al, 2012;Pinho et al, 2014); es considerada una especie monotípica en su género, el cual se ubica en la subfamilia Gilbertelloideae y familia Choanephoraceae (Hyde et al, 2014). En este estudio se observó el desarrollo de confirmed with the phylogenetic analysis of region 28S (LSU) Hoffmann et al, 2013;Hyde et al, 2014).…”

“…El morfotipo 1 (colonias petaladas, esporangios café) se observó en el 31% de los aislamientos; mientras que el resto de aislamientos mostró el morfotipo 2 (69%). G. persicaria es un patógeno común en regiones tropicales y subtropicales causando la pudrición blanda de tomate, pera, durazno, pitahaya, jambolán (Ginting et al, 1996;Guo et al, 2012;Pinho et al, 2014) y recientemente, se reportó causando enfermedad en frutos de papaya en el estado de Colima, México (Cruz-Lachica et al, 2016); en este estudio se reporta la presencia de esta especie en los estados de Oaxaca y Veracruz con lo que se demuestra que está presente en otras regiones de producción de papaya y debería considerarse su distribución como un factor de importancia.…”

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

“…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.…”