First Report of Botryosphaeria Dothidea Causing Stem-End Rot in Avocado (persea Americana) in China

HomePlant DiseaseVol. 104, No. 1First Report of Botryosphaeria dothidea Causing Stem-End Rot in Avocado (Persea americana) in China PreviousNext DISEASE NOTES OPENOpen Access licenseFirst Report of Botryosphaeria dothidea Causing Stem-End Rot in Avocado (Persea americana) in ChinaF. Qiu, G. Xu, J. Zhou, F. Q. Zheng, L. Zheng, W. G. Miao, W. L. Wang, and C. P. XieF. Qiuhttp://orcid.org/0000-0002-7903-8719College of Plant Protection, Hainan University/Key Laboratory of Green Prevention and Control of Tropical Plant Diseases and Pests (Hainan University), Ministry of Education, Haikou 570228, ChinaSearch for more papers by this author, G. Xuhttp://orcid.org/0000-0002-8642-8221College of Plant Protection, Hainan University/Key Laboratory of Green Prevention and Control of Tropical Plant Diseases and Pests (Hainan University), Ministry of Education, Haikou 570228, ChinaSearch for more papers by this author, J. ZhouCollege of Plant Protection, Hainan University/Key Laboratory of Green Prevention and Control of Tropical Plant Diseases and Pests (Hainan University), Ministry of Education, Haikou 570228, ChinaSearch for more papers by this author, F. Q. ZhengCollege of Plant Protection, Hainan University/Key Laboratory of Green Prevention and Control of Tropical Plant Diseases and Pests (Hainan University), Ministry of Education, Haikou 570228, ChinaSearch for more papers by this author, L. ZhengCollege of Plant Protection, Hainan University/Key Laboratory of Green Prevention and Control of Tropical Plant Diseases and Pests (Hainan University), Ministry of Education, Haikou 570228, ChinaSearch for more papers by this author, W. G. MiaoCollege of Plant Protection, Hainan University/Key Laboratory of Green Prevention and Control of Tropical Plant Diseases and Pests (Hainan University), Ministry of Education, Haikou 570228, ChinaSearch for more papers by this author, W. L. WangGuangxi South Subtropical Agricultural Sciences Research Institute, Guangxi, ChinaSearch for more papers by this author, and C. P. Xie†Corresponding author: C. P. Xie; E-mail Address: xiechangping009@163.comCollege of Plant Protection, Hainan University/Key Laboratory of Green Prevention and Control of Tropical Plant Diseases and Pests (Hainan University), Ministry of Education, Haikou 570228, ChinaSearch for more papers by this author AffiliationsAuthors and Affiliations F. Qiu1 G. Xu1 J. Zhou1 F. Q. Zheng1 L. Zheng1 W. G. Miao1 W. L. Wang2 C. P. Xie1 † 1College of Plant Protection, Hainan University/Key Laboratory of Green Prevention and Control of Tropical Plant Diseases and Pests (Hainan University), Ministry of Education, Haikou 570228, China 2Guangxi South Subtropical Agricultural Sciences Research Institute, Guangxi, China Published Online:6 Nov 2019https://doi.org/10.1094/PDIS-07-19-1439-PDNAboutSectionsSupplemental ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InRedditEmailWechat Species belonging to Botryosphaeriaceae are known to produce cankers, dieback, blights, and leaf spots on many woody hosts, mainly under stress conditions. Several Botryosphaeria spp. may also cause pre- or postharvest decay of stone fruit, such as peaches (Bird et al. 1995). In July 2017, fruit of avocado (Persea americana) showing a severe stem-end rot was observed in a commercial orchard of Guangxi, China. The incidence of the disease is estimated at around 14%. Initial disease symptoms on fruits were irregular brown lesions and yellowing. In the later stages, the whole fruit turned dark brown, causing fruit rot and peel shrinking. Finally, the infected fruits dropped to the ground. Ten random symptomatic fruits were collected and washed with tap water. Small pieces of affected tissues (4 × 4 mm) were cut from margin of the lesions, and they were surface disinfested in 75% ethanol solution for 10 s followed by 1 min in 0.1% HgCl2, rinsed three times with sterile water, plated on potato dextrose agar (PDA), and incubated at 28°C for 2 days with a 24-h photoperiod. Forty affected tissues were isolated, and the target fungi accounted for 91%. The resultant colony (78 mm in diameter) was grayish white and circular, round after 3 days. Eight-day-old colonies turned grayish black. Conidia tips were blunt, and the bases of conidia were slightly flat. Conidia were nonseptate, hyaline, fusiform, straight or slightly curved, smooth, and measured 18.0 to 27.5 µm long (average 22.2 µm; n = 100) × 5.5 to 8.1 µm wide (average 6.7 µm; n = 100). The pathogen was identified as Botryosphaeria YLDF120832 on the basis of its morphological and biometric characteristics. Sequences were generated from the isolate using primers for the rDNA ITS (ITS1/ITS4), TUB2 (βt2a/βt2b), and EF1-α (EF1-728F/EF1-986R) (Slippers et al. 2004). ITS (MN165109), TUB2 (MN165110), and EF1-α (MN165111) sequences were deposited at GenBank. BLAST searches showed 96 to 99% identity with the reference sequences of Botryosphaeria dothidea HuB10s1 (accession nos.: ITS, JX275786; TUB2, JX462268; and EF1-α, JX462294). A maximum likelihood phylogenetic analysis based on the multilocus alignment of the ITS, TUB2, and EF-1α sequences using MEGA7 revealed that the isolate was grouped in the same clade as B. dothidea with 98% of bootstrap support. Pathogenicity tests were conducted on eight healthy immature fruits of avocado from the same commercial orchard. Fruits were wound inoculated with 5-mm-diameter mycelial plugs of B. dothidea isolate YLDF120832 obtained from 3-day-old cultures grown on PDA as described above, which were deposited on the fruits. The same number of fruits treated with PDA plugs were wound included as controls. All fruits were incubated at 100% relative humidity at 28°C with a 24-h photoperiod. After 4 days, the inoculated fruits presented similar symptoms to those observed under natural conditions, whereas the control fruits showed no symptoms. The pathogenicity tests were carried out three times. The same fungus was reisolated from the infected fruits, and the identity was confirmed by cultural and morphological characteristics, confirming Koch’s postulates. This pathogen has been reported on blueberry in China (Xu et al. 2015). Some Botryosphaeriaceae species have also been reported on avocado fruit in Chile (Valencia et al. 2019). This is the first report of B. dothidea causing stem-end rot of avocado in China. This research provides a basis for further research on the control and epidemic of the disease.The author(s) declare no conflict of interest.References:Bird, G. W., et al. 1995. Compendium of Stone Fruit Diseases. American Phytopathological Society, St. Paul, MN. Google ScholarSlippers, B., et al. 2004. Mycologia 96:83. https://doi.org/10.1080/15572536.2005.11833000 Google ScholarValencia, A. L., et al. 2019. Plant Dis. 103:996. https://doi.org/10.1094/PDIS-07-18-1131-RE Link, ISI, Google ScholarXu, C., et al. 2015. Eur. J. Plant Pathol. 143:737. https://doi.org/10.1007/s10658-015-0724-6 Crossref, ISI, Google ScholarThe author(s) declare no conflict of interest.DetailsFiguresLiterature CitedRelated Vol. 104, No. 1 January 2020SubscribeISSN:0191-2917e-ISSN:1943-7692 DownloadCaptionStrawberry plant showing leaf blight caused by Pantoea ananatis FANS-1 (Bajpai et al.). Photo credit: B. Prithiviraj. Plasmopara velutina causing downy mildew on Impatiens balsamina (R. M. Silva et al.). Photo credit: R. W. Barreto. Metrics Downloaded 5,017 times Article History Issue Date: 2 Jan 2020Published: 6 Nov 2019First Look: 26 Aug 2019Accepted: 22 Aug 2019 Page: 286 Information© 2020 The American Phytopathological SocietyKeywordsBotryosphaeria dothideaavocadostem-end rotThe author(s) declare no conflict of interest.Cited ByEfficacy of Dimethyl Trisulfide on the Suppression of Ring Rot Disease Caused by Botryosphaeria dothidea and Induction of Defense-Related Genes on Apple Fruits7 February 2022 | Frontiers in Microbiology, Vol. 13