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Occurrence of Leaf Spot Caused by Neodeightonia phoenicum on Pygmy Date Palm ( Phoenix roebelenii ) in China

2021; American Phytopathological Society; Volume: 106; Issue: 8 Linguagem: Inglês

10.1094/pdis-10-21-2190-pdn

1943-7692

Wu Zhang, Xiuli Song,

Yeasts and Rust Fungi Studies

HomePlant DiseaseVol. 106, No. 8Occurrence of Leaf Spot Caused by Neodeightonia phoenicum on Pygmy Date Palm (Phoenix roebelenii) in China PreviousNext DISEASE NOTE OPENOpen Access licenseOccurrence of Leaf Spot Caused by Neodeightonia phoenicum on Pygmy Date Palm (Phoenix roebelenii) in ChinaWu Zhang and Xiuli SongWu Zhang†Corresponding authors: W. Zhang; E-mail Address: ldzw1987@163.com, and X. Song; E-mail Address: songxiuli5251@163.comhttps://orcid.org/0000-0002-7887-8345Lingnan Normal University, Zhanjiang, 524048, China and Xiuli Song†Corresponding authors: W. Zhang; E-mail Address: ldzw1987@163.com, and X. Song; E-mail Address: songxiuli5251@163.comLingnan Normal University, Zhanjiang, 524048, ChinaAffiliationsAuthors and Affiliations Wu Zhang † Xiuli Song † Lingnan Normal University, Zhanjiang, 524048, China Published Online:30 Jun 2022https://doi.org/10.1094/PDIS-10-21-2190-PDNAboutSectionsView articlePDFSupplemental ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InRedditEmailWechat View articleThe pygmy date palm (Phoenix roebelenii) is a popular ornamental plant widely cultivated in tropical regions as well as in China. In June 2018, new leaf spot symptoms were observed on P. roebelenii in several different parks in Zhanjiang City of China. The early symptoms of infected leaves were small, round, pale brown spots. As the size of these spots increased, they coalesced to form larger irregular necrotic lesions surrounded by dark brown edges, which eventually led to leaf wilting and defoliation. A filamentous fungus was consistently isolated from infected leaf samples. Colonies on PDA at 25°C (12 h light/dark) were initially white with abundant aerial mycelium, which turned fluffy and dark olivaceous after 1-week culture. Pycnidial conidiomata were black and globose and formed on pine needles in water agar at 25°C (12 h light/dark) after 21 days. Conidiogenous cells were hyaline, cylindrical, and holoblastic. The conidia were ovoid to ellipsoid, thick walled, initially hyaline and aseptate, and later turned dark brown and 1-septate with a striate appearance to conidia, being 11.6 to 25.0 × 9.6 to 12.0 μm (average 20.4 × 10.1 μm). For molecular identification, the partial sequences of internal transcribed spacer (ITS) regions, translation elongation factor (EF-1α), and β-tubulin (TUB) genes of two representative isolates (RYCK-1 and RYCK-2) were amplified and sequenced using primer pairs ITS/ITS4 (White et al. 1990), EF-688F/EF-986R (Carbone and Kohn 1999), and Bt2a/Bt2b (Glass and Donaldson 1995), respectively. The sequences of the above three loci of the two isolates (accession nos. ITS, OK329968 and OK329969; EF-1α, OK338067 and OK338068; TUB, OK338069 and OK338070) showed 98.4 to 100.0% identity with the existing sequences of ex-type culture CBS 122528 of N. phoenicum. A multilocus phylogenetic analysis of the three loci concatenated sequences using the maximum likelihood method showed that the isolates belonged to Neodeightonia phoenicum. Based on the morphological characteristics and molecular analysis of the isolates, the fungus was identified as N. phoenicum (Phillips et al. 2008). To confirm pathogenicity, five 1-year-old potted plants were used for each isolate (RYCK-1 and RYCK-2), and the plants were inoculated by pricking the epidermis of the leaf with a needle. Five leaves of each plant were sprayed with 100 µl of a conidial suspension (1 × 106 conidia/ml) to the wounded surface for each plant. Sterilized distilled water was used as the control and the experiment was repeated. All the plants were incubated at 26 ± 2°C (12 h light/dark) and covered with plastic bags to maintain constant high humidity. After 14 days, all the inoculated leaves showed the same symptoms as those observed in the original diseased plants, but the control plants remained healthy. The reisolated fungus was identified as N. phoenicum by morphological and molecular characteristics. N. phoenicum is an important pathogen of Phoenix species plants worldwide and has been reported to cause shoot blights and stalk rots on P. dactylifera and P. canariensis in Greece (Ligoxigakis et al. 2013) and root rot on P. dactylifera in Qatar (Nishad and Ahmed 2020). To our knowledge, this is first report of N. phoenicum causing leaf spot on P. roebelenii in China.The author(s) declare no conflict of interest.References:Carbone, I., and Kohn, L. M. 1999. Mycologia 91:553. https://doi.org/10.2307/3761358 Crossref, ISI, Google ScholarGlass, N. L., and Donaldson, G. 1995. Appl. Environ. Microbiol. 61:1323. https://doi.org/10.1128/aem.61.4.1323-1330.1995 Crossref, ISI, Google ScholarLigoxigakis, E. K., et al. 2013. Plant Dis. 97:286. https://doi.org/10.1094/PDIS-08-12-0727-PDN Link, ISI, Google ScholarNishad, R. N., and Ahmed, T. A. 2020. Plant Dis. 104:2498. https://doi.org/10.1094/PDIS-12-19-2556-RE Link, ISI, Google ScholarPhillips, A. J. L., et al. 2008. Persoonia 21:29. https://doi.org/10.3767/003158508X340742 Crossref, ISI, Google ScholarWhite, T. J., et al. 1990. Page 315 in: PCR Protocols: A Guide to Methods and Applications. Academic Press, San Diego, CA. Google ScholarFunding: This research was financially supported by the Key Scientific Research Platform and Project of Guangdong Education Department (2019KZDXM06, 2021KCXTD054), National Nature Science Foundation of Guangdong Province (2020A1515010238), and Science and Technology Development Special Fund Competitive Allocation Project of Zhanjiang City (2020A03007).The author(s) declare no conflict of interest.DetailsFiguresLiterature CitedRelated Vol. 106, No. 8 August 2022SubscribeISSN:0191-2917e-ISSN:1943-7692 Download Metrics Article History Issue Date: 29 Jul 2022Published: 30 Jun 2022First Look: 23 Dec 2021Accepted: 7 Dec 2021 Page: 2269 Information© 2022 The American Phytopathological SocietyFundingKey Scientific Research Platform and Project of Guangdong Education DepartmentGrant/Award Number: 2019KZDXM06Grant/Award Number: 2021KCXTD054National Nature Science Foundation of Guangdong ProvinceGrant/Award Number: 2020A1515010238Science and Technology Development Special Fund Competitive Allocation Project of Zhanjiang CityGrant/Award Number: 2020A03007Keywordsfungiornamentalspathogen detectionThe author(s) declare no conflict of interest.PDF downloadCited byA Bacterial Isolate Capable of Quenching Both Diffusible Signal Factor- and N -Acylhomoserine Lactone-Family Quorum Sensing Signals Shows Much Enhanced Biocontrol Potencies16 June 2022 | Journal of Agricultural and Food Chemistry, Vol. 70, No. 25