First Report of Leaf Blight of Dictyosperma album Caused by Pestalotiopsis adusta in China

Abstract

HomePlant DiseaseVol. 99, No. 7First Report of Leaf Blight of Dictyosperma album Caused by Pestalotiopsis adusta in China PreviousNext DISEASE NOTES OPENOpen Access licenseFirst Report of Leaf Blight of Dictyosperma album Caused by Pestalotiopsis adusta in ChinaH. Zhu, X.-Q. Niu, F.-Y. Yu, L. Liu, W. Yan, and W.-Q. QinH. ZhuSearch for more papers by this author, X.-Q. NiuSearch for more papers by this author, F.-Y. YuSearch for more papers by this author, L. LiuSearch for more papers by this author, W. YanSearch for more papers by this author, and W.-Q. QinSearch for more papers by this authorAffiliationsAuthors and Affiliations H. Zhu X.-Q. Niu F.-Y. Yu L. Liu W. Yan W.-Q. Qin , Coconut Research Institute, Chinese Academy of Tropical Agricultural Sciences, Wenchang, Hainan, 571339, China. Published Online:2 Jun 2015https://doi.org/10.1094/PDIS-10-14-1093-PDNAboutSectionsSupplemental ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InRedditEmailWechat Dictyosperma album, famous for its graceful appearance and ability to withstand strong winds, is a popular landscaping palm that is grown throughout the tropics. In April 2014, D. album plants with severe leaf blight were observed in commercial production fields located in Wenchang, Hainan Province of China. The disease was characterized by the initial appearance of minute yellow leaf spots with gray brown margins. The spots were oval in shape and expanded to 8 cm in length. The center of the spots became grayish-white. Spots coalesced to form larger irregular necrotic patches. Leaf pieces from lesion margins consistently yielded a fungus on potato dextrose agar (PDA). Monosporic cultures of this fungus on PDA were white with pale yellow pigmentation on the reverse side. Acervuli developed from small yellowish clumps of hyphae and gave rise to conspicuous greenish-black spore masses. The conidia were fusiform to ellipsoid, straight to slightly curved, 4-septate, 16.8 to 20.5 × 5.2 to 7.5 µm in size, with short hyaline basal cell, 3.5 to 4.3 µm long; with three median cells, doliform to subcylindrical, olivaceous and periclinal walls darker than the rest of the cell, together 12.5 to 14.2 µm long; apical cell hyaline, conic, 2.7 to 3.6 µm long; with 2 to 3 hyaline appendages, 7.2 to 15.3 µm long, arising from the apex of the apical cell. These observed morphological features showed that the fungus possessed the similar characteristics as previously described for Pestalotiopsis adusta (Ellis & Everh.) Steyaert (Maharachchikumbura et al. 2012; Steyaert 1953). For molecular identification, the ITS1-5.8S-ITS2 region and fragments of the β-tubulin and elongation factor 1-alpha (EF1-α) genes were sequenced and subjected to BLASTn searches in GenBank. Accession numbers of gene sequences submitted to GenBank were KJ885548 for ITS region, KJ885549 for β-tubulin, and KJ885550 for EF1-α. For all genes used, sequences were 99.63, 99.78, and 99.31% identical to epitype isolate ICMP6088 of P. adusta reported in GenBank (NR_111788, JX399037, and JX399070) (Maharachchikumbura et al. 2012). In addition, a phylogenetic tree based on the sequences of the ITS, β-tubulin, and EF1-α from 41 Pestalotiopsis species was generated via Bayesian inference concatenated (BI) analyses employing a Markov Chain Monte Carlo method (Huelsenbeck et al. 2001). This created tree placed the isolate in the same group as P. adusta. To confirm fungal pathogenicity, 10 asymptomatic leaves of D. album were spray-inoculated with a spore suspension (1.2 × 106 spores/ml) prepared from 7-day-old cultures. Another 10 control leaves were sprayed with sterile, double-distilled water. Plants were maintained in a moist chamber at 26°C with a 12-h photoperiod. All inoculated leaves produced typical lesions at 2 weeks after inoculation. The fungus was consistently reisolated from lesions on inoculated plants. Control plants did not show any symptoms. P. adusta has been reported as a pathogen on a wide range of hosts in China (Ge et al. 2009), but not previously reported causing disease on D. album. To our knowledge, this is the first report of leaf blight of D. album caused by P. adusta.