Occurrence of Anthracnose Disease Caused byColletotrichum siamenseon Dragon Fruit (Hylocereus undatus) in Andaman Islands, India

Abstract

HomePlant DiseaseVol. 103, No. 4Occurrence of Anthracnose Disease Caused by Colletotrichum siamense on Dragon Fruit (Hylocereus undatus) in Andaman Islands, India PreviousNext DISEASE NOTES OPENOpen Access licenseOccurrence of Anthracnose Disease Caused by Colletotrichum siamense on Dragon Fruit (Hylocereus undatus) in Andaman Islands, IndiaK. Abirami, K. Sakthivel, N. Sheoran, V. Baskaran, R. K. Gautam, B. A. Jerard, and A. KumarK. AbiramiICAR–Central Island Agricultural Research Institute (CIARI), Port Blair 744101, Andaman and Nicobar Islands, India; and Search for more papers by this author, K. SakthivelICAR–Central Island Agricultural Research Institute (CIARI), Port Blair 744101, Andaman and Nicobar Islands, India; and Search for more papers by this author, N. SheoranDivision of Plant Pathology, ICAR–Indian Agricultural Research Institute, New Delhi 110012, IndiaSearch for more papers by this author, V. BaskaranICAR–Central Island Agricultural Research Institute (CIARI), Port Blair 744101, Andaman and Nicobar Islands, India; and Search for more papers by this author, R. K. GautamICAR–Central Island Agricultural Research Institute (CIARI), Port Blair 744101, Andaman and Nicobar Islands, India; and Search for more papers by this author, B. A. JerardICAR–Central Island Agricultural Research Institute (CIARI), Port Blair 744101, Andaman and Nicobar Islands, India; and Search for more papers by this author, and A. Kumar†Corresponding author: A. Kumar; E-mail: E-mail Address: kumar@iari.res.inhttp://orcid.org/0000-0002-7401-9885Division of Plant Pathology, ICAR–Indian Agricultural Research Institute, New Delhi 110012, IndiaSearch for more papers by this authorAffiliationsAuthors and Affiliations K. Abirami1 K. Sakthivel1 N. Sheoran2 V. Baskaran1 R. K. Gautam1 B. A. Jerard1 A. Kumar2 † 1ICAR–Central Island Agricultural Research Institute (CIARI), Port Blair 744101, Andaman and Nicobar Islands, India; and 2Division of Plant Pathology, ICAR–Indian Agricultural Research Institute, New Delhi 110012, India Published Online:29 Jan 2019https://doi.org/10.1094/PDIS-09-18-1489-PDNAboutSectionsSupplemental ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InRedditEmailWechat Dragon fruit or pitaya (Hylocereus species) belongs to the family Cactaceae and is native to the tropical forest regions of Mexico, Central America, and South America (Mizrahi et al. 1997). From the center of origin, the cultivation of the fruit has spread to tropical and subtropical America, Asia, Australia, and Middle East (Patwary et al. 2013). The fruits have red, pink, or yellow peels, and the juicy flesh color ranges from white to magenta. The fruits are used for consumption considering their rich nutritional as well as nutraceutical properties. The cultivation of dragon fruit is of recent introduction in India and particularly for the Andaman group of islands, located in the Bay of Bengal, India. Most agricultural products including fruits are imported to Andaman and Nicobar Islands from mainland India, which is not economically viable. The government policies and local farmers aim to cultivate such nutritive, high value, and exotic fruits that can be climatically adapted to these Bay Islands. We have systematically established a dragon fruit (Hylocereus undatus) orchard in the research farm block (11°36′39.39″ N; 092°36′03.75″ E) at ICAR-CIARI, Port Blair, Andaman and Nicobar Islands, where the disease symptoms of reddish-orange spots with severe chlorotic halos were noticed on the stems during March 2017. The spots subsequently culminated in loss of stem portions, and about 30% of plants were affected with a consequent yield reduction. The surface-disinfected (in sodium hypochlorite 1%) symptomatic tissue incubated at 25°C on potato dextrose agar showed fungal colony with white mycelial growth during initial stages that turned orange and round blackish in later stages. Conidia were hyaline, cylindrical, and elongated with an average length and width of 12.32 ± 0.45 and 3.21 ± 0.14 µm respectively. The size of appressoria varied, with length of 7.82 ± 1.27 µm and width of 5.33 ± 0.85 µm. The conidiophores were hyaline and found with masses of black setae. To confirm Koch’s postulates, pathogenicity tests were conducted under field conditions by inoculating fresh conidial suspension (1 × 107 to 1 × 108 CFU/ml) on mature healthy stems of dragon fruit, by both wound (pin prick) and nonwound methods. Plants inoculated with sterile water served as a control. The experiment was repeated twice with three replications. Typical anthracnose symptoms could be observed on inoculated plants 15 days postinoculation. The fungal pathogen was reisolated, and the disease etiology was confirmed morphologically using a similar set of morphological characters. Morphological and cultural characteristics and pathogenicity tests placed the pathogen as a member of Colletotrichum genus (Sutton 1980). The fungus was further identified by analyzing genomic regions representing calmodulin (CAL), chalcone synthetase (CHS), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and tubulin (TUB). The multigene analysis revealed 99% similarity with type specimens of Colletotrichum siamense having the following NCBI accession numbers: CAL (JX009714), CHS (JX009842), GAPDH (JX010059), and TUB (KM245088), respectively. The sequences were submitted to GenBank with the following accession numbers: MG561762 (CAL); MG561763 (CHS); MG561764 (GAPDH), and MG561766 (TUB). The fungal culture is deposited at the National Fungal Culture Collection Center, Pune, India, with the accession identity number 4307. The occurrence of anthracnose on dragon fruit by C. siamense was earlier reported by Meetum et al. (2015) in Thailand. The perusal of records revealed that this is the first report of C. siamense causing anthracnose on dragon fruit in Andaman Islands. The results will be useful for devising effective disease management strategies for this economically important crop in the islands.