Occurrence of noni anthracnose caused by Colletotrichum siamense in Amazonas, Brazil.
Blenda Naara Santos da Silva, Ana Francisca Tibúrcia Amorim Ferreira e Ferreira, Adolfo José da Mota, Jânia Lília da Silva Bentes
Journal Title:Revista Agraria Academica / Agrarian Academic Journal
Noni (Morindacitrifolia L.) is native fromSoutheast Asia and was introduced in Brazil recently, where it haswelladapted to the edaphoclimatic conditions.Thefruits are consumed because of their numerous therapeutic properties.FromMarch to November 2018, circular brown spotswith concentric rings were observed on leaves of noniplants,atFederal University of Amazonascampus(UFAM), wherethe temperature and rainfall ranged from 23°Cand 32°C, and 47mmand 335mmin this period.Leaves with typical symptoms of anthracnose were taken to the laboratory and washed with tap water. Fragments (5 mm) were removed from the margin of leaf lesions, superficially disinfested with 70 % alcohol(1 min.) and1,5 %sodium hypochlorite (1 min.) followed by three washeswith distilled water, dried on filter paper and plated in Petri dishes with Potato Dextrose Agar(Kasvi). Plates were incubated at 25 °C.After 48 h, mycelial fragments were transferred to new PDA plates and incubated at 25 °C under fluorescent light (T8 tubular lamps, 40 w, 6400k daylight), located 25 cm above the plates.Morphological characteristicswere observed after 7 days.Colonies were light grey to white and orange conidium masses in the center. Reverse of the colony wasorange to white(Figure 1A).Conidia were hyaline, aseptate, oblong-elliptical and 5.75to 8.26× 1.82to 2.39μm (n= 30) (average ± SD = 7.09± 0.51× 2.09± 0.17μm). The morphological characteristics were similar to Colletotrichumsiamenseinto Colletotrichum gloeosporioides speciescomplex (Sharma et al., 2015; Weir et al., 2012). The 3 Kbp ribosomal, beta-tubulin2(TUB2)and glycerol-3-phosphate dehydrogenase(GAPDH)sequencing (acession number: MK299421, MK821246, MK821247)was carried out using NS1-NS8, ITS1, ITS4,Uni-R primers,T1-T2 and GDF-GDR(White&Lee, 1990; Fell,1993; O’Donnell& Cigelnik 1997; Templeton et al., 1992). Maximum parsimony phylogenetic tree (MEGA v. 7.0)fed with Colletotrichumsequences from noni and the reference isolates of Colletotrichumspp. deposited in GenBank, revealed that the isolate belonged to C. siamensespecies. The pathogenicity test was conducted with healthy noni leaves. The leaves were washed and disinfected superficially. Leaves wereinoculated with mycelial discs and with agar discas a control. Typical anthracnose lesions were observed on noni leaves after 7 days (Figure1B). C.siamensewas reisolated from the lesions, and their identity has been confirmed asdescribed above.Colletotrichumspecies is also responsible for anthracnose of M.citrifoliain the Brazilian statesofGoias, Mato Grosso andCeara. In countries like Mexico and India, anthracnose causes significant losses in noni culture (Ayvar-Serna et al., 2018; Hubballi et al., 2010). To the best of our knowledge this is the first report of C. siamense anthracnose of leaf noniin state of Amazonas (Brazil).