Colletotrichum gloeosporioides as the cause of stem tip dieback of cassava

Abstract

A fungus with morphological features corresponding to the group species Colletorichum gloeosporioides was consistently isolated from cassava with shoots showing dieback symptoms in Ghana. When four locally‐grown cultivars were inoculated with isolates of the fungus, they developed disease symptoms, which consisted of discrete dark brown lesions on the stems followed by defoliation. Koch's postulates were completed by re‐isolating the fungus from the inoculated plants. The relatedness of the isolates lo other members of the genus Calletotrichum, whose identities were well established, was investigated by comparison of the nucleotide sequence of domain 2 of their ribosomal DNA. The cassava isolates differed from authentic isolates of C. gloeosporioides by only one nucleotide among the 193 analysed. The causal agent of cassava stem tip dieback (STDB) is thus identified as a form of C. gloeosporioides.

Colletotrichum isolates related to Anthracnose of cashew trees in Brazil: morphological and molecular description using LSU rDNA sequences

“…Comparing the aligned nucleotide sequences of the D2 region (180 nucleotides) of the studied isolates, along with data of other previously-identified Colletotrichum species from LARS collection Moses et al, 1996;Sherriff et al, 1994), the maximum number of differences among the aligned bases was 16, i.e. 8.9%.…”

“…Isolates LARS 909 and 938 (G3) were identical to the ones obtained from Stylosanthes spp., and isolates from G4 (LARS 912,913,917,924,927,931,and 940) differed by two nucleotides from those in Stylosanthes spp., and by only one nucleotide from those on A. virginica, M. indica or C. melo. Different regions (D1, D2) of the LSU rDNA and intergenic sequences (ITS1, ITS2) have more variation in their rate of evolution than do the domains of the small subunit, being useful to distinguish groups in closely related taxa, like in the genus Colletotrichum Kohn, 1992;Moses et al, 1996;Moriwaki et al, 2002). Sherriff et al (1994; observed that sequence data from the D2 region was as informative as the combined D1, D2 and ITS2 regions (886 bp) in revealing the differences and relationships in Colletotrichum, since it has a sufficient proportion of sequence divergence to distinguish between the main species of this genus.…”

“…Sherriff et al (1994; observed that sequence data from the D2 region was as informative as the combined D1, D2 and ITS2 regions (886 bp) in revealing the differences and relationships in Colletotrichum, since it has a sufficient proportion of sequence divergence to distinguish between the main species of this genus. Moses et al (1996) identified C. gloeosporioides as the causal agent of stem tip dieback of cassava (Manihot esculenta), based on the relatedness between their D2-rDNA sequences and the ones of other Colletotrichum isolates. The authors found that cassava C. gloeosporioides isolates differed by only one nucleotide from those of A. virginica, M. indica and Stylosanthes spp., exactly as for some isolates in the present study.…”

“…The developed gel was read manually, and each sequence was aligned using GCG PileUp. Data obtained from the sequencing of the D2 region of all isolates were compared with those of the D2 regions of some Colletotrichum species previously studied Moses et al, 1996;Sherriff et al, 1994), using the neighbour-joining method of Kumar et al (1993), and a dendrogram depicting similarities was constructed using the MEGA (Molecular Evolutionary Genetic Analysis) software (version 1.01).…”

The Genomics of Colletotrichum

“…Colletotrichum postharvest fruit rots are responsible for major economic losses, with severe infections resulting in up to 100 % loss during storage (Prusky 1996). Colletotrichum diseases also produce substantial damage on important subsistence crops including lentil, cowpea, yam, banana, sorghum, and cassava (Adegbite and Amusa 2008;Chona 1980;Chongo et al 2002;Finlay and Brown 1993;Green and Simons 1994;Moses et al 1996;Moura-Costa et al 1993).…”