Genetic diversity of Mycosphaerella spp
on bananas in Nigeria
M. Zandjanakou-Tachin1,5, I. Vroh-Bi2, P.S. Ojiambo3, A. Tenkouano4, M. Gumedzoe5, and R. Bandyopadhyay1
Bananas (Musa spp.) commonly referred to as banana and plantain, All the 95 Mycosphaerella isolates analyzed in this study merged into
are i t t ith ld d ti
important crops with world production of 106 million tons per
f illi t l haplotypes (Fi 2 3A)
only 21 h l t (Fig. 2, 3A).
year The crop is susceptible to several devastating diseases,
84 (88.4%) isolates grouping into 14 SNP haplotypes were identified
including Mycosphaerella (Fig 1) leaf spot diseases caused by M M.
fijiensis, M. musicola, and M. eumusae. The disease causes severe
j , , as M. fijiensis (Fig. 3C), while 11 (11.6%) represented by 7 SNP
leaf necrosis and can reduce yields up to 75%. Relative prevalence haplotypes (Fig. 3D) were characterized as M. eumusae. M.
of Mycosphaerella species on bananas is not known in West Africa. i l tf d (Fi 3B)
musicola was not found (Fig. 3B).
Good diagnostic t l and understanding of the distribution and the
G d di ti tools d d t di f th di t ib ti d th The 21 SNP haplotypes were mapped geographically (Fig. 4).
genetic diversity of the pathogen are needed to help optimize Several haplotypes were found in multiple sites.
disease diagnosis and management using resistant cultivars.
The two species were distinguished from each other by molecular
markers. Some Nigerian isolates possess unique sequence variation
compared to the GenBank reference checks.
g g p p
There were significant genetic differences between most populations
Identify d d t i th
Id tif and determine the
(P < 0.001) with an average FST of 0.126.
distribution of Mycosphaerella
species pathogenic on Musa M eumusae displayed a higher (4.6%) intraspecific dissimilarity
M. (4 6%)
compared to M. fijiensis (2%).
Investigate th genetic
I ti t the ti
structure Mycosphaerella 21 haplotypes 21 haplotypes
population isolated from bp bp
Musa in Nigeria. g y p p
Figure 1. Mycosphaerella leaf spot of banana.
Materials d th d
M t i l and methods p yp
21 haplotypes 21 haplotypes
Ribosomal DNA was sequenced bp
and compared in 95 isolates of M.
species collected in Nigeria and 500
f h k (G B k
reference checks (GenBank
accessions with intercontinental C
Figure 3. Identification of Nigerian Mycosphaerella isolates using general PCR probe on actin and β-tubulin
(A), M. (B), M. (C), M.
(A) and specific primers for M musicola (B) M fijiensis (C) and M eumusae (D) (D).
Si l nucleotide polymorphism
Single l tid l hi
(SNP) was used to identify the
species and to determine the
genetic structure of the sampled
Species identity was further
g p p
confirmed using species-specific
probes for actin and β-tubulin
Populations were differentiated
using AMOVA and FST indices
calculated using Arlequin program
To determine the genetic Figure 4. Geographical distribution of Nigerian M. fijiensis (F) and M. eumusae (E) based on SNP haplotypes in
ib l DNA. Numbers on th map are Ni i states; collection sites are indicated by black dots. Numbers
ribosomal DNA N b the Nigerian t t ll ti it i di t d b bl k d t N b
relationships and clustering assigned to F and E are haplotypes and collection numbers are indicated in parentheses.
among the M h ll
isolates a distance matrix was
generated and subsequently
grouped by UPGMA method
g p y Our results suggest that M. musicola has been replaced by more frequently
using the NTSYS program ver. occurring M. fijiensis and M. eumusae against which disease management
2.02j. d i t breeding ff t h ld be directed in Ni i
and resistance b di efforts should b di t d i Nigeria; more
attention should also be given to M eumusae. The work is being expanded
to Ivory Coast to capture a greater amount of genetic diversity of the fungi
in West Africa.
M. Zandjanakou-Tachin, I. Vroh-Bi, P.S. Ojiambo, A. Tenkouano, Y. M. Gumedzoe, and R. Bandyopadhyay. 2008.
Identification and genetic diversity of Mycosphaerella species of banana and plantain in Nigeria. Plant Pathology
(In p )
A k l d t
Figure 2 Dendogram from unweighted paired group method with arithmetic means (UPGMA)
This project was supported by the Third World Organisation for Women in Science (TWOWS)
based on SNPs and Indels analysis in the ribosomal DNA. the Directorate General for Development Cooperation (DGDC, Belgium), and the IITA opportunity grant.
1Plant Pathology Laboratory, International Institute of Tropical Agriculture (IITA), Oyo Road, Ibadan, Nigeria; 2Central Biotechnology Laboratory,
IITA, Oyo Road, Ibadan, Nigeria; 3Department of Plant Pathology, North Carolina State University, Raleigh, NC, USA; 4Regional Center for Africa,
y g p gy y g g
AVRDC-The World Vegetable Center, Duluti, Arusha, Tanzania; 5Laboratoire de Virologie et de Biotechnologie des Plantes, Université de Lomé
(Togo), Ecole Supérieure d'Agronomie, Lomé (Togo).