Construction of a genetic linkage map of the fungal pathogen of banana Mycosphaerella fijiensis, causal agent of black leaf streak disease

Abstract

A genetic linkage map of the fungal plant pathogen Mycosphaerella fijiensis, causal agent of black leaf streak disease of banana was developed. A cross between the isolates CIRAD86 (from Cameroon) and CIRAD139A (from Colombia) was analyzed using molecular markers and the MAT locus. The genetic linkage map consists of 298 AFLP and 16 SSR markers with 23 linkage groups, containing five or more markers, covering 1,879 cM. Markers are separated on average by around 5.9 cM. The MAT locus was shown to segregate in a 1:1 ratio but could not be successfully mapped. An estimate of the relation between physical size and genetic distance was approximately 39.0 kb/cM. The estimated total haploid genome size was calculated using the genetic mapping data at 4,298.2 cM. This is the first genetic linkage map reported for this important foliar pathogen of banana. The great utility of the map will be for anchoring contigs in the genome sequence, evolutionary studies in comparison with other fungi, to identify quantitative trait loci (QTLs) associated with aggressiveness or oxidative stress resistance and with the recently available genome sequence, for positional cloning.

Response of banana genotypes to yellow Sigatoka in coastal tablelands of Sergipe, Brazil

“…The genus Mycosphaerella has been studied in several crops such as wheat (M. graminicola), pea (M. pinodes) and strawberry (M. fragariae), but the etiologic agents of black Sigatoka (M. fijiensis) and YS stand out in this context due to the economic impact caused by these diseases, by limiting the banana production in Brazil and worldwide (CHURCHILL, 2011;KABBAGE et al, 2008;MANZO-SÁNCHEZ et al, 2008;MAZARO et al, 2006;RIVAS et al, 2004;SETTI et al, 2011).…”

The origin, versatility and distribution of azole fungicide resistance in the banana black Sigatoka pathogen Pseudocercospora fijiensis

“…Therefore, we generated two new high marker density genetic linkage maps after crossing sensitive and resistant P. fijiensis isolates. These crosses were not at all routine, required a pragmatic approach compared to previous reports (Manzo-Sanchez et al 2008), and eventually resulted in two mapping populations. This classic genetic approach in combination with state of the art DArTseq molecular markers technology provided novel and key information to understand the development of DMI resistance and, hence, is the basis for optimizing their use for disease management.…”

“…Our sequencing data of the Pfcyp51 gene across all populations highlights a particularity of the CIRAD86 -originating from Cameroon -reference strain, which was selected for the first genetic linkage map and genome sequencing (Manzo-Sanchez et al 2008).…”

“…This has been supported by a number of population genetic analyses that indicate Southeast Asia, between Papua New Guinea and the Solomon Islands (Carlier et al 1996;Halkett et al 2010;Hayden et al 2003;Rivas et al 2004b) as the centre of origin. Consequently, founder effects and bottleneck phenomena were detected in populations outside Southeast Asia, which are potentially the main determinants of the global population structure (Carlier et al 1996;Fahleson et al 2009;Halkett et al 2010;Manzo-Sanchez et al 2008;Rivas et al 2004b;Zandjanakou-Tachin et al 2009). This is consistent with the stochastic nature of the disease spreading at continental and local scales in contrast to a steady advance of an epidemic front, although some populations within countries show a continuous range expansion as an epidemic front (Halkett et al 2010).…”

“…Interestingly, the P. fijiensis reference strain CIRAD86 that was used to generate the first linkage map (Manzo-Sanchez et al 2008) that was also used and improved in a recent whole genome sequencing project (Kema 2009), is the only strain among 268 isolates that encodes a valine instead of aspartic acid at position 106 in CYP51 (Chapter 2). Since South East Asia is the proposed centre of origin (Carlier et al 1996;Halkett et al 2010;Hayden et al 2003;Rivas et al 2004b) and CIRAD86 originates from Cameroon, we concluded that substitution D106V is a rare event that exclusively occurred in CIRAD86 rather than the reverse substitution in all other strains.…”