Diversity of Colletotrichum species associated with torch ginger anthracnose.

Anthracnose caused by Colletotrichum species is one of the most important diseases of torch ginger. The disease leads to loss of aesthetic and commercial value of torch ginger stems. This study aimed to characterize Colletotrichum species associated with torch ginger anthracnose in the production areas of Pernambuco and Ceará. A total of 48 Colletotrichum isolates were identified using molecular techniques. Pathogenicity tests were performed on torch ginger with representative isolates. Phylogenetic analyses based on seven loci-DNA lyase (APN2), intergenic spacer between DNA lyase and the mating-type locus MAT1-2-1 (APN2/MAT-IGS), calmodulin (CAL), intergenic spacer between glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and a hypothetical protein (GAP2-IGS), glutamine synthetase (GS), and ß-tubulin (TUB2)-revealed that they belong to five known Colletotrichum species, namely, C. chrysophilum, C. fructicola, C. siamense, C. theobromicola, and C. tropicale, and three newly discovered species, described here as C. atlanticum, C. floscerae, and C. zingibericola. Of these, C. atlanticum was the most dominant. Pathogenicity assays showed that all isolates were pathogenic to torch ginger bracts. All species are reported for the first time associated with torch ginger in Brazil. The present study contributes to the current understanding of the diversity of Colletotrichum species associated with anthracnose on torch ginger and demonstrates the importance of accurate species identification for effective disease management strategies.

Genetic diversity and structure of Brazilian ginger germplasm (Zingiber officinale) revealed by AFLP markers.

Ginger is a vegetable with medicinal and culinary properties widely cultivated in the Southern and Southeastern Brazil. The knowledge of ginger species' genetic variability is essential to direct correctly future studies of conservation and genetic improvement, but in Brazil, little is known about this species' genetic variability. In this study, we analyzed the genetic diversity and structure of 55 Brazilian accessions and 6 Colombian accessions of ginger, using AFLP (Amplified Fragment Length Polymorphism) molecular markers. The molecular characterization was based on 13 primers combinations, which generated an average of 113.5 polymorphic loci. The genetic diversity estimates of Nei (Hj), Shannon-Weiner index (I) and an effective number of alleles (n e ) were greater in the Colombian accessions in relation to the Brazilian accessions. The analysis of molecular variance showed that most of the genetic variation occurred between the two countries while in the Brazilian populations there is no genetic structure and probably each region harbors 100 % of genetic variation found in the samples. The bayesian model-based clustering and the dendrogram using the dissimilarity's coefficient of Jaccard were congruent with each other and showed that the Brazilian accessions are highly similar between themselves, regardless of the geographic region of origin. We suggested that the exploration of the interspecific variability and the introduction of new varieties of Z.officinale are viable alternatives for generating diversity in breeding programs in Brazil. The introduction of new genetic materials will certainly contribute to a higher genetic basis of such crop.

Species-specific AFLP markers for identification of Zingiber officinale, Z. montanum and Z. zerumbet (Zingiberaceae).

The Zingiber genus, which includes the herbs known as gingers, commonly used in cooking, is well known for its medicinal properties, as described in the Indian pharmacopoeia. Different members of this genus, although somewhat similar in morphology, differ widely in their pharmacological and therapeutic properties. The most important species of this genus, with maximal therapeutic properties, is Zingiber officinale (garden ginger), which is often adulterated with other less-potent Zingiber sp. There is an existing demand in the herbal drug industry for an authentication system for the Zingiber sp in order to facilitate their commercial use as genuine phytoceuticals. To this end, we used amplified fragment length polymorphism (AFLP) to produce DNA fingerprints for three Zingiber species. Sixteen collections (six of Z. officinale, five of Z. montanum, and five of Z. zerumbet) were used in the study. Seven selective primer pairs were found to be useful for all the accessions. A total of 837 fragments were produced by these primer pairs. Species-specific markers were identified for all three Zingiber species (91 for Z. officinale, 82 for Z. montanum, and 55 for Z. zerumbet). The dendogram analysis generated from AFLP patterns showed that Z. montanum and Z. zerumbet are phylogenetically closer to each other than to Z. officinale. The AFLP fingerprints of the Zingiber species could be used to authenticate Zingiber sp-derived drugs and to resolve adulteration-related problems faced by the commercial users of these herbs.

Characterization of the genetic structure of mango ginger (Curcuma amada Roxb) from Myanmar in farm and genebank collection by the neutral and functional genomic markers

A preliminary characterization was undertaken to describe genetic structure of mango ginger (Curcuma amada) acquired from farmers and ex situ genebank in Myanmar using neutral (rice SSR based RAPDs) and functional genomic (P450 based analog) markers. The high polymorphism (> 91 percent) depicted has displayed existence of genetic variability in the germplasm investigated. Large number of source-specific alleles (neutral-markers = 78, functional-markers = 63) was amplified which revealed that neutral regions of the mango ginger were more variable compared with the functional regions. The major fraction of the molecular variance (neutral-markers = 85 percent, functional-markers = 93 percent) was explained within germplasm acquisition sources and this tendency was also supported by the estimate of gene diversity. The genebank accessions have shown comparatively more genetic variability than farmers' accessions. The variability observed in mango ginger may possibly be associated with the long history of its cultivation under diverse ecological conditions. The two marker systems elucidated their high resolving power which detected variability even in fewer genotypes assayed. As the target sites of these markers are different, therefore, the variability detected is believed to cover diverse part of the genome together with neutral and functional regions. We found the concurrent use of the different types of molecular markers valuable to comprehend a dependable variability pattern in the germplasm assayed.