RESUMO
Morphological studies suggest that the major pathogen causing basal stem rot of oil palm in Papua New Guinea and Solomon Islands is Ganoderma boninense. This study presents the first evidence for conspecificity of G. boninense from four countries where basal stem rot is prevalent. Seventy-three dikaryotic isolates of Ganoderma boninense from Indonesia, Malaysia, Papua New Guinea, and Solomon Islands were studied via mating tests, analyses of nuc internal transcribed spacer ITS1-5.8S-ITS2 sequences, and microsatellite genotyping. Sequence similarity in the ITS1-5.8S-ITS2 region was >99%, and all exotic isolates successfully mated with Papua New Guinea tester strains. Transfer of nuclei during mating was also confirmed via microsatellite markers for the first time in this species. Four microsatellite primers were used to generate evidence for 33 alleles in the four populations. All isolates studied had unique genetic fingerprints but alleles were also shared, suggesting gene flow. Heterozygosities were lower than expected in Indonesian and Papua New Guinea populations, consistent with the possibility of localized inbreeding.
Assuntos
Arecaceae , Ganoderma , Ganoderma/genética , Repetições de Microssatélites/genética , Doenças das PlantasRESUMO
The production of adequate agricultural outputs to support the growing human population places great demands on agriculture, especially in light of ever-greater restrictions on input resources. Sorghum is a drought-adapted cereal capable of reliable production where other cereals fail, and thus represents a good candidate to address food security as agricultural inputs of water and arable land grow scarce. A long-standing issue with sorghum grain is that it has an inherently lower digestibility. Here we show that a low-frequency allele type in the starch metabolic gene, pullulanase, is associated with increased digestibility, regardless of genotypic background. We also provide evidence that the beneficial allele type is not associated with deleterious pleiotropic effects in the modern field environment. We argue that increasing the digestibility of an adapted crop is a viable way forward towards addressing food security while maximizing water and land-use efficiency.
Assuntos
Adaptação Fisiológica/genética , Alelos , Secas , Abastecimento de Alimentos , Genes de Plantas/genética , Variação Genética , Sorghum/genética , Sequência de Aminoácidos , Grão Comestível/genética , Grão Comestível/fisiologia , Frequência do Gene/genética , Genótipo , Glicosídeo Hidrolases/química , Glicosídeo Hidrolases/genética , Humanos , Endogamia , Dados de Sequência Molecular , Mutação/genética , Peptídeos/química , Fenótipo , Estrutura Terciária de Proteína , Sorghum/fisiologiaRESUMO
Detecting artificial selection in the genome of domesticated species can not only shed light on human history but can also be beneficial to future breeding strategies. Evidence for selection has been documented in domesticated species including maize and rice, but few studies have to date detected signals of artificial selection in the Sorghum bicolor genome. Based on evidence that domesticated S. bicolor and its wild relatives show significant differences in endosperm structure and quality, we sequenced three candidate seed storage protein (kafirin) loci and three candidate starch biosynthesis loci to test whether these genes show non-neutral evolution resulting from the domestication process. We found strong evidence of non-neutral selection at the starch synthase IIa gene, while both starch branching enzyme I and the beta kafirin gene showed weaker evidence of non-neutral selection. We argue that the power to detect consistent signals of non-neutral selection in our dataset is confounded by the absence of low frequency variants at four of the six candidate genes. A future challenge in the detection of positive selection associated with domestication in sorghum is to develop models that can accommodate for skewed frequency spectrums.
Assuntos
Produtos Agrícolas/genética , Evolução Molecular , Deriva Genética , Mutação/genética , Sorghum/genética , Sequência de Bases , Loci Gênicos/genética , Haplótipos/genética , HumanosRESUMO
We report the development of two new transformation systems, polyethylene glycol (PEG)-mediated transformation of protoplasts and Agrobacterium tumefaciens-mediated transformation of mycelium, for the filamentous ascomycete Venturia inaequalis. New binary vectors have been created for the latter. Although transformation was initially achieved using a PEG-mediated method, this was superseded by the A. tumefaciens-mediated approach. The advantages of the latter include: ease of the protocol, no requirement for protoplasts; higher transformation efficiency; and single-site integration. A comparison between the two transformation methods is presented.
