scholarly journals Genetic Basis for Spontaneous Hybrid Genome Doubling during Allopolyploid Speciation of Common Wheat Shown by Natural Variation Analyses of the Paternal Species

PLoS ONE ◽  
2013 ◽  
Vol 8 (8) ◽  
pp. e68310 ◽  
Author(s):  
Yoshihiro Matsuoka ◽  
Shuhei Nasuda ◽  
Yasuyo Ashida ◽  
Miyuki Nitta ◽  
Hisashi Tsujimoto ◽  
...  
Keyword(s):  
Common Wheat ◽  
Natural Variation ◽  
Genetic Basis ◽  
Genome Doubling ◽  
Allopolyploid Speciation ◽  
Hybrid Genome

scholarly journals DEFECTIVE ENDOSPERM-D1 (Dee-D1) is crucial for endosperm development in hexaploid wheat

2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Natalia Tikhenko ◽  
Ahmad M. Alqudah ◽  
Lioudmilla Borisjuk ◽  
Stefan Ortleb ◽  
Twan Rutten ◽  
...  
Keyword(s):  
Hexaploid Wheat ◽  
Endosperm Development ◽  
Thousand Grain Weight ◽  
Grain Number ◽  
Genome Doubling ◽  
Allopolyploid Speciation ◽  
Hybrid Genome ◽  
Genetic Mechanisms ◽  
Positive Effect ◽  
Development And Evolution

AbstractHexaploid wheat (Triticum aestivum L.) is a natural allopolyploid and provides a usable model system to better understand the genetic mechanisms that underlie allopolyploid speciation through the hybrid genome doubling. Here we aimed to identify the contribution of chromosome 1D in the development and evolution of hexaploid wheat. We identified and mapped a novel DEFECTIVE ENDOSPERM–D1 (Dee-D1) locus on 1DL that is involved in the genetic control of endosperm development. The absence of Dee-D1 leads to non-viable grains in distant crosses and alters grain shape, which negatively affects grain number and thousand-grain weight. Dee-D1 can be classified as speciation locus with a positive effect on the function of genes which are involved in endosperm development in hybrid genomes. The presence of Dee-D1 is necessary for the normal development of endosperm, and thus play an important role in the evolution and improvement of grain yield in hexaploid wheat.

scholarly journals The Genetic Basis of Natural Variation in Drosophila melanogaster Immune Defense against Enterococcus faecalis

Genes ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 234 ◽  
Author(s):  
Joanne R Chapman ◽  
Maureen A Dowell ◽  
Rosanna Chan ◽  
Robert L Unckless
Keyword(s):  
Drosophila Melanogaster ◽  
Enterococcus Faecalis ◽  
Natural Variation ◽  
Genetic Basis ◽  
Genome Wide Association Study ◽  
Association Studies ◽  
Immune Defense ◽  
Nucleotide Polymorphisms ◽  
Disease Response ◽  
A Genome

Dissecting the genetic basis of natural variation in disease response in hosts provides insights into the coevolutionary dynamics of host-pathogen interactions. Here, a genome-wide association study of Drosophila melanogaster survival after infection with the Gram-positive entomopathogenic bacterium Enterococcus faecalis is reported. There was considerable variation in defense against E. faecalis infection among inbred lines of the Drosophila Genetics Reference Panel. We identified single nucleotide polymorphisms associated with six genes with a significant (p < 10−08, corresponding to a false discovery rate of 2.4%) association with survival, none of which were canonical immune genes. To validate the role of these genes in immune defense, their expression was knocked-down using RNAi and survival of infected hosts was followed, which confirmed a role for the genes krishah and S6k in immune defense. We further identified a putative role for the Bomanin gene BomBc1 (also known as IM23), in E. faecalis infection response. This study adds to the growing set of association studies for infection in Drosophila melanogaster and suggests that the genetic causes of variation in immune defense differ for different pathogens.

Genetic Dissection of Haploid Male Fertility in Maize (Zea mays L.)

2018 ◽  
Author(s):  
Jiwei Yang ◽  
Haochuan Li ◽  
Yanzhi Qu ◽  
Qiong Chen ◽  
Jihua Tang ◽  
...  
Keyword(s):  
Male Fertility ◽  
Genetic Basis ◽  
Mapping Population ◽  
Transgressive Segregation ◽  
Haploid Genome ◽  
Genetic Dissection ◽  
Genome Doubling ◽  
Haploid Male ◽  
Female Donor ◽  
Simple Sequence

AbstractHaploid genome doubling is a key limiting step of haploid breeding in maize. Spontaneous restoration of haploid male fertility (HMF) provides a method by which costs can be saved and which does not require the use of toxic chemicals, in contrast to the artificial doubling process. To reveal the genetic basis of HMF, haploids were obtained from the offspring of 285 F2:3 families, derived from the cross Zheng58× K22. The F2:3 families were used as female donor and YHI-1 as the male inducer line. The rates of HMF from each family line were evaluated at two field sites over two planting seasons. Quantitative trait loci (QTL) for HMF were identified using a genetic linkage map containing 157 simple sequence repeat (SSR) markers. QTL for HMF displayed incomplete dominance. Transgressive segregation of haploids from F2:3 families was observed relative to haploids derived from the two parents of the mapping population. A total of nine QTL were detected, which were distributed on chromosomes 1, 3, 4, 7, and 8. Three QTL, qHMF3b, qHMF7a, and qHMF7b were detected in both locations, respectively. In our mapping population, HMF was controlled by three major QTL. These QTL could be useful to predict the ability of spontaneous haploid genome doubling in related breeding materials, and to accelerate the haploid breeding process by introgression or aggregation of those QTL.

scholarly journals Genetic architecture of natural variation in visual senescence in Drosophila

2016 ◽  
Vol 113 (43) ◽  
pp. E6620-E6629 ◽  
Author(s):  
Mary Anna Carbone ◽  
Akihiko Yamamoto ◽  
Wen Huang ◽  
Rachel A. Lyman ◽  
Tess Brune Meadors ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Genetic Variation ◽  
Life Span ◽  
Candidate Genes ◽  
Natural Variation ◽  
Genetic Basis ◽  
Nervous System Development ◽  
Interindividual Variation ◽  
Human Populations ◽  
Age Dependent

Senescence, i.e., functional decline with age, is a major determinant of health span in a rapidly aging population, but the genetic basis of interindividual variation in senescence remains largely unknown. Visual decline and age-related eye disorders are common manifestations of senescence, but disentangling age-dependent visual decline in human populations is challenging due to inability to control genetic background and variation in histories of environmental exposures. We assessed the genetic basis of natural variation in visual senescence by measuring age-dependent decline in phototaxis using Drosophila melanogaster as a genetic model system. We quantified phototaxis at 1, 2, and 4 wk of age in the sequenced, inbred lines of the Drosophila melanogaster Genetic Reference Panel (DGRP) and found an average decline in phototaxis with age. We observed significant genetic variation for phototaxis at each age and significant genetic variation in senescence of phototaxis that is only partly correlated with phototaxis. Genome-wide association analyses in the DGRP and a DGRP-derived outbred, advanced intercross population identified candidate genes and genetic networks associated with eye and nervous system development and function, including seven genes with human orthologs previously associated with eye diseases. Ninety percent of candidate genes were functionally validated with targeted RNAi-mediated suppression of gene expression. Absence of candidate genes previously implicated with longevity indicates physiological systems may undergo senescence independent of organismal life span. Furthermore, we show that genes that shape early developmental processes also contribute to senescence, demonstrating that senescence is part of a genetic continuum that acts throughout the life span.

scholarly journals Genomics of long- and short- term adaptation in maize and teosinte

2018 ◽  
Author(s):  
Anne Lorant ◽  
Jeffrey Ross-Ibarra ◽  
Maud Tenaillon
Keyword(s):  
Natural Variation ◽  
Genetic Basis ◽  
Wild Relatives ◽  
Short Term ◽  
Short Term Adaptation ◽  
Maize Domestication ◽  
Cultivated Populations ◽  
Genetic Bases

Maize is an excellent model for the study of plant adaptation. Indeed, post domestication maize quickly adapted to a host of new environments across the globe. And work over the last decade has begun to highlight the role of the wild relatives of maize – the teosintes Zea mays ssp. parviglumis and ssp. mexicana – as excellent models for dissecting long-term local adaptation. Although human-driven selection associated with maize domestication has been extensively studied, the genetic bases of natural variation is still poorly understood. Here we review studies on the genetic basis of adaptation and plasticity in maize and its wild relatives. We highlight a range of different processes that contribute to adaptation and discuss evidence from natural, cultivated, and experimental populations. From an applied perspective, understanding the genetic bases of adaptation and the contribution of plasticity will provide us with new tools to both better understand and mitigate the effect of climate changes on natural and cultivated populations.

scholarly journals Host adaptation through hybridization: Genome analysis of triticale powdery mildew reveals unique combination of lineage-specific effectors

2021 ◽  
Author(s):  
Marion Claudia Müller ◽  
Lukas Kunz ◽  
Johannes Peter Graf ◽  
Seraina Schudel ◽  
Beat Keller
Keyword(s):  
Powdery Mildew ◽  
Fungal Pathogens ◽  
Genetic Basis ◽  
Reference Genome ◽  
Resistance Breeding ◽  
Host Adaptation ◽  
Allelic Series ◽  
Hybrid Genome ◽  
Long Read ◽  
Bona Fide

The emergence of new fungal pathogens through hybridization represents a serious challenge for agriculture. Hybridization between the wheat mildew (Blumeria graminis f.sp. tritici) and rye mildew (B.g. f.sp. secalis) pathogens have led to the emergence of a new mildew form (B.g. f.sp. triticale) growing on triticale, a man-made amphiploid crop derived from crossing rye and wheat which was originally resistant to the powdery mildew disease. The identification of the genetic basis of host-adaptation in triticale mildew has been hampered by the lack of a reference genome. Here we report the 141.4 Mb reference assembly of triticale mildew isolate THUN-12 derived from long-read sequencing and genetic map-based scaffolding. All eleven triticale mildew chromosomes were assembled from telomere-to-telomere and revealed that 19.7% of the hybrid genome was inherited from the rye mildew parental lineage. We identified lineage-specific regions in the hybrid, inherited from the rye or wheat mildew parental lineages, that harbour numerous bona fide candidate effectors. We propose that the combination of lineage-specific effectors in the hybrid genome is crucial for host-adaptation, allowing the fungus to simultaneously circumvent the immune systems contributed by wheat and rye in the triticale crop. In line with this we demonstrate the functional transfer of the SvrPm3 effector from wheat to triticale mildew, a virulence effector that specifically suppresses resistance of the wheat Pm3 allelic series. This transfer is the likely underlying cause for the observed poor effectiveness of several Pm3 alleles against triticale mildew and exemplifies the negative implications of pathogen hybridizations on resistance breeding.

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