- Author Correction: Variation of a major facilitator superfamily gene contributes to differential cadmium accumulation between rice subspecies. [Published Erratum]
- NCNat Commun 2019 Jul 19; 10(1):3301
- An amendment to this paper has been published and can be accessed via a link at the top of the paper.
An amendment to this paper has been published and can be accessed via a link at the top of the paper.
- Hybrid Decay: A Transgenerational Epigenetic Decline in Vigor and Viability Triggered in Backcross Populations of Teosinte with Maize. [Journal Article]
- GGenetics 2019 Jul 18
- In the course of generating populations of maize with teosinte chromosomal introgressions, an unusual sickly plant phenotype was noted in individuals from crosses with two teosinte accessions collect…
In the course of generating populations of maize with teosinte chromosomal introgressions, an unusual sickly plant phenotype was noted in individuals from crosses with two teosinte accessions collected near Valle de Bravo, Mexico. The plants of these Bravo teosinte accessions appear phenotypically normal themselves and the F1 plants appear similar to typical maize x teosinte F1s. However, upon backcrossing to maize, the BC1 and subsequent generations display a number of detrimental characteristics including shorter stature, reduced seed set and abnormal floral structures. This phenomenon is observed in all BC individuals and there is no chromosomal segment linked to the sickly plant phenotype in advanced backcross generations. Once the sickly phenotype appears in a lineage, normal plants are never again recovered by continued backcrossing to the normal maize parent. Whole-genome shotgun sequencing reveals a small number of genomic sequences, some with homology to transposable elements, that have increased in copy number in the backcross populations. Transcriptome analysis of seedlings, which do not have striking phenotypic abnormalities, identified segments of 18 maize genes that exhibit increased expression in sickly plants. A de novo assembly of transcripts present in plants exhibiting the sickly phenotype identified a set of 59 up-regulated novel transcripts. These transcripts include some examples with sequence similarity to transposable elements and other sequences present in the recurrent maize parent (W22) genome as well as novel sequences not present in the W22 genome. Genome-wide profiles of gene expression, DNA methylation and sRNAs are similar between sickly plants and normal controls, although a few up-regulated transcripts and transposable elements are associated with altered sRNA or methylation profiles. This study documents hybrid incompatibility and genome instability triggered by the backcrossing of Bravo teosinte with maize. We name this phenomenon "hybrid decay" and present ideas on the mechanism that may underlie it.
- QTL mapping of combining ability for yield-related traits in wild rice Oryza longistaminata. [Journal Article]
- JAJ Agric Food Chem 2019 Jul 17
- In decades of hybrid rice breeding, combining ability has been successfully used to evaluate excellent parental lines and predict heterosis. However, previous studies for combining ability mainly foc…
In decades of hybrid rice breeding, combining ability has been successfully used to evaluate excellent parental lines and predict heterosis. However, previous studies for combining ability mainly focused on cultivated rice and rarely involved with wild rice. In this study, for the first time, we identified 20 new quantitative trait loci (QTLs) for combining ability in wild rice using a NCII mating design. Among them, qGCA1, one of the major QTL that can significantly improve the general combining ability of plant height, spikelet number and yield per plant, was delimited to an interval about 72 Kb on chromosome 1. qSCA8, another major QTL which can significantly improve the specific combining ability of seed-setting rate and yield per plant, was located in an interval about 90 Kb on chromosome 8. These QTLs discovered from wild rice will provide new ideas to explain the genetic mechanism of combining ability, and establish the basis for breeding of high combining ability rice.
- A genomic inference of the White Plymouth Rock genealogy. [Journal Article]
- PSPoult Sci 2019 Jul 15
- Crossing of populations has been, and still is, a central component in domestication and breed and variety formation. It is a way for breeders to utilize heterosis and to introduce new genetic variat…
Crossing of populations has been, and still is, a central component in domestication and breed and variety formation. It is a way for breeders to utilize heterosis and to introduce new genetic variation into existing plant and livestock populations. During the mid-19th century, several chicken breeds that had been introduced to America from Europe and Asia became the founders for those formed in the USA. Historical records about the genealogy of these populations are often unclear and inconsistent. Here, we used genomics in an attempt to describe the ancestry of the White Plymouth Rock (WPR) chicken. In total, 150 chickens from the WPR and 8 other stocks that historical records suggested contributed to its formation were whole-genome re-sequenced. The admixture analyses of the autosomal and sex chromosomes showed that the WPR was likely founded as a cross between a paternal lineage that was primarily Dominique, and a maternal lineage where Black Java and Cochin contributed in essentially equal proportions. These results were consistent and provided quantification with the historical records that they were the main contributors to the WPR. The genomic analyses also revealed genome-wide contributions (<10% each) by Brahma, Langshan, and Black Minorca. When viewed on an individual chromosomal basis, contributions varied considerably among stocks.
- How does genome size affect the evolution of pollen tube growth rate, a haploid performance trait? [Journal Article]
- AJAm J Bot 2019; 106(7):1011-1020
- CONCLUSIONS: Genome size increases should negatively affect PTGR when genetic consequences of WGDs are minimized, as found in intra-specific autopolyploids (low heterosis) and gymnosperms (few WGDs). But in angiosperms, the higher PTGR optimum of neo-polyploids and non-negative PTGR-DNA content correlation suggest that recurrent WGDs have caused substantial PTGR evolution in a non-haploid state.
- Engineered Male Sterility by Early Anther Ablation Using the Pea Anther-Specific Promoter PsEND1. [Review]
- FPFront Plant Sci 2019; 10:819
- Genetic engineered male sterility has different applications, ranging from hybrid seed production to bioconfinement of transgenes in genetic modified crops. The impact of this technology is currently…
Genetic engineered male sterility has different applications, ranging from hybrid seed production to bioconfinement of transgenes in genetic modified crops. The impact of this technology is currently patent in a wide range of crops, including legumes, which has helped to deal with the challenges of global food security. Production of engineered male sterile plants by expression of a ribonuclease gene under the control of an anther- or pollen-specific promoter has proven to be an efficient way to generate pollen-free elite cultivars. In the last years, we have been studying the genetic control of flower development in legumes and several genes that are specifically expressed in a determinate floral organ were identified. Pisum sativum ENDOTHECIUM 1 (PsEND1) is a pea anther-specific gene displaying very early expression in the anther primordium cells. This expression pattern has been assessed in both model plants and crops (tomato, tobacco, oilseed rape, rice, wheat) using genetic constructs carrying the PsEND1 promoter fused to the uidA reporter gene. This promoter fused to the barnase gene produces full anther ablation at early developmental stages, preventing the production of mature pollen grains in all plant species tested. Additional effects produced by the early anther ablation in the PsEND1::barnase-barstar plants, with interesting biotechnological applications, have also been described, such as redirection of resources to increase vegetative growth, reduction of the need for deadheading to extend the flowering period, or elimination of pollen allergens in ornamental plants (Kalanchoe, Pelargonium). Moreover, early anther ablation in transgenic PsEND1::barnase-barstar tomato plants promotes the developing of the ovaries into parthenocarpic fruits due to the absence of signals generated during the fertilization process and can be considered an efficient tool to promote fruit set and to produce seedless fruits. In legumes, the production of new hybrid cultivars will contribute to enhance yield and productivity by exploiting the hybrid vigor generated. The PsEND1::barnase-barstar construct could be also useful to generate parental lines in hybrid breeding approaches to produce new cultivars in different legume species.
- Genomic Prediction of Pumpkin Hybrid Performance. [Journal Article]
- PGPlant Genome 2019; 12(2)
- Genomic prediction has become an increasingly popular tool for hybrid performance evaluation in plant breeding mainly because that it can reduce cost and accelerate a breeding program. In this study,…
Genomic prediction has become an increasingly popular tool for hybrid performance evaluation in plant breeding mainly because that it can reduce cost and accelerate a breeding program. In this study, we propose a systematic procedure to predict hybrid performance using a genomic selection (GS) model that takes both additive and dominance marker effects into account. We first demonstrate the advantage of the additive-dominance effects model over the only additive effects model through a simulation study. Based on the additive-dominance model, we predict genomic estimated breeding values (GEBVs) for individual hybrid combinations and their parental lines. The GEBV-based specific combining ability (SCA) for each hybrid and general combining ability (GCA) for its parental lines are then derived to quantify the degree of midparent heterosis (MPH) or better-parent heterosis (BPH) of the hybrid. Finally, we estimate the variance components resulting from additive and dominance gene action effects and heritability using a genomic best linear unbiased predictor (g-BLUP) model. These estimates are used to justify the results of the genomic prediction study. A pumpkin (spp.) data set is given to illustrate the provided procedure. The data set consists of 320 parental lines with 61,179 collected single nucleotide polymorphism (SNP) markers; 119, 120, and 120 phenotypic values of hybrids on three quantitative traits within maxima Duchesne; and 89, 111, and 90 phenotypic values of hybrids on the same three quantitative traits within Dechesne.
- Dissecting a heterotic gene through GradedPool-Seq mapping informs a rice-improvement strategy. [Journal Article]
- NCNat Commun 2019 Jul 05; 10(1):2982
- Hybrid rice breeding for exploiting hybrid vigor, heterosis, has greatly increased grain yield. However, the heterosis-related genes associated with rice grain production remain largely unknown, part…
Hybrid rice breeding for exploiting hybrid vigor, heterosis, has greatly increased grain yield. However, the heterosis-related genes associated with rice grain production remain largely unknown, partly because comprehensive mapping of heterosis-related traits is still labor-intensive and time-consuming. Here, we present a quantitative trait locus (QTL) mapping method, GradedPool-Seq, for rapidly mapping QTLs by whole-genome sequencing of graded-pool samples from F2 progeny via bulked-segregant analysis. We implement this method and map-based cloning to dissect the heterotic QTL GW3p6 from the female line. We then generate the near isogenic line NIL-FH676::GW3p6 by introgressing the GW3p6 allele from the female line Guangzhan63-4S into the male inbred line Fuhui676. The NIL-FH676::GW3p6 exhibits grain yield highly increased compared to Fuhui676. This study demonstrates that it may be possible to achieve a high level of grain production in inbred rice lines without the need to construct hybrids.
- Hybrid Vigor (?). [Journal Article]
- AJAm J Sports Med 2019; 47(8):1785-1788
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- Gene action and heterosis in F1 clonal progenies of cassava for β-Carotene and farmers' preferred traits. [Journal Article]
- HHeliyon 2019; 5(6):e01807
- Gene action and heterosis provides information to assist breeder for selecting and generating improved plant recombinants. This study aimed at determining the gene action of selected cassava traits. …
Gene action and heterosis provides information to assist breeder for selecting and generating improved plant recombinants. This study aimed at determining the gene action of selected cassava traits. The F1 clones exhibited considerable phenotypic variability between families and offsprings. The best F1 progenies had a higher amount of β-carotene (β-C) of 6.12 mg 100 g-1 against 1.32 mg 100 g-1 of the best parent. This superiority could be attributed to the over-dominance from the recombination of additive gene action and epistasis. The general combining ability (GCA) of parents and specific combining ability (SCA) of combinations were significant for different traits, and indicating the role of additive and non-additive gene action in controlling such traits. The significant GCA for β-C and postharvest physiological deterioration (PPD) indicates the role of additive gene action. The significant SCA for cassava mosaic disease (CMD) and cassava brown streak disease (CBSD) showed a predominance of non-additive gene action. The F1 progenies from the family Mavoka x Garukunsubire expressed the highest positive heterosis for CMD, dry matter and β-C. The high positive heterosis for β-C and DMC could be linked to transgressive segregation, because one of the parents was poor combiner.