Grain Number,Plant Height,and Heading Date7Is a Central Regulator of Growth, Development, and Stress Response

Weng, Xiaoyu; Wang, Lei; Jia, Wang; Hu, Yong; Du, Hao; Xu, Caiguo; Li, Xianghua; Xiao, Jinghua; Zhang, Qifa

doi:10.1104/pp.113.231308

Cited by 207 publications

(184 citation statements)

References 62 publications

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“…In barley, VRN1 directly binds to the promoter of the flowering repressor VRN2, resulting in the downregulation of VRN2 during winter cold (Deng et al, 2015). However, although it likely functions as a flowering repressor across grasses (Yan et al, 2004a;Weng et al, 2014;Nemoto et al, 2016;Woods et al, 2016), noncore Pooideae VRN2 transcripts are not downregulated in response to cold or VRN1 up-regulation (Woods et al, 2016). The co-option of VRN2 into the vernalization network might therefore have occurred through changes in the DNA-binding domain of VRN1 or through novel cis-regulatory changes in the VRN2 promoter.…”

Section: Discussionmentioning

confidence: 99%

Evidence for an Early Origin of Vernalization Responsiveness in Temperate Pooideae Grasses

et al. 2016

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The ability of plants to match their reproductive output with favorable environmental conditions has major consequences both for lifetime fitness and geographic patterns of diversity. In temperate ecosystems, some plant species have evolved the ability to use winter nonfreezing cold (vernalization) as a cue to ready them for spring flowering. However, it is unknown how important the evolution of vernalization responsiveness has been for the colonization and subsequent diversification of taxa within the northern and southern temperate zones. Grasses of subfamily Pooideae, including several important crops, such as wheat (Triticum aestivum), barley (Hordeum vulgare), and oats (Avena sativa), predominate in the northern temperate zone, and it is hypothesized that their radiation was facilitated by the early evolution of vernalization responsiveness. Predictions of this early origin hypothesis are that a response to vernalization is widespread within the subfamily and that the genetic basis of this trait is conserved. To test these predictions, we determined and reconstructed vernalization responsiveness across Pooideae and compared expression of wheat vernalization gene orthologs VERNALIZATION1 (VRN1) and VRN3 in phylogenetically representative taxa under cold and control conditions. Our results demonstrate that vernalization responsive Pooideae species are widespread, suggesting that this trait evolved early in the lineage and that at least part of the vernalization gene network is conserved throughout the subfamily. These results are consistent with the hypothesis that the evolution of vernalization responsiveness was important for the initial transition of Pooideae out of the tropics and into the temperate zone.

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Section: Discussionmentioning

confidence: 99%

Evidence for an Early Origin of Vernalization Responsiveness in Temperate Pooideae Grasses

et al. 2016

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“…Functional alleles of the rice VRN2 ortholog Ghd7 likewise delay heading date under long days (Xue et al, 2008). Similar to many subtropical grasses, rice is a short-day plant, and the requirement for short days to flower in rice is augmented by the long-day repression conferred by Ghd7 (Xue et al, 2008;Weng et al, 2014). Although little is known about members of the VRN2/Ghd7 sister CO9 clade, barley CO9 has also been shown to prevent precocious flowering, but in this case under noninductive short-day conditions that accompany winter (Kikuchi et al, 2012).…”

Section: Conservation Of Vrn2 As a Flowering Repressormentioning

confidence: 99%

Evolution of VRN2/Ghd7-Like Genes in Vernalization-Mediated Repression of Grass Flowering

et al. 2016

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Flowering of many plant species is coordinated with seasonal environmental cues such as temperature and photoperiod. Vernalization provides competence to flower after prolonged cold exposure, and a vernalization requirement prevents flowering from occurring prior to winter. In winter wheat (Triticum aestivum) and barley (Hordeum vulgare), three genes VRN1, VRN2, and FT form a regulatory loop that regulates the initiation of flowering. Prior to cold exposure, VRN2 represses FT. During cold, VRN1 expression increases, resulting in the repression of VRN2, which in turn allows activation of FT during long days to induce flowering. Here, we test whether the circuitry of this regulatory loop is conserved across Pooideae, consistent with their niche transition from the tropics to the temperate zone. Our phylogenetic analyses of VRN2-like genes reveal a duplication event occurred before the diversification of the grasses that gave rise to a CO9 and VRN2/Ghd7 clade and support orthology between wheat/barley VRN2 and rice (Oryza sativa) Ghd7. Our Brachypodium distachyon VRN1 and VRN2 knockdown and overexpression experiments demonstrate functional conservation of grass VRN1 and VRN2 in the promotion and repression of flowering, respectively. However, expression analyses in a range of pooids demonstrate that the cold repression of VRN2 is unique to core Pooideae such as wheat and barley. Furthermore, VRN1 knockdown in B. distachyon demonstrates that the VRN1-mediated suppression of VRN2 is not conserved. Thus, the VRN1-VRN2 feature of the regulatory loop appears to have evolved late in the diversification of temperate grasses.The initiation of flowering is a major developmental transition in the plant life cycle. When flowering initiates, shoot apical meristems shift from forming vegetative organs such as leaves to forming flowers. In many plant species, flowering occurs at a particular time of year in response to the sensing of seasonal cues such as changes in day length and temperature. In some plants adapted to temperate climates, exposure to the prolonged cold of winter (vernalization) results in the ability to flower in the next growing season (Chouard, 1960;Amasino, 2010). Although vernalization ultimately enables flowering, vernalization responsiveness is typically an adaptation to ensure that flowering does not occur prematurely in the fall season. This has obvious adaptive value; for example, many vernalization-responsive plants become established in the fall season (during which flowering would not lead to successful reproduction) and then rapidly flower in the spring when conditions for reproduction and seed maturation are optimal.The grass family (Poaceae) originated approximately 70 million years ago as part of the tropical forest understory. However, grasses have since diversified across the globe occupying a variety of ecological niches (Kellogg, 2001). Exemplifying this, the ;3,800 species of grass subfamily Pooideae, including the economically important cereals wheat (Triticum aestivum, Triticeae), barley (...

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“…qGY1.2 was mapped to the close vicinity of Gn1a, a cloned gene that increases grain number per panicle and grain weight by reducing the expression of OsCKX2 that leads to accumulation of cytokinins in inflorescence meristems (Ashikari et al, 2005). The qGY7.4 overlaps with Ghd7, another cloned gene that regulates yield by modulating panicle branching (Weng et al, 2014). qGY5.2 is also in the vicinity of a previously cloned gene, GW5, which improves GY by regulating cell division during seed development (Weng et al, 2008).…”

Section: Discussionmentioning

confidence: 99%

Mapping quantitative trait loci in selected breeding populations: A segregation distortion approach

Cui

Zhang

et al. 2015

Heredity

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Quantitative trait locus (QTL) mapping is often conducted in line-crossing experiments where a sample of individuals is randomly selected from a pool of all potential progeny. QTLs detected from such an experiment are important for us to understand the genetic mechanisms governing a complex trait, but may not be directly relevant to plant breeding if they are not detected from the breeding population where selection is targeting for. QTLs segregating in one population may not necessarily segregate in another population. To facilitate marker-assisted selection, QTLs must be detected from the very population which the selection is targeting. However, selected breeding populations often have depleted genetic variation with small population sizes, resulting in low power in detecting useful QTLs. On the other hand, if selection is effective, loci controlling the selected trait will deviate from the expected Mendelian segregation ratio. In this study, we proposed to detect QTLs in selected breeding populations via the detection of marker segregation distortion in either a single population or multiple populations using the same selection scheme. Simulation studies showed that QTL can be detected in strong selected populations with selected population sizes as small as 25 plants. We applied the new method to detect QTLs in two breeding populations of rice selected for high grain yield. Seven QTLs were identified, four of which have been validated in advanced generations in a follow-up study. Cloned genes in the vicinity of the four QTLs were also reported in the literatures. This mapping-by-selection approach provides a new avenue for breeders to improve breeding progress. The new method can be applied to breeding programs not only in rice but also in other agricultural species including crops, trees and animals. Heredity (2015) 115, 538-546; doi:10.1038/hdy.2015.56; published online 1 July 2015 INTRODUCTIONOver a century of breeding efforts has produced numerous varieties of domestic plants and animals to provide ample food resources for human. The great successes in plant and animal breeding have largely been achieved by exploiting within-species genetic variation for traits of interest through phenotypic selection. Although appropriate phenotypic selection is effective to exploit useful genetic variation of complex traits in breeding populations, the rich sources of naturally occurring genetic variation in plants and animals are largely hidden at the phenotypic levels and remain uncharacterized at the genomic and molecular levels. As a result, they are very much under-utilized in the past breeding programs. Meanwhile, the past decades have witnessed tremendous progress in genetic dissections of complex traits in plants and animals using DNA markers and genomic technologies (Francia et al., 2005;Collard and Mackill, 2008;Miah et al., 2013). During this period of time, thousands of quantitative trait locus (QTL) affecting a wide range of complex traits have been identified in different plant and animal species. These ...

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Grain Number,Plant Height,and Heading Date7Is a Central Regulator of Growth, Development, and Stress Response

Cited by 207 publications

References 62 publications

Evidence for an Early Origin of Vernalization Responsiveness in Temperate Pooideae Grasses

Evidence for an Early Origin of Vernalization Responsiveness in Temperate Pooideae Grasses

Evolution of VRN2/Ghd7-Like Genes in Vernalization-Mediated Repression of Grass Flowering

Mapping quantitative trait loci in selected breeding populations: A segregation distortion approach

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