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Key message Genetic modification of spike architecture is essential for improving wheat yield. Newly identified loci for the ‘Miracle wheat’ phenotype on chromosomes 1AS and 2BS have significant effects on spike traits. Abstract The wheat (Triticum ssp.) inflorescence, also known as a spike, forms an unbranched inflorescence in which the inflorescence meristem generates axillary spikelet meristems (SMs) destined to become sessile spikelets. Previously, we identified the putatively causative mutation in the branched headt (bht) gene (TtBH-A1) of tetraploid wheat (T. turgidum convar. compositum (L.f.) Filat.) responsible for the loss of SM identity, converting the non-branching spike to a branched wheat spike. In the current study, we performed whole-genome quantitative trait loci (QTL) analysis using 146 recombinant inbred lines (RILs) derived from a cross between spike-branching wheat (‘Miracle wheat’) and an elite durum wheat cultivar showing broad phenotypic variation for spike architecture. Besides the previously found gene at the bht-A1 locus on the short arm of chromosome 2A, we also mapped two new modifier QTL for spike-branching on the short arm of chromosome 1A, termed bht-A2, and 2BS. Using biparental mapping population and GWAS in 302 diverse accessions, the 2BS locus was highly associated with coding sequence variation found at the homoeo-allele of TtBH-B1 (bht-B1). Thus, RILs that combined both bht-A1 and bht-B1 alleles showed additive genetic effects leading to increased penetrance and expressivity of the supernumerary spikelet and/or mini-spike formation.

Illuminating the mechanisms of inflorescence architecture of grain crops that feed our world may strengthen the goal towards sustainable agriculture. Lateral spikelet development of barley (Hordeum vulgare L.) is such an example of a floral architectural trait regulated by VRS1 (Vulgare Row-type Spike 1 or Six-rowed Spike 1, syn. HvHOX1). Its lateral spikelet-specific expression and the quantitative nature of suppressing spikelet development were previously shown in barley. However, the mechanistic function of this gene and its paralog HvHOX2 on spikelet development is still fragmentary.Here, we show that these duplicated transcription factors (TFs) have contrasting nucleotide diversity in various barley genotypes and several Hordeum species. Despite this difference, both proteins retain their basic properties of the homeodomain leucine zipper class I family of TFs. During spikelet development, these genes exhibit similar spatiotemporal expression patterns yet with anticyclic expression levels. A gene co-expression network analysis suggested that both have an ancestral relationship but their functions appear antagonistic to each other, i.e., HvHOX1 suppresses whereas HvHOX2 rather promotes spikelet development. Our transgenic promoter-swap analysis showed that HvHOX2 can restore suppressed lateral spikelets when expression levels are increased; however, at its low endogenous expression level, HvHOX2 appears dispensable for spikelet development. Collectively, this study proposes that the dosage of the two antagonistic TFs, HvHOX1 and HvHOX2, influence spikelet development in barley.

Significance Grain number is a key determinant of cereal grain yield, but its underlying genetic basis in wheat remains undefined. This study demonstrates a direct association between increased floret fertility, higher grain number per spike, and higher plot yields of field-grown wheat. The GNI1 gene, encoding an HD-Zip I transcription factor, was identified as responsible for increased floret fertility. The WT allele acts specifically during rachilla development, with its product serving to lower grain yield potential; in contrast, the reduced-function variant increased both floret and grain number. GNI1 evolved through gene duplication in the Triticeae, and its mutations have been under parallel selection in both wheat and barley over the course of domestication., Floret fertility is a key determinant of the number of grains per inflorescence in cereals. During the evolution of wheat (Triticum sp.), floret fertility has increased, such that current bread wheat (Triticum aestivum) cultivars set three to five grains per spikelet. However, little is known regarding the genetic basis of floret fertility. The locus Grain Number Increase 1 (GNI1) is shown here to be an important contributor to floret fertility. GNI1 evolved in the Triticeae through gene duplication. The gene, which encodes a homeodomain leucine zipper class I (HD-Zip I) transcription factor, was expressed most abundantly in the most apical floret primordia and in parts of the rachilla, suggesting that it acts to inhibit rachilla growth and development. The level of GNI1 expression has decreased over the course of wheat evolution under domestication, leading to the production of spikes bearing more fertile florets and setting more grains per spikelet. Genetic analysis has revealed that the reduced-function allele GNI-A1 contributes to the increased number of fertile florets per spikelet. The RNAi-based knockdown of GNI1 led to an increase in the number of both fertile florets and grains in hexaploid wheat. Mutants carrying an impaired GNI-A1 allele out-yielded WT allele carriers under field conditions. The data show that gene duplication generated evolutionary novelty affecting floret fertility while mutations favoring increased grain production have been under selection during wheat evolution under domestication.

Wild barley forms a two-rowed spike with a brittle rachis whereas domesticated barley has two- or six-rowed spikes with a tough rachis. Like domesticated barley, 'agriocrithon' forms a six-rowed spike; however, the spike is brittle as in wild barley, which makes the origin of agriocrithon obscure. Haplotype analysis of the Six-rowed spike 1 (vrs1) and Non-brittle rachis 1 (btr1) and 2 (btr2) genes was conducted to infer the origin of agriocrithon barley. Some agriocrithon barley accessions (eu-agriocrithon) carried Btr1 and Btr2 haplotypes that are not found in any cultivars, implying that they are directly derived from wild barley through a mutation at the vrs1 locus. Other agriocrithon barley accessions (pseudo-agriocrithon) carried Btr1 or Btr2 from cultivated barley, thus implying that they originated from hybridization between six-rowed landraces carrying btr1Btr2 and Btr1btr2 genotypes followed by recombination to produce Btr1Btr2. All materials we collected from Tibet belong to pseudo-agriocrithon and thus do not support the Tibetan Plateau as being a center of barley domestication. Tracing the evolutionary history of these allelic variants revealed that eu-agriocrithon represents six-rowed barley lineages that were selected by early farmers, once in south-eastern Turkmenistan (vrs1.a1) and again in the eastern part of Uzbekistan (vrs1.a4).

Increasing grain yield is an endless challenge for cereal crop breeding. In barley (Hordeum vulgare), grain number is controlled mainly by Six-rowed spike 1 (Vrs1), which encodes a homeodomain leucine zipper class I transcription factor. However, little is known about the genetic basis of grain size. Here, we show that extreme suppression of lateral florets contributes to enlarged grains in deficiens barley. Through a combination of fine-mapping and resequencing of deficiens mutants, we have identified that a single amino acid substitution at a putative phosphorylation site in VRS1 is responsible for the deficiens phenotype. deficiens mutant alleles confer an increase in grain size, a reduction in plant height, and a significant increase in thousand grain weight in contemporary cultivated germplasm. Haplotype analysis revealed that barley carrying the deficiens allele (Vrs1.t1) originated from two-rowed types carrying the Vrs1.b2 allele, predominantly found in germplasm from northern Africa. In situ hybridization of histone H4, a marker for cell cycle or proliferation, showed weaker expression in the lateral spikelets compared with central spikelets in deficiens. Transcriptome analysis revealed that a number of histone superfamily genes were up-regulated in the deficiens mutant, suggesting that enhanced cell proliferation in the central spikelet may contribute to larger grains. Our data suggest that grain yield can be improved by suppressing the development of specific organs that are not positively involved in sink/source relationships.

In every country, the construction of large steel bridges, such as cable-stayed bridges, is carried out actively, and the number of bridges has been progressively increasing. In the case of large steel bridges, inspections must be carried out every five years. Because frequent inspections of such bridges are required, working robots capable of performing inspections in difficult environments would be very useful. This paper proposes a vibration actuator with a very simple structure capable of movement on a magnetic substance via the inertial force of a mass–spring model. Through theoretical analysis using the energy method, it was determined that the vibration actuator is propelled by the difference between the frictional forces acting during the forward and backward motions of the actuator. The experimental and analytical results were compared, verifying the validity of the novel motion principle. Additionally, based on the asymmetric magnetic field that arises when a copper wire is asymmetrically wound around the iron core of an electromagnet, a method of increasing the magnetic field strength at one pole of the electromagnet is newly proposed. By attaching an iron plate to the iron core of the electromagnet, the effects of the resulting asymmetric magnetic field of the electromagnet on the actuator motion were examined. The experimental results indicate that the actuator is able to climb upward while pulling a load mass of 110 g. The maximum efficiency of the actuator was 20.5 % for an actuator pulling its own weight. The efficiency of the actuator with the attached iron plate was considerably greater than that without the iron plate.

Although intercommunication among the different areas of the brain is well known, the rules of communication in the brain are not clear. Many previous studies have examined the firing patterns of neural networks in general, while we have examined the involvement of the firing patterns of neural networks in communication. In order to understand information processing in the brain, we simulated the interactions of the firing activities of a large number of neural networks in a 25 × 25 two-dimensional array for analyzing spike behavior. We stimulated the transmitting neurons at 0.1 msec. Then we observed the generated spike propagation for 120 msec. In addition, the positions of the firing neurons were determined with spike waves for different variances in the temporal fluctuations of the neuronal characteristics. These results suggested that for the changes (diversity) in the propagation routes of neuronal transmission resulted from variance in synaptic propagation delays and refractory periods. The simulation was used to examine differences in the percentages of neurons with significantly larger test statistics and the variances in the synaptic delay and refractory period. These results suggested that multiplex communication was more stable if the synaptic delay and refractory period varied.

Wheat yellow mosaic virus (WYMV), a member of Bymovirus, is a plant pathogenic virus transmitted by the soil-borne plasmodiophorid Polymyxa graminis. The in planta titer of the virus must be quantified to elucidate the dynamics of WYMV infection and the mechanism(s) underlying host resistance. Here, we describe a robust and sensitive TaqMan-based real time PCR assay based on the sequence of the WYMV coat protein gene. WYMV was undetectable in either the leaves or roots of plants of WYMV-resistant cultivar Madsen grown in infected soil. However, when Madsen leaves were mechanically inoculated with the virus, viral multiplication was not inhibited, showing that the cultivar’s resistance was ineffective in the leaf. The virus was able to move from the virus-inoculated leaf to the stem but not into the roots of Madsen, indicating that Madsen’s resistance was effective only in the roots.

In recent years, periodical inspection of large structures, such as large steel bridges with main towers of over 200 m, has been necessary. However, robots capable of a reciprocating movement over a long range have not been established yet. In this paper, a propulsion module with a bobbin-type electromagnet to increase the magnetic force was proposed. By changing the magnetic circuit, the experimental result demonstrates that the maximum efficiency of the magnetic actuator is 36.2% and the maximum pulling power is $\sim 1.5$ N. Furthermore, consideration of reciprocating movement by using two mass–spring models was given. The actuator system was capable of reciprocating movement with almost the same movement properties when powered by the same input power.

This paper proposes a magnetic actuator capable of movement on a magnetic substance by means of the inertia force produced by the vibration of a mass-spring model. The magnetic actuator is operated by the difference in frictional force during one period of vibration. The experimental results reveal that this magnetic actuator is able to pull a load mass of 110 g. Furthermore, this actuator is able to propel a load mass of approximately 8.5 times the weight of the actuator itself. The maximum efficiency of the actuator was 12.9% for an actuator pulling its own weight. The results also demonstrate that the magnetic actuator can move stably in slide-on-ceiling and wall-climbing plane motions. This magnetic actuator is able to move freely without a control unit on an iron rail of any shape.

Wheat domestication was a crucial step in the evolution of stable human societies. The loss of rachis brittleness is a major change that differentiates the earliest forms of domesticated wheat from their wild ancestors. We recently identified a novel quan- titative trait locus (QTL) for rachis fragility on the long arm of chromosome 3D using an F2 mapping population derived from the cross between Triticum aestivum 'Chinese Spring' (CS) and a synthetic wheat line, S-6214. Here, we show that the QTL region, in the deletion bin 3DL2-0.27-0.81, is syntenous to the rice chromosome 1 region harboring the seed shatter- ing gene qSH1. We isolated the wheat qSH1 ortholog, TaqSH1-D, on chromosome 3DL. The gene mapped into theconfidenceintervaloftherachis fragility QTL, indicating that it represents a potential candidate gene. Sequence comparison between the parental lines revealed a 189-bp repetitive sequence insertion located 275 bp downstream of the translation termi- nation site of the gene in CS. Although the putative parental proteins are identical, as in rice, a polymor- phism in the regulatory regions may specifically affect its control of rachis fragility.

This paper describes ship response by “zigzag maneuver with equal time-alternative steering”. This maneuver runs as follows: firstly the helm is turned to a certain angle during a certain time, secondly it is turned to the opposite side to the same angle during the same time, and thirdly it is returned again to the original position. In this maneuver, the analytical solutions of response, that is, angular velocity, heading angle and trajectory, etc., are obtained using first order model of Nomoto. These equations clarify the relationship between the steering quality indices and the ship response. The response of actual ships from published existing data is also checked out using the equations. The obtained charts summarized here will be available for design review of maneuverability. Finally, the trajectories are analyzed under some conditions that for instance the ships have the same non-dimensional steering quality indices and the different ship lengths. The significant difference of them indicates it is effective to consider trajectory in the early stage of design.

Allopolyploidization in plants is an important event that enhances heterosis and environmental adaptation. Common wheat, Triticum aestivum (AABBDD), which is an allohexaploid that evolved from an allopolyploidization event between T. turgidum (AABB) and Aegilops tauschii (DD), shows more growth vigor and wider adaptation than tetraploid wheats. To better understand the molecular basis for the heterosis of hexaploid wheat, we systematically analyzed the genome-wide gene expression patterns of two combinations of newly hybridized triploids (ABD), their chromosome-doubled hexaploids (AABBDD), stable synthetic hexaploids (AABBDD) and natural hexaploids, in addition to their parents, T. turgidum (AABB) and Ae. tauschii (DD), using a microarray to reconstruct the events of allopolyploidization and genome stabilization. Overall comparisons of gene expression profiles showed that the newly generated hexaploids exhibited gene expression patterns similar to those of their maternal tetraploids, irrespective of hybrid combination. With successive generations, the gene expression profiles of nascent hexaploids became less similar to the maternal profiles, and belonged to a separate cluster from the natural hexaploids. Triploids revealed characteristic expression patterns, suggesting endosperm effects. In the newly hybridized triploids (ABD) of two independent synthetic lines, approximately one-fifth of expressed genes displayed non-additive expression; the number of these genes decreased with polyploidization and genome stabilization. Approximately 20% of the non-additively expressed genes were transmitted across generations throughout allopolyploidization and successive self-pollinations, and 43 genes overlapped between the two combinations, indicating that shared gene expression patterns can be seen during allohexaploidization. Furthermore, four of these 43 genes were involved in starch and sucrose metabolism, suggesting that these metabolic events play key roles in the hybrid vigor of hexaploid wheat.

This report deals with the stability of ships having comparatively large projected lateral area above water line and shallow draft. Such ships usually have wide breadth because they have tendency to raise their center of gravity. Large GM made by the wide breadth brings strong stability. But it gets weaker if the ship has higher center of gravity because GM/(OG+T/2) becomes smaller. A research challenge of this report consists of the procedure to clarify the acceptable center of gravity and how breadth and draft to be examined and determined. These procedures enable the optimization method in the initial design. In the analysis, the metacenter is estimated by Ohgushi’s and Morish’s formula and the accuracy of the estimation is confirmed using merchant ships’ data released for public. The present method obtained by the analysis shows effectiveness to find out reasonable dimensions and acceptable height of center of gravity in the early stage of ship design.

In every country, large steel bridges, such as cable-stayed bridges, are actively being constructed, and the number of such bridges has been progressively increasing. These bridges are often inspected using drones, but inspection techniques have not been established because of strong winds and thunder. Therefore, robots capable of working in difficult environments are desired. In the present study, a prototype of a rotary actuator system combining two iron disks and two electromagnetic-vibration-type actuators was fabricated. A new operation principle was developed that drives the system using the reaction force of the vibration-type actuator. Two shape memory alloy coils and two friction pads were integrated into the system to enable it to carry out turning operations, which were successfully demonstrated. The proposed actuator system can thus move in any direction. In addition, with this actuator system, both slide-on-ceiling and wall-climbing motions are possible.

Inflorescence architecture of barley ( Hordeum vulgare L.) is common among the Triticeae species, which bear one to three single-flowered spikelets at each rachis internode. Triple spikelet meristem is one of the unique features of barley spikes, in which three spikelets (one central and two lateral spikelets) are produced at each rachis internode. Fertility of the lateral spikelets at triple spikelet meristem gives row-type identity to barley spikes. Six-rowed spikes show fertile lateral spikelets and produce increased grain yield per spike, compared with two-rowed spikes with sterile lateral spikelets. Thus, far, two loci governing the row-type phenotype were isolated in barley that include Six-rowed spike1 ( Vrs1 ) and Intermedium-C . In the present study, we isolated Six-rowed spike4 ( Vrs4 ), a barley ortholog of the maize ( Zea mays L.) inflorescence architecture gene RAMOSA2 ( RA2 ). Eighteen coding mutations in barley RA2 ( HvRA2 ) were specifically associated with lateral spikelet fertility and loss of spikelet determinacy. Expression analyses through mRNA in situ hybridization and microarray showed that Vrs4 ( HvRA2 ) controls the row-type pathway through Vrs1 ( HvHox1 ), a negative regulator of lateral spikelet fertility in barley. Moreover, Vrs4 may also regulate transcripts of barley SISTER OF RAMOSA3 ( HvSRA ), a putative trehalose-6-phosphate phosphatase involved in trehalose-6-phosphate homeostasis implicated to control spikelet determinacy. Our expression data illustrated that, although RA2 is conserved among different grass species, its down-stream target genes appear to be modified in barley and possibly other species of tribe Triticeae.

The bread wheat genome harbors three homoeologs of the barley gene HvAP2, which determines the cleistogamous/non-cleistogamous flowering. The three homoeologs, TaAP2-A, TaAP2-B and TaAP2-D, are derived from the A, B and D genomes. The importance of lodicule swelling in assuring non-cleistogamous flowering in a range of wild and domesticated wheat accessions of varying ploidy level was established. Re-sequencing of wheat AP2 homoeologous genes was carried out to identify natural variation at both the nucleotide and polypeptide level. The sequences of wheat AP2 homoeologs are highly conserved even across different ploidy levels and no functional variants at the key miR172 targeting site were detected. These results indicate that engineering of cleistogamous wheat will require the presence of a functional TaAP2 modification at each of the three homoeologs.

Plant architecture has clear agronomic and economic implications for crops such as wheat and barley, as it is a critical factor for determining grain yield. Despite this, only limited molecular information is available about how grain-bearing inflorescences, called spikes, are formed and maintain their regular, distichous pattern. Here we elucidate the molecular and hormonal role of Six-rowed spike 2 (Vrs2), which encodes a SHORT INTERNODES (SHI) transcriptional regulator during barley inflorescence and shoot development. We show that Vrs2 is specifically involved in floral organ patterning and phase duration by maintaining hormonal homeostasis and gradients during normal spike development and similarly influences plant stature traits. Furthermore, we establish a link between the SHI protein family and sucrose metabolism during organ growth and development that may have implications for deeper molecular insights into inflorescence and plant architecture in crops.

The process of crop domestication began 10,000 years ago in the transition of early humans from hunter/gatherers to pastoralists/farmers. Recent research has revealed the identity of some of the main genes responsible for domestication. Two of the major domestication events in barley were (i) the failure of the spike to disarticulate and (ii) the six-rowed spike. The former mutation increased grain yield by preventing grain loss after maturity, while the latter resulted in an up to 3-fold increase in yield potential. Here we provide an overview of the disarticulation systems and inflorescence characteristics, along with the genes underlying these traits, occurring in the Triticeae tribe.

Land plants have developed a cuticle preventing uncontrolled water loss. Here we report that an ATP-binding cassette (ABC) subfamily G (ABCG) full transporter is required for leaf water conservation in both wild barley and rice. A spontaneous mutation, eibi1.b , in wild barley has a low capacity to retain leaf water, a phenotype associated with reduced cutin deposition and a thin cuticle. Map-based cloning revealed that Eibi1 encodes an HvABCG31 full transporter. The gene was highly expressed in the elongation zone of a growing leaf (the site of cutin synthesis), and its gene product also was localized in developing, but not in mature tissue. A de novo wild barley mutant named “ eibi1.c ,” along with two transposon insertion lines of rice mutated in the ortholog of HvABCG31 also were unable to restrict water loss from detached leaves. HvABCG31 is hypothesized to function as a transporter involved in cutin formation. Homologs of HvABCG31 were found in green algae, moss, and lycopods, indicating that this full transporter is highly conserved in the evolution of land plants.

Three spikelets are formed at each rachis node of the cultivated barley (Hordeum vulgare ssp. vulgare) spike. In two-rowed barley, the central one is fertile and the two lateral ones are sterile, whereas in the six-rowed type, all three are fertile. This characteristic is determined by the allelic constitution at the six-rowed spike 1 (vrs1) locus on the long arm of chromosome 2H, with the recessive allele (vrs1) being responsible for the six-rowed phenotype. The Vrs1 (HvHox1) gene encodes a homeodomain-leucine zipper (HD-Zip) transcription factor. Here, we show that the Vrs1 gene evolved in the Poaceae via a duplication, with a second copy of the gene, HvHox2, present on the short arm of chromosome 2H. Micro-collinearity and polypeptide sequences were both well conserved between HvHox2 and its Poaceae orthologs, but Vrs1 is unique to the barley tribe. The Vrs1 gene product lacks a motif which is conserved among the HvHox2 orthologs. A phylogenetic analysis demonstrated that Vrs1 and HvHox2 must have diverged after the separation of Brachypodium distachyon from the Pooideae and suggests that Vrs1 arose following the duplication of HvHox2, and acquired its new function during the evolution of the barley tribe. HvHox2 was expressed in all organs examined but Vrs1 was predominantly expressed in immature inflorescence. Electronic supplementary material The online version of this article (doi:10.1007/s10142-009-0134-y) contains supplementary material, which is available to authorized users.

Allopolyploidization is an important evolutionary event in plants, but its genome-wide effects are not fully understood. Common wheat, Triticum aestivum (AABBDD), evolved through amphidiploidization between T. turgidum (AABB) and Aegilops tauschii (DD). Here, global gene expression patterns in the seedlings of a synthetic triploid wheat line (ABD), its chromosome-doubled hexaploid (AABBDD) and stable synthetic hexaploid (AABBDD), and the parental lines T. turgidum (AABB) and Ae. tauschii (DD) were compared using an oligo-DNA microarray to identify metabolic pathways affected by the genome conflict that occurs during allopolyploidization and genome stabilization. Characteristic gene expression patterns of non-additively expressed genes were detected in the newly synthesized triploid and hexaploid, and in the stable synthetic hexaploid. Hierarchical clustering of all differentially expressed and non-additively expressed genes revealed that the gene expression patterns of the triploid (ABD) were similar to those of the maternal parent (AABB), and that expression patterns in successive generations arising from self-pollination became closer to that of the pollen parent (DD). The non-additive gene expression profiles markedly differed between the triploid (ABD) and chromosome-doubled hexaploid (AABBDD), as supported by Gene Ontology (GOSlim) analysis. Four hundred and nineteen non-additively expressed genes were commonly detected in all three generations. GOSlim analysis indicated that these non-additively expressed genes were predominantly involved in "biological pathways". Notably, four of 11 genes related to sugar metabolism displayed elevated expression throughout allopolyploidization. These may be useful candidates for promoting heterosis and adaptation in plants.

Inflorescences of the tribe Triticeae, which includes wheat (Triticum sp. L.) and barley (Hordeum vulgare L.) are characterized by sessile spikelets directly borne on the main axis, thus forming a branchless spike. "Compositum-Barley" and tetraploid "Miracle-Wheat" (T. turgidum convar. compositum (L.f.) Filat.) display non-canonical spike-branching in which spikelets are replaced by lateral branch-like structures resembling small-sized secondary spikes. As a result of this branch formation "Miracle-Wheat" produces significantly more grains per spike, leading to higher spike yield. In this study, we first isolated the gene underlying spike-branching in "Compositum-Barley", i.e. compositum 2 (com2). Moreover, we found that COM2 is orthologous to the branched head(t) (bh(t)) locus regulating spike-branching in tetraploid "Miracle-Wheat". Both genes possess orthologs with similar functions in maize BRANCHED SILKLESS 1 (BD1) and rice FRIZZY PANICLE/BRANCHED FLORETLESS 1 (FZP/BFL1) encoding AP2/ERF transcription factors. Sequence analysis of the bh(t) locus in a collection of mutant and wild type tetraploid wheat accessions revealed that a single amino acid substitution in the DNA-binding domain gave rise to the domestication of "Miracle-Wheat". mRNA in situ hybridization, microarray experiments, and independent qRT-PCR validation analyses revealed that the branch repression pathway in barley is governed through the spike architecture gene Six-rowed spike 4 regulating COM2 expression, while HvIDS1 (barley ortholog of maize INDETERMINATE SPIKELET 1) is a putative down-stream target of COM2. These findings presented here provide new insights into the genetic basis of spike architecture in Triticeae, and have disclosed new targets for genetic manipulations aiming at boosting wheat's yield potential.

Domestication-related changes that govern a spike morphology suitable for seed harvesting in cereals have resulted from mutation and selection of the genes. A synthetic hexaploid wheat (S-6214, genome AABBDD) produced by a cross between durum wheat (AABB) and wild goat grass (DD) showed partial non-domestication-related phenotypes due to genetic effects of the wild goat grass genome. Quantitative trait loci (QTLs) affecting wheat domestication-related spike characters including spike threshability, rachis fragility and spike compactness were investigated in F2 progeny of a cross between Chinese Spring (CS) wheat (AABBDD) and S-6214. Of 15 relevant QTLs identified, eight seemed to be consistent with peaks previously reported in wheat, while four QTL regions were novel. Four QTLs that affected spike threshability were localized to chromosomes 2BS, 2DS, 4D and 5DS. The QTL on 2DS probably represents the tenacious glume gene, Tg-D1. Based on its map position, the QTL located on 2BS coincides with Ppd-B1 and seems to be a homoeolocus of the soft glume gene. Two novel QTLs were detected on 4D and 5DS, and their goat grass alleles increased glume tenacity. Three novel QTLs located on 2DL, 3DL and 4D for rachis fragility were found. Based on the map position, the QTL on 3DL seems different from Br1 and Br2 loci and its CS allele appears to promote the generation of barrel-type diaspores. Three disarticulation types of spikelets were found in F2 individuals: wedge-type, barrel-type and both types. Among eight QTL peaks that governed spike morphology, six, located on 2AS, 2BS, 2DS, 4AL and 5AL, coincided with ones previously reported. A QTL for spike compactness on 5AL was distinct from the Q gene. A novel QTL that controls spike length was detected on 5DL. Complex genetic interactions between genetic background and the action of each gene were suggested.

Enzymes fixed on the electrode of biosensor are gradually inactivated and the electrode is discarded after using several times. In order to prepare the stable biosensor, we try to use a stable enzyme from extreme thermophilic bacteria, Thermus thermophilus HB8. It is very important that a stable enzyme from T. thermophilus HB8 is overproduced in Escherichia coli, for the purpose of enough supply of enzyme. Thereby, we determined the important sequence for overexpression of NADH oxidase (nox) gene from T. thermophilus HB8 in E. coli. As a result, it is revealed that ten nucleotides sequence, GAAATTAACT, in the upstream of start codon of nox gene was important for its overexpression in E. coli.

The majority of genes present in the hexaploid bread wheat genome are present as three homoeologs. Here, we describe the three homoeologous orthologs of the barley cleistogamy gene Cly1, a member of the AP2 gene family. As in barley, the wheat genes (designated TaAP2-A, -B and -D) map to the sub-telomeric region of the long arms of the group 2 chromosomes. The structure and pattern of transcription of the TaAP2 homoeologs were similar to those of Cly1. Transcript abundance was high in the florets, and particularly in the lodicule. The TaAP2 message was cleaved at its miR172 target sites. The set of homoeolog-specific PCR assays developed will be informative for identifying either naturally occurring or induced cleistogamous alleles at each of the three wheat homoeologs. By combining such alleles via conventional crossing, it should be possible to generate a cleistogamous form of bread wheat, which would be advantageous both with respect to improving the level of the crop's resistance against the causative pathogen of fusarium head blight, and for controlling pollen-mediated gene flow to and from genetically modified cultivars.

Background The cuticle is an important adaptive structure whose origin played a crucial role in the transition of plants from aqueous to terrestrial conditions. HvABCG31/Eibi1 is an ABCG transporter gene, involved in cuticle formation that was recently identified in wild barley (Hordeum vulgare ssp. spontaneum). To study the genetic variation of HvABCG31 in different habitats, its 2 kb promoter region was sequenced from 112 wild barley accessions collected from five natural populations from southern and northern Israel. The sites included three mesic and two xeric habitats, and differed in annual rainfall, soil type, and soil water capacity. Results Phylogenetic analysis of the aligned HvABCG31 promoter sequences clustered the majority of accessions (69 out of 71) from the three northern mesic populations into one cluster, while all 21 accessions from the Dead Sea area, a xeric southern population, and two isolated accessions (one from a xeric population at Mitzpe Ramon and one from the xeric ‘African Slope’ of “Evolution Canyon”) formed the second cluster. The southern arid populations included six haplotypes, but they differed from the consensus sequence at a large number of positions, while the northern mesic populations included 15 haplotypes that were, on average, more similar to the consensus sequence. Most of the haplotypes (20 of 22) were unique to a population. Interestingly, higher genetic variation occurred within populations (54.2%) than among populations (45.8%). Analysis of the promoter region detected a large number of transcription factor binding sites: 121–128 and 121–134 sites in the two southern arid populations, and 123–128,125–128, and 123–125 sites in the three northern mesic populations. Three types of TFBSs were significantly enriched: those related to GA (gibberellin), Dof (DNA binding with one finger), and light. Conclusions Drought stress and adaptive natural selection may have been important determinants in the observed sequence variation of HvABCG31 promoter. Abiotic stresses may be involved in the HvABCG31 gene transcription regulations, generating more protective cuticles in plants under stresses.

Barley (Hordeum vulgare) spikes are developmentally switched from two-rowed to six-rowed by a single recessive gene, six-rowed spike 1 (vrs1), which encodes a homeodomain-leucine zipper I class transcription factor. Vrs1 is a paralog of HvHox2 and both were generated by duplication of an ancestral gene. HvHox2 is conserved among cereals, whereas Vrs1 acquired its current function during the evolution of barley. It was unclear whether divergence of expression pattern or protein function accounted for the functionalization of Vrs1. Here, we conducted a comparative analysis of protein functions and gene expression between HvHox2 and Vrs1 to clarify the functionalization mechanism. We revealed that the transcriptional activation activity of HvHOX2 and VRS1 was conserved. In situ hybridization analysis showed that HvHox2 is localized in vascular bundles in developing spikes, whereas Vrs1 is expressed exclusively in the pistil, lemma, palea and lodicule of lateral spikelets. The transcript abundance of Vrs1 was > 10-fold greater than that of HvHox2 during the pistil developmental stage, suggesting that the essential function of Vrs1 is to inhibit gynoecial development. We demonstrated the quantitative function of Vrs1 using RNAi transgenic plants and Vrs1 expression variants. Expression analysis of six-rowed spike mutants that are nonallelic to vrs1 showed that Vrs1 expression was up-regulated by Vrs4, whereas HvHox2 expression was not. These data demonstrate that the divergence of gene expression pattern contributed to the neofunctionalization of Vrs1.