Plant Gene Seeker -PGS
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Plant Gene Seeker -PGS
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Curated by Andres Zurita
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TIME FOR COFFEE controls root meristem size by changes in auxin accumulation in Arabidopsis

TIME FOR COFFEE controls root meristem size by changes in auxin accumulation in Arabidopsis | Plant Gene Seeker -PGS | Scoop.it
Andres Zurita's insight:

Roots play important roles in plant survival and productivity as they not only anchor the plants in the soil but are also the primary organ for the uptake of nutrients from the outside. The growth and development of roots depend on the specification and maintenance of the root meristem. Here, we report a previously unknown role of TIME FOR COFFEE (TIC) in controlling root meristem size in Arabidopsis. The results showed that loss of function of TIC reduced root meristem length and cell number by decreasing the competence of meristematic cells to divide. This was due to the repressed expression of PIN genes for decreased acropetal auxin transport in tic-2, leading to low auxin accumulation in the roots responsible for reduced root meristem, which was verified by exogenous application of indole-3-acetic acid. Downregulated expression ofPLETHORA1 (PLT1) and PLT2, key transcription factors in mediating the patterning of the root stem cell niche, was also assayed in tic-2. Similar results were obtained with tic-2 and wild-type plants at either dawn or dusk. We also suggested that the MYC2-mediated jasmonic acid signalling pathway may not be involved in the regulation of TIC in controlling the root meristem. Taken together, these results suggest that TIC functions in an auxin–PLTs loop for maintenance of post-embryonic root meristem.


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PLOS Genetics: Tomato Yield Heterosis Is Triggered by a Dosage Sensitivity of the Florigen Pathway That Fine-Tunes Shoot Architecture

PLOS Genetics: Tomato Yield Heterosis Is Triggered by a Dosage Sensitivity of the Florigen Pathway That Fine-Tunes Shoot Architecture | Plant Gene Seeker -PGS | Scoop.it
PLOS Genetics is an open-access
Andres Zurita's insight:

The superiority of hybrids has long been exploited in agriculture, and although many models explaining “heterosis” have been put forth, direct empirical support is limited. Particularly elusive have been cases of heterozygosity for single gene mutations causing heterosis under a genetic model known as overdominance. In tomato (Solanum lycopersicum), plants carrying mutations in SINGLE FLOWER TRUSS (SFT) encoding the flowering hormone florigen are severely delayed in flowering, become extremely large, and produce few flowers and fruits, but when heterozygous, yields are dramatically increased. Curiously, this overdominance is evident only in the background of “determinate” plants, in which the continuous production of side shoots and inflorescences gradually halts due to a defect in the flowering repressor SELF PRUNING (SP). How sp facilitates sft overdominance is unclear, but is thought to relate to the opposing functions these genes have on flowering time and shoot architecture. We show thatsft mutant heterozygosity (sft/+) causes weak semi-dominant delays in flowering of both primary and side shoots. Using transcriptome sequencing of shoot meristems, we demonstrate that this delay begins before seedling meristems become reproductive, followed by delays in subsequent side shoot meristems that, in turn, postpone the arrest of shoot and inflorescence production. Reducing SFT levels in sp plants by artificial microRNAs recapitulates the dose-dependent modification of shoot and inflorescence production of sft/+ heterozygotes, confirming that fine-tuning levels of functional SFT transcripts provides a foundation for higher yields. Finally, we show that although flowering delays by florigen mutant heterozygosity are conserved in Arabidopsis, increased yield is not, likely because cyclical flowering is absent. We suggest sft heterozygosity triggers a yield improvement by optimizing plant architecture via its dosage response in the florigen pathway. Exploiting dosage sensitivity of florigen and its family members therefore provides a path to enhance productivity in other crops, but species-specific tuning will be required.

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My body is a cage: mechanisms and modulation of plant cell growth - Braidwood - 2013 - New Phytologist - Wiley Online Library

My body is a cage: mechanisms and modulation of plant cell growth - Braidwood - 2013 - New Phytologist - Wiley Online Library | Plant Gene Seeker -PGS | Scoop.it
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Summary

The wall surrounding plant cells provides protection from abiotic and biotic stresses, and support through the action of turgor pressure. However, the presence of this strong elastic wall also prevents cell movement and resists cell growth. This growth can be likened to extending a house from the inside, using extremely high pressures to push out the walls. Plants must increase cell volume in order to explore their environment, acquire nutrients and reproduce. Cell wall material must stretch and flow in a controlled manner and, concomitantly, new cell wall material must be deposited at the correct rate and site to prevent wall and cell rupture. In this review, we examine biomechanics, cell wall structure and growth regulatory networks to provide a ‘big picture’ of plant cell growth.

 

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Our Future is Rooted in Plant Science

Our Future is Rooted in Plant Science | Plant Gene Seeker -PGS | Scoop.it

Via Mary Williams
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Genomic resources for breeding crops with enhanced abiotic stress tolerance - Bansal - 2013 - Plant Breeding - Wiley Online Library

Genomic resources for breeding crops with enhanced abiotic stress tolerance - Bansal - 2013 - Plant Breeding - Wiley Online Library | Plant Gene Seeker -PGS | Scoop.it
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Abstract

To meet the challenges of climate change, exploring natural diversity in the existing plant genetic resource pool as well as creation of new mutants through chemical mutagenesis and molecular biology is needed for developing climate-resilient elite genotypes. Ever-increasing area under existing abiotic stresses as well as emerging abiotic stress factors and their combinations have further added to the problems of the current crop improvement programmes. However, with the advancement in modern techniques such as next-generation sequencing technologies, it is now possible to generate on a whole-genome scale, genomic resources for crop species at a much faster pace with considerably less efforts and money. The genomic resources thus generated will be useful for various plant breeding applications such as marker-assisted breeding for gene introgression, mapping QTLs or identifying new or rare alleles associated with a particular trait. In this article, we discuss various aspects of generation of genomic resources and their utilization for developing abiotic stress-tolerant crops to ensure sustainable agricultural production and food security in the backdrop of rapid climate change.

 

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Adaptation to spring heat and drought in northeastern Spanish Arabidopsis thaliana - Wolfe - 2013 - New Phytologist - Wiley Online Library

Adaptation to spring heat and drought in northeastern Spanish Arabidopsis thaliana - Wolfe - 2013 - New Phytologist - Wiley Online Library | Plant Gene Seeker -PGS | Scoop.it
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SummaryThe extent to which a species' environmental range reflects adaptive differentiation remains an open question. Environmental gradients can lead to adaptive divergence when differences in stressors among sites along the gradient place conflicting demands on the balance of stress responses. The extent to which this is accomplished through stress tolerance vs stress avoidance is also an open question.We present results from a controlled environment study of 48 lineages of Arabidopsis thaliana collected along a gradient in northeastern Spain across which temperatures increase and precipitation decreases with decreasing elevation. We tested the extent to which clinal adaptive divergence in heat and drought is explained through tolerance and avoidance traits by subjecting plants to a dynamic growth chamber cycle of increasing heat and drought stress analogous to low elevation spring in northeastern Spain.Lineages collected at low elevation were the most fit and fitness scaled with elevation of origin. Higher fitness was associated with earlier bolting, greater early allocation to increased numbers of inflorescences, reduction in rosette leaf photosynthesis and earlier fruit ripening.We propose that this is a syndrome of avoidance through early flowering accompanied by restructuring of the organism that adaptsA. thaliana to low-elevation Mediterranean climates.
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Mycorrhizal Networks: Common Goods of Plants Shared under Unequal Terms of Trade

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Abstract

Plants commonly live in a symbiotic association with arbuscular mycorrhizal fungi (AMF). They invest photosynthetic products to feed their fungal partners, which, in return, provide mineral nutrients foraged in the soil by their intricate hyphal networks. Intriguingly, AMF can link neighboring plants, forming common mycorrhizal networks (CMNs). What are the terms of trade in such CMNs between plants and their shared fungal partners? To address this question, we set up microcosms containing a pair of test plants, interlinked by a CMN of Glomus intraradices or Glomus mosseae. The plants were flax (Linum usitatissimum; a C3plant) and sorghum (Sorghum bicolor; a C4 plant), which display distinctly different 13C/12C isotope compositions. This allowed us to differentially assess the carbon investment of the two plants into the CMN through stable isotope tracing. In parallel, we determined the plants’ “return of investment” (i.e. the acquisition of nutrients via CMN) using 15N and 33P as tracers. Depending on theAMF species, we found a strong asymmetry in the terms of trade: flax invested little carbon but gained up to 94% of the nitrogen and phosphorus provided by the CMN, which highly facilitated growth, whereas the neighboring sorghum invested massive amounts of carbon with little return but was barely affected in growth. Overall biomass production in the mixed culture surpassed the mean of the two monocultures. Thus, CMNs may contribute to interplant facilitation and the productivity boosts often found with intercropping compared with conventional monocropping.

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TIME FOR COFFEE controls root meristem size by changes in auxin accumulation in Arabidopsis

TIME FOR COFFEE controls root meristem size by changes in auxin accumulation in Arabidopsis | Plant Gene Seeker -PGS | Scoop.it
Andres Zurita's insight:

Roots play important roles in plant survival and productivity as they not only anchor the plants in the soil but are also the primary organ for the uptake of nutrients from the outside. The growth and development of roots depend on the specification and maintenance of the root meristem. Here, we report a previously unknown role of TIME FOR COFFEE (TIC) in controlling root meristem size in Arabidopsis. The results showed that loss of function of TIC reduced root meristem length and cell number by decreasing the competence of meristematic cells to divide. This was due to the repressed expression of PIN genes for decreased acropetal auxin transport in tic-2, leading to low auxin accumulation in the roots responsible for reduced root meristem, which was verified by exogenous application of indole-3-acetic acid. Downregulated expression ofPLETHORA1 (PLT1) and PLT2, key transcription factors in mediating the patterning of the root stem cell niche, was also assayed in tic-2. Similar results were obtained with tic-2 and wild-type plants at either dawn or dusk. We also suggested that the MYC2-mediated jasmonic acid signalling pathway may not be involved in the regulation of TIC in controlling the root meristem. Taken together, these results suggest that TIC functions in an auxin–PLTs loop for maintenance of post-embryonic root meristem.

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Water: the most important ‘molecular’ component of water stress tolerance research. Functional Plant Biology

Water: the most important ‘molecular’ component of water stress tolerance research. Functional Plant Biology | Plant Gene Seeker -PGS | Scoop.it
Functional Plant Biology is an international journal of plant function publishing high quality research papers in all areas of plant physiology, applied agricultural research and pure molecular biology...
Andres Zurita's insight:

Water deficit is the main yield-limiting factor across the Asian and African semiarid tropics and a basic consideration when developing crop cultivars for water-limited conditions is to ensure that crop water demand matches season water supply. Conventional breeding has contributed to the development of varieties that are better adapted to water stress, such as early maturing cultivars that match water supply and demand and then escape terminal water stress. However, an optimisation of this match is possible. Also, further progress in breeding varieties that cope with water stress is hampered by the typically large genotype × environment interactions in most field studies. Therefore, a more comprehensive approach is required to revitalise the development of materials that are adapted to water stress. In the past two decades, transgenic and candidate gene approaches have been proposed for improving crop productivity under water stress, but have had limited real success. The major drawback of these approaches has been their failure to consider realistic water limitations and their link to yield when designing biotechnological experiments. Although the genes are many, the plant traits contributing to crop adaptation to water limitation are few and revolve around the critical need to match water supply and demand. We focus here on the genetic aspects of this, although we acknowledge that crop management options also have a role to play. These traits are related in part to increased, better or more conservative uses of soil water. However, the traits themselves are highly dynamic during crop development: they interact with each other and with the environment. Hence, success in breeding cultivars that are more resilient under water stress requires an understanding of plant traits affecting yield under water deficit as well as an understanding of their mutual and environmental interactions. Given that the phenotypic evaluation of germplasm/breeding material is limited by the number of locations and years of testing, crop simulation modelling then becomes a powerful tool for navigating the complexity of biological systems, for predicting the effects on yield and for determining the probability of success of specific traits or trait combinations across water stress scenarios.

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Inflorescences: concepts, function, development and evolution

Inflorescences: concepts, function, development and evolution | Plant Gene Seeker -PGS | Scoop.it
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Background Inflorescences are complex structures with many functions. At anthesis they present the flowers in ways that allow for the transfer of pollen and optimization of the plant's reproductive success. During flower and fruit development they provide nutrients to the developing flowers and fruits. At fruit maturity they support the fruits prior to dispersal, and facilitate effective fruit and seed dispersal. From a structural point of view, inflorescences have played important roles in systematic and phylogenetic studies. As functional units they facilitate reproduction, and are largely shaped by natural selection.

Scope The papers in this Special Issue bridge the gap between structural and functional approaches to inflorescence evolution. They include a literature review of inflorescence function, an experimental study of inflorescences as essential contributors to the display of flowers, and two papers that present new methods and concepts for understanding inflorescence diversity and for dealing with terminological problems. The transient model of inflorescence development is evaluated in an ontogenetic study, and partially supported. Four papers present morphological and ontogenetic studies of inflorescence development in monophyletic groups, and two of these evaluate the usefulness of Hofmeister's Rule and inhibitory fields to predict inflorescence structure. In the final two papers, Bayesian and Monte-Carlo methods are used to elucidate inflorescence evolution in the Panicoid grasses, and a candidate gene approach is used in an attempt to understand the evolutionary genetics of inflorescence evolution in the genus Cornus (Cornaceae). Taken as a whole, the papers in this issue provide a glimpse of contemporary approaches to the study of the structure, development, and evolution of inflorescences, and suggest fruitful new directions for research.

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Maize ARGOS1 (ZAR1) transgenic alleles increase hybrid maize yield

Maize ARGOS1 (ZAR1) transgenic alleles increase hybrid maize yield | Plant Gene Seeker -PGS | Scoop.it
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Crop improvement for yield and drought tolerance is challenging due to the complex genetic nature of these traits and environmental dependencies. This study reports that transgenic over-expression of Zea mays AR GOS1 (ZAR1) enhanced maize organ growth, grain yield, and drought-stress tolerance. The ZAR1 transgene exhibited environmental interactions, with yield increase under Temperate Dry and yield reduction under Temperate Humid or High Latitude environments. Native ZAR1 allele variation associated with drought-stress tolerance. Two founder alleles identified in the mid-maturity germplasm of North America now predominate in Pioneer’s modern breeding programme, and have distinct proteins, promoters and expression patterns. These two major alleles show heterotic group partitioning, with one predominant in Pioneer’s female and the other in the male heterotic groups, respectively. These two alleles also associate with favourable crop performance when heterozygous. Allele-specific transgene testing showed that, of the two alleles discussed here, each allele differed in their impact on yield and environmental interactions. Moreover, when transgenically stacked together the allelic pair showed yield and environmental performance advantages over either single allele, resembling heterosis effects. This work demonstrates differences in transgenic efficacy of native alleles and the differences reflect their association with hybrid breeding performance.

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Plant biomechanics and mechanobiology are convergent paths to flourishing interdisciplinary research

Plant biomechanics and mechanobiology are convergent paths to flourishing interdisciplinary research | Plant Gene Seeker -PGS | Scoop.it
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‘One sole point of view is always false.’

Paul Valéry (1871–1945)

Over recent decades, there has been a real renaissance of interest in how inner and outer mechanical forces influence biological systems at all scales from macromolecules up to functional ecology. Many areas of animal and medical science are being reshaped by considering biomechanical and mechanobiological aspects, like stiffness-driven differentiation of stem cells, embryo development, tumour invasion, bone and cartilage adaptation, cardiac and arterial remodelling, brain neurobiology, touch and haptics, motion control, and proprioception (e.g. Discher et al., 2005;Stoltz et al., 2005, Boccafoschi et al., 2013; Bukoreshtliev et al., 2013). The same is true and no less impressive in plant sciences where researchers continue to be fascinated by the features that plants have evolved in order to grow and sense, withstand, acclimate, and adapt to the mechanical challenges they face. But what are the major frontiers in plant biomechanics and mechanobiology, the hotspots where physical and biological disciplines cross over? Is this really a new field or can we trace it back in time, and if so, how far? And what exactly do the seemingly mirror-image names biomechanics and mechanobiology mean?

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Environment: Waste production must peak this century

Environment: Waste production must peak this century | Plant Gene Seeker -PGS | Scoop.it
Without drastic action, population growth and urbanization will outpace waste reduction, warn Daniel Hoornweg, Perinaz Bhada-Tata and Chris Kennedy.
Andres Zurita's insight:

Solid waste — the stuff we send down our chutes, discard at work and put on the curb every week — is a striking by-product of civilization. The average person in the United States throws away their body weight in rubbish every month. When waste management works well, we give it little thought: out of sight and, usually, quickly out of mind. Discarded materials are collected, some are recycled or composted, and most are landfilled or incinerated. But the global view is troubling.

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Liana Bianco-Caputo's curator insight, July 8, 2015 1:14 AM

This article has good links to reliable sources.

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AtERF070 Regulates Root Development and Phosphate-Starvation-Mediated-Responses

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Phosphate (Pi) availability is a major factor determining growth and consequently the productivity of crops. However it is one of the least available macronutrient due to its high fixation in the rhizosphere. To overcome this constraint, plants have developed adaptive responses to better acquire, utilize and recycle Pi. Molecular determinants of these adaptive mechanisms include transcription factors (TFs) that play a major role in transcriptional control thereby regulating genome-scale networks. In this study, we have characterized the biological role of AtERF070, a Pi-starvation induced ethylene response factor belonging to AP2/ERF family of TFs in Arabidopsis thaliana. It is localized to the nucleus and induced specifically in Pi-deprived roots and shoots. RNAi mediated suppression of AtERF070 led to augmented lateral root development resulting in higher Pi accumulation. Whereas, there were reductions in both primary root length and lateral root number in 12d-old transgenic seedlings overexpressing AtERF070. When the overexpressing lines were grown to maturity under green house conditions they revealed a stunted bushy appearance that could be rescued by gibberellic acid application. Further, a number of Pi-starvation responsive genes were modulated in AtERF070 overexpressing and RNAi lines thereby suggesting a potential role for this TF in maintaining Pi homeostasis.


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Advanced genetic tools for plant biotechnology | Nature Reviews Genetics

Advanced genetic tools for plant biotechnology | Nature Reviews Genetics | Plant Gene Seeker -PGS | Scoop.it
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AbstractBasic research has provided a much better understanding of the genetic networks and regulatory hierarchies in plants. To meet the challenges of agriculture, we must be able to rapidly translate this knowledge into generating improved plants. Therefore, in this Review, we discuss advanced tools that are currently available for use in plant biotechnology to produce new products in plants and to generate plants with new functions. These tools include synthetic promoters, 'tunable' transcription factors, genome-editing tools and site-specific recombinases. We also review some tools with the potential to enable crop improvement, such as methods for the assembly and synthesis of large DNA molecules, plant transformation with linked multigenes and plant artificial chromosomes. These genetic technologies should be integrated to realize their potential for applications to pressing agricultural and environmental problems.

PAYWALL

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High-dose resveratrol shows heart health for overweight and obese people: Human data

High-dose resveratrol shows heart health for overweight and obese people: Human data | Plant Gene Seeker -PGS | Scoop.it
Daily supplements containing resveratrol may reduce the production of compounds responsible for the build-up of cholesterol in the body of overweight and obese people, says a new study.

Via Meristemi
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Steve Kingsley's curator insight, November 19, 2013 8:35 PM

Not just for overweight and obese people.And the best way to ingest is... to drink 2 cups of well aged red wine. 

Steve Kingsley's curator insight, December 2, 2013 9:07 PM

At a daily dose of 1 gram in the first week and and 2 grams in the second week, this is not a cheap proposition.

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Identification and Validation of Promoters and Cis-acting Regulatory Elements

Identification and Validation of Promoters and Cis-acting Regulatory Elements | Plant Gene Seeker -PGS | Scoop.it
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Review Highlights

• We present an overview of native promoter structure and function.

• The use and application of promoters in transgenics are emphasized.• Use of cis-acting regulatory elements in synthetic promoters is highlighted.• A new approach of developing and using synthetic introns in promoters is presented.• Different promoter gene expression validation approaches are compared.

 

Abstract

Studies of promoters that largely regulate gene expression at the transcriptional level are crucial for improving our basic understanding of gene regulation and will expand the toolbox of available promoters for use in plant biotechnology. In this review, we present a comprehensive analysis of promoters and their underlying mechanisms in transcriptional regulation, including epigenetic marks and chromatin-based regulation. Large-scale prediction of promoter sequences and their contributing cis-acting elements has become routine due to recent advances in transcriptomic technologies and genome sequencing of several plants. However, predicted regulatory sequences may or may not be functional and demonstration of the contribution of the element to promoter activity is essential for confirmation of regulatory sequences. Use of synthetic promoters and introns represent useful approaches for functional validation of promoter sequences. The development and improvement of gene expression tools for rapid, efficient, predictable, and high-throughput analysis of promoter components will be critical for confirmation of the functional regulatory element sequences identified through transcriptomic and genomic analyses.

 

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Unlocking Triticeae genomics to sustainably feed the future

Unlocking Triticeae genomics to sustainably feed the future | Plant Gene Seeker -PGS | Scoop.it
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The tribe Triticeae includes the major crops wheat and barley. Within the last few years, the whole genomes of four Triticeae species—barley, wheat, Tausch’s goatgrass (Aegilops tauschii) and wild einkorn wheat (Triticum urartu)—have been sequenced. The availability of these genomic resources for Triticeae plants and innovative analytical applications using next-generation sequencing technologies are helping to revitalize our approaches in genetic work and to accelerate improvement of the Triticeae crops. Comparative genomics and integration of genomic resources from Triticeae plants and the model grass Brachypodium distachyon are aiding the discovery of new genes and functional analyses of genes in Triticeae crops. Innovative approaches and tools such as analysis of next-generation populations, evolutionary genomics and systems approaches with mathematical modeling are new strategies that will help us discover alleles for adaptive traits to future agronomic environments. In this review, we provide an update on genomic tools for use with Triticeae plants andBrachypodium and describe emerging approaches toward crop improvements in Triticeae.

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Entomological Society of America Resistance to Bt Corn by Western Corn Rootworm (Coleoptera: Chrys...

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Transgenic Bt corn hybrids that produce insecticidal proteins from the bacterium Bacillus thuringiensis Berliner have become the standard insect management tactic across the U.S. Corn Belt. Widespread planting of Bt corn places intense selection pressure on target insects to develop resistance, and evolution of resistance threatens to erode benefits associated with Bt corn, such as reduced reliance on conventional insecticides. Recognizing the threat of resistance, the U.S. Environmental Protection Agency requires seed companies to include an insect resistance management (IRM) plan when registering a Bt trait. The goal of IRM plans is to delay Bt resistance in populations of target insects. One element of IRM is the presence of a non-Bt refuge to maintain Bt-susceptible individuals within a population, and growers are required to implement IRM on-farm by planting a refuge. Field-evolved resistance has not been detected for the European corn borer, Ostrinia nubilalis (Hubner), even though this species has been exposed to Bt proteins common in U.S. corn hybrids since 1996. The IRM situation is unfolding differently for Bt corn targeting the western corn rootworm, Diabrotica virgifera virgifera LeConte. In this article, we examine the scientific evidence for D. v. virgifera resistance to Bt rootworm traits and the cropping system practices that have contributed to the first reports of field-evolved resistance to a Bt toxin by D. v. virgifera. We explain why this issue has developed, and emphasize the necessity of an integrated pest management approach to address the issue.

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Alternative Splicing at the Intersection of Biological Timing, Development, and Stress Responses

Alternative Splicing at the Intersection of Biological Timing, Development, and Stress Responses | Plant Gene Seeker -PGS | Scoop.it
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High-throughput sequencing for transcript profiling in plants has revealed that alternative splicing (AS) affects a much higher proportion of the transcriptome than was previously assumed. AS is involved in most plant processes and is particularly prevalent in plants exposed to environmental stress. The identification of mutations in predicted splicing factors and spliceosomal proteins that affect cell fate, the circadian clock, plant defense, and tolerance/sensitivity to abiotic stress all point to a fundamental role of splicing/AS in plant growth, development, and responses to external cues. Splicing factors affect the AS of multiple downstream target genes, thereby transferring signals to alter gene expression via splicing factor/AS networks. The last two to three years have seen an ever-increasing number of examples of functional AS. At a time when the identification of AS in individual genes and at a global level is exploding, this review aims to bring together such examples to illustrate the extent and importance of AS, which are not always obvious from individual publications. It also aims to ensure that plant scientists are aware that AS is likely to occur in the genes that they study and that dynamic changes in AS and its consequences need to be considered routinely.


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Gene networks controlling Arabidopsis thaliana flower development

Gene networks controlling Arabidopsis thaliana flower development | Plant Gene Seeker -PGS | Scoop.it
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The formation of flowers is one of the main models for studying the regulatory mechanisms that underlie plant development and evolution. Over the past three decades, extensive genetic and molecular analyses have led to the identification of a large number of key floral regulators and to detailed insights into how they control flower morphogenesis. In recent years, genome-wide approaches have been applied to obtaining a global view of the gene regulatory networks underlying flower formation. Furthermore, mathematical models have been developed that can simulate certain aspects of this process and drive further experimentation. Here, we review some of the main findings made in the field of Arabidopsis thaliana flower development, with an emphasis on recent advances. In particular, we discuss the activities of the floral organ identity factors, which are pivotal for the specification of the different types of floral organs, and explore the experimental avenues that may elucidate the molecular mechanisms and gene expression programs through which these master regulators of flower development act.

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Heterosis, stress, and the environment: a possible road map towards the general improvement of crop yield

Heterosis, stress, and the environment: a possible road map towards the general improvement of crop yield | Plant Gene Seeker -PGS | Scoop.it
Andres Zurita's insight:

Contemporary plant breeding is under pressure to improve crop productivity at a rate surpassing past achievements. Different research groups dealing with this issue reached similar conclusions that the solution lies in improved biomass production by way of enhanced light capture and use efficiency, modified photosystem biochemistry, and improved partitioning of assimilates to the economic part of the plant. There seems to be a consensus of sorts. This ‘opinion paper’ calls attention to the phenomenon of heterosis, as expressed in maize, sorghum, and other crops where, depending on the case and the trait, larger biomass and greater yield have been achieved without a change in growth duration, photosystem biochemistry, or harvest index. This discussion maintains that there is no consensus about the genetics or the genomics of heterosis in regulating yield under diverse environments. Therefore, in a search for the basis of heterosis in yield and adaptation, the discussion bypasses the genetics and searches for answers in the phenomics of heterosis. The heterotic phenotype in itself provides challenging and important hints towards improving the yield of open-pollinated crops in general. These hints are linked to the homeostasis of photosynthesis with respect to temperature, the photobiology of the plant as mediated by phytochrome, the architectural foundations of the formation of a large sink, and the associated hormones and signals in controlling sink differentiation and source–sink communication. This discussion does not lay out plans and protocols but provides clues to explore within and beyond the current thinking about breeding for high yield.

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Responses of foliar antioxidative and photoprotective defence systems of trees to drought: a meta-analysis

Responses of foliar antioxidative and photoprotective defence systems of trees to drought: a meta-analysis | Plant Gene Seeker -PGS | Scoop.it
Andres Zurita's insight:

Current climate change predictions hint to more frequent extreme weather events, including extended droughts, making better understanding of the impacts of water stress on trees even more important. At the individual plant level, stomatal closure as a result of water deficit leads to reduced CO2 availability in the leaf, which can lead to photo-oxidative stress. Photorespiration and the Mehler reaction can maintain electron transport rates under low internal CO2, but result in production of reactive oxygen species (ROS). If electron consumption is decreased, upstream photochemical processes can be affected and light energy is absorbed in excess of photochemical requirements. Trees evolved to cope with excess energy and elevated concentration of ROS by activating photoprotective and antioxidative defence systems. The meta-analysis we present here assessed responses of these defence systems reported in 50 studies. We found responses to vary depending on stress intensity, foliage type and habitat, and on whether experiments were done in the field or in controlled environments. In general, drought increased concentrations of antioxidants and photoprotective pigments. However, severe stress caused degradation of antioxidant concentrations and oxidation of antioxidant pools. Evergreen trees seemed to preferentially reinforce membrane-bound protection systems zeaxanthin and tocopherol, whereas deciduous species showed greater responses in water-soluble antioxidants ascorbic acid and glutathione. Trees and shrubs from arid versus humid habitats vary in their antioxidative and photoprotective defence responses. In field experiments, drought had greater effects on some defence compounds than under controlled conditions.

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ATLs and BTLs, plant-specific and general eukaryotic structurally-related E3 ubiquitin ligases

ATLs and BTLs, plant-specific and general eukaryotic structurally-related E3 ubiquitin ligases | Plant Gene Seeker -PGS | Scoop.it
Andres Zurita's insight:

Major components of the ubiquitin proteasome system are the enzymes that operate on the transfer of ubiquitin to selected target substrate, known as ubiquitin ligases. The RING finger is a domain that is present in key classes of ubiquitin ligases. This domain coordinates the interaction with a suitable E2 conjugase and the transfer of ubiquitin from the E2 to protein targets. Additional domains coupled to the same polypeptide are important for modulating the function of these ubiquitin ligases. Plants contain several types of E3 ubiquitin ligases that in many cases have expanded as multigene families. Some families are specific to the plant lineage, whereas others may have a common ancestor among plants and other eukaryotic lineages. Arabidopsis Tóxicos en Levadura (ATLs) and BCA2 zinc finger ATLs (BTLs) are two families of ubiquitin ligases that share some common structural features. These are intronless genes that encode a highly related RING finger domain, and yet during evolutionary history, their mode of gene expansion and function is rather different. In each of these two families, the co-occurrence of transmembrane helices or C2/C2 (BZF finger) domains with a selected variation on the RING finger has been subjected to strong selection pressure in order to preserve their unique domain architectures during evolution.

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Decoupling of soil nutrient cycles as a function of aridity in global drylands : Nature : Nature Publishing Group

Decoupling of soil nutrient cycles as a function of aridity in global drylands : Nature : Nature Publishing Group | Plant Gene Seeker -PGS | Scoop.it
The biogeochemical cycles of carbon (C), nitrogen (N) and phosphorus (P) are interlinked by primary production, respiration and decomposition in terrestrial ecosystems.
Andres Zurita's insight:

The biogeochemical cycles of carbon (C), nitrogen (N) and phosphorus (P) are interlinked by primary production, respiration and decomposition in terrestrial ecosystems1. It has been suggested that the C, N and P cycles could become uncoupled under rapid climate change because of the different degrees of control exerted on the supply of these elements by biological and geochemical processes1, 2, 3, 4, 5. Climatic controls on biogeochemical cycles are particularly relevant in arid, semi-arid and dry sub-humid ecosystems (drylands) because their biological activity is mainly driven by water availability6, 7, 8. The increase in aridity predicted for the twenty-first century in many drylands worldwide9, 10, 11 may therefore threaten the balance between these cycles, differentially affecting the availability of essential nutrients12, 13, 14. Here we evaluate how aridity affects the balance between C, N and P in soils collected from 224 dryland sites from all continents except Antarctica. We find a negative effect of aridity on the concentration of soil organic C and total N, but a positive effect on the concentration of inorganic P. Aridity is negatively related to plant cover, which may favour the dominance of physical processes such as rock weathering, a major source of P to ecosystems, over biological processes that provide more C and N, such as litter decomposition12, 13, 14. Our findings suggest that any predicted increase in aridity with climate change will probably reduce the concentrations of N and C in global drylands, but increase that of P. These changes would uncouple the C, N and P cycles in drylands and could negatively affect the provision of key services provided by these ecosystems.

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