Adaptive Strategy of the Perennial Halophyte Grass to Long-Term Salinity Stress.

Salinity stress influences plants throughout their entire life cycle. However, little is known about the response of plants to long-term salinity stress (LSS). In this study, , a perennial halophyte grass, was exposed to 300 mM NaCl for two years (completely randomized experiment design with three biological replicates).

Regulation of Root Exudation in Wheat Plants in Response to Alkali Stress.

Soil alkalization is an important environmental factor limiting crop production. Despite the importance of root secretion in the response of plants to alkali stress, the regulatory mechanism is unclear. In this study, we applied a widely targeted metabolomics approach using a local MS/MS data library constructed with authentic standards to identify and quantify root exudates of wheat under salt and alkali stresses.

Chromosome translocation affects multiple phenotypes, causes genome-wide dysregulation of gene expression, and remodels metabolome in hexaploid wheat.

Chromosomal rearrangements (CRs) may occur in newly formed polyploids due to compromised meiotic fidelity. Moreover, CRs can be more readily tolerated in polyploids allowing their longer-term retention and hence potential spreading/fixation within a lineage. The direct functional consequences of CRs in plant polyploids remain unexplored.

Homoeologous exchange enables rapid evolution of tolerance to salinity and hyper-osmotic stresses in a synthetic allotetraploid wheat.

The link between polyploidy and enhanced adaptation to environmental stresses could be a result of polyploidy itself harbouring higher tolerance to adverse conditions, or polyploidy possessing higher evolvability than diploids under stress conditions. Natural polyploids are inherently unsuitable to disentangle these two possibilities. Using selfed progenies of a synthetic allotetraploid wheat AT3 (AADD) along with its diploid parents, Triticum urartu TMU38 (AA) and Aegilops tauschii TQ27 (DD), we addressed the foregoing issue under abiotic salinity and hyper-osmotic (drought-like) stress.

Salinity Tolerance in a Synthetic Allotetraploid Wheat (SSAA) Is Similar to Its Higher Tolerant Parent (SS) and Linked to Flavonoids Metabolism.

Allotetraploidization between A and S (closely related to B) genome species led to the speciation of allotetraploid wheat (genome BBAA). However, the immediate metabolic outcomes and adaptive changes caused by the allotetraploidization event are poorly understood. Here, we investigated how allotetraploidization affected salinity tolerance using a synthetic allotetraploid wheat line (genome SSAA, labeled as 4x), its (genome SS, labeled as SS) and (AA genome, labeled as AA) parents.

Extensive secretion of phenolic acids and fatty acids facilitates rhizosphere pH regulation in halophyte Puccinellia tenuiflora under alkali stress.

Puccinellia tenuiflora is a forage grass with high nutritional value that is an extreme alkali-tolerant halophyte: it can survive at pH 10-11. Root secretion is perceived as a major plant alkali tolerance mechanism. In the present study, we applied a widely targeted metabolomic approach to identify and quantify the root exudates of P.

Multiomics analysis provides insights into alkali stress tolerance of sunflower (Helianthus annuus L.).

Alkali stress is an extreme complex stress type, which exerts negative effects on plants via chemical destruction, osmotic stress, ion injury, nutrient deficiency, and oxygen deficiency. Soil alkalization has produced severe problems in some area, while plant alkali tolerance is poorly understood. Sunflower (Helianthus annuus L.

Comparative Genomics and Transcriptomics of the Extreme Halophyte Provides Insights Into Salinity Tolerance Differentiation Between Halophytes and Glycophytes.

Halophytes and glycophytes exhibit clear differences in their tolerance to high levels of salinity. The genetic mechanisms underlying this differentiation, however, remain unclear. To unveil these mechanisms, we surveyed the evolution of salinity-tolerant gene families through comparative genomic analyses between the model halophyte and glycophytic Gramineae plants, and compared their transcriptional and physiological responses to salinity stress.

Genome-wide DNA methylation analysis and biochemical responses provide insights into the initial domestication of halophyte Puccinellia tenuiflora.

Puccinellia tenuiflora was domesticated for two years by growing it under non-saline conditions, providing epigenetic and biochemical insights into the initial domestication of extreme halophytes. Some halophytes have economic value as crop species. The domestication of halophytes may offer hope in solving the problem of soil salinization.

Adaptive strategy of allohexaploid wheat to long-term salinity stress.

Background: Most studies of crop salinity tolerance are conducted under short-term stress condition within one growth stage. Understanding of the mechanisms of crop response to long-term salinity stress (LSS) is valuable for achieving the improvement of crop salinity tolerance. In the current study, we exposed allohexaploid wheat seeds to LSS conditions from germination stage to young seedling stage for 30 days.

Genome of extreme halophyte Puccinellia tenuiflora.

Background: Puccinellia tenuiflora, a forage grass, is considered a model halophyte given its strong tolerance for multiple stress conditions and its close genetic relationship with cereals. This halophyte has enormous values for improving our understanding of salinity tolerance mechanisms. The genetic information of P.

An extracted tetraploid wheat harbouring the BBAA component of common wheat shows anomalous shikimate and sucrose metabolism.

Background: The BBAA subgenomes of hexaploid common wheat are structurally intact, which makes it possible to extract the BBAA subgenomes to constitute a novel plant type, namely, extracted tetraploid wheat (ETW). ETW displays multiple abnormal phenotypes such as massively reduced biomass and abnormal spike development, compared to extant tetraploid wheat with a BBAA genome. The genetic, biochemical and physiological basis underlying the phenotypic abnormality of ETW remains unknown.

Proteomic profiling sheds light on alkali tolerance of common wheat (Triticum aestivum L.).

Alkali (high-pH) stress is an important factor limiting agricultural production and has complex effects on plant metabolism. Transcriptomics is widely used in the discovery of stress-response genes, but it provides only a rough estimation for gene expression. Proteomics may be more helpful than transcriptomics for the discovery and identification of stress-response genes.

Rapid and pervasive development- and tissue-specific homeolog expression partitioning in newly formed inter-subspecific rice segmental allotetraploids.

Background: In diverse plant taxa, whole-genome duplication (WGD) events are major sources of phenotypic novelty. Studies of gene expression in synthetic polyploids have shown immediate expression and functional partitioning of duplicated genes among different tissues. Many studies of the tissue-specific homeolog expression partitioning have focused on allopolyploids that have very different parental genomes, while few studies have focused on autopolyploids or allopolyploids that have similar parental genomes.

Meiotic chromosome stability of a newly formed allohexaploid wheat is facilitated by selection under abiotic stress as a spandrel.

Polyploidy is a prominent route to speciation in plants; however, this entails resolving the challenges of meiotic instability facing abrupt doubling of chromosome complement. This issue remains poorly understood. We subjected progenies of a synthetic hexaploid wheat, analogous to natural common wheat, but exhibiting extensive meiotic chromosome instability, to heat or salt stress.

A newly formed hexaploid wheat exhibits immediate higher tolerance to nitrogen-deficiency than its parental lines.

Background: It is known that hexaploid common wheat (Triticum aestivum L.) has stronger adaptability to many stressful environments than its tetraploid wheat progenitor. However, the physiological basis and evolutionary course to acquire these enhanced adaptabilities by common wheat remain understudied.

Transcriptomic Profiling and Physiological Responses of Halophyte Provide Insights into Salt Tolerance.

Halophytes are remarkable plants that can tolerate extremely high-salinity conditions, and have different salinity tolerance mechanisms from those of glycophytic plants. In this work, we investigated the mechanisms of salinity tolerance of an extreme halophyte, (Pall.) C.

Segmental allotetraploidy generates extensive homoeologous expression rewiring and phenotypic diversity at the population level in rice.

Allopolyploidization, that is, concomitant merging and doubling of two or more divergent genomes in a common nucleus/cytoplasm, is known to instantly alter genomewide transcriptome dynamics, a phenomenon referred to as "transcriptomic shock." However, the immediate effects of transcriptomic alteration in generating phenotypic diversity at the population level remain underinvestigated. Here, we employed the MassARRAY-based Sequenom platform to assess and compare orthologous, allelic and homoeologous gene expression status in two tissues (leaf and root) of a set of randomly chosen individuals from populations of parental rice subspecies (indica and japonica), in vitro "hybrids" (parental mixes), reciprocal F1 hybrids and reciprocal tetraploids at the 5th-selfed generation (S5).

Comparison of Ionomic and Metabolites Response under Alkali Stress in Old and Young Leaves of Cotton ( L.) Seedlings.

Soil salinization is an important agriculture-related environmental problem. Alkali stress and salt stress strongly influence the metabolic balance in plants. Salt and alkali stresses exert varied effects on old and young tissues, which display different adaptive strategies.

Evolution of physiological responses to salt stress in hexaploid wheat.

Hexaploid bread wheat (Triticum aestivum L., genome BBAADD) is generally more salt tolerant than its tetraploid wheat progenitor (Triticum turgidum L.).

Evolution of the BBAA component of bread wheat during its history at the allohexaploid level.

Subgenome integrity in bread wheat (Triticum aestivum; BBAADD) makes possible the extraction of its BBAA component to restitute a novel plant type. The availability of such a ploidy-reversed wheat (extracted tetraploid wheat [ETW]) provides a unique opportunity to address whether and to what extent the BBAA component of bread wheat has been modified in phenotype, karyotype, and gene expression during its evolutionary history at the allohexaploid level. We report here that ETW was anomalous in multiple phenotypic traits but maintained a stable karyotype.

Transcriptome alteration in a rice introgression line with enhanced alkali tolerance.

Alkali stress inhibits plant growth and development and thus limits crop productivity. To investigate the possible genetic basis of alkali tolerance in rice, we generated an introgressed rice line (K83) with significantly enhanced tolerance to alkali stress compared to its recipient parental cultivar (Jijing88). By using microarray analysis, we examined the global gene expression profiles of K83 and Jijing88, and found that more than 1200 genes were constitutively and differentially expressed in K83 in comparison to Jijing88 with 572 genes up- and 654 down-regulated.

Effects of salt stress on ion balance and nitrogen metabolism of old and young leaves in rice (Oryza sativa L.).

Background: It is well known that salt stress has different effects on old and young tissues. However, it remains largely unexplored whether old and young tissues have different regulatory mechanism during adaptation of plants to salt stress. The aim of this study was to investigate whether salt stress has different effects on the ion balance and nitrogen metabolism in the old and young leaves of rice, and to compare functions of both organs in rice salt tolerance.

Comparison of ion balance and nitrogen metabolism in old and young leaves of alkali-stressed rice plants.

Background: Alkali stress is an important agricultural contaminant and has complex effects on plant metabolism. The aim of this study was to investigate whether the alkali stress has different effects on the growth, ion balance, and nitrogen metabolism in old and young leaves of rice plants, and to compare functions of both organs in alkali tolerance.

Methodology/principal Findings: The results showed that alkali stress only produced a small effect on the growth of young leaves, whereas strongly damaged old leaves.

Heritable alteration in salt-tolerance in rice induced by introgression from wild rice (Zizania latifolia).

Background: Introgression as a means of generating phenotypic novelty, including altered stress tolerance, is increasingly being recognized as common. The underlying basis for de novo genesis of phenotypic variation in the introgression lines remains largely unexplored. In this investigation, we used a rice line (RZ35) derived from introgressive hybridization between rice (Oryza sativa L.