Additional file 3: of Cloning and characterization of an ABA-independent DREB transcription factor gene, HcDREB2, in Hemarthria compressa

Nucleotide sequence and deduced amino-acid sequence of HcDREB cDNA. (DOC 31 kb

AFLP-based genetic diversity of wild orchardgrass germplasm collections from Central Asia and Western China, and the relation to environmental factors

<div><p><i>Dactylis glomerata</i> L. (orchardgrass) is an important perennial forage species in temperate areas of the world. It is usually used for silage, grazing and hay because of its high nutritional value and reproducibility. Central Asia, Xinjiang and Tibetan Plateau in China possess various special micro-environments that harbor many valuable resources, while different degrees of degradation of the grassland ecosystem occurred due to climatic changing and human activities. Investigating the genetic diversity of wild <i>D</i>. <i>glomerat</i> could provide basis for collection, protection, and utilization of some excellent germplasm resources. Totally 210 individuals from 14 populations—five from Xinjiang, two from Kangding (Tibetan Plateau), and seven from Central Asia were identified using AFLP technology. The average values of Nei’s genetic diversity (<i>H</i>_<i>j</i>) and Shannon information index (<i>H</i>_<i>o</i>) were 0.383 and 0.394 respectively. UPGMA tree, STRUCTURE analysis and principal coordinate analysis (PCoA) showed populations from same region clustered together. AMOVA revealed 35.10% of the genetic differentiation (<i>F</i>_<i>st</i>) occurred among populations. Gene flow (<i>N</i>_<i>m</i>) was limited among all populations. Genetic diversity of <i>D</i>. <i>glomerata</i> was high but limited under isolation-by-distance pattern, resulting in high genetic differentiation and low gene flow among populations. Adjacent regions also exhibited similar results because of the barriers of high mountains. The environmental factors, such as precipitation, elevation, latitude and longitude also had some impacts on genetic diversity and structure pattern of populations.</p></div

Principle coordinate plot of 210 <i>D</i>. <i>glomerata</i> individuals.

<p>The 15 individuals of per population were represented by the same dots.</p

Pearson correlation analysis between genetic diversity and environmental factors.

<p>Codes: <i>H</i>_<i>j</i>, Nei’s genetic diversity; <i>H</i>_<i>o</i>, Shannon information index; <i>N</i>_<i>p</i>, Number of polymorphic loci; LD, linkage disequilibrium.</p

Geographical locations of analyzed populations of <i>Dactylis glomerata</i>.

<p>Geographical locations of analyzed populations of <i>Dactylis glomerata</i>.</p

Analysis of molecular variance of <i>D</i>. <i>glomerata</i>.

<p>Analysis of molecular variance of <i>D</i>. <i>glomerata</i>.</p

Metabolic Pathways Regulated by Chitosan Contributing to Drought Resistance in White Clover

Increased endogenous chitosan (CTS) could be associated with improved drought resistance in white clover (<i>Trifolium repens</i>). Plants were pretreated with or without 1 mg/mL CTS and then were subjected to optimal or water-limited condition in controlled growth chambers for 6 days. Phenotypic and physiological results indicated that exogenous CTS significantly improved drought resistance of white clover. Metabolome results showed that exogenous CTS induced a significant increase in endogenous CTS content during dehydration accompanied by the maintenance of greater accumulation of sugars, sugar alcohols, amino acids, organic acids, and other metabolites (ascorbate, glutathione, flavonoids, putrescine, and spermidine). These compounds are associated with osmotic adjustment, antioxidant defense, stress signaling, and energy metabolism under stress condition. Similarly, transcriptome revealed that many genes in relation to amino acid and carbohydrate metabolism, energy production and conversion, and ascorbate–glutathione and flavonoid metabolism were significantly up-regulated by CTS in response to dehydration stress. CTS-induced drought resistance was associated with the accumulation of stress protective metabolites, the enhancement of ascorbate–glutathione and tricarboxylic acid cycle, and increases in the γ-aminobutyric acid shunt, polyamine synthesis, and flavonoids metabolism contributing to improved osmotic adjustment, antioxidant capacity, stress signaling, and energy production for stress defense, thereby maintaining metabolic homeostasis under dehydration stress

List of Mantel test, genetic differentiation and gene flow for <i>D</i>. <i>glomerata</i> in different regions.

<p>Codes: <i>F</i>_<i>st</i>, Nei’s genetic differentiation; <i>G’</i>_<i>st</i>, Shannon differentiation coefficient; <i>N</i>_<i>m</i>, gene flow.</p

Physiological and iTRAQ-Based Proteomic Analyses Reveal the Function of Spermidine on Improving Drought Tolerance in White Clover

Endogenous spermidine interacting with phytohormones may be involved in the regulation of differentially expressed proteins (DEPs) associated with drought tolerance in white clover. Plants treated with or without spermidine (50 μM) were subjected to 20% PEG 6000 nutrient solution to induce drought stress (50% leaf-relative water content). The results showed that increased endogenous spermidine induced by exogenous spermidine altered endogenous phytohormones in association with improved drought tolerance, as demonstrated by the delay in water-deficit development, improved photosynthesis and water use efficiency, and lower oxidative damage. As compared to untreated plants, Spd-treated plants maintained a higher abundance of DEPs under drought stress involved in (1) protein biosynthesis (ribosomal and chaperone proteins); (2) amino acids synthesis; (3) the carbon and energy metabolism; (4) antioxidant and stress defense (ascorbate peroxidase, glutathione peroxidase, and dehydrins); and (5) GA and ABA signaling pathways (gibberellin receptor GID1, ABA-responsive protein 17, and ABA stress ripening protein). Thus, the findings of proteome could explain the Spd-induced physiological effects associated with drought tolerance. The analysis of functional protein–protein networks further proved that the alteration of endogenous spermidine and phytohormones induced the interaction among ribosome, photosynthesis, carbon metabolism, and amino acid biosynthesis. These differences could contribute to improved drought tolerance

Additional file 6: of Genome-wide association study of rust traits in orchardgrass using SLAF-seq technology

(XLSX 50 kb