Mu Peng

Chromatographic analysis of fatty acid composition in differently sized seeds of castor accessions

The aim of this study was to examine the relationship between oil content and seed size in 32 castor accessions. The oil content and fatty acid composition were determined using the Soxhlet extraction method and capillary gas chromatography. The results indicated that the values of seed characteristics were very variable. The crude fat percentage among the accessions ranged from 36.62% to 49.19%. The content of ricinoleic acid was highest in all fatty acid compositions, from 82.3% to 88.6%. The other fatty acids appeared at a low content (less than 1%). Correlation analysis revealed that seed size was significantly positively correlated with 100-seed weight, the crude fat content and the ricinoleic acid content but showed negative correlation with the content of palmitic and arachidic acids. Hierarchical clustering of castor cultivars separated the 32 accessions into four independent clusters. The obtained results provide useful information for further research in breeding and utilization of castor oil.

Genetic diversity of strawberry (Fragaria ananassa Duch.) from the Motuo County of the Tibet Plateau determined by AFLP markers

Strawberry (Fragaria ananassa Duch.) is one of the most important berries in the world. Amplified fragment length polymorphism (AFLP) was used to evaluate the genetic diversity of strawberry in Motuo County of the Tibet Plateau. Seventy strawberry samples grown in Motuo County were collected for AFLP analysis using 256 primer combinations. A set of 10 primer combinations produced 374 clearly identifiable AFLP loci. The polymorphism ranged from 50% to 64% with an average of 58.8%. Neis genetic differentiation index for AFLP was 0.75, and the estimate of gene flow was less than 1 (Nm, 0.41). The unweighted pair group method with arithmetic mean dendrogram and Bayesian analysis clustered 70 samples into six groups. These findings clearly indicated high genetic diversity in wild strawberry from the Motuo County. These results could lay the foundation for further breeding and conservation of strawberry.

Comparative mitochondrial proteomic, physiological, biochemical and ultrastructural profiling reveal factors underpinning salt tolerance in tetraploid black locust (Robinia pseudoacacia L.)

BackgroundPolyploidy is an important phenomenon in plants because of its roles in agricultural and forestry production as well as in plant tolerance to environmental stresses. Tetraploid black locust (Robinia pseudoacacia L.) is a polyploid plant and a pioneer tree species due to its wide ranging adaptability to adverse environments. To evaluate the ploidy-dependent differences in leaf mitochondria between diploid and tetraploid black locust under salinity stress, we conducted comparative proteomic, physiological, biochemical and ultrastructural profiling of mitochondria from leaves.ResultsMitochondrial proteomic analysis was performed with 2-DE and MALDI-TOF-MS, and the ultrastructure of leaf mitochondria was observed by transmission electron microscopy. According to 2-DE analysis, 66 proteins that responded to salinity stress significantly were identified from diploid and/or tetraploid plants and classified into 9 functional categories. Assays of physiological characters indicated that tetraploids were more tolerant to salinity stress than diploids. The mitochondrial ultrastructure of diploids was damaged more severely under salinity stress than that of tetraploids.ConclusionsTetraploid black locust possessed more tolerance of, and ability to acclimate to, salinity stress than diploids, which may be attributable to the ability to maintain mitochondrial structure and to trigger different expression patterns of mitochondrial proteins during salinity stress.

Methyl jasmonate regulated diploid and tetraploid black locust (Robinia pseudoacacia L.) tolerance to salt stress

Methyl jasmonate (MeJA) is an essential and promising plant growth regulation factor that can improve plant development and growth. Here, we explored the mechanism by which MeJA regulates the tolerance of black locust (Robinia pseudoacacia L.) to salt stress. In this study, diploid and tetraploid R.pseudoacacia were subjected to three treatments: 500xa0mM NaCl; 100xa0μM MeJA; and 500xa0mM NaCl and 100xa0μM MeJA, and the changes in plant growth, endogenous MeJA levels and the anti-oxidative metabolism of leaves were investigated. The results showed that salt stress significantly inhibited plant growth and induced the accumulation of Na+ and Cl− ions, malondialdehyde (MDA) content and reactive oxygen species. However, these adverse effects could be alleviated by applying MeJA, which was followed by a marked increase in the activities of antioxidant enzymes. In addition, some genes encoding several antioxidant enzymes were also up-regulated. Simultaneously, the endogenous MeJA content in MeJA-treated plants was lower than in salt-treated plants. It is noteworthy that tetraploids always possessed higher salt tolerance and obtained greater positive effects from MeJA than diploids. These results suggested that MeJA might play a protective role in defense responses, enabling diploid and tetraploid black locust, especially tetraploid, to better tolerate the adverse effects of salt stress.

Isolation and detection of transcript-derived fragments (TDFs) in NaCl-stressed black locust (Robinia pseudoacacia L.) using cDNA-AFLP analysis

AbstractPlant physiology and biochemistry are both naffected by salinity, which is an important abiotic stressor. In this study, we identified transcript-derived fragments (TDFs) in response to salt stress in black locust (Robinia pseudoacacia L.) using cDNA-amplified fragment length polymorphism (cDNA-AFLP) analysis. Seventy-four TDFs were identified in the leaves of two-year-old plants after NaCl treatment (500xa0mM for 0, 5, 10 and 15xa0days). Based on the gene ontology (GO) terminology, 30 TDFs shared high homology with known genes and were classified into 6 groups: metabolism-related factors, defense-related proteins, transcription factors, stress and signal transduction-related factors and energy-related factors. Eight TDFs were selected for further study, and their expression patterns in the leaves were verified by real-time polymerase chain reaction (RT-PCR) at different stages of salt stress. Our data provide a theoretical basis for research on the mechanisms of salt tolerance in woody plants.

Phytochemical Screening and Antimicrobial Activities of Stem, Leaves and Fruit Extracts of Viscum album L.

The current research was conducted to study the qualitative analysis and antimicrobial activity of different extracts of Viscum. album L. Screening of Viscum album for their chemicals was led by familiar qualitative procedures, which exposed the existence of a number of bioactive compounds including alkaloids, saponins, tannins, flavonoids, terpenoids, steroids, reducing sugar and phenols. The antimicrobial activities were investigated by disc diffusion method. Investigation of the data discovered that all of the five extracts of Viscum album stems, leaves and fruit showed diverse range of antimicrobial activities. Ethyl acetate, butanol, water and crude extracts showed maximum inhibitory effects against all the microbial species. Especially, Gram-positive bacterial and fungal pathogen. The most liable, gram-positive bacteria were Bacillus subtilis, Bacillus atrophaeus and Staphylococcus aureus, which were repressed by all extracts except n-hexane. The most susceptible gram-negative bacterial species were Escherichia coli, Erwinia carotovora and Agrobacterium tumefaciens where as the most resilient gram-negative bacterium was Salmonella typhi. The results have also supported the practice of aqueous extract were found to be in effect against Salmonella typhi and Escherichia coli. Thus, our findings have provided support for the use of Viscum album stems, leaves and fruit in traditional medicines.

Evaluation of genetic diversity among Piptoporus betulinus as revealed by inter simple sequence repeat markers

ABSTRACT Four populations of Piptoporus betulinus from Maoer, Changbai, Daxingan and Xiaoxingan Mountains were sampled. DNA was isolated and purified from fruiting bodies. Inter simple sequence repeat markers were first used to evaluate the genetic diversity and differentiation of P. betulinus in this study. The results showed that the strains from Xiaoxingan Mountain had the highest diversity among the four populations, followed by the samples from Maoer and Daxingan Mountains, whereas the Changbai Mountain samples harboured the lowest value. Cluster analysis and principal coordinates analysis indicated that all of the populations had the same type of geographical distribution (geographical affiliations). These findings will provide useful information for further research and utilization of wood-rotting fungi and will lay the foundation for development of genetic diversity in P. betulinus from various geographic origins.