Chemical investigation of one fungal strain P. chlamydosporia YMF 1.00613 isolated from root knots of tobacco infected by Meloidogyne incognita led to the isolation and identification of four aurovertin-type metabolites, which include a new compound, aurovertin I (A1), and three known metabolites, aurovertins E, F and D (A2-A4). Their structures were established by spectroscopic studies such as 1D- and 2D-NMR and MS analysis. Aurovertin I (A1) is the first natural product with an aurovertin skeleton with one less carbon. Compounds A3 and A4 showed the toxicity to the worms of the free-living nematode Panagrellus redivevus with the LC(50) values 88.6 and 41.7 microg/mL at 48 h, respectively. All four aurovertins did not show obvious inhibitory effects on egg hatch of root knot nematode Meloidogyne incognita. The results suggested that the aurovertin-type metabolites produced by P. chlamydosporia might be one of the pathogenic factors involved in the suppression of nematodes.

Autophagy (self-eating), a conserved pathway in eukaryotes, which is designed to handle cytoplasmic material in bulk and plays an important role in the remobilization of nutrient, such as nitrogen (N) under suboptimal nutrient conditions. Here, we identified a core component of an autophagy gene in rice ( Oryza sativa ), OsATG8a , with increased expression levels under N starvation conditions. Overexpression of OsATG8a significantly enhanced the level of autophagy and the number of effective tillers in the transgenic rice. In addition, the transgenic lines accumulated more N in grains than in the dry remains and the yield was significantly increased under normal N conditions. Further N allocation studies revealed that the nitrogen uptake efficiency (NUpE) and nitrogen use efficiency (NUE) significantly increased. Otherwise, under suboptimal N conditions, overexpression of OsATG8a did not seem to have any effect on yield and NUE, but NUpE was still improved significantly. Based on our findings, we consider OsATG8a to be a great candidate gene to increase NUE and yield.

Soybean [Glycine max (L.) Merr.] seed, which contains high levels of oil and protein, is one of China's most important native crops. The aim of this study was to investigate how regional and environmental factors affect the compositions of protein, amino acids, oil, and fatty acids. A total of 127 soybean cultivars from four main regions of China were analyzed. The levels of total protein and most of amino acids showed a trend of increasing from Northern to Southern China, while the levels of total oil, stearic acid, linolenic acid, and proline showed a trend of decreasing. The variation of protein, oil, palmitic acid, and linoleic acid content of soybean grown in the four regions was low, while variation of other constituents remained high. Most amino acids contents were positively correlated with protein content. The total oil content showed a negative correlation with protein content. The content of linolenic acid was positively correlated with the content of palmitic acid and stearic acid but negatively correlated with the oleic acid content. The southern regions have the potential for high‐protein soybean production, while the northern regions of China have the potential for high‐oil soybean production.

We tested for a tradeoff across species between plant maximum photosynthetic rate and the ability to maintain photosynthesis under adverse conditions in the unfavorable season. Such a trade-off would be consistent with the observed trade-off between maximum speed and endurance in athletes and some animals that has been explained by cost-benefit theory. This trend would have importance for the general understanding of leaf design, and would simplify models of annual leaf carbon relations. We tested for such a trade-off using a database analysis across vascular plants and using an experimental approach for 29 cycad species, representing an ancient plant lineage with diversified evergreen leaves. In both tests, a higher photosynthetic rate per mass or per area in the favorable season was associated with a stronger absolute or percent decline in the unfavorable season. We resolved a possible mechanism based on biomechanics and nitrogen allocation; cycads with high leaf toughness (leaf mass per area) and higher investment in leaf construction than in physiological function (C/N ratio) tended to have lower warm season photosynthesis but less depression in the cool season. We propose that this trade-off, consistent with cost-benefit theory, represents a significant physio-phenological constraint on the diversity and seasonal dynamics of photosynthetic rate.

No abstract

Cobalt and nickel play important roles in various biological processes. The present work focuses on the enrichment and identification of Co- and Ni-binding motifs and proteins in Gram-positive bacteria. Immobilized metal affinity column (IMAC) was used to partially enrich putative metal-binding proteins and peptides from Streptococcus pneumoniae, and then LTQ-Orbitrap mass spectrometry (MS) was applied to identify and characterize the metal-binding motifs and proteins. In total, 208 and 223 proteins were isolated by Co- and Ni-IMAC columns respectively, in which 129 proteins were present in both preparations. Based on the gene ontology (GO) analysis, the putative metal-binding proteins were found to be mainly involved in protein metabolism, gene expression regulation and carbohydrate metabolism. These putative metal-binding proteins form a highly connected network, indicating that they may synergistically work together to achieve specific biological functions. Putative Co- and Ni-binding motifs were identified with H(X)nH, M(X)nH and H(X)nM derived from the identified 51 Co-binding peptides and 66 Ni-binding peptides. Statistics of frequency of amino acids in the metal-binding motifs showed that cobalt and nickel prefer to bind histidine and methionine, but not cysteine. These results obtained by a systematic metalloproteomic approach provide important clues for the further investigation of metal homeostasis and metal-related virulence of bacteria.

ObjectivesObtain endophyte strains with effective resveratrol production from superior grapevine variety Cabernet Sauvignon in Xinjiang and determine related taxonomic position of the strain.ResultsSeventy-three strains of endophytes, including 23 strains of bacteria, 14 ones of actinomycetes, 24 fungus and 12 yeasts, were isolated, respectively. The distribution law of endophytes was spring (30.14 %) = summer (30.14 %) < autumn (39.73 %) in different seasons, while the fruit (12.33 %) < leaf (20.55 %) < stem (32.88 %) < root (34.25 %) in different tissues and organs. From the 36 strains of endophytic fungi isolated, seven strains producing polyphenols were screened by ferric chloride–potassium ferricyanide color reaction. C2J6, stable genetic properties producing highly 1.48 mg L−1 of resveratrol, was identified as Aspergillus niger by 26S rDNA-ITS sequence analysis after thin-layer chromatography sieve analysis, ultra violet wavelength scanning and high performance liquid chromatography, respectively.ConclusionsThere were the certain number and kinds of endophytes in the various tissues of Cabernet Sauvignon, which, to a certain extent, reflected the biological diversity of plant endophytes. The fact that the fungus C2J6 producing resveratrol in grape was acquired attested the special ability of the endophytes to produce the same or similar bioactive substances as the host plants.

No abstract