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In order to improve the production of the anticancer dimeric indole alkaloids in Catharanthuse roseus, much research has been dedicated to culturing cell lines, hairy roots, and efforts to elucidate the regulation of the monoterpenoid indole alkaloid (MIA) biosynthesis. In this study, the ORCA3 (Octadecanoid-derivative Responsive Catharanthus AP2-domain) gene alone or integrated with the G10H (geraniol 10-hydroxylase) gene were first introduced into C. roseus plants. Transgenic C. roseus plants overexpressing ORCA3 alone (OR lines), or co-overexpressing G10H and ORCA3 (GO lines) were obtained by genetic modification. ORCA3 overexpression induced an increase of AS, TDC, STR and D4H transcripts but did not affect CRMYC2 and G10H transcription. G10H transcripts showed a significant increase under G10H and ORCA3 co-overexpression. ORCA3 and G10H overexpression significantly increased the accumulation of strictosidine, vindoline, catharanthine and ajmalicine but had limited effects on anhydrovinblastine and vinblastine levels. NMR-based metabolomics confirmed the higher accumulation of monomeric indole alkaloids in OR and GO lines. Multivariate data analysis of 1H NMR spectra showed change of amino acid, organic acid, sugar and phenylpropanoid levels in both OR and GO lines compared to the controls. The result indicated that enhancement of MIA biosynthesis by ORCA3 and G10H overexpression might affect other metabolic pathways in the plant metabolism of C. roseus.

BackgroundPlants are oftentimes exposed to many types of abiotic stresses. Drought is one of the main environmental stresses which limits plant growth, distribution and crop yield worldwide. Amygdalus mira (Koehne) Yü et Lu is an important wild peach, and it is considered an ideal wild peach germplasm for improving cultivated peach plants. Because of the loss of genetic variation, cultivated peach plants are sensitive to biotic and abiotic stresses. Wild peach germplasm can offer many useful genes for peach improvement. Responses to drought by withholding water have been studied in Amygdalus mira (Koehne) Yü et Lu roots. In this study, plants were divided into well-watered (control) and water-stressed (treatment) groups, and the treatment group did not receive water until the recovery period (day 16).ResultsSeveral physiological parameters, including root water content and root length, were reduced by drought stress and recovered after rewatering. In addition, the relative conductivity, the levels of proline, MDA and H2O2, and the activities of ROS scavenging enzymes (POD, APX and CAT) were increased, and none of these factors, except the level of proline, recovered after rewatering. In total, 95 differentially expressed proteins were revealed after drought. The identified proteins refer to a extensive range of biological processes, molecular functions and cellular components, including cytoskeleton dynamics (3.16% of the total 95 proteins), carbohydrate and nitrogen metabolism (6.33% of the total 95 proteins), energy metabolism (7.37% of the total 95 proteins), transcription and translation (18.95% of the total 95 proteins), transport (4.21% of the total 95 proteins), inducers (3.16% of the total 95 proteins), stress and defense (26.31% of the total 95 proteins), molecular chaperones (9.47% of the total 95 proteins), protein degradation (3.16% of the total 95 proteins), signal transduction (7.37% of the total 95 proteins), other materials metabolism (5.26% of the total 95 proteins) and unknown functions (5.26% of the total 95 proteins). Proteins related to defense, stress, transcription and translation play an important role in drought response. In addition, we also examined the correlation between protein and transcript levels.ConclusionsThe interaction between enzymatic and non-enzymatic antioxidants, the levels of proline, MDA, H2O2 and the relative conductivity, and the expression level of proteins in drought-treated plants all contribute to drought resistance in Amygdalus mira (Koehne) Yü et Lu. Electronic supplementary materialThe online version of this article (doi:10.1186/s12870-017-1000-z) contains supplementary material, which is available to authorized users.

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Manganese oxides of various crystal structures (α-, β-, γ-and δ-MnO 2 , Mn 2 O 3 , Mn 3 O 4 and amorphous) were synthesized by facile methods. The adsorption capacities for methyl orange of these materials were investigated and the resulting materials were characterized by different techniques, such as SEM, XRD and BET surface area measurement. The adsorption capacities were strongly depend on the crystallographic structures and morphologies, and followed an order of A-MnO 2 ＞ Mn 2 O 3 ＞Mn 3 O 4 ＞α-MnO 2 nanowires＞β-MnO 2 ＞γ-MnO 2 ＞α-MnO 2 nanotubes＞ δ-MnO 2 , while the adsorption property could be greatly improved by increasing the surface area and pore properties of the adsorbents. A-MnO 2 was found to be the most effective adsorbent among the other materials and the adsorption process was systematically investigated. The adsorption kinetics data closely followed the pseudo-second-order kinetic model and the results obtained from intraparticle diffusion model indicated that the overall process was jointly influenced by external mass transfer and intra-particle diffusion. The maximum adsorption capacity determined from Langmuir isotherm model was 1488.7 mg g -1 . Moreover, thermodynamic analyses revealed that the adsorption of MO onto A-MnO 2 was spontaneous and exothermic, and the physical adsorption mechanisms including electrostatic interaction played a dominant role in the adsorption process between MO and A-MnO 2 . These combined results indicated that A-MnO 2 was an efficient adsorbent for the removal of MO from wasterwater. composition of the adsorbent, namely, the adsorption process is mainly physical in nature, which is in good accordance with results discussed above. The crystal structure and morphology of samples significantly influence its adsorption capacity while the adsorption property could be greatly improved by increasing the surface area and pore properties, as schematically illustrated in Scheme 1. Fig. 12The XPS analysis of the A-MnO 2 (a) and the MO adsorbed A-MnO 2 (b).A-MnO 2 has the best adsorption capacity for methyl orange among other manganese oxides materials.

Obtaining genetic variation information from indica rice hybrid parents and identification of loci associated with heterosis are important for hybrid rice breeding. Here, we resequence 1,143 indica accessions mostly selected from the parents of superior hybrid rice cultivars of China, identify genetic variations, and perform kinship analysis. We find different hybrid rice crossing patterns between 3- and 2-line superior hybrid lines. By calculating frequencies of parental variation differences (FPVDs), a more direct approach for studying rice heterosis, we identify loci that are linked to heterosis, which include 98 in superior 3-line hybrids and 36 in superior 2-line hybrids. As a proof of concept, we find two accessions harboring a deletion in OsNramp5, a previously reported gene functioning in cadmium absorption, which can be used to mitigate rice grain cadmium levels through hybrid breeding. Resource of indica rice genetic variation reported in this study will be valuable to geneticists and breeders.

Catharanthuse roseus is a well-known medicinal plant for its two valuable anticancer compounds: vinblastine and vincristine, which belongs to terpenoid indole alkaloids. Great efforts have been made to study the principles of its secondary metabolic pathways to regulate the alkaloids biosynthesis. In this article, different plant growth regulators were shortly applied to Catharanthus roseus plants during the blooming period to study their effects on the biosynthesis of vinblastine, vindoline and catharanthine. Salicylic acid and ethylene (ethephon) treatments resulted in a significant increase of vinblastine, vindoline and catharanthine while abscisic acid and gibberellic acid had a strongly negative influence on the accumulation of the three important alkaloids. Methyl jasmonate showed no great effect on the production of these valuable alkaloids. Chlormequat chloride highly enhanced the accumulation of vinblastine but greatly decreased the contents of vindoline and catharanthine.

The tetraploid plants of Catharanthus roseus (L.) G. Don was obtained by colchicine induction from seeds explants, and the ploidy of the plants was identified by flow cytometry. The optimal treatment is 0.2% colchicine solution treated for 24 hours, and the induction rate reaches up to 30%. Comparing with morphological characteristics and growth habits between tetraploids and the control, we found that tetraploids of C. roseus had larger stoma and more branches and leaves. HPLC analysis showed tetraploidization could increase the contents of terpenoid indole alkaloids in C. roseus. Thus, tetraploidization could be used to produce higher alkaloids lines for commercial use. QRT-PCR results showed that the expression of enzymes involved in terpenoid indole alkaloids biosynthesis pathway had increased in the tetraploid plants. To our knowledge, this was the first paper to explore the secondary metabolism in autotetraploid C. roseus induced by colchicine.