Differences in Albizia odoratissima genetic diversity between Hainan Island and mainland populations in China

BackgroundThis study aimed at exploring unique population genetic characteristics of Albizia odoratissima (Linn. f) Benth on Hainan Island to provide a scientific basis for its rational utilization and protection.MethodsIt analyzed the genetic diversity and structure of 280 individuals from 10 subpopulations of A. odoratissima from Hainan Island and Baise City using 16 expression sequence markers - simple sequence repeat markers.ResultsThe genetic diversity of Hainan population (I = 0.7290, He = 0.4483) was lower than that of the Baise population (I = 0.8722, He = 0.5121). Compared with the Baise population (Nm = 2.0709, FST = 0.1077), the Hainan Island population (Nm = 1.7519, FST = 0.1249) exhibited lower gene flow and higher degree of genetic differentiation. Molecular variance and genetic differentiation analyses showed that the main variation originated from individuals within the subpopulation. There were significant differences in the genetic structure between Hainan and Baise populations. It grouped according to geographical distance, consistent with the Mantel test results (R2 = 0.77, p = 0.001). In conclusion, the genetic diversity of the island A. odoratissima population was lower than that distributed on land, the two populations exhibited obvious genetic structure differences. Both the degrees of inbreeding and genetic differentiation were higher in the island population than in the land population

Enhancing Digestibility and Ethanol Yield of Populus Wood via Expression of an Engineered Monolignol 4-O-Methyltransferase

Producing cellulosic biofuels and bio-based chemicals from woody biomass is impeded by the presence of lignin polymer in the plant cell wall. Manipulating the monolignol biosynthetic pathway offers a promising approach to improved processability, but often impairs plant growth and development. Here, we show that expressing an engineered 4-O-methyltransferase that chemically modifies the phenolic moiety of lignin monomeric precursors, thus preventing their incorporation into the lignin polymer, substantially alters hybrid aspens’ lignin content and structure. Woody biomass derived from the transgenic aspens shows a 62% increase in the release of simple sugars and up to a 49% increase in the yield of ethanol when the woody biomass is subjected to enzymatic digestion and yeast-mediated fermentation. Moreover, the cell wall structural changes do not affect growth and biomass production of the trees. Our study provides a useful strategy for tailoring woody biomass for bio-based applications

Uncovering miRNA-mRNA Regulatory Modules in Developing Xylem of Pinus massoniana via Small RNA and Degradome Sequencing

Xylem is required for the growth and development of higher plants to provide water and mineral elements. The thickening of the xylem secondary cell wall (SCW) not only improves plant survival, but also provides raw materials for industrial production. Numerous studies have found that transcription factors and non-coding RNAs regulate the process of SCW thickening. Pinus massoniana is an important woody tree species in China and is widely used to produce materials for construction, furniture, and packaging. However, the target genes of microRNAs (miRNAs) in the developing xylem of P. massoniana are not known. In this study, a total of 25 conserved miRNAs and 173 novel miRNAs were identified via small RNA sequencing, and 58 differentially expressed miRNAs were identified between the developing xylem (PM_X) and protoplasts isolated from the developing xylem (PM_XP); 26 of these miRNAs were significantly up-regulated in PM_XP compared with PM_X, and 32 were significantly down-regulated. A total of 153 target genes of 20 conserved miRNAs and 712 target genes of 113 novel miRNAs were verified by degradome sequencing. There may be conserved miRNA-mRNA modules (miRNA-MYB, miRNA-ARF, and miRNA-LAC) involved in softwood and hardwood formation. The results of qRT-PCR-based parallel validation were in relatively high agreement. This study explored the potential regulatory network of miRNAs in the developing xylem of P. massoniana and provides new insights into wood formation in coniferous species

High-throughput sequencing-based assembly of chloroplast genomes of five pine tree species

Pinus plants are the largest existing group of gymnosperms and one of the most highly differentiated taxa. Due to its huge ecological, economic, and scientific value, the genetic diversity and the relationship between the intraspecific evolution of Pinus plants have gained wide attention. In this study, the chloroplast genomes of several common pine trees in southwest and south China, including P. massoniana (masson pine), P. yunnanensis (yunnan pine), P. latteri (south asia pine), P. crassicorticea (la ya pine), and P. elliottii (slash pine), and entire cpDNA sequences were obtained. Characteristics including the structure, repeated sequence, and codon bias of the cpDNA for these five pine tree species were analyzed

Optimization of Extraction Process of Pine Needle Essential Oil by Response Surface Methodology and its Chemical Composition Analysis

The extraction of essential oil from pine needles was optimized by response surface methodology, and the following optimal conditions were obtained: a fresh pine needle of 100 g, an extraction time of 2 h, a water dosage of 850 mL, and a NaCl concentration of 2.50%. The extraction yield of essential oil was 0.611% under optimal conditions, which was extremely close to the predicted value. The extraction yields of essential oil from needles of 12 common pines in Guangxi were compared. The contents of essential oil in needles of Pinus massoniana, Pinus crassicorticea, and Pinus taeda were relatively higher than other pines. A total of 44 chemical components were identified by GC-MS, including 12 monoterpenes, 14 sesquiterpenes, and 12 alcohols. The chemical components of essential oil from different pines have their own features, and it is speculated that they have good and diversified application potential in the fields of medicine, food, spices, and so on. The chemical compositions of essential oil with high extraction yield have similar characteristics. This phenomenon can be used as the basis and means for the selection of pines with high content of essential oil in needles

Ultrasound-assisted aqueous two-phase extraction of phenylethanoid glycosides from Cistanche deserticola Y. C. Ma stems

An efficient ultrasound-assisted aqueous two-phase extraction and enrichment process for phenylethanoid glycosides from Cistanche deserticola Y. C. Ma stems was developed in this work. An ethanol/ammonium sulfate system was chosen for the aqueous two-phase system due to its fine partitioning and recycling behaviors. Single-factorexperiments and response surface methodology were used to optimize the process parameters of the ultrasound-assisted aqueous two-phase extraction. The optimal conditions were as follows: a salt concentration of 23.5%, an ethanol concentration of 20%, an extraction time of 37 min, an extraction temperature of 30 degrees C, a liquid/solid ratio of 30:1 w/w, and an ultrasound power of 300 W. Under the above conditions, the extraction yields of echinacoside and acteoside (the main components of phenylethanoid glycosides) reached 5.35 and 6.22 mg/g dry material weight, respectively. The contents of echinacoside and acteoside in the extracts reached 27.56 and 30.23 mg/g, respectively, which were 2.46- and 2.58-fold higher than the amounts obtained in ultrasound-assisted extraction. In conclusion, ultrasound-assisted aqueous two-phase extraction was an efficient, ecofriendly, and economical method, and it may be a promising technique for extracting and enriching bioactive components from plants

One-Pot Regiospecific Synthesis of Indolizines: A Solvent-Free, Metal-Free, Three-Component Reaction of 2‑(Pyridin-2-yl)acetates, Ynals, and Alcohols or Thiols

A novel approach for the synthesis of indolizines from 2-(pyridin-2-yl)­acetates, ynals, and alcohols or thiols has been developed. This MCR (multicomponent reaction) that proceeds under the solvent- and metal-free conditions has provided a straightforward path to construct indolizines. Furthermore, this reaction demonstrates other attractive features such as widely available starting materials, mild conditions, good functional group tolerance, and high efficiency

Human BAMBI Cooperates with Smad7 to Inhibit Transforming Growth Factor-β Signaling*

Transforming growth factor β (TGF-β) and related growth factors are essential regulators of embryogenesis and tissue homeostasis. The signaling pathways mediated by their receptors and Smad proteins are precisely modulated by various means. Xenopus BAMBI (bone morphogenic protein (BMP) and activin membrane-bound inhibitor) has been shown to function as a general negative regulator of TGF-β/BMP/activin signaling. Here, we provide evidence that human BAMBI (hBAMBI), like its Xenopus homolog, inhibits TGF-β- and BMP-mediated transcriptional responses as well as TGF-β-induced R-Smad phosphorylation and cell growth arrest, whereas knockdown of endogenous BAMBI enhances the TGF-β-induced reporter expression. Mechanistically, in addition to interfering with the complex formation between the type I and type II receptors, hBAMBI cooperates with Smad7 to inhibit TGF-β signaling. hBAMBI forms a ternary complex with Smad7 and the TGF-β type I receptor ALK5/TβRI and inhibits the interaction between ALK5/TβRI and Smad3, thus impairing Smad3 activation. These findings provide a novel insight to understand the molecular mechanism underlying the inhibitory effect of BAMBI on TGF-β signaling