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opencc-zeroDec 2016View details →

Data from: Soil microbial communities alter leaf chemistry and influence allelopathic potential among coexisting plant species

While both plant–soil feedbacks and allelochemical interactions are key drivers of plant community dynamics, the potential for these two drivers to interact with each other remains largely unexplored. If soil microbes influence allelochemical production, this would represent a novel dimension of heterogeneity in plant–soil feedbacks. To explore the linkage between soil microbial communities and plant chemistry, we experimentally generated soil microbial communities and evaluated their impact on leaf chemical composition and allelopathic potential. Four native perennial old-field species (two each of Aster and Solidago) were grown in pairwise combination with each species' soil microbial community as well as a sterilized inoculum. We demonstrated unequivocally that variation in soil microbial communities altered leaf chemical fingerprints for all focal plant species and also changed their allelopathic potential. Soil microbes reduced allelopathic potential in bioassays by increasing germination 25–54% relative to sterile control soils in all four species. Plants grown with their own microbial communities had the lowest allelopathic potential, suggesting that allelochemical production may be lessened when growing with microbes from conspecifics. The allelopathic potential of plants grown in congener and confamilial soils was indistinguishable from each other, indicating an equivalent response to all non-conspecific microbial communities within these closely related genera. Our results clearly demonstrated that soil microbial communities cause changes in leaf tissue chemistry that altered their allelopathic properties. These findings represent a new mechanism of plant–soil feedbacks that may structure perennial plant communities over very small spatial scales that must be explored in much more detail.

opencc-zeroMar 2023View details →

Data from: Geographic variation of litter chemistry and palatability in an invasive plant versus its native competitor

Aim: Latitudinal variation in biotic interactions is recognized as a driver underlying variation in plant invasion success and therefore an important issue in conservation biogeography. However, previous studies have mainly focused on interactions between living plants and herbivores, whereas litter traits and detritivory have been hardly studied along latitude or compared between native and invasive plants. Our aim was to compare latitudinal variation in leaf-litter chemistry and palatability to detritivores between invasive and native plants, and investigate which chemical traits determine detritivory and whether they are climate-driven. Location: China. Taxa: Spartina alterniflora, Phragmites australis, Porcellio laevis, Chiromantes dehaani. Methods: We combined field surveys with laboratory experiments to compare latitudinal variation in litter chemistry between the widespread invasive Spartina alterniflora and its native competitor Phragmites australis across their co-occurring range (20.9–40.7°N, ~2200km). For both species, we examined litter palatability to two common detritivores (Porcellio laevis and Chiromantes dehaani) along the same latitude. We also analyzed relationships among climate, litter traits, and detritivory. Results: In five out of nine litter traits, we found latitudinal clines, with little difference between the two plant species in how they responded across the gradient. Litter palatability decreased with increasing latitude, but was generally higher in Spartina than Phragmites. Two key litter traits (C:P ratio and flavonoid content) were significantly associated with temperature of origin and with detritivory. Main conclusions: There were geographic clines in litter traits and palatability, with strong links between climate, litter chemistry and detritivory, in both Spartina and Phragmites. Spartina litter, however, was more rapidly decomposed by detritivores, which could create positive feedbacks, and contribute to the successful Spartina invasion along China's coast. Future ecological restoration projects should therefore dispose Spartina plant tissue or litter off-site, to reduce the competitiveness of Spartina and support the conservation of native Phragmites.

opencc-zeroMay 2023View details →

Plant litter chemistry drives long-lasting changes in the catabolic capacities of soil microbial communities

Although microbial communities play an important role in explaining plant litter decomposition rates, whether and how litter chemistry may alter catabolic capacities of soil microbial communities remains poorly studied. During a one-year litter decomposition experiment of twelve herbaceous species with contrasting litter chemistry, we examined the effect of plant litter type (roots vs leaves) and litter chemical traits on the resulting capacity of soil microbial communities to degrade a wide range of carbon substrates of variable complexity (MicroRespTM method). Litter chemistry impacted both the total catabolic activity as well as specific catabolic capacities of microbial communities. In early stages of litter decomposition total catabolic activity was mainly influenced by the amount of C and N in litter leachates, and litter N, P and Mg, then, later, by lignin concentrations. Some specific catabolic capacities could also be related to litter initial chemistry. Overall, litter trait effects on soil microbial communities decreased over time and the relative importance of traits shifted during the decomposition process. Our results highlight that litter chemistry is a strong driver of catabolic capacities of microbial decomposers and, whilst its effect fades with time, it remains substantial throughout the litter decomposition process. These long-lasting effects of litter chemistry suggest a persistent control on microbial catabolic capacities in ecosystems with recurrent litter production. Soil microbial catabolic activities were driven by broadly the same chemical traits across leaf and root litters. Synthesis. Such long-lasting effects of litter chemistry on catabolic capacities of microbial communities may represent a substantial indirect driver of the decomposition process. Disentangling the relative importance of this overlooked effect of litter chemistry on decomposition represents the next challenge. We argue that such research line should open ground-breaking perspectives for reconsidering our current understanding of the mechanistic links between litter traits and decomposition rate.

Fig. 16 in Stilbenes: Source plants, chemistry, biosynthesis, pharmacology, application and problems related to their clinical Application-A comprehensive review

Fig. 16. Biological activities of stilbenes and their action mechanisms: The major biological activities of stilbenes are anticancer (through inhibiting β-hexosaminidase, DNA topoisomerase, expression of cylin B1 & D1, and NOR 1 activity); anti-inflammatory (through inhibition of expression of proinflammatory cytokines such as Tumor necrosis factor-alpha (TNF-α) and Interleukin-1 (IL-1)); regulation of Nrf2/HO-1 and NF-kB/ TGF-β pathway as well as inhibiting direct binding between siCAM-1 and LFA-1); antimicrobial (by damaging microbial cell wall and cell membrane damage, condensation of cytoplasm, perturbation of membrane potential, interacting with the conserved ubiquitin-specific protease residues of PLpro), and down-regulation of ergosterol biosynthesis and Camp/Ras pathway; antidiabetic (through inhibiting TNF-α, α-glucosidase, intestinal sucrose transfer, elevation of blood glucose as well as inducing/ increasing PPAR gamma 2 and GLUT4); antioxidant (through inhibiting lipid peroxidation, NO production, NOS activity, and increasing SOD activity); and neuroprotective (by inhibiting NOS activity, NO production, and HO-1 expression) activities.

Fig. 12 in Stilbenes: Source plants, chemistry, biosynthesis, pharmacology, application and problems related to their clinical Application-A comprehensive review

Fig. 12. Biosynthesis of stilbenes in microbes: For high production of stilbenes in microbes such as E. coli, the metabolic pathway of malonyl-CoA, the major and common extender substrate during conversion of coumaroyl, cinnamyl, and caffeoyl-CoAs to their respective monomeric stilbenes, is mainly manipulated. Enzymes of side pathways leading to the synthesis of fatty acids and acetate from acetyl-CoA, the direct precursor of malonyl-CoA, are inhibited, or their encoding enzymes are down-regulated or knocked out. For more efficient and high production of the stilbenes, there is also host, pathway, and enzyme engineering in the pathway of converting coumaroyl, cinnamyl, and caffeoyl- CoAs to monomeric stilbenes using STS.

Fig. 15 in Stilbenes: Source plants, chemistry, biosynthesis, pharmacology, application and problems related to their clinical Application-A comprehensive review

Fig. 15. Chemical synthesis of resveratrol derivatives: The derivatives 3,4′,5-trimethoxy-cis-stilbene (b), 3,4′,5-trimethoxy-trans-stilbene (c), 3,4,4′,5-tetramethoxytrans-stilbene (DMU-212, d), 2,3′,4,4′,5′-pentamethoxy-trans-stilbene (PMS, e), and 2′,3,4′,5-tetramethoxy (TMS; f) are synthesized by methoxylation of the central resveratrol (a), while the synthetic analogs 3′,4′,3,5-tetrahydroxy-trans-stilbene (piceatannol); (g) and 3,3′,4,4′,5,5′-hexahydroxy-trans-stilbene (h) are produced by hydroxylation of (a). The result of fluorination and esterification is 3,4-difluoro-4′-acetoxy-trans-stilbene (i), while bromination and methoxylation give 3,4,5-trimethoxy-4′-bromostilbene (j). The analogous 2,3-thiazolidin-4-one RSV derivatives (l and k) are synthesized through replacement of the olefinic group of (a) by heterocyclic compounds.

Fig. 1 in Stilbenes: Source plants, chemistry, biosynthesis, pharmacology, application and problems related to their clinical Application-A comprehensive review

Fig. 1. Phylogenetic tree of known stilbene-producing plants: Each family was marked with a different color in the figure. The circle-marked species are capable of producing stilbenes. Kappaphycus striatum (JN897024.1) and Silvetia siliquosa (JF718409.1) are included as out-groups. The phylogenetic tree was constructed using the ITS2 (ribosomal internal transcribed spacer 2) genus sequence. ITS2 sequences were obtained from NCBI (National Center for Biotechnology Information) (https://www.ncbi.nlm.nih.gov/). Some unannotated sequences were identified and delimited based on Hidden Markov models (HMMs), which was performed through the online website-ITS2 Database (http://its2.bioapps.biozentrum.uni-wuerzburg.de/). The MUSCLE program in MEGA6.0 software was used to perform multiple sequence alignments, and the neighbor-joining (NJ) method was used to construct phylogenetic trees with 1000 bootstrap replicates. The kimura-2- parameter substitution model was also employed, and the confidence interval was 95%. The evolutionary tree is visualized and beautified by the online software iTOL (https://itol.embl.de/). (For interpretation of the references to color in this figure legend, the reader is referred to the Web version of this article.)

Fig. 11 in Stilbenes: Source plants, chemistry, biosynthesis, pharmacology, application and problems related to their clinical Application-A comprehensive review

Fig. 11. Biosynthesis of stilbenes in plant suspension cell culture: plants with a high stilbene content will be cut to a specific size. These will be incubated in agarized medium (Murashige and Skoog (MS) medium or CHU (N6) medium or Gamborg's B5 medium (B5)) with supplements such as 6-benzyl amino purine (6-BA), kinetin (KT), Naphthalene acetic acid (NAA), and 2,4-Dichlorophenoxyacetic acid (2,4-D). After some specific days, friable cells will be produced in the medium, and these cells are then transferred into a new fresh medium with the specific supplements. Finally, elicitors such as 12-oxo-phytodienoic acid (OPDA), cornatine (COR), jasmonic acid (JA), methyl jasmonate (MeJA), salicylic acid (SA), ethylene (ET), abscisic acid (ABA), and reactive oxygen species (ROS) will be added for high production of stilbenes.

Fig. 14 in Stilbenes: Source plants, chemistry, biosynthesis, pharmacology, application and problems related to their clinical Application-A comprehensive review

Fig. 14. Synthetic derivatives of CA-4 (1): These are produced by replacement, substitution, and modification at both the cis-olefinic bond and the aromatic rings of 1. N-acyl hydrazone CA-4 (4), azo CA-4 (3), 1, 3, 4, oxadiazole CA-4 (9), benzoxazole CA-4 (8) which are produced by replacement and modifications at the olefinic group. Through modifications to the cis-olefinic bond and aromatic rings of CA-4, analogs such as 2 and 7 (benzothiazole derivatives of CA-4 with fluorine), 5 and 6 (imidazole and indole derivatives of CA-4) are also synthesized.