Immunochemical Identification of the Main Cell Wall Polysaccharides of the Early Land Plant Marchantia polymorpha.

Plant primary cell walls are composite structures surrounding the protoplast and containing pectins, hemicelluloses, and cellulose polysaccharides, as well as proteins. Their composition changed during the evolution of the green lineage from algae to terrestrial plants, i.e., from an aquatic to a terrestrial environment. The constraints of life in terrestrial environments have generated new requirements for the organisms, necessitating adaptations, such as cell wall modifications. We have studied the cell wall polysaccharide composition of thalli of Marchantia polymorpha, a bryophyte belonging to one of the first land plant genera. Using a collection of specific antibodies raised against different cell wall polysaccharide epitopes, we were able to identify in polysaccharide-enriched fractions: pectins, including low-methylesterified homogalacturonans; rhamnogalacturonan I with arabinan side-chains; and hemicelluloses, such as xyloglucans with XXLG and XXXG modules, mannans, including galactomannans, and xylans. We could also show the even distribution of XXLG xyloglucans and galactomannans in the cell walls of thalli by immunocytochemistry. These results are discussed with regard to the cell wall proteome composition and in the context of the evolution of the green lineage. The cell wall polysaccharides of M. polymorpha illustrate the transition from the charophyte ancestors of terrestrial plants containing xyloglucans, xylans and mannans as hemicelluloses, and embryophytes which do not exhibit mannans as major primary cell wall polysaccharides.

Marchantia polymorpha L. Flavonoids Protect Liver From CCl4-Induced Injury by Antioxidant and Gene-Regulatory Effects.

Marchantia polymorpha L. (MPL), a common type of liverwort, has been used as herbal medicine to improve liver function in China for many years. Although modern studies revealed that MPL contains various polyphenols, terpenoids, and bis[bibenzyls], its biological effects on liver function have never been systemically studied in any animal model. In this study, flavonoids were extracted from MPL and the components in the MPL flavonoids as well as the antioxidant capacity of MPL flavonoids were analysed. A rat model of liver injury was induced by intraperitoneal injection of 10% carbon tetrachloride (CCl4). MPL flavonoids were administered daily at a dose of 50, 100, and 200 mg/kg body weight to the rats for 2 weeks prior to injection of CC14. Treatment with MPL flavonoids, especially at a dose of 200 mg/kg, attenuated CCl4-induced increases in alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, γ-glutamyl transpeptidase, nitric oxide, malondialdehyde, tumour necrosis factor-α, interleukin-1ß, and interleukin-6, as well as reductions in superoxide dismutase and glutathione peroxidase. Microarray analyses showed that co-treatment with MPL flavonoids and CCl4 up-regulated many antioxidant and anti-apoptotic genes, but down-regulated several pro-inflammatory genes, compared to treatment with CCl4 alone. PCR and western blot assays further identified that MPL flavonoids increased GPX1, TMX1, TXN, and XIAP expression, but decreased IL-1 and IL1RAP expression and inhibited Jak/stat3 signalling. In conclusion, MPL flavonoids exerted hepatoprotective effects via antioxidant and gene regulatory mechanisms. (Altern Ther Health Med.

Mass spectrometry-based quantification and spatial localization of small organic acid exudates in plant roots under phosphorus deficiency and aluminum toxicity.

Low-molecular-weight organic acid (OA) extrusion by plant roots is critical for plant nutrition, tolerance to cations toxicity, and plant-microbe interactions. Therefore, methodologies for the rapid and precise quantification of OAs are necessary to be incorporated in the analysis of roots and their exudates. The spatial location of root exudates is also important to understand the molecular mechanisms directing OA production and release into the rhizosphere. Here, we report the development of two complementary methodologies for OA determination, which were employed to evaluate the effect of inorganic ortho-phosphate (Pi) deficiency and aluminum toxicity on OA excretion by Arabidopsis roots. OA exudation by roots is considered a core response to different types of abiotic stress and for the interaction of roots with soil microbes, and for decades has been a target trait to produce plant varieties with increased capacities of Pi uptake and Al tolerance. Using targeted ultra-performance liquid chromatography coupled with high-resolution tandem mass spectrometry (UPLC-HRMS/MS), we achieved the quantification of six OAs in root exudates at sub-micromolar detection limits with an analysis time of less than 5 min per sample. We also employed targeted (MS/MS) matrix-assisted laser desorption/ionization (MALDI) mass spectrometry imaging (MSI) to detect the spatial location of citric and malic acid with high specificity in roots and exudates. Using these methods, we studied OA exudation in response to Al toxicity and Pi deficiency in Arabidopsis seedlings overexpressing genes involved in OA excretion. Finally, we show the transferability of the MALDI-MSI method by analyzing OA excretion in Marchantia polymorpha gemmalings subjected to Pi deficiency.

Oil Body Formation in Marchantia polymorpha Is Controlled by MpC1HDZ and Serves as a Defense against Arthropod Herbivores.

The origin of a terrestrial flora in the Ordovician required adaptation to novel biotic and abiotic stressors. Oil bodies, a synapomorphy of liverworts, accumulate secondary metabolites, but their function and development are poorly understood. Oil bodies of Marchantia polymorpha develop within specialized cells as one single large organelle. Here, we show that a class I homeodomain leucine-zipper (C1HDZ) transcription factor controls the differentiation of oil body cells in two different ecotypes of the liverwort M. polymorpha, a model genetic system for early divergent land plants. In flowering plants, these transcription factors primarily modulate responses to abiotic stress, including drought. However, loss-of-function alleles of the single ortholog gene, MpC1HDZ, in M. polymorpha did not exhibit phenotypes associated with abiotic stress. Rather, Mpc1hdz mutant plants were more susceptible to herbivory, and total plant extracts of the mutant exhibited reduced antibacterial activity. Transcriptomic analysis of the mutant revealed a reduction in expression of genes related to secondary metabolism that was accompanied by a specific depletion of oil body terpenoid compounds. Through time-lapse imaging, we observed that MpC1HDZ expression maxima precede oil body formation, indicating that MpC1HDZ mediates differentiation of oil body cells. Our results indicate that M. polymorpha oil bodies, and MpC1HDZ, are critical for defense against herbivory, but not for abiotic stress tolerance. Thus, C1HDZ genes were co-opted to regulate separate responses to biotic and abiotic stressors in two distinct land plant lineages.

Formation of tetrahydrocurcumin by reduction of curcumin with cultured plant cells of Marchantia polymorpha.

Cultured plant cells of Marchantia polymorpha, Nicotiana tabacum, Phytolacca americana, Catharanthus roseus, and Gossypium hirsutum were examined for their ability to reduce curcumin. Only M. polymorpha cells converted curcumin into tetrahydrocurcumin in 90% yield in one day. Time-course experiment revealed a two-step formation of tetrahydrocurcumin via dihydrocurcumin.