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Medicinal plants are well known to have the advantages of high concentration of medicinal ingredients having clinical importance, curative value, small toxic and side effects. Important compounds viz., paclitaxel, camptothecin, and vincristine have been developed from medicinal plants as first-line of clinical drugs, leading to their consistently increasing demand globally. However, the destruction of natural environment due to excessive mining threatened such resources jeopardizing the successful growing of medicinal plants. A group of beneficial arbuscular mycorrhizal (AM) fungi is known to exist in the rhizosphere of medicinal plants, which can establish a reciprocal symbiosis with their roots, namely arbuscular mycorrhizas. These AM fungi are pivotal in the habitat adaptation of medicinal plants. Studies have demonstrated that AM fungi aided in growth promotion and nutrient absorption of medicinal plants, thereby, accelerating the accumulation of medicinal ingredients and aiding resistance against abiotic stresses such as drought, low temperature, and salinity. An AMlike fungus Piriformospora indica is known to be cultured in vitro without roots, later showed analogous effects of AM fungi on medicinal plants. These fungi provide new mechanistic pathways towards the artificial cultivation of medicinal plants loaded with ingredients in huge demand in international market. This review provides an overview of the diversity of AM fungi inhabiting the rhizosphere of medicinal plants, and analyzes the functioning of AM fungi and P. indica, coupled with future lines of research. [ABSTRACT FROM AUTHOR]

The aim of the present study was to analyze the effects of two arbuscular mycorrhizal fungi (AMF), Funneliformis mosseae and Paraglomus occultum, on leaf water status, root morphology, root sugar accumulation, root abscisic acid (ABA) levels, root malondialdehyde (MDA) content, and root antioxidant enzyme activities in white clover ( Trifolium repens L.) exposed to well-watered (WW) and drought stress (DS) conditions. The results showed that root colonization by F. mosseae and P. occultum was significantly decreased by 7-week soil drought treatment. Under drought stress conditions, mycorrhizal fungal treatment considerably stimulated root total length, surface area and volume, as compared with non-mycorrhizal controls. In addition, inoculation with arbuscular mycorrhizal fungi also increased leaf relative water content and accelerated the accumulation of root glucose and fructose under drought stress. Mycorrhizal plants under drought stress registered higher activities of superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) and ABA levels in roots, while lower MDA contents, relative to non-mycorrhizal plants. As a result, mycorrhiza-inoculated plants represented better physiological activities (e.g. antioxidant defense systems, root morphology, and sugar accumulation) than non-inoculated plants in response to soil drought, whilst P. occultum had superior effects than F. mosseae. [ABSTRACT FROM AUTHOR]

The present study aimed to evaluate the effect of an arbuscular mycorrhizal fungus (AMF), Clariodeoglomus etunicatum, on leaf food quality and relevant gene expression levels of tea (Camellia sinensis cv. 'Fuding Dabaicha') seedlings exposed to 0.5 µM P (P0.5) and 50 µM P (P50) levels. Twenty-four weeks later, the seedlings recorded higher root mycorrhizal fungal colonization in P50 than in P0.5. AMF-inoculated tea plants represented significantly higher leaf fructose and glucose contents and lower sucrose content than noninoculated plants, irrespective of substate P levels. AMF treatment also increased total amino acids content in P0.5 and P50, accompanied with higher expression of glutamate dehydrogenase (CsGDH) and lower expression of glutamine synthetase (CsGS) and glutamine oxoglutarate aminotransferase (CsGOGAT). The total flavonoid content was higher in mycorrhizal versus non-mycorrhizal plants under P0.5 and P50, together with induced expression of phenylalanine ammonia-lyase (CsPAL) and cinnamic acid 4-hydroxylase (CsC4H). Mycorrhizal fungal inoculation improved catechins content, which is due to the up-regulated expression of flavanone 3-hydroxylase ( CsF3H), flavonoid 3'-hydroxylase ( CsF3'H), dihydroflavonol 4-reductase ( CsDFR), leucoanthocyanidin reductase ( CsLAR), anthocyanidin reductase ( CsANR), and chalcone isomerase ( CsCHI) under P0.5. However, under P50, the gene involved in catechins synthesis was not affected or down-regulated by mycorrhization, implying a complex mechanism (e.g. nutrient improvement). AMF also inhibited the tea caffeine synthase 1 (CsTCS1) expression regardless of P levels. Therefore, the results of this study concluded that inoculation with C. etunicatum improves leaf food quality of tea exposed to P stress, but the improved mechanisms were different between P0.5 and P50. [ABSTRACT FROM AUTHOR]

The demand for ornamental plants is increasing due to urban greening and rural construction, while the growing environment of plants, especially the soil environment, is deteriorating. Hence, sustainable methods of ornamental plant cultivation need to be developed quickly. The application of arbuscular mycorrhizal fungi (AMF) to ornamental plants can be one of the eco-friendly ways to achieve the objective. Soil AMF establish mycorrhizal symbiosis with roots of ornamental plants, which can develop a marvelous mycorrhizal mycelium network in the rhizosphere to stimulate nutrient and water acquisition of host plants. Numerous researches have proven that AMF improved the quality of ornamental plants, like fruit yield, height, biomass, seed quality, the size and number of flowers, leaf, and root. In addition, mycorrhizal fungi also improve nutrient uptake and endogenous hormone balance of host plants. Another important function of AMF is to regulate the physiological, biochemical, and molecular responses of host plants to adversity, including drought stress, temperature stress, heavy-metal stress, and insect and disease stress. From the perspective of the ecological garden landscape, AMF richness would maintain plant abundance, nutrient and energy balance, and higher productivity in normal and soil environment stress, thus, establishing a friendly-environmental ecosystem. This review also provides the basis to exploit and improve the commercial application of AMF in ornamental plants in the future. [ABSTRACT FROM AUTHOR]

Arbuscular mycorrhizal fungi (AMF) enhance plant disease resistance, while the underlying mechanisms in the molecular levels are not yet known. In this study, five-leaf-old trifoliate orange seedlings were inoculated with Funneliformis mosseae for 14 weeks and subsequently were infected by a citrus root rot pathogen Phytophthora parasitica by 7 days. The transcriptome results by Illumina HiSeq 4000 revealed that the percentage of Q30 bases reached 92.99% or above, and 29696 unigenes were annotated in a total of 63531 unigenes. 654 and 103 differentially expressed genes (DEGs) were respectively annotated in AMF-inoculated versus non-AMF-inoculated plants under non-infection and infection with P. parasitica, respectively, whilst these DEGs were related to defense mechanisms, signal transduction mechanisms and secondary metabolites biosynthesis. Forty-two genes were functionally annotated as the putative 'defense mechanism', whilst AMF inoculation induced 1 gene down-regulated and 3 genes up-regulated under P. parasitica infection. AMF inoculation stimulated more genes linked to signal transduction mechanism down-regulated than non-AMF plants. Eight genes were involved in secondary metabolites biosynthesis in AMF versus non-AMF seedlings under P. parasitica-infection conditions. Such transcriptome database provided total information in the molecular levels regarding mycorrhizal roles in tolerating Phytophthora parasitica infection. [ABSTRACT FROM AUTHOR]

Rainfall use efficiency (RUE) of subtropics evergreen coniferous forests and RUE spatial patterns in Chinese subtropical zone were estimated. RUE and ecosystem net primary productivity (NPP) spatial distribution, as well as the relationship between RUE and rainfall were particularly focused. RUE of subtropical evergreen coniferous forests and the spatial patterns were estimated based on the data collected from the related weather stations and peer-reviewed literatures. In our study, a gradually increasing tendency of NPP from northwestern to southeastern part of the subtropical zone is observed. No significant differences in RUE among these tree species are visible. RUE of the evergreen coniferous forests reduces as the rainfall increases. RUE reaches the peak when rainfall is less than 700 mm. However, the distribution of RUE is not evident. In linear regression, longitude, latitude, and PAR account for approximately 1.4% of the variability in RUE. These findings suggest that the RUE of evergreen coniferous forests in southern China has a functional convergence. [ABSTRACT FROM AUTHOR]

Circadian clock is usually involved in many physiological processes of plants, including responses to abiotic stress, whilst pseudo-response regulator 7 (PRR7) gene is the main component of the circadian clock. In this study, the cDNA of the PRR7 gene was obtained from trifoliate orange (Poncirus trifoliata). Based on the sequence analysis, the PtPRR7 gene had an open reading frame of 2343 bp, encoded 780 amino acids, and contained proteins of the REC and CCT domains. Subcellular localization indicated that PtPRR7 was mainly localized in the nucleus and a small amount of cytoplasm. qRT-PCR analysis revealed the highest expression level of PtPRR7 in roots than in both shoots and leaves. The PtPRR7 gene during 24 hours of soil water deficit exhibited a circadian rhythmic expression pattern: the expression peak at 9:00 am in leaves and at 21:00 pm in roots. Drought treatment affected PtPRR7 gene expression. Such data provide important references for understanding the characteristics of PtPRR7 gene in citrus plants. [ABSTRACT FROM AUTHOR]

Piriformospora indica is a discovered endophytic fungus colonizing in roots of plants in 1998. The fungus can form the mycelium, mycelial roll, and pear-shaped spores in intercellular and intracellular regions of roots. The fungus colonizes various host plants and also realizes the pure culture in vitro without roots of host plants. P. indica shows many positive effects on host plants, including the promotion of plant growth, the enhancement of nutrient acquisition and stress tolerance, the improvement of disease resistance, and the promoted accumulation of bioactive substances. The commercial production of the fungal spores is established in bioreactor with nanostructured materials "zinc oxide" as nano embedded fungus, which provides provides changes into confers. The review simply summarized the biological characteristics of P. indica, physiological roles in plants, and potential utilization as a biofertilizer. [ABSTRACT FROM AUTHOR]

Tea (Camellia sinensis) plants inhabit arbuscular mycorrhizal fungi (AMF) in rhizosphere, whereas it is not clear whether AMF improves leaf food quality of tea plants. A potted study was conducted to determine effects of Claroideoglomus etunicatum, Diversispora spurca, D. versiformis and a mixture of the three AMF species on leaf sugar, amino acid, soluble protein, tea polyphenol, catechuic acid, and flavonoid contents of Camellia sinensis 'Fuding Dabaicha' seedlings. After 12 weeks of AMF inoculation, mycorrhizal plants recorded significantly higher shoot biomass and total leaf area, whilst the effect was ranked as C. etunicatum > D. spurca > mixed-AMF > D. versiformis in the decreasing order. AMF treatments significantly increased leaf total amino acid concentrations, accompanied with up-regulation of amino acid synthetic enzymes genes glutamine synthetase (CsGS), glutamate synthase (CsGOGAT) and glutamate dehydrogenase (CsGDH). Leaf glucose, sucrose, total soluble protein, tea polyphenol, catechuic acid, and flavonoid contents were significantly higher in AMF- than in non- AMF-inoculated plants. In addition, mycorrhizal inoculation notably up-regulated the expression level of leaf 3-hydroxy-3- methylglutaryl coenzyme gene (CsHMGR), ascorbate peroxidase gene (CsAPX), and tea caffeine synthase 1 gene (CsTCS1). These results implied that AMF inoculation had positive effects on leaf food quality partly by means of up-regulation of relevant gene expression in 'Fuding Dabaicha' seedlings. [ABSTRACT FROM AUTHOR]