Arbuscular mycorrhizal fungi ameliorate the chemical properties and enzyme activities of rhizosphere soil in reclaimed mining subsidence in northwestern China

In semi-arid region of northwestern China, underground mining subsidence often results in decreased vegetation coverage, impoverishment of soil fertility and water stress. In addition, the physical-chemical and biological properties of soil also change, resulting in more susceptible to degradation. In particular, subsidence causes disturbance of the symbioses of plant and microbe that can play a beneficial role in the establishment of vegetation communities in degraded ecosystems. The objective of this study was to evaluate the effects of revegetation with exotic arbuscular mycorrhizal fungi(AMF) inoculum on the chemical and biological properties of soil over time in mining subsidence areas. Soils were sampled at a depth up to 30 cm in the adjacent rhizosphere of Amorpha fruticose Linn. from five reclaimed vegetation communities in northwestern China. In August 2015, a field trial was set up with five historical revegetation experiments established in 2008(7-year), 2011(4-year), 2012(3-year), 2013(2-year) and 2014(1-year), respectively. Each reclamation experiment included two treatments, i.e., revegetation with exotic AMF inoculum(AMF) and non-AMF inoculum(the control). Root mycorrhizal colonization, glomalin-related soil protein(GRSP), soil organic carbon(SOC), soil nutrients, and enzyme activities were also assessed. The results showed that mycorrhizal colonization of inoculated plants increased by 33.3%–163.0% compared to that of non-inoculated plants(P<0.05). Revegetation with exotic AMF inoculum also significantly improved total GRSR(T-GRSP) and easily extracted GRSP(EE-GRSP) concentrations compared to control, besides the T-GRSP in 1-year experiment and the EE-GRSP in 2-year experiment. A significant increase in SOC content was only observed in 7-year AMF reclaimed soils compared to non-AMF reclaimed soils. Soil total N(TN), Olsen phosphorus(P) and available potassium(K) were significantly higher in inoculated soil after 1–7 years of reclamation(except for individual cases), and increased with reclamation time(besides soil Olsen P). The exotic AMF inoculum markedly increased the average soil invertase, catalase, urease and alkaline phosphatase by 23.8%, 21.3%, 18.8% and 8.6%, respectively(P<0.01), compared with the control. Root mycorrhizal colonization was positively correlated with soil parameters(SOC, TN and soil available K) and soil enzyme activities(soil invertase, catalase, urease and alkaline phosphatase) in both AMF and non-AMF reclaimed soils(P<0.05), excluding availableK in non-AMF reclaimed soils. T-GRSP(P<0.01) and EE-GRSP(P<0.05) were significantly correlated with the majority of edaphic factors, except for soil Olsen P. The positive correlation between root mycorrhizal colonization and available K was observed in AMF reclaimed soils, indicating that the AMF reclaimed soil with a high root mycorrhizal colonization could potentially accumulate available K in soils. Our findings concluded that revegetation with exotic AMF inoculum influenced soil nutrient availability and enzyme activities in the semi-arid ecosystem, suggesting that inoculating AMF can be an effective method to improve soil fertility and support restoration of vegetation communities under poor conditions like soil nutrient deficiency and drought.

Transcriptome analysis of the symbiosis-related genes between Funneliformis mosseae and Amorpha fruticosa

Arbuscular mycorrhizal fungi(AMF) can colonize and form associations with the roots of Amorpha fruticosa L.(desert false indigo). Various genes are induced during the symbiotic process. In this study, de novo transcriptome sequencing using RNA-seq was conducted for the first time for a comprehensive analysis of AMF-A. fruticosa symbionts at the transcript level. We obtained 12 G of raw data from illumina sequencing and recovered 115,786 unigenes with an average length of547 bp, among them 41,848 of significance. A total of2460 diffexpression genes were identified, including 1579 down-regulated and 881 up-regulated genes. A threshold for false discovery rate of \ 0.001 and fold change of [ 1 determined significant differences in gene expression.Using these criteria, we screened 285 significant differentially expressed genes, of which 82 were up-regulated and203 down-regulated. The 82 up-regulated genes were classified according to their functions and assigned into seven categories: stress and defense, metabolism, signaling transduction, protein folding and degradation, energy,protein synthesis, and transcription. The 203 down-regulated genes were screened according to fold change [ 2,and 50 highly significant down-regulated genes were obtained related to stress and defense. The results of this study will provide a useful foundation for further investigation on the metabolic characteristics and molecular mechanisms of AMF associations with leguminous woody shrubs.

Review of the lichen genus Usnea in the Philippines

The fruticose lichen Usnea is a cosmopolitan genus also found in the mountains of the Philippines.Despite its abundance,though,this lichen genus is not extensively studied in the country.Since the Philippine Usnea holds great potential in pharmaceutical and agricultural research,the basic knowledge on this lichen is important to establish.Therefore,this paper takes a detailed review of Usnea in the Philippines and summarizes all the literatures that have been conducted on it in all aspects.Further,the provinces that were already reported of the occurrence of this genus are plotted in one figure to also highlight those that have not been explored yet.Currently,81 species of Usnea were reported in the country.This includes a species that was previously under the genus Usnea but has been arguably reclassified to a different genus in the present(i.e.,Eumitria).This review also hopes to direct future studies regarding Usnea.

New additions of macrolichens to the lichen flora of Arunachal Pradesh,India in Eastern Himalaya

Lichen exploration of West Kameng district and Tawang district of Arunachal Pradesh state,India located in the Eastern Himalayas reveal seventy nine lichens represented primarily by foliose(73%),a few fruticose(15%),dimorphic(8%),leprose(2%)and crustose(1%)types.Of these,seventeen species,one fruticose,sixteen foliose growth forms,belonging to 12 genera and 5 families are recorded as new additions to the lichen flora of Arunachal Pradesh state.The lichens were sampled at an elevation ranging from 1618 meter to 4509 meter.The diagnostic features of new additions to macrolichens of Arunachal Pradesh based on the phytogeographic affinities and distribution of species is briefly described.