Arbuscular mycorrhizal symbiosis facilitates apricot seedling(Prunus sibirica L.)growth and photosynthesis in northwest China

Arbuscular mycorrhizal(AM)fungi can successfully enhance photosynthesis(P_(n))and plants growth in agricultural or grassland ecosystems.However,how the symbionts affect species restoration in sunlight-intensive areas remains largely unexplored.Therefore,this study’s objective was to assess the effect of AM fungi on apricot seedling physiology,within a specific time period,in northwest China.In 2010,an experimental field was established in Shaanxi Province,northwest China.The experimental treatments included two AM fungi inoculation levels(0 or 100 g of AM fungal inoculum per seedling),three shade levels(1900,1100,and 550µmol m^(−2) s^(−1)),and three ages(1,3,and 5 years)of transplantation.We examined growth,Pn,and morphological indicators of apricot(Prunus sibirica L.)seedling performances in 2011,2013,and 2015.The colonization rate in mycorrhizal seedlings with similar amounts of shade is higher than the corresponding controls.The mycorrhizal seedling biomass is significantly higher than the corresponding non-mycorrhizal seedling biomass.Generally,P_(n),stomatal conductance(G_(s)),transpiration rate(T_(r)),and water use efficiency are also significantly higher in the mycorrhizal seedlings.Moreover,mycorrhizal seedlings with light shade(LS)have the highest Pn.WUE is increased in non-mycorrhizal seedlings because of the reduction in T_(r),while T_(r) is increased in mycorrhizal seedlings with shade.There is a significant increase in the N,P,and K fractions detected in roots compared with shoots.This means that LS had apparent benefits for mycorrhizal seedlings.Our results also indicate that AM fungi,combined with LS,exert a positive effect on apricot behavior.

The RNAome landscape of tomato during arbuscular mycorrhizal symbiosis reveals an evolving RNA layer symbiotic regulatory network

Arbuscular mycorrhizal symbiosis(AMS)is an ancient plant-fungus relationship that is widely distributed in terrestrial plants.The formation of symbiotic structures and bidirectional nutrient exchange requires the regulation of numerous genes.However,the landscape of RNAome during plant AMS involving different types of regulatory RNA is poorly understood.In this study,a combinatorial strategy utilizing multiple sequencing approaches was used to decipher the landscape of RNAome in tomato,an emerging AMS model.The annotation of the tomato genome was improved by a multiple-platform sequencing strategy.A total of 3,174 protein-coding genes were upregulated during AMS,42%of which were alternatively spliced.Comparative-transcriptome analysis revealed that genes from 24 orthogroups were consistently induced by AMS in eight phylogenetically distant angiosperms.Seven additional orthogroups were specifically induced by AMS in all surveyed dicot AMS host plants.However,these orthogroups were absent or not induced in monocots and/or non-AMS hosts,suggesting a continuously evolving AMS-responsive network in addition to a conserved core regulatory module.Additionally,we detected 587 lncRNAs,ten miRNAs,and 146 circRNAs that responded to AMS,which were incorporated to establish a tomato AMSresponsive,competing RNA-responsive endogenous RNA(ceRNA)network.Finally,a tomato symbiotic transcriptome database(TSTD,https://efg.nju.edu.cn/TSTD)was constructed to serve as a resource for deep deciphering of the AMS regulatory network.These results help elucidate the reconfiguration of the tomato RNAome during AMS and suggest a sophisticated and evolving RNA layer responsive network during AMS processes.

Effects of microplastic polystyrene,simulated acid rain and arbuscular mycorrhizal fungi on Trifolium repens growth and soil microbial community composition

Microplastic pollution is a global and ubiquitous environmental problem in the oceans as well as in the terrestrial environment.We examined the fate of microplastic polystyrene(MPS)beads in experimental soil in the presence and absence of symbiotic arbuscular mycorrhizal fungi(AMF)and simulated acid rain(SAR)to determine whether the combinations of these three factors altered the growth of white clover Trifolium repens.We found that MPS,SAR,or AMF added singly to soil did not alter T.repens growth or yields.In contrast,MPS and AMF together significantly reduced shoot biomass,while SAR and MPS together significantly reduced soil available phosphorus independent of AMF presence.Microplastic polystyrene,AMF,and SAR together significantly reduced soil NO_(3)^(-)-N.Arbuscular mycorrhizal fungi added singly also enriched the beneficial soil bacteria(genus Solirubrobacter),while MPS combined with AMF significantly enriched the potential plant pathogenic fungus Spiromastix.Arbuscular mycorrhizal fungi inoculation with MPS increased the abundance of soil hydrocarbon degraders independent of the presence of SAR.In addition,the abundance of soil nitrate reducers was increased by MPS,especially in the presence of AMF and SAR.Moreover,SAR alone increased the abundance of soil pathogens within the fungal community including antibiotic producers.These findings indicate that the coexistence of MPS,SAR,and AMF may exacerbate the adverse effects of MPS on soil and plant health.

Nutrient Exchange and Regulation in Arbuscular Vlycorrhizal Symbiosis

Most land plants form symbiotic associations with arbuscular mycorrhizal （AM） fungi. These are the most common and widespread terrestrial plant symbioses, which have a global impact on plant mineral nutrition. The establishment of AM symbiosis involves recognition of the two partners and bidirectional transport of different mineral and carbon nutrients through the symbiotic interfaces within the host root cells. Intrigu- ingly, recent discoveries have highlighted that lipids are transferred from the plant host to AM fungus as a major carbon source, in this review, we discuss the transporter-mediated transfer of carbon, nitrogen, phosphate, potassium and sulfate, and present hypotheses pertaining to the potential regulatory mecha- nisms of nutrient exchange in AM symbiosis. Current challenges and future perspectives on AM symbiosis research are also discussed.