Screening,Diversity Analysis And Application Of AM Fungi In Different Saline-Alkali Habitats

Soil salinization is one of the most serious environmental problems,which greatly restricts the development of agriculture.Arbuscular mycorrhizal(AM)fungi can enhance plant tolerance to salt stress through a variety of mechanisms,increase plant survival,and decrease soil salinization.However,AM fungi isolated from different saline habitats have different roles in enhancing plant tolerance to salt stress,therefore,it is necessary and significant to develop resource of AM fungi with salt tolerance.Unfortunately,it is little known about this subject up to now.This study takes soil samples from the salt-lake located Xinjiang Autonomous Region(86°40?-87°25?E,41°56?-42°14? N),the salinealkali grassland located Inner Mongolia Autonomous Region(109°32?E,39°07? N),and the coastal saline-alkali land located Tangshan city,Hebei Province(118°14?E,39°13?N).The screening,isolation,diversity of AM fungi were done,and soil properties were analyzed.The relationship between AM fungi diversity and soil properties was discussed.Moreover,effects of isolated AM fungi on plant tolerance to salt stress were studied.In order to fully understand the existing effects of AM fungi on plant salt tolerance,we collected all the relevant papers about the effects of AM fungi on salt tolerance and did Meta-analysis.The main results are as follows:(1)Meta-analysis results:A randomized effects model was used to conduct a meta-analysis based on 153 literatures and 1165 subexperimental data to discuss the effects of host plant types,source and species of AM fungi,and environmental factors on AM function under salt stress.Results showed that compared with non-saline-alkali AM fungi,AM fungi with saline-alkali tolerance ability increased aboveground,underground and total biomass of plant as well as SOD activity by 2.69%,25%,9.47%and 91.6%,and decreased MDA content by 52.1%respectively.Compared with AM fungi from agent,indigenous AM fungi increased aboveground,underground and total biomass of plant,as well as SOD activity by 7.74%,15.7%,6.25%and 30.2%and decreased MDA content by 52.1%respectively.Compared with monocot plants,the AM fungi increased aboveground,underground and total biomass of plant as well as SOD activity by 81.9%,38.8%,46.3%and 27.9%,and decreased MDA content by 290%in dicot plants respectively.In addition,AM effects on plant tolerance to salt stress were affected by experimental duration,salt concentrations,inoculation mode of AM fungi,etc.(2)AM fungi diversity in different saline-alkali habitats.In three saline-alkali habitats,Glomus and Paraglomus were the primary,and Glomus was dominant Genus based on the analysis of spore morphology and high throughput technology.Microbial community structure of AM fungi showed difference in three saline-alkali habitats.OUT number was the largest in the salt-lake located Xinjiang Autonomous Region,and Shannon index was the highest as 4.32 in the saline-alkali grassland located Inner Mongolia Autonomous Region,and Simpson was highest as 0.0631 in the coastal saline-alkali land located Tangshan city.No evidence showed there was correlation between AM fungi diversity and soil prosperities due to less sample size.(3)Application of AM fungi with salt tolerance.Maize was as host plant and salt concentration was 5‰.AM fungi from Xinjiang salt-lake and from Inner Mongolia saline-alkali grassland had higher colonization rate as 56%,which was higher 197 than AM fungi from Tangshan coastal saline-alkali land.Relative to the non-mycorrhizal plant,AM fungi from Xinjiang,Inner Mongolia and Tangshan increased the underground biomass by 28.5%,11.2%and 25.9%,decreased Na+concentration in the plant aboveground part by 21.7%,15.1%and 23.8%,respectively.AM fungi from Xinjiang showed the best effect in this study.We continuous to isolate AM fungi under Genus level,and three Genus AM fungi were isolated,namely Glomus,Acaulospora and Gigaspora.Colonization rate of Glomus AM fungi was higher by 25.6%and 176%than Gigaspora AM fungi and Claroideoglomus AM fungi respectively.Aboveground biomass in plant inoculated with Glomus AM fungi was higher 30.6%and 24.9%than that inoculated with Gigaspora AM fungi and Claroideoglomus AM fungi respectively.Na+concentration in aboveground of plant inoculated with Glomus AM fungi decreased by 63.6%and 7.63%than that inoculated with Gigaspora AM fungi and Claroideoglomus AM fungi respectively.Na+concentration in underground of plant inoculated with Glomus AM fungi decreased by 43.4%and 63.5%than that inoculated with Gigaspora AM fungi and Claroideoglomus AM fungi respectively.