Table 1.

Examples of studies reporting beneficial activities between microbial endophytes and their plant host under drought and salinity stress conditions.

Endophytic Strain	Type	Type of Stress	Mechanism of Stress Amelioration and/or Beneficial Activity	Plant Host	Ref.
Phoma species	Fungi	Drought	Increased Proline Peroxidase (POD), Catalase (CAT), Superoxide dismutase (SOD)	Pinus tabulaeformis	[66]
Glomus mosseae, G. versiforme and G. diaphanum	Fungi	Drought	Increment of peroxidase activity and beneficial effects on soil structure	Poncirus trifoliata	[67]
Endophyte consortia (Rhodotorula graminis, Burkholderia vietnamiensis, Rhizobium tropici, Acinetobacter calcoaceticus, Rahnella sp., Burkholderia sp., Enterobacter asburiae, Sphingomonas yanoikuyae, Pseudomonas sp., Curtobacterium sp.)	Fungi + bacteria	Drought	Reduced damage by reactive oxygen species (ROS), Increment of IAA	Populus sp.	[68]
Bacillus, Achromobacter, Klebsiella and Citrobacter	Bacteria	Drought	Production of 1-aminocyclopropane-1- carboxylate (ACC) deaminase	Capsicum annuum L.	[69]
Burkholderia phytofirmans PsJN and Enterobacter sp. FD17		Drought	Reduced H2O2 induced damage	Zea mays L.	[71]
Streptomyces coelicolor DE07, S. olivaceus DE10 and Streptomyces geysiriensis DE27	Bacteria	Drought	Phytohormone (IAA) synthesis and increment in water stress tolerance	Triticum aestivum	[72]
Bacillus sp. Acb9, Providencia sp. Acb11, Staphylococcus sp. Acb12, Staphylococcus sp. Acb13 and Staphylococcus sp. Acb14	Bacteria	Drought	Production of indole acetic acid, ACC deaminase and promotion of plant growth	Ananas comosus, Vigna radiata	[73]
Pseudomonas spp., Acitenobacter brumalii strain MZ30V92, Enterobacter asburiae strain MRC12, Sinorhizobium meliloti strain MRC31	Bacteria	Drought	Multiple plant growth-promoting traits	Not evaluated	[74]
Pantoea alhagi strain LTYR-11ZT	Bacteria	Drought	Increment on accumulation of soluble sugars, decreased accumulation of proline and malondialdehyde, and decreased degradation of chlorophyll in leaves of drought-stressed wheat plants	Arabidopsis and wheat	[75]
Bacillus subtilis B26	Bacteria	Drought	Upregulation of the drought-response genes, such as DREB2B-like, DHN3-like and LEA-14-A-like and modulation of the DNA methylation genes, such as MET1B-like, CMT3-like and DRM2-like, that regulate the process	Brachypodium distachyon	[76]
Ampelomyces sp. and Penicillium sp.	Fungi	Drought and salinity	Enhanced plant growth, stress tolerance, recovery and fruit yield	Tomato plants	[77]
Bacillus subtilis BERA 71	Bacteria	Salinity	Enhanced level of ROS scavenging antioxidant enzymes (superoxide dismutase, peroxidase, catalase)	Cicer arietinum seedling	[78]
Streptomyces sp.	Bacteria	Salinity	Increased proline, K+, Ca+ and water contents and decreased ethylene, ROS, Na+ and Na+/K+ ratio	Oryza sativa seedling	[79]
Epichloë bromicola	Fungi	Salinity	Increased photosynthesis, chlorophyll content, antioxidant capacity and glycine betaine content	Hordeum brevisubulatum Seedling	[80]
Curvularia sp.	Fungi	Salinity	Elevates antioxidant enzymes (SOD and APX)	Poplar plant	[81]
Piriformospora indica	Fungi	Salinity	Modulation of the expression levels of the major Na+ and K+ ion channels and balanced ion homeostasis of Na+/K+	Arabidopsis thaliana	[82]
Brachybacterium paraconglomeratum	Bacteria	Salinity	Enhanced level of proline, MDA, IAA in the inoculated plants	Chlorophytum borivilianum	[83]
Trichoderma harzianum	Fungi	Salinity	Reduces lipid peroxidation	Lycopersicum esculentum seed	[84]
Piriformospora indica	Fungi	Salinity	Enhanced plant growth and attenuated the NaCl-induced lipid peroxidation, metabolic heat efflux and fatty acid desaturation in leaves. In addition, significantly elevated the amount of ascorbic acid and increased the activities of antioxidant enzymes catalase, ascorbate peroxidase, dehydroascorbate reductase, monodehydroascorbate reductase and glutathione reductase	Hordeaum Vulgare Seedling	[85]