ABSTRACT
BACKGROUND: Salinization of soil is an urgent problem that restricts agroforestry production and environmental protection. Substantial accumulation of metal ions or highly alkaline soil alters plant metabolites and may even cause plant death. To explore the differences in the response strategies between Suaeda salsa (S. salsa) and Puccinellia tenuiflora (P. tenuiflora), two main constructive species that survive in saline-alkali soil, their metabolic differences were characterized. RESULT: Metabolomics was conducted to study the role of metabolic differences between S. salsa and P. tenuiflora under saline-alkali stress. A total of 68 significantly different metabolites were identified by GC-MS, including 9 sugars, 13 amino acids, 8 alcohols, and 34 acids. A more detailed analysis indicated that P. tenuiflora utilizes sugars more effectively and may be saline-alkali tolerant via sugar consumption, while S. salsa utilizes mainly amino acids, alcohols, and acids to resist saline-alkali stress. Measurement of phenolic compounds showed that more C6C3C6-compounds accumulated in P. tenuiflora, while more C6C1-compounds, phenolic compounds that can be used as signalling molecules to defend against stress, accumulated in S. salsa. CONCLUSIONS: Our observations suggest that S. salsa resists the toxicity of saline-alkali stress using aboveground organs and that P. tenuiflora eliminates this toxicity via roots. S. salsa has a stronger habitat transformation ability and can provide better habitat for other plants.
Subject(s)
Chenopodiaceae/metabolism , Grassland , Poaceae/metabolism , Soil/chemistry , Acids/metabolism , Alcohols/metabolism , Alkalies , China , Plant Roots/chemistry , Plant Roots/metabolism , Plant Stems/chemistry , Plant Stems/metabolism , Salinity , Salt Tolerance , Salt-Tolerant Plants/physiology , Species Specificity , Stress, PhysiologicalABSTRACT
OBJECTIVE: We isolated and identified endophytic bacteria from halotolerant plants collected from coastal shoal of Nantong and investigated their heavy-metal tolerance and plant growth promoting potential. METHODS: In total 45 strains were obtained from 4 halotolerant plants and 23 representative isolates were selected to detect their tolerance against NaCl and heavy metals of Cu2+, Pb2+, Cd2+, Zn2+, Hg2+; plant growth promoting index of nitrogen fixation, phosphate solubilization, indoleacetic acid (IAA) production and 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase. RESULTS: Most of the isolates could grow under high consistency of Cu2+ and Pb2+. Of the bacteria 26.1% had the ability of nitrogen fixation, 21.7% of phosphate solubilization, 60.9% of IAA production and 39.1% of ACC deaminase activity. The results of 16S rRNA sequencing show that they belonged to the genera of Bacillus, Halobacillus, Oceanobacillus, Exiguobacterium, Serratia, Brevundimonas, Vibrio and Staphylococcus. Among them, strains KLBMP 2432 and KLBMP 2447 were potential novel species. CONCLUSION: The halotolerant plants located in the area of coastal shoal contain a variety of endophytic bacteria as well as the source of novel taxa. Some of them had the ability of plant growth promoting and high resistance against heavy-metal Cu2+ and Pb2+.