Plant growth-promoting effect and genomic analysis of the beneficial endophyte Streptomyces sp. KLBMP 5084 isolated from halophyte Limonium sinense

• Published in: Plant and soil 2017-07, Vol.416 (1/2), p.117-132
• Main Authors: Qin, Sheng, Feng, Wei-Wei, Wang, Tian-Tian, Ding, Peng, Xing, Ke, Jiang, Ji-Hong
• Format: Article
• Language: English
• Subjects: Actinomycetes; Biomedical and Life Sciences; Botanical research; Chlorophyll; Crop production; Ecology; Endophytes; Enzymes; Genes; Genomes; Genomic analysis; Growth; Halophytes; Host plants; Identification methods; Inoculation; Leaves; Life Sciences; Malondialdehyde; Methods; Physiological aspects; Physiological responses; Plant growth; Plant Physiology; Plant Sciences; Plants; Proline; Regular Article; Salinity; Salinity effects; Salinity tolerance; Salt; Salt tolerance; Seedlings; Sodium chloride; Soil salinity; Soil Science & Conservation; Strain; Stresses
• ISSN: 0032-079X; 1573-5036
• DOI: 10.1007/s11104-017-3192-2

Background and aims Soil salinity is a worldwide environmental problem that can hinder plant development and therefore negatively impact crop production. Inoculation of halophytic plants with plant growth-promoting (PGP) actinobacteria has been suggested as one strategy to improve salt tolerance. Here we performed a glasshouse experiment to test the effect of a PGP halotolerant endophytic actinomycete strain, KLBMP 5084 on the performance of the halophyte Limonium sinense under conditions of salt stress. Methods Strain KLBMP 5084 was identified and screened for multiple PGP traits. The complete genome of strain KLBMP 5084 was sequenced and analyzed. L. sinense control seedlings (no inoculation) and seedlings inoculated with KLBMP 5084 were given different NaCl (0, 100 and 250 mM) salt-stress treatments. Growth parameters and physiological responses of L. sinense were determined after harvest. Results Compared with the control, plants inoculated with strain KLBMP 5084 had greater in fresh weight, root length, leaf length and total chlorophyll and proline contents under both normal and high salinity conditions. Compared with control, inoculated plants had significantly lower leaf malondialdehyde (MDA) content and significantly more antioxidant enzymes. Moreover, inoculated plants had significantly lower accumulation of Na+ in both leaves and roots under high salt-stress conditions. Genomic analysis of strain KLBMP 5084 revealed many PGP related genes, including some genes putatively involved in salt tolerance and harsh environment adaptation. Conclusion Strain KLBMP 5084 seems to confer salt tolerance to host plant L. sinense through more than one mechanism, suggesting KLBMP 5084 could be a strong PGP agent to improve plant yields and tolerance to salinity stress.