Background

Soil salinity is a severe environmental stress, limiting plant growth and sustainable agriculture. Plant growth promoting rhizobacteria (PGPR) and Epichloë gansuensis endophyte can be used to alleviate the adverse effects of soil salinization, promote plant growth and improve resistance to biotic and abiotic stresses.

Aims

The present study was conducted to investigate the diversity of culturable rhizosphere soil bacteria associated with Achnatherum inebrians, as well as the effect of E. gansuensis and PGPR on the germination of A. inebrians seeds under high concentrations of NaCl.

Materials and methods

The PGPR strains were obtained by traditional isolation and culture techniques, and then endophyte-infected and endophyte-free A. inebrians seeds exposed to different concentrations of NaCl were inoculated with PGPR.

Results

A total of 990 bacterial colonies were isolated, and these were assigned to 65 species within 18 genera and 4 phyla. Principal component analysis (PCA) indicated that the rhizosphere soil of A. inebrians plants with Epichloë had differing bacterial diversity from that without Epichloë. When A. inebrians seeds were exposed to NaCl concentrations of 0, 50, 100, 200 mmol/L, seed germination was enhanced at the low salt concentration (50 mmol/L) and inhibited at the highest salt concentration (200 mmol/L). E. gansuensis significantly (P < 0.05) promoted the germination and peroxidase (POD) activity of the seedlings under different NaCl concentrations. Inoculation with three selected isolates of rhizosphere bacteria significantly (P < 0.05) improved seed germination under the four different NaCl concentrations.

Conclusions

This study provides new evidence that inoculation with PGPR of both endophyte-infected and uninfected A. inebrians seeds reduces the impact of NaCl stress on seed germination and provides a basis for further research on the mechanism of PGPR promotion of seed germination of A. inebrians.

中文翻译：

---

使用从感染了Epichloë gansuensis 内生菌的Achnatherum inebrians 根际土壤中分离的促进植物生长的根际细菌减轻对种子的盐胁迫

背景

土壤盐分是一种严重的环境压力，限制了植物生长和可持续农业。植物促生根际细菌（PGPR）和甘肃Epichloë gansuensis内生菌可用于减轻土壤盐渍化的不利影响，促进植物生长并提高对生物和非生物胁迫的抵抗力。

宗旨

本研究旨在调查与Achnatherum inebrians相关的可培养根际土壤细菌的多样性，以及E. gansuensis和 PGPR在高浓度 NaCl 下对A. inebrians种子萌发的影响。

材料和方法

PGPR 菌株是通过传统的分离和培养技术获得的，然后用 PGPR 接种暴露于不同浓度 NaCl 的内生菌感染和无内生菌的A.inebrians种子。

结果

共分离出 990 个细菌菌落，这些菌落被分配到 18 个属和 4 个门的 65 个物种中。主成分分析 (PCA) 表明，带有Epichloë的A. inebrians植物的根际土壤与没有Epichloë 的植物具有不同的细菌多样性。当A.inebrians种子暴露于0、50、100、200 mmol/L的NaCl浓度时，低盐浓度（50 mmol/L）促进种子萌发，最高盐浓度（200 mmol/L）抑制种子萌发. E. gansuensis显着 ( P < 0.05) 促进了不同 NaCl 浓度下幼苗的萌发和过氧化物酶 (POD) 活性。 在四种不同的 NaCl 浓度下，接种三种选定的根际细菌分离株显着 ( P < 0.05) 提高了种子发芽率。

结论

本研究为内生菌感染和未感染A. inebrians种子接种 PGPR降低了 NaCl 胁迫对种子萌发的影响提供了新的证据，并为进一步研究 PGPR 促进A. inebrians种子萌发的机制提供了依据。