Ji Chao, Ge Yuhan, Zhang Hua, Zhang Yingxiang, Xin Zhiwen, Li Jian, Zheng Jinghe, Liang Zengwen, Cao Hui, Li Kun
College of Seed and Facility Agricultural Engineering, Weifang University, Weifang, China.
Key Laboratory of Biochemistry and Molecular Biology in University of Shandong Province, Weifang University, Weifang, China.
Front Microbiol. 2024 Mar 13;15:1288865. doi: 10.3389/fmicb.2024.1288865. eCollection 2024.
Soil salinity negatively affects crop development. Halotolerant nitrogen-fixing bacteria (HNFB) and arbuscular mycorrhizal fungi (AMF) are essential microorganisms that enhance crop nutrient availability and salt tolerance in saline soils. Studying the impact of HNFB on AMF communities and using HNFB in biofertilizers can help in selecting the optimal HNFB-AMF combinations to improve crop productivity in saline soils.
We established three experimental groups comprising apple plants treated with low-nitrogen (0 mg N/kg, N0), normal-nitrogen (200 mg N/kg, N1), and high-nitrogen (300 mg N/kg, N2) fertilizer under salt stress without bacteria (CK, with the addition of 1,500 mL sterile water +2 g sterile diatomite), or with bacteria [BIO, with the addition of 1,500 mL sterile water +2 g mixed bacterial preparation (including HG-15 and JC-K3)].
HNFB inoculation significantly increased microbial biomass and the relative abundance of beta-glucosidase-related genes in the rhizosphere soil under identical nitrogen application levels ( < 0.05). High-nitrogen treatment significantly reduced AMF diversity and the relative abundance of beta-glucosidase, acid phosphatase, and urea-related genes. A two-way analysis of variance showed that combined nitrogen application and HNFB treatment could significantly affect soil physicochemical properties and rhizosphere AMF abundance ( < 0.05). Specifically, HNFB application resulted in a significantly higher relative abundance of compared to that in the CK group at equal nitrogen levels.
The impact of HNFB on the AMF community in apple rhizospheres is influenced by soil nitrogen levels. The study reveals how varying nitrogen levels mediate the relationship between exogenous HNFB, soil properties, and rhizosphere microbes.
土壤盐分对作物生长发育产生负面影响。耐盐固氮细菌（HNFB）和丛枝菌根真菌（AMF）是重要的微生物，可提高盐渍土壤中作物的养分有效性和耐盐性。研究HNFB对AMF群落的影响并将HNFB用于生物肥料，有助于选择最佳的HNFB-AMF组合，以提高盐渍土壤中的作物生产力。
我们设立了三个实验组，包括在盐胁迫下分别用低氮（0 mg N/kg，N0）、正常氮（200 mg N/kg，N1）和高氮（300 mg N/kg，N2）肥料处理的苹果植株，一组不接种细菌（CK，添加1500 mL无菌水+2 g无菌硅藻土），另一组接种细菌[BIO，添加1500 mL无菌水+2 g混合细菌制剂（包括HG-15和JC-K3）]。
在相同施氮水平下，接种HNFB显著增加了根际土壤中的微生物生物量和β-葡萄糖苷酶相关基因的相对丰度（<0.05）。高氮处理显著降低了AMF多样性以及β-葡萄糖苷酶、酸性磷酸酶和尿素相关基因的相对丰度。双向方差分析表明，氮肥施用和HNFB处理相结合可显著影响土壤理化性质和根际AMF丰度（<0.05）。具体而言，在相同氮水平下，与CK组相比，施用HNFB导致 的相对丰度显著更高。
HNFB对苹果根际AMF群落的影响受土壤氮水平的影响。该研究揭示了不同氮水平如何调节外源HNFB、土壤性质和根际微生物之间的关系。
