芒萁根际复合微生物菌剂对绿豆幼苗生长及根际微生物群落的影响

Rhizosphere complex microbial agent of Dicranopteris dichotoma regulates the growth and rhizosphere microbial community of mung bean seedlings

摘要:

【背景】 在农业可持续发展背景下，复合微生物菌剂因其多种微生物间的互补作用成为促进植物生长的有效策略。【目的】 研究芒萁(Dicranopteris dichotoma)根际复合微生物菌剂对绿豆幼苗的促生效果，以及对根际微生物群落结构变化的影响。【方法】 以前期分离自芒萁根际土壤的4株根际促生菌为供试菌株，组合配制成2种复合微生物菌剂BFF和BBF接种至绿豆幼苗根际，测定绿豆幼苗培养36 d后的生理指标及土壤理化性质，并利用16S rRNA基因和ITS扩增子测序技术分析根际微生物结构组成和多样性。【结果】 BFF组显著提高了绿豆幼苗的株高、地上部分鲜重和干重以及地下部分干重，分别比对照组提高了29.38%、81.47%、175.73%和936.49%；BBF组则显著增加了绿豆幼苗的地上部分鲜重和干重，分别提高了92.64%和179.67%。高通量测序结果显示，接种复合微生物菌剂BFF和BBF均显著提高了细菌群落的多样性和丰富度，同时降低了真菌群落的多样性。在门水平上，显著增加了黏球菌门(Myxococcota)的相对丰度，降低了接合菌门(Zygomycota)的相对丰度。在细菌属水平上，显著减少了罗河杆菌属(Rhodanobacter)的相对丰度，增加了黏液杆菌属(Mucilaginibacter)和慢生根瘤菌属(Bradyrhizobium)的相对丰度；在真菌属水平上，显著增加了隐球菌属(Cryptococcus)的相对丰度，同时降低了被孢霉属(Mortierella)和Gliocladiopsis的相对丰度。功能预测结果表明，接种复合微生物菌剂显著提高了根际细菌中的固氮作用，同时增加了致病-腐生-共生型真菌的相对丰度，降低了腐生型和腐生-共生型真菌的相对丰度。【结论】 接种复合微生物菌剂可以提升土壤养分，调节根际微生物群落的结构和多样性，增加有益菌的数量，减少病原菌的存在，从而为绿豆幼苗创造更有利的根系生长环境，促进它们的生长发育。研究结果不仅为绿豆幼苗的生长提供了新的理论支持，也为复合微生物菌剂在农业生产中的应用提供了理论基础。

关键词:根际;复合微生物菌剂;绿豆;根际微生物组;促生

Abstract:

[Background] In the context of sustainable agricultural development, complex microbial agents have emerged as a potent means for enhancing plant growth, attributed to the synergistic effects of diverse microorganisms. [Objective] To investigate the rhizosphere complex microbial agent of Dicranopteris dichotoma regarding the effects on the growth and rhizosphere microbial community structure of mung bean seedlings. [Methods] Four plant growth-promoting strains isolated from the rhizosphere soil of D.dichotoma were used to formulate two complex microbial agents: BBF and BFF. The agents were inoculated into the rhizosphere of mung bean seedlings, and the physiological parameters and soil physicochemical characteristics of the mung bean seedlings were evaluated after 36 days of cultivation. The community structure and diversity of rhizosphere microorganisms were assessed by 16S rRNA gene and ITS amplicon sequencing. [Results] BFF increased the plant height, aboveground fresh and dry weights, and underground dry weight of mung bean seedlings by 29.38%, 81.47%, 175.73%, and 936.49%, respectively. BBF increased the aboveground fresh weight and dry weight of mung bean seedlings by 92.64% and 179.67%, respectively. High-throughput sequencing results revealed that both BFF and BBF significantly boosted the bacterial diversity and richness, while reducing the fungal diversity. At the phylum level, the two agents increased the relative abundance of Myxococcota while decreasing that of Zygomycota. At the bacterial genus level, the two agents decreased the relative abundance of Rhodanobacter while increasing that of Mucilaginibacter and Bradyrhizobium; at the fungal genus level, the two agents increased the relative abundance of Cryptococcus while decreasing that of Mortierella and Gliocladiopsis. Functional prediction indicated that the application of complex microbial agents notably enhanced bacterial nitrogen fixation in the rhizosphere, increased the relative abundance of pathogenic-saprophytic-symbiotic fungi, and decreased the relative abundance of saprophytic and saprophytic-symbiotic fungi. [Conclusion] Inoculating complex microbial agents increases soil nutrients, regulates rhizosphere microbial community structure and diversity, boosts beneficial bacterial count, and suppresses pathogen presence, thus creating a favorable environment for the root growth and promoting the growth and development of mung bean seedlings. These findings offer new theoretical support for the growth of mung bean seedlings and establish a basis for applying complex microbial agents in agricultural production.

Key words:rhizosphere;complex microbial agent;mung bean;rhizosphere microbiome;growth promotion