应用BOX分子标记技术筛选南苜蓿高效根瘤菌菌株

Screening effective rhizobial strains associated with Medicago polymorpha by BOX molecular fingerprint

摘要:

【目的】应用BOX-PCR技术对12株南苜蓿(Medicago polymorpha)接种根瘤菌菌株在土壤中的竞争结瘤能力进行研究, 以占瘤率的高低配合植物生长性状最终确定与南苜蓿共生的高效根瘤菌菌株。【方法】对接种根瘤菌产生的南苜蓿根瘤进行分离培养, 选择部分结瘤菌株和12株全部供试接种菌株进行BOX分子指纹图谱研究, 经过对图谱的比较与分析获得了各接种菌株的占瘤率。【结果】在供试菌株中, 来自于云南盈江的菌株SWF67523占瘤率最高, 为93.33%, 说明菌株SWF67523具有较强的竞争结瘤能力, 该菌株对南苜蓿干重增幅也较高, 为100%; 菌株SWF67409来自于云南楚雄, 其占瘤率略低于菌株SWF67523, 但其对提高植物干重的贡献最大(增幅106.5%); 来自于云南楚雄的菌株SWF67394占瘤率较低, 但其结瘤率高, 对植物生长的影响作用也较明显。【结论】将根瘤菌菌株的竞争结瘤能力纳入南苜蓿高效根瘤菌菌株的筛选中, 研究获得了一株竞争结瘤能力强、显著提高植物生物量的菌株SWF67523, 以及促生根瘤菌菌株SWF67409和SWF67394, 为生产高效根瘤菌菌剂提供了物质基础。

Abstract:

[Objective] Competitive nodulation ability of 12 rhizobial strains associated with Medicago polymorpha is tested by using BOX-PCR Molecular fingerprint; effective rhizobial strains were finally confirmed using the nodule occupancy rate combined with plant growth. [Methods] The nodule occupancy rate calculated by comparing BOX-PCR Molecular finger-prints of inoculated strains with those part of re-isolated strains. [Results] It showed that nod-ule occupancy of strain SWF67523 from Yingjiang district was of the highest occupation nodulation rate, reach 93.33%, showing strong ability of competitive nodulation, and it in-creased the dry-weight of their host-plants for 100% by plant test; while the other strain SWF67409 was of lower nodule occupancy rate, but with highly nodulation rate and increased the dry-weight of their host-plants for 106.5%. Furthermore, strain SWF67394 obviously in-creased the dry-weight of their host-plants and with high nodulation rate and lower nodule occupancy rate, these two strains may had effect on influencing activities of the native rhizobia and other microorganisms in soil. [Conclusion] We have introduced the competitive nodula-tion ability in screening effective rhizobial strains, and obtained a strain SWF67523 that with highly competitive nodulation ability and highly ability of plant growth promoting, and plant growth promoting strains of SWF67409 and SWF67394, this will provide precarious strains resources for producing rhizobial inoculants.