Faculty of Agriculture and Life Sciences, Lincoln University, Christchurch, New Zealand.
Scion Research Ltd, Christchurch, New Zealand.
J Microbiol Methods. 2022 Apr;195:106455. doi: 10.1016/j.mimet.2022.106455. Epub 2022 Apr 1.
The purpose of developing this high throughput assay was to determine whether there was evidence of pH adaptation in strains of rhizobia which nodulate subterranean clover (SC) and white clover (WC), and whether this was related to the pH of the soil of origin. pH is a first-order factor influencing the niche preferences of soil microorganisms and has been convincingly shown to be a key driver of soil bacterial communities. Naturalised strains of Rhizobium spp. that are pH-adapted may have the potential to better compete and/or persist in acidic or alkaline soils compared with introduced commercial strains. Three pilot studies were conducted to design the optimised bioassay. This bioassay tested the effect of pH-amended yeast mannitol broth (seven pH values from pH 4.5-9.0), across three time points, on the in vitro growth of 299 Rhizobium strains isolated from the nodules of SC and WC. The media pH where strains demonstrated fastest growth was related to the pH of the soil that strains were isolated from. However, the correlation between media pH and soil pH was strongly influenced by the growth of strains from alkaline soils (alkaline adaptation), especially in strains isolated from SC nodules.
本研究旨在开发高通量检测方法，以确定是否有证据表明能够结瘤三叶草（ subterranean clover，SC）和白三叶草（ white clover，WC）的根瘤菌菌株具有适应 pH 值的能力，以及这种能力是否与根瘤菌起源土壤的 pH 值有关。pH 值是影响土壤微生物生态位偏好的一级因素，并且已被证实是土壤细菌群落的关键驱动因素。与引入的商业菌株相比，能够适应 pH 值的天然根瘤菌菌株可能具有更好的竞争和/或在酸性或碱性土壤中生存的潜力。本研究进行了三项初步研究来设计优化的生物测定。该生物测定测试了在三个时间点下，添加 pH 值的酵母甘露醇肉汤（七个 pH 值范围从 pH 4.5-9.0）对从 SC 和 WC 根瘤中分离的 299 株根瘤菌菌株的体外生长的影响。菌株表现出最快生长的培养基 pH 值与菌株分离的土壤 pH 值有关。然而，培养基 pH 值与土壤 pH 值之间的相关性受到来自碱性土壤的菌株生长的强烈影响（碱性适应），特别是从 SC 根瘤中分离的菌株。
