School of Life Sciences, Anhui Agricultural University, Hefei 230036, Anhui, China.
School of Life Sciences, Anhui Agricultural University, Hefei 230036, Anhui, China.
Microbiol Res. 2022 Aug;261:127076. doi: 10.1016/j.micres.2022.127076. Epub 2022 May 20.
The basic requirements of plant growth-promoting rhizobacteria (PGPR) for field applications are that they have an affinity for the host plant and that they can colonize the rhizosphere. Here, a new technique was established using soybean agglutin (SBA) as a tool to isolate soybean-specific PGPR. Thirty-three PGPR strains with an affinity for soybean were obtained via the screening method with SBA. All 33 isolates were able to produce indole acetic acid and solubilize inorganic phosphate and potassium. Most isolates (93.94%) were able to solubilize organic phosphate and almost half (45.45%) were able to produce siderophores. More than 40% of the isolates exhibited all five plant growth-promoting traits. The isolate Enterobacter sp. strain DN9 was selected for further analyses of its rhizosphere colonization and soybean growth-promoting effects because of its excellent activity in phosphate and potassium solubilization. The luciferase luxAB gene was electrotransformed into DN9, and the labelled DN9 (DN9-L) was able to survive in the soybean rhizosphere and colonize new spaces as the soybean roots elongated. This strain positively affected root system development and soybean seedling growth. In pot and field experiments, the isolates DN9, DW1, and DW13 significantly increased the nutrient contents in rhizosphere soil and soybean leaves. On average, the seed number per plant and the seed weight per plant were increased by 20% and 24% respectively, in plants inoculated with these PGPR strains in the pot experiment. In a field experiment, compared with uninoculated plants, those inoculated with DW1 showed 46.78% higher pod number per plant and 5.23% higher seed oil content; those inoculated with DW13 showed 79.82% higher seed number per plant and 65.10% higher seed weight per plant; and those inoculated with DN9 showed 9.13% higher 100-seed weight. These results show that SBA can be used as a tool to isolate efficient PGPR to enhance soybean production.
植物促生根际细菌（PGPR）的田间应用的基本要求是它们对宿主植物具有亲和力，并且能够定殖根际。在这里，建立了一种新的技术，使用大豆凝集素（SBA）作为工具来分离大豆特异性 PGPR。通过使用 SBA 的筛选方法，获得了 33 株对大豆具有亲和力的 PGPR 菌株。所有 33 株分离株都能够产生吲哚乙酸并溶解无机磷酸盐和钾。大多数分离株（93.94%）能够溶解有机磷酸盐，近一半（45.45%）能够产生铁载体。超过 40%的分离株表现出所有五种促进植物生长的特性。由于其在磷酸盐和钾溶解方面的优异活性，选择肠杆菌属 sp. 菌株 DN9 进行进一步分析其根际定殖和大豆促生长效应。荧光素酶 luxAB 基因被电转化到 DN9 中，标记的 DN9（DN9-L）能够在大豆根际中存活，并随着大豆根系的伸长而殖民新的空间。该菌株对根系发育和大豆幼苗生长有积极影响。在盆栽和田间试验中，分离株 DN9、DW1 和 DW13 显著增加了根际土壤和大豆叶片中的养分含量。平均而言，在盆栽试验中接种这些 PGPR 菌株的植物的每株植物的种子数和每株植物的种子重量分别增加了 20%和 24%。在田间试验中，与未接种植物相比，接种 DW1 的植物每株植物的荚数增加了 46.78%，种子油含量增加了 5.23%；接种 DW13 的植物每株植物的种子数增加了 79.82%，每株植物的种子重量增加了 65.10%；接种 DN9 的植物每株植物的百粒重增加了 9.13%。这些结果表明，SBA 可以用作分离有效 PGPR 以提高大豆产量的工具。
