Screening the maize rhizobiome for consortia that improve Azospirillum brasilense root colonization and plant growth outcomes
Screening the maize rhizobiome for consortia that improve Azospirillum brasilense root colonization and plant growth outcomes
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DOI：
10.3389/fsufs.2023.1106528
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发表时间：
2023-04
期刊：
影响因子：
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通讯作者：
Niloy Barua;Kayla M. Clouse;D. R. Ruiz Diaz;Maggie R. Wagner;Thomas G. Platt;Ryan R. Hansen
中科院分区：
文献类型：
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作者：
Niloy Barua;Kayla M. Clouse;D. R. Ruiz Diaz;Maggie R. Wagner;Thomas G. Platt;Ryan R. Hansen
植物促生长细菌（PGPB）对支持可持续粮食生产具有重要价值，并可减轻化肥对人类健康和环境的负面影响。虽然单株接种被证明是不可靠的，因为在根际的生存和定植能力差，但在多物种联合体中应用PGPB有可能改善这些结果。在这里，我们描述了一种筛选和鉴定细菌联合体的新方法，相对于接种单一菌株的植物，细菌联合体可以改善玉米的生长。该方法使用微孔恢复阵列（MRA），一种微型制造的高通量筛选装置，快速探索玉米（Zea mays L.）根瘤菌群，寻找促进固氮PGPB， Azospirillum brasilense生长和定植的高阶细菌组合。该装置同时产生数千种随机的、独特的细菌组合，其中包括巴西芽孢杆菌和玉米根瘤菌群的成员，然后在共培养过程中跟踪每种组合中的巴西芽孢杆菌生长情况。显示出最高水平的巴西芽孢杆菌生长促进的细菌，然后使用图案光提取技术从设备中回收并鉴定。通过这种方法，筛选发现了主要由不动杆菌-肠杆菌-沙雷氏菌属细菌组成的促进生长的菌群，然后将其与巴西芽孢杆菌共接种在无菌玉米幼苗上，并在植物生长室内进行监测。与单独接种巴西芽孢杆菌的玉米植株相比，与这些菌群共接种的植株在15 d后的生长速度加快。后续的根定殖试验表明，巴西松在共接种苗的根上的定殖水平较高。这些发现表明了一种快速生物勘探根和土壤群落的新方法，可用于互补的PGPB，并可用于开发具有下一代生物肥料潜力的多物种群落。
Plant growth-promoting bacteria (PGPB) are valuable for supporting sustainable food production and may alleviate the negative impacts of chemical fertilizers on human health and the environment. While single-strain inoculations have proven unreliable due to poor survival and colonization in the rhizosphere, application of PGPB in multispecies consortia has the potential to improve these outcomes. Here, we describe a new approach for screening and identifying bacterial consortia that improve the growth of corn relative to plants inoculated with a single strain. The method uses the microwell recovery array (MRA), a microfabricated high-throughput screening device, to rapidly explore the maize (Zea mays L.) rhizobiome for higher-order combinations of bacteria that promote the growth and colonization of the nitrogen-fixing PGPB, Azospirillum brasilense. The device simultaneously generates thousands of random, unique combinations of bacteria that include A. brasilense and members of the maize rhizobiome, then tracks A. brasilense growth in each combination during co-culture. Bacteria that show the highest levels of A. brasilense growth promotion are then recovered from the device using a patterned light extraction technique and are identified. With this approach, the screen uncovered growth-promoting consortia consisting primarily of bacteria from the Acinetobacter-Enterobacter-Serratia genera, which were then co-inoculated with A. brasilense on axenic maize seedlings that were monitored inside a plant growth chamber. Compared to maize plants inoculated with A. brasilense alone, plants that were co-inoculated with these consortia showed accelerated growth after 15 days. Follow-up root colonization assays revealed that A. brasilense colonized at higher levels on roots from the co-inoculated seedlings. These findings demonstrate a new method for rapid bioprospecting of root and soil communities for complementary PGPB and for developing multispecies consortia with potential use as next-generation biofertilizers.