Table_4_Wheat Production Alters Soil Microbial Profiles and Enhances Beneficial Microbes in Double-Cropping Soybean.XLSX

Plant-parasitic nematodes represent a substantial constraint on global food security by reducing the yield potential of all major crops. The soybean cyst nematode (SCN) (Heterodera glycines Ichinohe) is widely distributed across important soybean production areas of the U.S., being the major soybean yield-limiting factor, especially in the Midwestern U.S. Double cropped (DC) soybean is commonly planted following winter wheat. We previously reported double-cropping soybean fields with reduced SCN counts compared to fallow at both R1 growth stage (beginning of flowering) (−31.8%) and after soybean harvest (−32.7%). To test if higher counts of beneficial and SCN antagonistic microorganisms could be correlated with the suppression of SCN in fields previously planted with wheat, three field locations with noted SCN suppression were selected for a metagenomics study. Ten subplots were selected (5 wheat and 5 fallow pre-soybean) from each location. A total of 90 soil samples were selected: 3 fields ×2 treatments × 3 timepoints × 5 replications. Three DNA markers targeted distinct microbial groups: bacteria (16S V4-V5), fungi (ITS2), and Fusarium (tef1). Amplicons were sequenced using an Illumina MiSeq platform (300 bp paired-end). Sequencing datasets were processed in R using the DADA2 pipeline. Fungal populations were affected by location in all sampling periods and differed significantly between DC and fallow plots at soybean planting and after harvest (P < 0.001). Several enriched fungal and bacterial taxa in wheat plots, including Mortierella, Exophiala, Conocybe, Rhizobacter spp., and others, were previously reported to parasitize SCN and other plant-parasitic nematodes, suggesting a potential role of beneficial microbes in suppression of SCN in soybean fields double-cropped with wheat.

植物寄生线虫对全球粮食安全构成了重大制约，它们通过降低所有主要作物的产量潜力来影响农业生产。大豆胞囊线虫（大豆根腐病，学名Heterodera glycines Ichinohe）在美国大豆主要产区广泛分布，是限制大豆产量的主要因素，尤其是在美国中西部地区。冬小麦之后的连作大豆种植是一种常见的耕作方式。我们先前报道了与休闲地相比，在R1生长阶段（花蕾初期）（−31.8%）和大豆收获后（−32.7%）的连作大豆田中大豆胞囊线虫数量有所减少。为了测试在先前种植小麦的田地中，有益微生物和与大豆胞囊线虫拮抗的微生物数量是否与大豆胞囊线虫的抑制相关，我们选择了三个具有显著大豆胞囊线虫抑制效果的田地作为元基因组研究的对象。从每个地点选择了十个子图（5个小麦和5个休闲大豆前地）。总共选择了90个土壤样本：3个田地×2种处理×3个时间点×5个重复。三种DNA标记针对不同的微生物组：细菌（16S V4-V5）、真菌（ITS2）和 Fusarium（tef1）。扩增子使用Illumina MiSeq平台进行测序（300 bp配对末端）。测序数据集使用R中的DADA2流程进行处理。在所有采样期间，真菌种群受地点影响，在播种大豆和收获后的大豆连作和休闲田地之间差异显著（P < 0.001）。在小麦田地中发现的几种富含真菌和细菌的类群，包括Mortierella、Exophiala、Conocybe、Rhizobacter spp.等，先前已被报道为寄生于大豆胞囊线虫和其他植物寄生线虫，这表明有益微生物可能在小麦连作大豆田地中大豆胞囊线虫的抑制中发挥潜在作用。