Prospects of alleviating early planting-associated cold susceptibility of soybean using microbes: New insights from microbiome analysis

Cold susceptibility is a concern when growing crops of tropical origin in temperate regions. Crops such as rice, corn, sorghum, and soybean are generally susceptible to chilling stress. From production standpoint, a crop's cold tolerance is particularly important when the general recommendation is to adopt earlier than currently practicing planting dates in the spring. Early planting is a potential route to increase soybean yield in the United States. Nonetheless, early planting is often not practically feasible due to low soil temperatures. Although some commercial varieties are cold-tolerant, soybean is generally prone to cold stress. Soil temperatures below 10°C reduce germination and seedling vigour. Cold temperatures can also increase soybean vulnerability to soilborne seed/seedling diseases. Microorganisms are experimentally shown to alleviate cold stress in agriculturally important crops such as rice, wheat, tomato and grapes. Although microbial inoculants are available to augment soybean yields through enhanced nitrogen fixation, phosphorus solubilization and improved water/nutrient uptake, currently there are no commercially available inoculants to enhance soybean cold tolerance. Here we provide insights into the value of soybean rhizosphere microbiome analysis to identify microbial taxa that could potentially enhance soybean cold tolerance. Formulation of promising candidates into a seed treatment could contribute to early planting-enabled soybean yield gains.