Abstract
Drought limits crop productivity, especially of sugarcane, which is predominantly grown in the subtropical parts of China. Soil microbes perform a wide range of functions that are important for plant productivity and responses to drought stress, and fungi play an important role in plant–soil interactions. The Ea-DREB2B gene of sugarcane, Saccharum arundinaceum, is involved in regulating the response to drought stress. In this study, fungal communities of the transgenic (TG) sugarcane variety GN18, harboring the drought-tolerant gene Ea-DREB2B and its corresponding non-TG wild-type (WT) variety, FN95-1702, were investigated in three soil compartments (rhizoplane, rhizosphere, and bulk soil) by assessing the internal transcribed spacer region using Illumina MiSeq. As the soil microbial community is also affected by various environmental factors, such as pH, carbon availability, and soil moisture, we determined the total carbon (TC), total nitrogen (TN), and total phosphorus (TP) contents in the rhizoplane, rhizosphere, and bulk soil compartments to explore the associations between soil fungal communities and host plant characteristics. The differences between the soil fungal communities of TG and WT plants were detected. The alpha diversity of TG fungal communities was more correlated to environmental factors than the beta diversity. The abundance of operational taxonomic units (OTUs) enriched in TG root-related area was far more than that in the root-related area of WT plants. Thereinto, more saprotrophs were enriched in the TG root-related area, indicating altered niches of fungal guilds around TG roots. These results revealed that host plant genotype did play a key role for strengthening plant–fungi interaction and enhancing beneficial fungal function in the root-related area (rhizoplane and rhizosphere) of TG sugarcane in order to respond to drought stress.
Highlights
Drought is a major constraint for plant growth and agricultural productivity in many parts of the world
Fungal diversity was affected in lettuce and Arabidopsis thaliana due to plant genotype (Hunter et al, 2015; Urbina et al, 2018), while no significant differences of fungal diversity between the WT and TG lines were found in potato and rice (Milling et al, 2005; Sohn et al, 2016)
Ea-DREB2B belongs to the dehydration-responsive element-binding (DREB) subfamily, the members of which are capable of regulating drought response via Abscisic acid (ABA)-dependent as well as ABA-independent pathways (Vargas et al, 2014)
Summary
Drought is a major constraint for plant growth and agricultural productivity in many parts of the world. There are several aspects of the plant response to drought, such as sensing stress, activating systemic signaling pathways, and genetically regulating the responses (Zolla et al, 2013). Soil Fungal Communities of Drought-Resistant Ea-DREB2B effectively used to improve drought tolerance (Gosti et al, 1995; Iuchi et al, 2001; Li et al, 2017) by developing new drought-tolerant crop varieties through genetic modifications to increase crop productivity and reduce costs (Romão-Dumaresq et al, 2016). Soil microbes have a wide range of functions that are important for plant productivity, such as cycling nutrients, inducing disease resistance, and responding to environmental stresses, including drought and salinity (Zolla et al, 2013). Soil fungi play important roles in ecosystem nutrient cycling and as mutualists and pathogens of host plants (Yang et al, 2017). As a significant resource of sugar and ethanol, has high requirements for irrigation and is very sensitive to water shortage (Ferreira et al, 2017); genetic engineering has been applied to enhance its drought resistance (Ramiro et al, 2016)
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