Effect of Water Stress on Microbial Community and Diversity in the Rhizosphere of Winter Wheat

Abstract

【Objective】 Winter wheat at anthesis stage is sensitive to water stress and in this paper, we elucidate how enzymatic activity, microbial community and diversity in its rhizosphere respond to change in water stress. 【Method】 The cultivar Jimai 22 was used as the model plant; we compared three water stresses: mild water stress (L), moderate water stress (M), and severe water stress (S), all occurring at the flowering stage. Sufficient irrigation was taken as the control (CK). In each treatment, we sampled the rhizosphere soil and then measured the enzymatic activities, microbial community and diversity in each sample using the Illumina high-throughput sequencing technology. 【Result】 Compared with CK, mild water stress increased and the severe water stress reduced the activity of sucrase, both at significant level, while the activity of the alkaline phosphatase remaining unchanged in the treatments. Water stress affected the diversity index of bacteria and fungi differently. Compared with CK, water stress reduced the Shannon index of bacteria significantly, while the Shannon index of fungi decreased significantly only under severe water stress. ACE, Chao1 and Simpson diversity indices of bacteria and fungi showed significant change only under severe water stress. It was found that water stress increased the relative abundance of Geobacter, Marseilla and Promicromonospora (P<0.05). The abundance of Gibberella, Mortierella, Olpidium, Blumeria, Cladosporium, Lectera, Alternaria and Acremonium varied with water stress. The relative abundance of Olpidium and Alternaria was higher in CK, while the relative abundance of Alternaria in the mild water stress was significantly higher than that in CK. Severe water stress significantly increased the abundance of Olpidium and Blumeria, while reducing the abundance of Mortierella. Redundancy analysis showed that soil water content and the activity of sucrose enzyme were negatively correlated with bacterial communities of Nocardia, Marseillaria, norank_f_Saccharimonadaceae, Promicromonospora, Geobacter, Gibberella, Oleomycete and Cladosporium (P<0.01), and were positively correlated with Mortierella and Acremonium. 【Conclusion】 Mild water stress at flowering stage increased the activity of sucrase in the rhizosphere of winter wheat. Water stress altered microbial community and diversity, the activity of sucrose enzymes, and the relative abundance of dominant bacteria and fungi in the rhizosphere.

Keywords

• winter wheat
• water stress
• soil enzymatic activity
• soil microbial community structure and diversity