Silicon Application Modulates the Growth, Rhizosphere Soil Characteristics, and Bacterial Community Structure in Sugarcane

Quanqing Deng,Zhen Zeng,Wankuan Shen,Qihan Shi,Wardah Muzaffar,Umair Ashraf,Tengxiang Lian,Taobing Yu,Suihua Huang,Jianwen Chen

doi:10.3389/fpls.2021.710139

Abstract

Silicon (Si) deficiency, caused by acidic soil and rainy climate, is a major constraint for sugarcane production in southern China. Si application generally improves sugarcane growth; however, there are few studies on the relationships between enhanced plant growth, changes in rhizosphere soil, and bacterial communities. A field experiment was conducted to measure sugarcane agronomic traits, plant nutrient contents, rhizosphere soil enzyme activities and chemical properties, and the rhizosphere bacterial community diversity and structure of three predominant sugarcane varieties under two Si treatments, i.e., 0 and 200 kg of silicon dioxide (SiO2) ha−1 regarded as Si0 and Si200, respectively. Results showed that Si application substantially improved the sugarcane stalk fresh weight and Si, phosphorus (P), and potassium (K) contents comparing to Si0, and had an obvious impact on rhizosphere soil pH, available Si (ASi), available P (AP), available K (AK), total phosphorus (TP), and the activity of acid phosphatase. Furthermore, the relative abundances of Proteobacteria showed a remarkable increase in Si200, which may be the dominant group in sugarcane growth under Si application. Interestingly, the AP was noticed as a major factor that caused bacterial community structure differences between the two Si treatments according to canonical correspondence analysis (CCA). In addition, the association network analysis indicated that Si application enriched the rhizosphere bacterial network, which could be beneficial to sugarcane growth. Overall, appropriate Si application, i.e., 200 kg SiO2 ha−1 promoted sugarcane growth, changed rhizosphere soil enzyme activities and chemical properties, and bacterial community structures.

Highlights

Silicon (Si), an ubiquitous and abundant (∼28%) element in soil, is mostly insoluble and not readily available for plants (Liang et al, 2015; Mo et al, 2017)
Previous reports indicated that an inverse relationship exists between phosphorus and Soil acid phosphatase (SAP) (Moscatelli et al, 2005; Nannipieri et al, 2010), whereas partial least squares-discriminant analysis (PLS-DA) showed that the soil available Si (ASi), available P (AP), and available K (AK) were significantly altered with Si application (Figure 2)
Our results revealed that Si application substantially improved sugarcane growth and changed rhizosphere soil properties and bacterial diversities and compositions

Summary

Introduction

Silicon (Si), an ubiquitous and abundant (∼28%) element in soil, is mostly insoluble and not readily available for plants (Liang et al, 2015; Mo et al, 2017). Si has not been considered as an essential plant element; its roles in improving crop growth and inducing biotic and abiotic stress resistance in plants have been well-documented (Frayssinet et al, 2019; Lin et al, 2020). Sugarcane (Saccharum spp. hybrids) is globally recognized as a “sugar crop” and a renewable green energy crop (Chen et al, 2017; Liu X. et al, 2018). There are more than 100 cane-growing tropical countries that depend on the sugarcane industry for economic opportunities. For China, being the third largest sucrose producing country in the world, the sugarcane industry has had significant contributions for poverty alleviation

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Discussion

Conclusion