Alterations in Arbuscular Mycorrhizal Community Along a Chronosequence of Teak (Tectona grandis) Plantations in Tropical Forests of China.

Zhi Yu,Xianbang Wang,Zaizhi Zhou,Guihua Huang,Guihua Huang,Kunnan Liang,Zaizhi Zhou,Kunnan Liang,Yinglong Chen,Xianbang Wang,Mingping Lin,Mingping Lin

doi:10.3389/fmicb.2021.737068

Abstract

Arbuscular mycorrhizal (AM) fungi play a crucial role in promoting plant growth, enhancing plant stress resistance, and sustaining a healthy ecosystem. However, little is known about the mycorrhizal status of teak plantations. Here, we evaluated how the AM fungal communities of rhizosphere soils and roots respond to different stand ages of teak: 22, 35, 45, and 55-year-old from the adjacent native grassland (CK). A high-throughput sequencing method was used to compare the differences in soil and root AM fungal community structures. In combination with soil parameters, mechanisms driving the AM fungal community were revealed by redundancy analysis and the Mantel test. Additionally, spore density and colonization rates were analyzed. With increasing stand age, the AM fungal colonization rates and spore density increased linearly. Catalase activity and ammonium nitrogen content also increased, and soil organic carbon, total phosphorous, acid phosphatase activity, available potassium, and available phosphorus first increased and then decreased. Stand age significantly changed the structure of the AM fungal community but had no significant impact on the diversity of the AM fungal community. However, the diversity of the AM fungal community in soils was statistically higher than that in the roots. In total, nine and seven AM fungal genera were detected in the soil and root samples, respectively. The majority of sequences in soils and roots belonged to Glomus. Age-induced changes in soil properties could largely explain the alterations in the structure of the AM fungal community along a chronosequence, which included total potassium, carbon-nitrogen ratio, ammonium nitrogen, catalase, and acid phosphatase levels in soils and catalase, acid phosphatase, pH, and total potassium levels in roots. Soil nutrient availability and enzyme activity were the main driving factors regulating the shift in the AM fungal community structure along a chronosequence of the teak plantations.

Highlights

Tropical forests are one of the most abundant and complex terrestrial ecosystems and play a vital role in maintaining biodiversity and regulating the global climate (Jing et al, 2020)
We found no significant differences in the diversity (Shannon) and richness (Sobs and Chao 1) of the Arbuscular mycorrhizal (AM) fungal communities in the rhizosphere soil and roots with increasing stand age (Figure 2), indicating that stand age had no significant effect on the diversity and richness of the AM fungal community
Pearson correlation analysis showed that spore density was significantly related to soil properties (Supplementary Table 1), suggesting that the increase in spore density with a chronosequence of teak plantation could be mediated by soil parameters induced by stand age

Summary

Introduction

Tropical forests are one of the most abundant and complex terrestrial ecosystems and play a vital role in maintaining biodiversity and regulating the global climate (Jing et al, 2020). It is generally accepted that AM fungi can affect plant growth by promoting nutrient uptake, especially phosphorus (P) (Smith and Read, 2008), protecting plants against abiotic stresses, such as drought (Zou et al, 2015; Mo et al, 2016; Ren et al, 2019), salinity (Wu et al, 2015; Chen et al, 2017), heavy metals (Zhang et al, 2020), low temperature (Zhou et al, 2012b), protection of host plants from pathogenic infections (Lin et al, 2021), improving soil aggregate stability by secreting glomalin (Zou et al, 2014; Ji et al, 2019), and affecting ecosystem productivity (van der Heijden et al, 2008; Zhu et al, 2017) These physiological and ecological functions of AM fungi are highly dependent on species diversity and community composition (Jiang et al, 2018). A growing number of studies are focused on the diversity and mechanisms of the assembly of AM fungal communities in ecosystems and the exploration of factors shaping AM fungal community composition

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