Diversity and heavy metal tolerance of endophytic fungi from Dysphania ambrosioides, a hyperaccumulator from Pb–Zn contaminated soils

Xinya Li,Haiyan Li,Long Chu,Zhi Xiong,James F. White,Wei Li

doi:10.1080/17429145.2016.1266043

Abstract

ABSTRACTThe diversity and heavy metal (HM) tolerance of endophytic fungi (EF) associated with Dysphania ambrosioides, a hyperaccumulator from two Pb–Zn contaminated sites were investigated. A total of 237 culturable EF were isolated and identified to 43 taxa based on morphological characteristics and rDNA internal transcribed spacer analysis, of which 13 occurred as endophytes of both sites, while other taxa were only found in either site. The colonization rate, dominant genera, community structure of EF as well as the HM content in the plant from two sites were significantly different. We suggest that these differences may result from the difference in the soil HM content: lower HM content in the soil, more EF in the plant, which may enhance the plant HM accumulation and thus result higher HM in it. HM tolerance tests indicated that 50% of the isolates exhibited HM tolerance. Among them, two isolates exhibited better HM tolerance, of which FT2G59 could tolerate Pb, Zn, and Cd, and the minimum inhibitory concentration (MIC) of them were 30–50, > 680, 20–30 mmol/l, respectively. While, the isolate FT2G7 could tolerate Cd, and the MIC was 30–50 mmol/l. These isolates may have potential application in phytoremediation.

Highlights

The soil is an important life-supporting system and is central to essential planetary functions such as primary production, the regulation of biogenic gases and the earth’s climate, biogeochemical and water cycling, and the maintenance of biodiversity (Abhilash et al 2012)
A total of 237 endophytic fungi (EF) were isolated from 368 tissue segments, of which 83 from D. ambrosioides growing in the slag heap and 154 from D. ambrosioides growing in the wasteland (Table 1)
The total CR of EF of plants growing in the slag heap (35.20%) was significantly lower than that of plants growing in the wasteland (57.67%) (P < .05, chi-squared test)

Summary

Introduction

The soil is an important life-supporting system and is central to essential planetary functions such as primary production, the regulation of biogenic gases and the earth’s climate, biogeochemical and water cycling, and the maintenance of biodiversity (Abhilash et al 2012). Phytotoxicity of HM, limited biomass capacity, and slow growth of plants have reduced the application of phytoremediation in most circumstances (Gerhardt et al 2009; Weyens, van der Lelie, Taghavi, Newman, et al 2009). To overcome these problems, microbial-assisted phytoremediation is being explored. Microorganisms could promote plant growth by transformation of nutrient elements, production of phytohormones, or provide iron to reduce the deleterious effects of metal contamination to plants (Rajkumar et al 2010)

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Discussion

Conclusion