Journal Article

The diversity and abundance of As(III) oxidizers on root iron plaque is critical for arsenic bioavailability to rice

Li, Fangbai, Hu, Min, Liu, Chuanping, Wu, Weijian

2015

Overview

Iron plaque is a strong adsorbent on rice roots, acting as a barrier to prevent metal uptake by rice. However, the role of root iron plaque microbes in governing metal redox cycling and metal bioavailability is unknown. In this study, the microbial community structure on the iron plaque of rice roots from an arsenic-contaminated paddy soil was explored using high-throughput next-generation sequencing. The microbial composition and diversity of the root iron plaque were significantly different from those of the bulk and rhizosphere soils. Using the aoxB gene as an identifying marker, we determined that the arsenite-oxidizing microbiota on the iron plaque was dominated by Acidovorax and Hydrogenophaga -affiliated bacteria. More importantly, the abundance of arsenite-oxidizing bacteria (AsOB) on the root iron plaque was significantly negatively correlated with the arsenic concentration in the rice root, straw and grain, indicating that the microbes on the iron plaque, particularly the AsOB, were actively catalyzing arsenic transformation and greatly influencing metal uptake by rice. This exploratory research represents a preliminary examination of the microbial community structure of the root iron plaque formed under arsenic pollution and emphasizes the importance of the root iron plaque environment in arsenic biogeochemical cycling compared with the soil-rhizosphere biotope.

• Publisher: Nature Publishing Group UK,Nature Publishing Group
• Subject: 631/326/171 / 704/172 / Abundance / Arsenic / Arsenite / Arsenites - chemistry / Arsenites - metabolism / Bacterial Proteins - genetics / Bacterial Proteins - metabolism / Bioavailability / Biogeochemical cycles / Biological Availability / Cloning, Molecular / Comamonadaceae - enzymology / Comamonadaceae - isolation & purification / Community structure / Humanities and Social Sciences / Iron / Iron - chemistry / Iron - metabolism / Metals / multidisciplinary / Oryza - chemistry / Oryza - microbiology / Oxidation-Reduction / Oxidoreductases - genetics / Oxidoreductases - metabolism / Plant Roots - chemistry / Plant Roots - microbiology / Principal Component Analysis / Real-Time Polymerase Chain Reaction / Redox properties / Rhizosphere / Rice / Rice fields / Roots / Science / Soil contamination / Soil Pollutants - chemistry / Soil Pollutants - metabolism / Soil pollution / Straw