Intervention of the rice microbiome in abating arsenic toxicity in rice
Date
2019
Authors
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Publisher
University of Delaware
Abstract
Food security and crop protection are of vital importance as the world is challenged with supplying enough food for the growing population. Arsenite (As (III)) is a naturally occurring, inorganic, form of Arsenic (As), and is responsible for polluting groundwater in areas of South East Asia, India, and Bangladesh. This contamination poses a serious health concern to people using As(III)- polluted water for drinking and irrigation. Rice (Oryza sativa) is among one of the largest agronomic crops in Asia and provides essential caloric intake to much of the world’s population. Rice plants exposed to inorganic As(III) suffer from low grain yields and overall poor plant health as a result of increased As concentrations in the plant grains and tissues. It is hypothesized that plant growth promoting rhizobacteria (PGPR) can be used to ameliorate the effects of As contamination by limiting uptake into the rice plant. There has been minimal research done to identify the effects of As or bio-inoculants on plant hormone expression levels, which play an active role in plant growth, development, and defense. Through a series of hydroponic and gene expression assays I analyzed the effects of varying As toxicity and bacterial inoculants on rice plant development. As- tolerant Nipponbare varieties show grain production at high As(III) concentrations compared to As- susceptible IR66 variety. Treatment of bio-inoculum to both susceptible and tolerant varieties under moderate As environment led to upregulation of auxin and brassinosteroids biosynthetic genes. Future work includes a detailed
genetic and biochemical mapping in rice to understand As toxicity, uptake, and the potential use of bio-inoculants in As alleviation.