Research Projects

Arsenic (As), a major environmental concern and considered as a toxic metalloid, which is naturally distributed in soil and water (Singh and Srivastava, 2020). Irrigation of agricultural soil with arsenic-contaminated water leads to arsenic accumulation in cereals and vegetables, which can enter the human body through consumption and pose significant health hazards (Singh et al., 2017). Compared to physical and chemical approaches, phytoremediation using hyperaccumulator plants offers a promising solution because of its cost-effectiveness, high efficiency, and environmental suitability (Ma et al., 2020). However, widespread implementation of hyperaccumulator plants remains limited because of their low biomass, slow growth rates, and limited availability of metals in soils (Sarwar et al., 2017). To overcome this, recent strategies have suggested combining hyperaccumulators with conventional low-accumulating crops in intercropping systems, which can enhance overall remediation effectiveness in agriculture (Hu et al., 2019; Tang et al., 2020). Such intercropping systems boost the biomass and metal uptake of hyperaccumulators while reducing metal accumulation in crops, offering a viable method for agricultural lands (Luo et al., 2017; Xia et al., 2018). For instance, cassava/peanut and water spinach/rice intercropping systems have demonstrated increased yields and lower cadmium levels in target crops (Kang et al., 2020; Zeng et al., 2019). Moreover, Brereton et al. (2020) found that intercropping can reshape the rhizosphere microbial community in contaminated soils, enhancing root exudation and modifying metal bioavailability. Millions of people remain at risk of arsenic (As) poisoning due to rice consumption (Meharg and Rahman, 2003; Awasthi et al., 2017). Compared to wheat and maize, rice is particularly susceptible to arsenic uptake, because of its flooded growing conditions and reliance on arsenic-contaminated groundwater (Williams et al., 2009). Currently, microbial remediation has emerged as a promising method for arsenic detoxification in rice, with studies highlighting the role of arsenic-resistant Pseudomonas species in enhancing plant growth (Srivastava et al., 2018; Anand et al., 2023). However, limited research has explored the effectiveness of vetiver grass inoculated with arsenic-resistant bacteria in intercropping systems to mitigate arsenic toxicity in rice. Therefore, this project proposes to examine the impacts of a vetiver–rice intercropping system with and without inoculation of arsenic-resistant bacteria on rice plant physiology, subcellular arsenic distribution, root exudate secretion patterns, and rhizosphere microbial diversity using metagenomic analysis. We hypothesize that combination of intercropping and microbial inoculation will reduce arsenic accumulation in rice by influencing key metabolite secretion, modulating the subcellular distribution of arsenic, and altering microbial community structure in the rhizosphere.

Arsenic speciation, Intercropping, Vetiver, Rice, metagenomics, subcellular distribution