Application of Aspergillus aculeatus to rice roots reduces Cd concentration in grain
Background and aims
‘Cd toxicity in rice’ events have resulted in vast public concern and uncertainty. Effective bioremediation could be accomplished via applying microbes that are capable of alleviating Cd content in rice grains.
Here, we investigated the effect of inoculating Aspergillus aculeatus on tolerance, uptake and transportation of Cd in rice cultivated in Cd contaminated growth medium.
A. aculeatus facilitated rice growth in Cd polluted growth medium and alleviated Cd toxic effects according to our observations on biomass, leaf and root length and grain yield. Cd accumulation analysis indicated that the plants which were inoculated with A. aculeatus exhibited minimum Cd level in all organs. Particularly in grain we observed a 40.5% reduction compared to the Cd only treated plants. Differences in Cd accumulation in rice inoculated with A. aculeatus might be attributed to the enhancement of cell wall-bound Cd, decreasing the Cd inorganic forms in roots, and inhibiting the expression of OsNRAMP5 and OsNRAMP1. A. aculeatus inoculation also led to minimum growth medium DTPA-Cd concentration, which possibly reduced the availability of the metals for plant uptake.
These results suggested that A. aculeatus might potentially be applicable to improve Cd tolerance and reduce Cd transportation in grains of rice.
KeywordsAspergillus aculeatus Cadmium Rice Tolerance Transport
- Begg SL, Eijkelkamp BA, Luo Z, Couñago RM, Morey JR, Maher MJ, Cheryl-lynn YO, McEwan AG, Kobe B, O’Mara ML (2015) Dysregulation of transition metal ion homeostasis is the molecular basis for cadmium toxicity in Streptococcus Pneumoniae. Nat Commun 6Google Scholar
- Burd GI, Dixon DG, Glick BR (1998) A plant growth-promoting bacterium that decreases nickel toxicity in seedlings. Appl Environ Microb 64(10):3663Google Scholar
- Chang AC, Pan G, Page AL, Asano T (2002) Developing human health-related chemical guidelines for reclaimed waster and sewage sludge applications in agriculture. World Health Organization, Geneva, SwitzerlandGoogle Scholar
- Ishimaru Y, Suzuki M, Tsukamoto T, Suzuki K, Nakazono M, Kobayashi T, Wada Y, Watanabe S, Matsuhashi S, Takahashi M, Nakanishi H, Mori S, Nishizawa NK (2006) Rice plants take up iron as an Fe3+-phytosiderophore and as Fe2+. Plant journal for cell. Mol Biol 45(3):335–346Google Scholar
- Kobayashi T, Ogo Y, Itai RN, Nakanishi H, Takahashi M, Mori S, Nishizawa NK (2007) The transcription factor IDEF1 regulates the response to and tolerance of iron deficiency in plants. P Natl Acad of Sci 104(48):19150–19155Google Scholar
- Li J, Bao S, Zhang Y, Ma X, Mishra-Knyrim M, Sun J, Sa G, Shen X, Polle A, Chen S (2012) Paxillus involutus strains MAJ and NAU mediate K(+)/Na(+) homeostasis in ectomycorrhizal Populus x canescens under sodium chloride stress. Plant Physiol 159Google Scholar
- Nevo Y, Nelson N (2006) The NRAMP family of metal-ion transporters. Biochimica et Biophysica Acta (BBA)-molecular. Cell Res 1763:609–620Google Scholar
- Sasaki A, Yamaji N, Yokosho K, Ma JF (2012) Nramp5 is a major transporter responsible for manganese and cadmium uptake in rice. Plant Cell 24(5):2155–2167Google Scholar
- Villegas L, Amoroso MJ, Figueroa LICD, Spencer JFT, Ragout dS (2004) Selection of tolerant heavy metal yeasts from different polluted sites. Methods in Biotechnology 16:249–256Google Scholar
- Wang X, Liu Y, Zeng G, Chai L, Song X, Min Z, Xiao X (2008) Subcellular distribution and chemical forms of cadmium in Bechmeria nivea (L.) Gaud. Environ Exp Bot 62:389–395Google Scholar
- Zhang W, Lin K, Zhou J, Zhang W, Liu L, Zhang Q (2014) Cadmium accumulation, sub-cellular distribution and chemical forms in rice seedling in the presence of sulfur. Environmental toxicology. Pharmacology 37(1):348–353Google Scholar