Arsenic pollution in some soils in Asia is now so high, that is also causing significant crop losses as the element is poisoning the plant.
A Chinese-German research team has discovered a rice variant that is resistant to the uptake of arsenic. The team comprised of scientists from the Centre for Organismal Studies of Heidelberg University, Germany, and Nanjing Agricultural University, China, studied over 4000 rice variants. Their work is published in Nature Communications.
While the newly discovered variant will thrive in arsenic contaminated fields, the grains contain far less of the element, as well as having 75% higher content of the essential trace element selenium. It was also noted that the yield is comparable to standard high-yield rice variants; making is suitable for agricultural use.
The rice variant found to be resistant to arsenic uptake is called astol1, the grains of which absorb one third less arsenic than conventional rice grains exposed to contaminated water. It was found that a so-called amino acid exchange in a single protein is what biologically characterises the astol1 variant. ‘This protein is part of a sensor complex and controls the formation of the amino acid cysteine, which is an important component in the synthesis of phytochelatins. Plants form these detoxifying substances in response to toxic metals and thus neutralise them,’ explained Professor Dr Hell, from the Centre for Organismal Studies of Heidelberg University. The neutralised arsenic is stored in the roots of the plant before it reaches the edible rice grains.
The researchers explain that much of Asia’s agricultural regions have metalloid arsenic in the ground water due to large scale fertilisation or wastewater sludge. As rice is cultivated in submerged fields, the plants absorb significant quantities of arsenic through the roots. This creates a pathway for the potential carcinogen into the food chain. According to Professor Dr Hell; arsenic pollution in some soils in Asia is now so high that it is also causing significant crop losses as the element is poisoning the plant.
Dr Sheng-Kai Sun, the junior researcher who was instrumental in discovering the rice variant during his PhD research at Nanjing Agricultural University added; ‘In future, rice plants like astol1 could be used in arsenic contaminated regions to feed the population as well as help diet-related selenium deficiency.’