Chinese scientists pinpoint gene to boost crop yields in high-alkaline soils

Chinese scientists pinpoint gene to boost crop yields in high-alkaline soils

• Researchers have produced modified sorghum, rice, wheat, maize and millet crops after finding a gene that helps counter the harmful effects of high levels of alkaline in the soil

• Previous research has focused on high-saline soils – which have different characteristics – and scientists behind the latest study say it helps ‘fill a gap’

The team tested the technology on sorghum grown at a site in Pingluo, Ningxia.

Chinese scientists have identified a gene that allows crops to grow in salty soil, a discovery that allowed them to produce modified sorghum and rice crops that improve yields by at least 20 per cent and produce more nutrients.

The researchers said their findings could help communities adapt to the global trend of salinisation caused by climate change, the overuse of fertilisers and increasing shortages of fresh water.

The study, published in Science magazine on Friday, was led by Professor Xie Qi from the Chinese Academy of Science’s Institute of Genetics and Development Biology, Professor Yu Feifei from China Agricultural University and Professor Ouyang Yidan from Huazhong Agricultural University.

Salty soil can be either saline or alkaline, and most research has focused on the former. However, the two have very different characteristics – with salinised soil containing sodium chloride and sodium sulphate, while alkaline soils are dominated by sodium carbonate and sodium bicarbonate – and Yu described the new study as “filling the gap” that resulted.

“Although salinity tolerance has been studied extensively, alkalinity tolerance in plants has not been studied in depth,” she added.

The research initially focused on sorghum, a crop that originates from central Africa and has evolved to help it tolerate sodium-rich soils.

The team’s work started by searching a natural gene database using a genome-wide association study (GWAS), a painstaking statistical method that examines the entire genome of individual plants to look for associations between millions of genetic variants and specific traits.

After examining more than 352 representative sorghum accessions, they detected a gene site – Alkaline tolerance 1 (AT1) – that is linked to the desired traits.

High alkalinity leads to stress behaviour in plants, where damaging chemicals accumulate, oxidising and eventually killing the cells.

But AT1 encodes a special G protein that can prevent plant cells from pumping out the damaging chemicals.

“On the basis of GWAS results, we further explore the molecular mechanism behind the tolerance. Crops experience different patterns in salinised soil and sodic soil, the chemical reaction inside the crops should be different,” Yu said.

“Through knocking out AT1 or replacing it with another non-functional piece, we promoted the plant’s protective response against stress caused by alkaline conditions. The technology leads to higher survival rates and yield of sorghum on sodic soils.”

On the basis of this knowledge, the team genetically edited close relative genes of AT1 in other crops such as rice, maize and millet.

Field tests carried out in high-alkaline soils in Pingluo, in the northwestern Chinese region of Ningxia, found that the technology increased the grain yields of sorghum and millet by 20 per cent. A trial conducted in similar soils in Daan in Jilin saw annual rice yields increasing by 20 to 30 per cent.

“Crops grown in saline-alkali land have a longer growth cycle and accumulate more nutrients, as a result they taste better,” said Yu.

“The workload behind this research is huge, some of the research on stress tolerance of sorghum began as early as 2014 in Professor Xie’s team. Our current work mainly involved verification in sorghum, rice, millet and maize. We might expand the theory to other plants like beans and potatoes in the future.”

According to a report published by the Institute of Genetics and Development Biology on Friday, 618 million hectares (1.5 billion acres) of land worldwide is affected by salinisation.

“If this technology can be used on the low saline-alkali soil – about 20 per cent of the affected total – 250 million tons of grain will be produced every year, half the total US grain supply in 2022,” the report said.

Source: SCMP