New Delhi, Aug. 22: A gene from a rice variety that evolved in northeast India has been used by scientists to create new breeding lines of rice that promise high yields in phosphorus-deficient soil unfavourable for plant growth.
Plant biologists at the International Rice Research Institute (IRRI), Manila, Philippines, have transferred a gene from India’s traditional variety called Kasalath into five commercial rice varieties from Indonesia and Japan.
Their gene-hunting and breeding experiments, to be described in the journal Nature on Thursday, are part of research efforts to create new rice varieties that can tolerate stress, including low levels of nutrients in the soil.
The gene from Kasalath named phosphorus-starvation tolerance 1, or PSTOL1, enhances root growth, thus allowing the plants to extract more phosphorus and other nutrients from a larger surface area underground.
“The PSTOL1 gene helps more phosphorus from the soil reach the plants,” said Sigrid Heuer, a German plant molecular biologist who has been at the IRRI since 2003. “The greater root surface area may also help improve the uptake of phosphorus fertiliser by the plants, which could mean significant economic gains,” Heuer told The Telegraph in a telephone interview.
Heuer and her colleagues have conducted pot and field experiments at the IRRI, Indonesia, and Japan and have multiplied the seeds to be able to begin trials in multiple locations, including India.
“This work reveals a gem, among the hidden treasures in our traditional rice germplasm,” said Akhilesh Tyagi, the director of India’s National Institute for Plant Genome Research, who was not associated with the IRRI study.
Tyagi, a rice genome specialist, said the studies with the PSTOL1 gene would complement current Indian efforts to develop new breeding lines through other stress-tolerant genes.
Scientists believe Kasalath, identified about a decade ago, had evolved in northeast India under poor soil conditions. It is a traditional variety but not attractive for farmers despite its ability to grow in phosphorus-deficient soil.
“Kasalath has undesirable agro-economic traits — it has low yields, and its grains just fall off — but it also has this special gene,” Heuer said.
Heuer, collaborating with Matthias Wissuwa at Japan's International Research Centre for Agricultural Sciences in Tsukuba, Japan, and other colleagues, used conventional breeding and molecular marker technology to breed the PSTOL1 into different rice varieties.
The technique involves using molecular markers —signposts for genes — to track down the gene of interest and use conventional breeding to introduce it into new breeding lines of rice.
Scientists at the Central Rice Research Institute in Cuttack, Odisha, said they are also using similar molecular marker assisted techniques to breed new lines. In one such effort, CRRI scientists have introduced a submergence-tolerance gene into rice through breeding.
“This flood-resistant gene is expected to allow plants to survive submergence for upto two weeks,” said Onkar Nath Singh, a plant breeder at the CRRI. In another project, Singh and his colleagues plan to breed rice with a drought-tolerance gene.