Chinese researchers on Monday announced that they have completed sequencing the genome of adzuki bean, an important source of starch, digestible protein, mineral elements and vitamins for at least a billion people worldwide.

"Adzuki bean is a legume crop known for its high starch (57.06 percent) and low fat (0.59 percent) content relative to soybean and other legumes," senior author Wan Ping, professor at the Beijing University of Agriculture, told Xinhua. "The genome sequence of adzuki bean will facilitate the identification of agronomically important genes and accelerate the improvement of adzuki bean."

The draft genome sequence, published in the U.S. journal Proceedings of the National Academy of Sciences, was generated by a collaborated team led by Wan, Ling Hong-Qing, Tian Zhixi from the Chinese Academy of Sciences, and Wang Jun from the Beijing Genomics Institute, which is based in Shenzhen, a city in south China's Guangdong Province.

A total of 34,183 protein-coding genes were predicted, Wan said.

And adzuki bean is more closely related to common bean than to soybean and other legumes, Wan said.

More important, functional analysis revealed that significant differences in starch and fat content between adzuki bean and soybean were likely due to the so-called transcriptional level, rather than copy number variations, of the genes related to starch and oil synthesis.

Furthermore, re-sequencing of 49 accessions including 11 wild, 11 semi-wild, 17 landraces, and 10 improved varieties and population analyses revealed that semi-wild adzuki bean is the progenitor species of cultivated adzuki bean.

"Generally, our results valuably reinforce the legume species genomes, provide insight into evolution and metabolic differences of legumes, and will accelerate studying of genetics and genomics for adzuki bean improvement," they wrote.

Adzuki bean, domesticated in China 12,000 years ago, is currently grown in more than 30 countries of the world, especially in East Asia.

Because of its low caloric and fat content, digestible protein and abundant bioactive compounds, adzuki bean is referred to as the "weight loss bean."

Given its health benefits, adzuki bean is widely used by at least a billion people in a variety of foods, including paste in pastries, desserts, cake, porridge, adzuki rice, jelly, adzuki milk, ice cream.

Furthermore, adzuki bean is a traditional medicine that has been used as a diuretic and antidote, and to alleviate symptoms of dropsy and beriberi in China. (ecns)