Unlocking genetic codes for salt- and drought-tolerant soybeans

Promoting sustainable agriculture is vital to achieving zero hunger, eliminating poverty and tackling the global challenge of climate change. Researchers from the State Key Laboratory of Agrobiotechnology (CUHK) have made a number of ground-breaking achievements including applying state-of-the-art genomics technologies to the cultivation of soybeans, the most eco-friendly food staple, to help alleviate looming problems in world food security and planetary health.

Global agriculture has long been plagued by the lack of arable land, depletion of topsoil and scarcity of water resources. Developing climate-smart farming practices that strike a better balance between sustainable agriculture and food security will be critical to securing the future needs of people and planet.

With its high nutritional value and low carbon footprint, the soybean may emerge as one of humanity’s most important food sources in the future. However, it will first be necessary to find climate-friendly ways to increase soybean yields and create crop varieties that can adapt to tough conditions.

Prof. LAM Hon-Ming is a pioneer in soybean genomic and genetic research.

Building a more resilient soybean

This is where CUHK’s longstanding expertise in biotechnology is making a crucial difference.

In 2019, an international collaborative research team led by Prof. LAM Hon-Ming, Director of the State Key Laboratory of Agrobiotechnology (CUHK), achieved a crucial breakthrough in soybean cultivation by completing the world’s first reference-grade wild soybean genome. This has created a solid foundation for developing high-yield, high-quality and high-tolerance soybean varieties by enabling research teams around the globe to engage in comparative genomic studies of legume and soybean improvement programmes.

Prof. Lam completes the world’s first reference-grade wild soybean genome, paving way for developing high-yield, high-quality and high-tolerance soybean varieties.

The team was brought together by the AoE (Areas of Excellence) Centre for Genomic Studies on Plant-Environment Interaction for Sustainable Agriculture and Food Security, which in 2017 was awarded HK$81 million (US$10.3 million) in funding for eight years from the prestigious AoE Scheme of the Hong Kong Research Grants Council.

The achievement marked the culmination of two decades of collaboration between CUHK researchers and soybean breeders, as well as researchers in China, to improve soybean cultivation in adverse conditions such as drought and salinity. Through genomic analysis and cross-breeding, they have developed stress-tolerance soybeans and reclaimed abandoned land in remote areas for soybean cultivation.

Collaborating with international researchers to grow soybeans in marginal lands.

Blending 21st century science with folk wisdom

A key breakthrough came when the research team decoded the genomes of 31 wild and cultivated soybeans. They discovered that wild soybeans have more genetic biodiversity within themselves than cultivated ones, including stress-tolerance genes that have been lost during the historical process of soybean domestication. This highlighted the possibility of cross-breeding new varieties that combine the productivity and nutritional value of cultivated soybeans with the adaptability and stress-tolerance of wild soybeans.

After successfully cloning a major salt-tolerance gene from wild soybeans using a genomic approach, Prof. Lam extended his research journey from laboratory to field by working with scientists in Gansu Province in China to develop and release three new stress-tolerance soybean cultivars. These cultivars passed provincial tests in Gansu and are now used by Gansu farmers on marginal lands.

Salt-tolerance soybean and salt-sensitive soybean tested on saline lands in China.

Notably, the research team combines integrated state-of-the-art genomics technology with traditional breeding methods in order to develop desirable new cultivars, which currently cover the Loess Highland regions spanning 2,000 km from the east to west of Gansu. As such, the programme’s achievements reflect a blend of traditional wisdom and advanced biotechnology.

This leap forward in soybean cultivation exemplifies how CUHK’s leadership and collaboration in agricultural technology is driving progress towards the SDGs by making agriculture more sustainable.