Healthy rice plants in Telangana, India
Rice is the most important food crop in developing countries and the staple food for more than half of the world's population. Unlike the other two staple crops, wheat and maize, 80% of the world's rice farmers are smallholders, with less than 2 hectares under cultivation. In addition, in low-income countires, more than two-thirds of workers are employed in rural areas. This means that food insecurity and rural poverty often go hand in hand.
Although 90% of the world's rice production is grown in Asia, its growth is not limited to that continent. In fact, rice is grown on every continent except Antarctica. It thrives in a wide variety of soils and climates - from the high mountains of the Himalayas to the tropical Mekong Delta to the semi-arid desert of West Africa. All of this has been possible through centuries of breeding efforts that have produced adaptable rice varieties that, among other things, have developed resistance to existing threats.
In sub-Saharan Africa, rice is the fastest growing staple food. However, Africa does not produce enough rice to meet demand and must import rice at a high economic cost. In 2008, rice imports for sub-Saharan Africa were an estimated $3.6 billion. To close this gap in rice production, rice yields must be increased.
A large number of scientific projects are addressing the question of how to combat world hunger. Unfortunately, a major study by an international consortium called Ceres2030 has shown that scientists often set the wrong priorities. The Ceres2030 team members found more than 95% of the agricultural-research publications they assessed were unable to provide solutions, to the needs of small-sclae producers and their families.
One of the scientific challenges is to make the cultivated rice more resistant to climatic changes or diseases. However, these achievements must also be shared with small-scale producers to the right extent to ensure efficient cultivation. It has been shown that small-scale producers are more likely to adopt new approaches, such as growing resistant crops, if they are supported by technical advice, input, and ideas known as extension services.
Therefore, in our project, we combine scientific expertise for the generation of new disease resistant rice lines, together with the help of experts from international and national organisations to support the small-scale producers in multiple ways. This already includes education in disease detection and assistance with prevention strategies and hygiene measures. For example, we created a diagnostic toolbox that already enables a rapid disease diagnosis of newly occurring pathogenic bacterial strains. In addition, we will distribute our resistant lines to smallscale producers in the future to prevent crop losses in severely affected regions.
Bacterial blight - caused by the bacterium Xanthomonas oryzae pv. oryzae (Xoo) - ranks among the biggest constraints for rice production. The disease causes 20-50% yield losses; in extreme up to 70% losses for rice growers.
Typical bacterial blight symptoms include leaf blight, pale yellow leaves and wilting (named "kresek" symptom). Kresek is the most devastating manifestations of the pathogen and is most commonly observed at the seedling stage. Both leaf blight and kresek are the primary effects of the disease while a "pale-yellow" leaf is a secondary effect, appearing on newly emerging leaves of plants recovering from blight or kresek syndrome.
In the US, fear of the rice bacterial blight is so big that the Xoo bacterium is classified as a select agent with potential for bioterrorism. Click here to learn how we can use our molecular understanding of the the bacterial blight infection to engineer resistance against bacterial blight.