Towards a C₄ Rice

摘要

The success of the green revolution that began in the 1960s led to an increase in rice yield of up to 10 fold that was sufficient to meet the food demand of a continually growing population. This rapid increase in rice yield has not been repeated even after four decades, while the global population continues to grow rapidly. To meet the food demand of the soaring population, rice yields should increase by at least 50% within next four decades. Despite the best efforts of plant breeders, the prospect of a second drastic increase in yield using conventional approaches is unlikely but may be possible if we redesign rice photosynthesis into C₄ type. A C₄ type of photosynthesis is much more efficient than the C₃ type found in wheat and rice and could facilitate an increase in yield potential to levels found in C₄ crops like sorghum and maize. Although, C₄ plants evolved from the C₃, there are distinct differences in their leaf structure (evolution of Kranz anatomy) and biochemistry. The same would be needed for the development of a C₄ rice plant. In 2009, a consortium of scientists was formed to develop C₄ rice. The consortium is using multiple approaches which include but are not limited to; alteration of genomes of C₃ and C₄ plant species, exploration of wild Oryza accessions and bioinformatics to discover new genes underlying C₄ photosynthesis. The already known or newly discovered genes of C₄ pathway are being systematically introduced into rice. Here we review the strategies adopted by the C₄ rice project coordinated by the International Rice Research Institute.