Growing maize with faba bean enhances ecosystem productivity and has important implications for developing sustainable agriculture, according to research at China Agricultural University, Beijing and The University of Western Australia.
The breakthrough research, recently published in the prestigious journal PNAS, revealed that when faba bean and maize are intercropped, root interactions between the two species boosted faba bean biomass and grain by a staggering 35% and 61%, respectively.
Professor Hans Lambers from UWA’s School of Plant Biology and Institute of Agriculture, who collaborated in two year field experiments with colleagues in China, said plants communicate by releasing root exudates which act as an underground highway, promoting nitrogen fixation by their neighbours.
“We explored the cross-talk between maize and faba bean through the below-ground rhizosphere processes, and entirely novel physiological and molecular mechanisms underpinning this communication,” Professor Lambers said.
“Part of this communication is through the release of flavonoids, which are key signals in nodulation of legume plants, which fix atmospheric nitrogen.”
The researchers used permeable and impermeable root barriers to show that root-root interactions between faba bean and maize significantly increase both nodulation and symbiotic nitrogen fixation in intercropped faba bean.
Roots of faba bean treated with maize root exudates exhibited an immediate 11-fold increase in the expression of genes synthesising flavonoids, together with a significantly increased expression of genes mediating nodulation and auxin response. Wheat and barley root exudates did not have a similar effect.
The United Nation’s Food and Agriculture Organization Special Ambassador for Pulses 2016, and Director of The UWA Institute of Agriculture Professor Kadambot Siddique said such a discovery has large-scale implications for legume/cereal intercropping or mixed cropping systems to build agro-diversity and resilience.
“There is a need for sustainable intensification of agricultural systems for global food production to meet the needs of 9.7 billion people by 2050,” Professor Siddique said.
“There is a renewed interest in legume/cereal intercropping/mixed cropping, to build agro-diversity and resilient cropping systems, and this research has important implications for developing sustainable agro-diversity. It is also great to see the collaboration between UWA and China Agricultural University leading to breakthrough discoveries in Crop Science”
The findings were published in the paper Root exudates drive interspecific facilitation by enhancing nodulation and N2 fixation in the prestigious journal PNAS. The research was supported by National Science Foundation of China and National Basic Research Programme of China.
Professor Hans Lambers (+61 8) 6488 7381
Diana Boykett (Communications Officer, The UWA Institute of Agriculture)
(+61 8) 6488 3756 / (+61 4) 04 152 262