Rice in a different light: Shoot architecture from genome to field

Abstract

How does a rice plant in the field fight against the weeds growing next to it? Rice feeds more than half of the world’s human population. Driven by climate change, rice farming is shifting to direct seeding, where weeds, traditionally suppressed by standing water, are becoming a major problem. In urgent need for sustainable weed-control, here we investigated how rice shoot architecture could be optimized for weed suppression. We explored the natural diversity of rice varieties and defined which traits are important for increased shade of rice shoots. In a genomic analysis, we found the genes encoding these relevant traits. In a field study, the selected rice varieties suppressed weed growth to an extent from 40 up to 70%. Insights from the field assay, and the genetic information can now be used for future rice-breeding and will help to reduce the amount of herbicide usage and enable a more sustainable and climate-change resilient rice-farming. Rice is also an interesting study object. Surprising results were found when treating rice with far-red light. Far-red light, is known to be a signal for plants for dense vegetation, to which they react with strong elongation and reduced formation of leaves. However, we observed, that rice plants were growing much faster and bushier under far-red light. Gas-exchange measurements proved that photosynthetic activity was almost doubled. This is a very new discovery in the field of photobiology, where to date, it was thought, that plants cannot use far-red light efficiently for photosynthesis. These findings open up a new field of research, in how plants balance between far-red light as a signal for dense vegetation and as energy for photosynthesis.