AN INTERNATIONAL research group including researchers from the Institute for Environmental Biotechnology at Graz University of Technology have shown how a bacterium inside the seeds of rice plants effectively and environmentally friendly inhibits destructive plant pathogens.
The research group has been investigating the microbiome of rice plant seeds for some time in order to establish correlations between plant health and the occurrence of certain microorganisms. The group has now come to a major breakthrough and identified a bacterium inside the rice seed that can lead to complete resistance to a particular pathogen and is naturally transmitted from one generation of plants to another.
In China’s province of Zhejiang, it was observed that rice genotype (cultivar Zhongzao 39) was sometimes resistant to the plant pathogen Burkholderia plantarii which leads to crop failures and produces a biotoxin that leads to organ damage and tumors in continuously exposed people and animals. The research group examined the microbiome of rice seeds from different regions in detail and found that resistant plants have a different bacterial composition inside the seeds, with the bacteria Sphingomonas significantly more present in resistant seeds.
The researchers isolated the bacteria from the seeds and identified the bacterium Sphingomonas melonis as the functional unit. This bacterium produces an organic acid (anthranilic acid) that paralyzes the pathogen and thereby renders it harmless. The bacterium establishes itself in certain rice genotypes and is then naturally passed on from one generation of plants to the next.