US scientists reported on Sunday they have decoded the genome of a bacterium that protects plants from diseases.

This study, published in the journal Nature Biotechnology, provides clues to better explain how the helpful bacterium, Pseudomonas fluorescens (Pf-5), naturally safeguards roots and seeds from infection by harmful microbes that cause plant diseases. It is expected to greatly benefit crop plants, said scientists at The Institute for Genomic Research.

Two decades ago, scientists found the Pf-5's capability to suppress two major cotton diseases. Since then, plant pathologists around the world have used this strain as a laboratory model to study beneficial microbes. The paper in Nature Biotechnology presents the first complete genome sequence of a biological control agent for combating plant diseases.

The researchers determined the genome of this microbe is composed of 7.1 million base pairs.

The genome sequence has helped identify new chemical pathways that the microbe apparently uses to create what are known as " secondary metabolites," possibly including new antibiotic compounds, according to Joyce Loper, a plant pathologist from US Agricultural Research Service (ARS) who led the sequencing.

The use of naturally-occurring, beneficial microbes such as P. fluorescens to control plant pathogens is called "biological control." That method is gaining momentum as a way to grow healthy plants without using synthetic fungicides. In all, about three dozen beneficial microbes are currently used as an environmentally- friendly way to fight plant diseases.

Loper predicted that the new genomic data will help scientists more quickly develop new ways to boost the effectiveness of beneficial microbes in fighting plant diseases.

"This genomic sequence reveals previously unknown traits of P. fluorescens that increase its potential for biological control," Loper said.

The Pf-5 project also pioneered a new methodology, the researchers noted. This novel approach relies on the analysis of repeated regions of the DNA sequence to help identify segments of the genome that appear to have been transferred from other microbes.

Source: Xinhua