A broad-spectrum antimicrobial peptide identified from Burkholderia bacterium

Microbial pesticides are widely applied to improve crop production, but the active molecules are largely unexplored. In a recent study, Mohamed et al., identified an antimicrobial peptide (AMP) from crop-associated microbes and showed its inhibitory effects on various phytopathogens. The authors first isolated bacterial strains from healthy crops and tested their antifungal activities. A Burkholderia strain highly inhibited the phytopathogen Rhizoctonia solani. A genomic library of the Burkholderia strain was constructed, and the antimicrobial effects of the genomic fragments were tested in Bacillus subtilis. Colony morphology and DNA sequence analyses revealed 29 AMPs, which were then tested for their antimicrobial effects. The 24aa AMP, namely HR2-7, weakened the pathogenicity of Botryosphaeria dothidea MAO, Dissotis theifolia CJP4-1, and Pseudomonas syringae DC 3000, which are pathogens of pear, tea, and tomato respectively. To explore the possible application of HR2-7 in the field, the authors tested its stability under different conditions including heat, UV exposure, and extreme pHs. Despite the sensitivity to UV exposure and extreme pHs, HR2-7 retained its antipathogenic effects at 60 °C. The thermostability favours its potential use in the field under global warming. (Summary by Yee-Shan Ku @YeeShanKu1) Plant Biotechnology Journal 10.1111/pbi.14506