A Malian Rice Seed Endophyte Bacteria Control Efficiently the Growth of Xanthomonas oryzae pv oryzae and Xanthomonas oryzae pv oryzicola

Abstract

Aims: In Mali, rice (Oryza sativa L.) is a very important cereal in the food system and important losses in rice production are caused by bacterial diseases. Despite the important rice losses in production and the proven ability of some bacteria to control rice pathogens, in Mali very few studies have been carried out in biocontrol. With the aim of improving food security, the objective of this work is to select, at least one endophyte bacteria with great capacity to inhibit the growth Xanthomonas oryzae pv oryzae and Xanthomonas oryzae pv oryzicola. Study Design: This experimental research involving a Malian local rice cultivar named Kogoni and biocontrol endophyte bacteria isolated from rice in Mali. Pace and Duration of Study: This research was carried out in greenhouse at LaboREM-Biotech and in the field at the Office of irrigated perimeters of Baguineda (OPIB) for 3 years. To achieve this objective, pathogenic bacteria (Xoo and Xoc) circulating in rice fields of Mali were identified, endophyte bacteria from the bacterial collection of the LaboREM with high antagonistic activities against the identified pathogens were selected, and the efficacy of the selected endophytes to inhibit the growth of these pathogens in vitro were tested. Results: A total of five isolates, including 3 from Xoo and 2 from Xoc, were isolated in Niono from two varieties of rice: Kogoni91-1 and Adny11. No isolate characteristic of Xanthomonas oryzae was observed on samples from Baguineda. The three selected rice endophytes were tested in vitro to assess their effectiveness in controlling Xoo and Xoc. Following this test, 100% of the endophytes showed significant antimicrobial activity against Xoo and Xoc with an inhibition diameter varying between 6 and 28.5mm. endo Ad9 was selected for its strong ability to inhibit the growth of both pathogens at the same time.