EVALUATION OF SUGARCANE PLANT-GROWTH PROMOTING AND COLONIZATION ABILITY OF ENDOPHYTIC BACTERIUM  PANTOEA AGGLOMERANS

Maria Carolina Quecine (ESALQ-USP); Welington Luiz Araújo (UMC); Anderson Ferreira (ESALQ-USP); Aline Aparecida Pizzirani-kleiner (ESALQ-USP)

The term endophyte was coined some years ago to refer to interior colonization of plants by microorganisms that usually do not cause damage to the hosts and live most of their life inside of the plant tissues without eliciting any pathogenic symptoms. Some endophytes establish active relationship with their host plants and promote benefits to the plant. The potential for practical applications of endophytes has led to studies addressing the bacteria’s ability to control both disease and insect infestations, as well as promoting plant growth. The endophytic bacterium Pantoea agglomerans strain 33.1 have been related with biological control and promoting plant growth of important crops as eucalyptus and citrus. In this context, the aim of this work was to investigate the colonization of sugarcane by 33.1 and its role on plant-growth promoting. 33.1 was transformed with plasmid pNKBOR and same strain was transformed with other plasmid pNKGFP. Sugarcane seedlings transplanted to substrate and acclimated in greenhouse were inoculated using 33.1-wild type, 33.1:pNKBOR and 33.1:pNKGFP in a bacterial concentration of 10⁸ CFU/plant. The natural colonization of sugarcane by 33.1 strains was confirmed by re-isolation and qPCR. Density of bacterial community associated with sugarcane were not affecting by 33.1 strains. Chitinase production and the plant-growth promoting increased during the sugarcane colonization by 33.1-wild type. However, plants colonized by 33.1:pNKBOR and 33.1:pNKGFP had a slightly reduction on plant-growth promoting. This study provides evidence that P. agglomerans can colonize sugarcane tissues promoting plant-growth and influencing the vegetal metabolism. However, the colonization and plant-growth promoting by transformants strains were different, suggesting that there is specificity between the host plant and the endophytic transformant.