Evaluation of plant-growth promoting properties of Gluconacetobacter diazotrophicus and Gluconacetobacter sacchari isolated from sugarcane and tomato in West Central region of Colombia

Abstract

The genus Gluconacetobacter comprises different species with agricultural and industrial importance. This study aims at determining the presence of Gluconacetobacter diazotrophicus and Gluconacetobacter sacchari in sugarcane and tomato crops considering their potential biotechnological applications. Bacteria were isolated from roots, stems and leaf tissues and identified using phenotypic and biochemical evaluations, and molecular and phylogenetic analyses. Isolates were characterized by the production of indolic compounds, nitrogenase activity and phosphate solubilization. For this, G. diazotrophicus ATCC 49037 was used as the reference strain. The results showed that all isolates of native G. diazotrophicus exhibited equal or better phosphate solubilization index (SI) for CaCO 3 and AlPO 4 than reference strain. For G. sacchari, GIBI031 isolate displayed better SI for both phosphate sources and GIBI014 isolate had better SI only for AlPO 4 . G. diazotrophicus GIBI029 had a greater production of indolic compounds than ATCC 49037 strain in the presence of tryptophan. All isolates except G sacchari GIBI031, showed better nitrogenase activity than the control. These results constitute the first report confirming the presence of G. diazotrophicus and G. sacchari associated with sugarcane in Colombia. In addition, this is the first report on the presence of G. sacchari in tomato under natural conditions. Finally, one G. sacchari isolate presented nitrogenase activity despite the fact that this is a differential characteristic between G. diazotrophicus and G. sacchari. These findings have ecological significance and will advance research towards the evaluation of plant-soil interactions involving these bacteria in crops other than sugarcane. The isolates found are potential candidates for the development of novel biotechnological processes for production of new alternative biofertilizers considering the significant plant-growth promotion properties determined in this work.

Microbial inoculants: reviewing the past, discussing the present and previewing an outstanding future for the use of beneficial bacteria in agriculture

“…Sugarcane is able to associate with a great diversity of diazotrophic plant growth-promoting bacteria, including species of the genera Azospirillum (Reis Junior et al 2000; Tejera et al 2005), Azotobacter (Tejera et al 2005), Burkholderia (Perin et al 2006; Antonio et al 2016; Silva et al 2016; Leite et al 2018a, b), Herbaspirillum (Baldani et al 1996; Reis Junior et al 2000), Pantoeae (Taulé et al 2012; Fischer et al 2012, Silva et al 2016), and the species Gluconacetobacter diazotrophicus (basonym Acetobacter diazotrophicus ) (Cavalcante and Döbereiner 1988; Munõz-Rojas and Caballero-Mellado 2003; Restrepo et al 2017), among others.…”

Effect of the Application of Gluconacetobacter diazotrophicus and Its Interaction with Nitrogen and Phosphorus Fertilization on Carrot Yield in the Field

“…In this way, it was shown that G. diazotrophicus exhibits plant growth-promoting properties not only in crops such as sugarcane (for which commercial preparations already exist) but also in economically important vegetable crops. Te carrot crop growth promotion is based on the special characteristics of G. diazotrophicus already demonstrated in a previous work by Restrepo et al [8]: biological nitrogen fxation thanks to its nitrogenase activity, phosphorus solubilization, and production of indole compounds. Te results obtained will contribute to the development of a novel microbial inoculant for vegetables under agroecological conditions in tropical areas.…”

“…Te standard strain G. diazotrophicus ATCC 49037 and the native isolate of G. diazotrophicus GIBI029 recovered from sugarcane [8] were used as inoculants, which were multiplied in modifed DYGS media [14] and LGI-P [15]. Te production of the inoculum and the liquid preparation were carried out in three stages.…”

“…Gluconacetobacter diazotrophicus is an endophytic rhizobacterium initially recovered from sugarcane crops [8], which has important characteristics for plant growth promotion such as biological nitrogen fxation, biosynthesis of phytohormones such as auxins (indole compounds), and solubilization of phosphates, which were demonstrated in a previous work [8]. Particularly, the isolate G. diazotrophicus GIBI029 was obtained from sugarcane crops in the Central Western region of Colombia.…”