The Mo- and Fe-nitrogenases of the endophyte Kosakonia sp. UYSO10 are necessary for growth promotion of sugarcane

Abstract

Aim Sugarcane is a multipurpose crop primarily used to produce sugar, energy and bioethanol. It requires high amounts of Nfertilization for optimal growth, which increases production costs and environmental degradation. The contribution of biological nitrogen fixation to Uruguayan commercial sugarcane cultivars was demonstrated previously, and diazotrophic bacteria that were isolated from the stems were characterized and identified. From this collection, the isolate UYSO10 related to the Kosakonia genus (formerly Enterobacter) was described as a plant growth-promoting endophyte of sugarcane plants. Purpose To evaluate the effect of the inoculation of wild-type and nitrogenase-deficient strains of Kosakonia sp. UYSO10 on sugarcane growth promotion under non-sterile conditions. Methods Kosakonia sp. UYSO10 was inoculated onto sugarcane setts for plant growth promotion greenhouse experiments. Single and double mutants resulting to the nitrogenase-encoding genes (nifH, anfH) were constructed, and the phenotypes were evaluated in vitro and in vivo. Results Kosakonia sp. UYSO10 is able to promote sugarcane growth under non-sterile conditions, that strain UYSO10 harbors two functional nitrogenases and the inactivation of both nitrogenase-encoding genes diminish its capacity of promoting growth on sugarcane. Conclusion All together, the results obtained showed that the biological nitrogen fixation ability of Kosakonia sp. UYSO10 is required for sugarcane growth promotion.

Biological nitrogen fixation in maize: optimizing nitrogenase expression in a root-associated diazotroph

“…When detected, PBC6.1 colonized to ~2×10 5 CFU g –1 of root FW. Kosakonia sacchari is known to be associated with sugarcane ( Saccharum officinarum ) ( Chen et al , 2014 ; Gu et al , 2014 ) and sweet potato ( Ipomoea batatas ) ( Shinjo et al , 2016 ), while other members of the genus Kosakonia (formerly part of Enterobacter ) are beneficially associated with cereal crops including wheat ( Kämpfer et al ., 2005 ), sugarcane ( Taule et al , 2016 ; Beracochea et al , 2019 ; Taule et al , 2019 ), rice ( Oryza sativa ) ( Li et al , 2016 ; Li et al , 2017 ), and corn ( Kämpfer et al ., 2016 ). Using fluorescence microscopy of roots inoculated with a strain of PBC6.1 expressing RFP, we observed colonization of the corn root surface along the perimeters of cells ( Supplementary Fig.…”

Draft Genome Sequence of Kosakonia radicincitans UYSO10, an Endophytic Plant Growth-Promoting Bacterium of Sugarcane ( Saccharum officinarum )

“…FAM8177 cultivated in Uruguay, on LGI-P semisolid medium at 30°C, as described by Taulé et al (5). Strain UYSO10 showed plant growth promotion effects upon inoculation onto micropropagated and setts of sugarcane cultivar LCP85384 under greenhouse conditions (6, 7). In vitro analysis showed that it is capable of producing indoleacetic acid to fix N 2 and that it has endoglucanase activity (5, 6).…”

“…Moreover, the strain was defined as a true endophyte of sugarcane plants (6). Genomics and functional analysis of the genes involved in biological nitrogen fixation (BNF) showed that the UYSO10 genome harbors two functional nitrogenases and that the inactivation of both nitrogenase-encoding genes diminishes its capacity for promoting plant growth (7).…”

Modulation of the endophytic strain Kosakonia radicincitans UYSO10 proteome by sugarcane roots exudate

“…Through greenhouse assays, it was shown that strain UYSO10 promotes the growth of micropropagated and cutting sugarcane plants cv. LCP 85-384 (LCP) (Taulé et al 2016(Taulé et al , 2019. In addition, the strain UYSO10 was de ned as a diazotroph and as a true endophyte of sugarcane plants (Taulé et al 2012(Taulé et al , 2016.…”