Changes in environmental CO2 concentration can modify Rhizobium-soybean specificity and condition plant fitness and productivity

Soybean Inoculated With One Bradyrhizobium Strain Isolated at Elevated [CO2] Show an Impaired C and N Metabolism When Grown at Ambient [CO2]

“…Consequently, a complex respiratory homeostasis between two opposing forces: mitochondrial energy requirements and photorespiratory Glu demand is observed in leaves. Our data showed a general increase of dicarboxylic acids involved in Krebs cycle (fumarate, succinate, citrate, and malate) under a[CO 2 ] that was especially marked in the case of SFJ14-36 strain, which is in accordance with previous respiratory data showed by Sanz-Sáez et al (2019) and with the enhanced Glu demand by photorespiration in SFJ14-36 under a[CO 2 ]. Interestingly, α-KG was not significantly affected by CO 2 treatment in SFJ14-36 and may be due to the fact that is involved in the synthesis of Glu and Gln and, therefore, diverted at a[CO 2 ] to the production of these two amino acids.…”

“…Plants inoculated with USDA110 showed the highest sucrose levels (especially at e[CO 2 ]); on the contrary, SFJ4-24 showed almost no sucrose in both ambient and elevated [CO 2 ] when compared with USDA110 (Figure 7). This strain-specific sucrose content was in opposition with the lack of statistically photosynthetic differences observed by Sanz-Sáez et al (2019) between USDA110 and SFJ4-24. Such results point to the fact that other reasons may exist behind this contrasting sucrose content between plants inoculated with the two strains.…”

“…These strains were provided by Prof. Michael Sadowsky (University of Minnesota; SFJ4-24, and SFJ14-36) and by USDA-ARS Rhizobium Germplasm Resource Collection in Belstville, MD (USDA110). The different B. japonicum cultures were made exactly as explained in Sanz-Sáez et al (2019) .…”

“…They observed that the strain SFJ14-36, isolated at e[CO 2 ], significantly overexpressed genes encoding for N 2 -fixation and nodulation in comparison with the strain isolated at a[CO 2 ] and the control strain (USDA 110). More recently, Sanz-Sáez et al (2019) tested if the same strain isolated under e[CO 2 ] conditions (SFJ14-36) showed higher BNF and nodule number at e[CO 2 ] compared with plants inoculated with USDA110 as it was suggested by the expression profiles published by Sugawara and Sadowsky (2013) ; however, no statistical differences were observed between plants inoculated with different strains when grown at e[CO 2 ]. Therefore, the overexpression of genes observed by Sugawara and Sadowsky (2013) were not matched by a higher BNF.…”

“…The aim of this work was to elucidate the metabolic features involved in Bradyrhizobium -soybean specificity under contrasting CO 2 conditions. With this purpose, metabolic profiling analysis were carried out under two contrasting levels of CO 2 using the same three B. japonicum strains isolated at different [CO 2 ] ( Sugawara and Sadowsky, 2013 ) and whose physiologic and photosynthetic parameters were studied by Sanz-Sáez et al (2019) .…”