Burkholderia sp. AQ12-mediated Molecular Adjustments Assist Growth of Salt-stressed Cotton (Gossypium hirsutum L.) By Modulating Biochemical Status and Nutrient Acquisition Patterns

PurposeSoil salinity negatively modulates plant growth and physio-biochemical attributes. The present study deciphered the Burkholderia sp. AQ12-mediated responses in cotton plants.MethodsSeeds of FH-941 (salt sensitive) and FH-326 (tolerant) genotypes were inoculated using AQ12 or water. Half of the both (inoculated and un-inoculated) received no salt while other received salt/NaCl stress. The raised plants were analyzed for various bio-chemical indicators.ResultsIn presence of salt stress, chlorophyll (chl) a content (24.68 mg g-1 FW) in FH-941 was 11.3% and 8.6% less in comparison to its control group and chl a content in FH-326, respectively. FH-941 exhibited a higher oxidant response as indicated by 8.69 and 25.54 mu mol g-1 FW malondialdehyde (MDA) and hydrogen peroxide (H2O2), respectively. A balanced catalase (CAT) and peroxidase (POD) activity across all treatments particularly under salt stress (23.82 and 40.98 U mg-1 protein, respectively) was recorded in FH-326 indicating its potential to cope NaCl induced oxidative injury. Further, FH-326 exhibited 17.58 mg g-1 DW root K+ associated with balanced expression of NHX1 and HAK5. A higher expression of HKT1 but reduced expression of NHX1, SOS1 and HAK5 indicted poor salt tolerance by FH-941. However, AQ12 inoculation resulted in optimum chl a (28.66 mg g-1 FW), chl b (13.93 mg g-1 FW), MDA (6.89 mu mol g-1 FW), H2O2 (20.11 mu mol g-1 FW) content in FH-941 resulting in better growth in saline soil.ConclusionsThe findings highlighted the biochemical and molecular basis of salt tolerance in cotton and signify the importance of AQ12 inoculation for cotton cultivation in saline soils.