Role of biotin carboxyl carrier protein subunit 2 (BCCP2) in resistance to multiple stresses in Arabidopsis thaliana.

Abiotic stresses, including drought, salinity, and temperature extremes, are serious constraints to plant growth and agricultural development. These stresses that plants face in nature are often multiple and complex. Biotin carboxyl carrier protein subunit 2 (BCCP2) is one of the two subunits of biotin carboxyl carrier protein, which is a functional subunit of acetyl coenzyme A carboxylase, primarily studied for its role in fatty acid synthesis. In this study, we identified the expression pattern of AtBCCP2 under various stress conditions, including 4 mM NaHCO₃, 2 mM Na₂CO₃, 150 mM NaCl, 300 mM D-mannitol, 100 μM ABA, 5 mM H₂O₂, 4 °C, and 37 °C. It was determined that AtBCCP2 is positively regulated by NaHCO₃, Na₂CO₃, NaCl, and ABA, but negatively regulated by D-mannitol. Phenotypic experiment confirmed that the AtBCCP2 transgenic overexpression plants exhibited increased resistance to NaHCO₃, Na₂CO₃, NaCl, and ABA stresses, but more sensitive to drought stress simulated by D-mannitol. In contrast, mutant plants showed the opposite phenotypes. Additionally, AtBCCP2 transgenic overexpression plants demonstrated stronger antioxidant activity and lower MDA content under stresses such as NaHCO₃, Na₂CO₃, NaCl, and ABA, in contrast to the mutant plants. In response to D-mannitol simulated drought stress, AtBCCP2 transgenic overexpression plants showed lower antioxidant activity and higher MDA content, while mutant plants exhibited the opposite trend. In conclusion, this study provides a theoretical basis for understanding the role of AtBCCP2 in response to multiple stresses and contributes a new gene to the pool of those involved in abiotic stress responses.