Genomic Analysis of Soybean PP2A-B′′ Family and Its Effects on Drought and Salt Tolerance
Xiong Yang, Xuhong Fan, Qiang Wang, Zheng-Gong Yin, Xue-Wen Sheng, Jun Chen, Yongbin Zhou, Ming Chen, You‐Zhi Ma, Jian Ma, Zhao‐Shi Xu
Abstract
Abiotic stresses induce the accumulation of reactive oxygen species (ROS) and significantly affect plant growth. Protein phosphatase 2A (PP2A) plays an important role in controlling intracellular and extracellular ROS signals. However, the interaction between PP2A, ROS, and stress tolerance remains largely unclear. In this study, we found that the B <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="INEQ2"><mml:msup><mml:mi/><mml:mmultiscripts><mml:msup><mml:mi/><mml:mo>′</mml:mo></mml:msup><mml:mprescripts/><mml:none/><mml:mo>′</mml:mo></mml:mmultiscripts></mml:msup></mml:math> subunit of PP2A (PP2A-B <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="INEQ3"><mml:msup><mml:mi/><mml:mmultiscripts><mml:msup><mml:mi/><mml:mo>′</mml:mo></mml:msup><mml:mprescripts/><mml:none/><mml:mo>′</mml:mo></mml:mmultiscripts></mml:msup></mml:math> ) can be significantly induced and was analyzed using drought- and salt-induced soybean transcriptome data. Eighty-three soybean PP2A-B <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="INEQ4"><mml:msup><mml:mi/><mml:mmultiscripts><mml:msup><mml:mi/><mml:mo>′</mml:mo></mml:msup><mml:mprescripts/><mml:none/><mml:mo>′</mml:mo></mml:mmultiscripts></mml:msup></mml:math> genes were identified from the soybean genome via homologous sequence alignment, which was distributed across 20 soybean chromosomes. Among soybean PP2A-B <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="INEQ5"><mml:msup><mml:mi/><mml:mmultiscripts><mml:msup><mml:mi/><mml:mo>′</mml:mo></mml:msup><mml:mprescripts/><mml:none/><mml:mo>′</mml:mo></mml:mmultiscripts></mml:msup></mml:math> family genes, 26 GmPP2A-B <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="INEQ6"><mml:msup><mml:mi/><mml:mmultiscripts><mml:msup><mml:mi/><mml:mo>′</mml:mo></mml:msup><mml:mprescripts/><mml:none/><mml:mo>′</mml:mo></mml:mmultiscripts></mml:msup></mml:math> members were found to be responsive to drought and salt stresses in soybean transcriptome data. Quantitative PCR (qPCR) analysis demonstrated that GmPP2A-B <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="INEQ7"><mml:msup><mml:mi/><mml:mmultiscripts><mml:msup><mml:mi/><mml:mo>′</mml:mo></mml:msup><mml:mprescripts/><mml:none/><mml:mo>′</mml:mo></mml:mmultiscripts></mml:msup></mml:math> 71 had the highest expression levels under salt and drought stresses. Functional analysis demonstrated that overexpression of GmPP2A-B <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="INEQ8"><mml:msup><mml:mi/><mml:mmultiscripts><mml:msup><mml:mi/><mml:mo>′</mml:mo></mml:msup><mml:mprescripts/><mml:none/><mml:mo>′</mml:mo></mml:mmultiscripts></mml:msup></mml:math> 71 in soybeans can improve plant tolerance to drought and salt stresses; however, the interference of GmPP2A-B <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="INEQ9"><mml:msup><mml:mi/><mml:mmultiscripts><mml:msup><mml:mi/><mml:mo>′</mml:mo></mml:msup><mml:mprescripts/><mml:none/><mml:mo>′</mml:mo></mml:mmultiscripts></mml:msup></mml:math> 71 in soybean increased the sensibility to drought and salt stresses. Further analysis demonstrated that overexpression of GmPP2A-B <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="INEQ10"><mml:msup><mml:mi/><mml:mmultiscripts><mml:msup><mml:mi/><mml:mo>′</mml:mo></mml:msup><mml:mprescripts/><mml:none/><mml:mo>′</mml:mo></mml:mmultiscripts></mml:msup></mml:math> 71 in soybean could enhance the expression levels of stress-responsive genes, particularly genes associated with ROS elimination. These results indicate that PP2A-B <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="INEQ11"><mml:msup><mml:mi/><mml:mmultiscripts><mml:msup><mml:mi/><mml:mo>′</mml:mo></mml:msup><mml:mprescripts/><mml:none/><mml:mo>′</mml:mo></mml:mmultiscripts></mml:msup></mml:math> can promote plant stress tolerance by regulating the ROS signaling, which will contribute to improving the drought resistance of crops.