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′′ subunit of PP2A (PP2A-B′′) can be significantly induced and was analyzed using drought- and salt-induced soybean transcriptome data. Eighty-three soybean PP2A-B′′ genes were identified from the soybean genome via homologous sequence alignment, which was distributed across 20 soybean chromosomes. Among soybean PP2A-B′′ family genes, 26 GmPP2A-B′′ members were found to be responsive to drought and salt stresses in soybean transcriptome data. Quantitative PCR (qPCR) analysis demonstrated that GmPP2A-B′′71 had the highest expression levels under salt and drought stresses. Functional analysis demonstrated that overexpression of GmPP2A-B′′71 in soybeans can improve plant tolerance to drought and salt stresses; however, the interference of GmPP2A-B′′71 in soybean increased the sensibility to drought and salt stresses. Further analysis demonstrated that overexpression of GmPP2A-B′′71 in soybean could enhance the expression levels of stress-responsive genes, particularly genes associated with ROS elimination. These results indicate that PP2A-B′′ can promote plant stress tolerance by regulating the ROS signaling, which will contribute to improving the drought resistance of crops.

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The Dachang tin-polymetallic deposit, which is located in the northwestern part of the Guangxi Zhuang Autonomous Region, contains great amounts of indium. But the occurrence and enrichment of indium are rather complex and not yet well understood. In this paper, the Dachang West ore belt (Tongkeng, Gaofeng) sphalerite is taken as the research object. Based on detailed field investigation and indoor microscopic observation of mineral phase, the spatial distribution law, occurrence state and relationship with main metallogenic elements of scattered elements indium were studied by means of high-precision electron probe and plasma mass spectrometry, in order to reveal its enrichment in sphalerite. The study results show that the content of scattered elements indium in the sphalerite of the Tongkeng deposit decreases with the increase of depth, while the Gaofeng deposit remains stable. Indium occurs mainly in the form of isomorphism and enters sphalerite lattice in the form of double substitution of zinc with copper, but does not exclude the possibility of indium being deposited as a sub-microinclusions. On the basis of previous studies, it is inferred that the indium-rich and copper-rich fluids produced by magma crystallization are metasomatic and enriched with the early-formed sphalerite in the late evolution of Granite Magma. The results of this study point the way to mineral processing and the search for scattered elements indium.