AUTHOR=Cheng Qun , Li Ninghui , Dong Lidong , Zhang Dayong , Fan Sujie , Jiang Liangyu , Wang Xin , Xu Pengfei , Zhang Shuzhen 

TITLE=Overexpression of Soybean Isoflavone Reductase (GmIFR) Enhances Resistance to Phytophthora sojae in Soybean

JOURNAL=Frontiers in Plant Science

VOLUME=6

YEAR=2015

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2015.01024

DOI=10.3389/fpls.2015.01024

ISSN=1664-462X

ABSTRACT=<p>Isoflavone reductase (IFR) is an enzyme involved in the biosynthetic pathway of isoflavonoid phytoalexin in plants. IFRs are unique to the plant kingdom and are considered to have crucial roles in plant response to various biotic and abiotic environmental stresses. Here, we report the characterization of a novel member of the soybean isoflavone reductase gene family <italic>GmIFR</italic>. Overexpression of <italic>GmIFR</italic> transgenic soybean exhibited enhanced resistance to <italic>Phytophthora sojae</italic>. Following stress treatments, <italic>GmIFR</italic> was significantly induced by <italic>P. sojae</italic>, ethephon (ET), abscisic acid (placeCityABA), salicylic acid (SA). It is located in the cytoplasm when transiently expressed in soybean protoplasts. The daidzein levels reduced greatly for the seeds of transgenic plants, while the relative content of glyceollins in transgenic plants was significantly higher than that of non-transgenic plants. Furthermore, we found that the relative expression levels of reactive oxygen species (ROS) of transgenic soybean plants were significantly lower than those of non-transgenic plants after incubation with <italic>P. sojae</italic>, suggesting an important role of <italic>GmIFR</italic> might function as an antioxidant to reduce ROS in soybean. The enzyme activity assay suggested that GmIFR has isoflavone reductase activity.</p>