Find in Library

The mediator complex is an essential link between transcription factors and RNA polymerase II, and mainly functions in the transduction of diverse signals to genes involved in different pathways. Limited information is available on the role of soybean mediator subunits in growth and development, and their participation in defense response regulation. Here, we performed genome-wide identification of the 95 soybean mediator subunits, which were unevenly localized on the 20 chromosomes and only segmental duplication events were detected. We focused on <i>GmMED16-1</i>, which is highly expressed in the roots, for further functional analysis. Transcription of <i>GmMED16-1</i> was induced in response to <i>Phytophthora sojae</i> infection. <i>Agrobacterium rhizogenes</i> mediated soybean hairy root transformation was performed for the silencing of the <i>GmMED16-1</i> gene. Silencing of <i>GmMED16-1</i> led to an enhanced susceptibility phenotype and increased accumulation of <i>P. sojae</i> biomass in hairy roots of transformants. The transcript levels of <i>NPR1</i>, <i>PR1a</i>, and <i>PR5</i> in the salicylic acid defense pathway in roots of <i>GmMED16-1</i>-silenced transformants were lower than those of empty-vector transformants. The results provide evidence that <i>GmMED16-1</i> may participate in the soybean&#8722;<i>P. sojae</i> interaction via a salicylic acid-dependent process.