The Stylo Cysteine-Rich Peptide Sgsnakin1 Involves In Aluminum Tolerance Through Enhancing Reactive Oxygen Species Scavenging

Abstract

Stylo (Stylosanthes spp.) is an important pasture legume with strong Aluminum (Al) resistance in the tropic and subtropic areas. However, the molecular mechanisms underlying its Al tolerance remains fragmentary. Here, due to the incomplete genome sequence information of Stylo, we first conducted full-length transcriptome sequencing for the stylo root tips treated with and without Al and identified three Snakin/GASA genes, namely SgSnakin1/2/3. Through quantitative RT-PCR, we found that only SgSnakin1 was significantly up-regulated by Al treatments in stylo root tips. Histochemical localization assays further verified the Al-enhanced expression of SgSnakin1 in stylo root tips. Subcellular localization in both tobacco and onion epidermic cells found that SgSnakin1 localized on cell-wall. Overexpression of SgSnakin1 conferred Al tolerance in transgenic Arabidopsis, as reflected by higher relative root growth and cell vitality, as well as lower Al concentration in the roots of transgenic plants. Meanwhile, overexpressing SgSnakin1 also increased the activities of SOD and POD, and decreased the content of O2-· and H2O2 in transgenic Arabidopsis in response to Al stress. These results suggested that SgSnakin1 might function in Al resistance by enhancing the reactive oxygen species scavenging through regulating antioxidant enzymes activities.

Keywords: Stylosanthes, Snakin/GASA family, aluminum, ROS