Heterologous expression of GmSIP1;3 from soybean in tobacco showed and growth retardation and tolerance to hydrogen peroxide.

Aquaporins (AQPs) are transmembrane protein channels that are members of Major Intrinsic Proteins (MIP) superfamily. AQPs play important roles in plant reproduction, cell elongation, osmoregulation, influence leaf physiology and are responsive to drought and salt tolerance. Small intrinsic proteins (SIPs)belongs to one of the groups of AQPs, which are mainly localized to endoplasmic reticulum(ER). While this group of aquaporin is being well studied in Arabidopsis, grape and other plant species, not much is known about the molecular regulatory mechanisms driven by ER-type AQPs in Glycine Max. In this study, the function of GmSIP1;3 is studied in detail by using both yeast and plant systems. GmSIP1;3 showed a ubiquitous expression pattern in all different tissues in Glycine Max. Heterologous expression of GmSIP1;3 in Nicotiana tabacum conferred a short root phenotype,growth retardation at seedling stage and significant tolerance to oxidative stress (HO) both in yeast and plant systems. Auxin (IAA) content significantly increased in transgenic plants compared with that of wild type, however, the abscisic acid (ABA) content was significantly reduced. Subcellular localization and colocalization analyses showed GmSIP1;3 localized to ER plasma membrane. On the basis of these observations, we postulate that GmSIP1;3 is involved in oxidative stress pathways.