small RNA-seq of soybean seedlings sample Water-stressed 1
The soybean seedlings (Magellan genotype) growth and treatments were conducted as reported previously (Yamaguchi et al., 2010a). In brief, seedlings with primary roots approximately 15 mm in length were transplanted against the interior surface of Plexiglas cylinders (14.5 cm diameter) filled with a 1:1 (v/v) mixture of vermiculite (no. 2A, Therm-ORock East Inc., New Eagle, PA, USA) and Turface (Profile Products LLC, Buffalo Grove, IL, USA) at water potentials of -0.1 MPa (well-watered control, moistened to the drip point) or -1.6 MPa (water-stress), which were obtained by thorough mixing with different volumes of 5 mm CaCl2 + 5 mm Ca(NO3)2 solution. Primary root tip region (0-8 mm) was collected after 48 hrs of treatment along with the control samples in two replicates and total RNA was isolated and used for constructing small RNA libraries. Root tip water stress level was assessed by measuring water potential of the growing media using an isopiestic thermocouple psychrometer.