Primer design and PCR conditions
WRI1 primers were designed based on sequence information of the E. guineensis cDNA libraries from Bourgis
et al.10 and Tranbarger et al.11. The WRI1 gene was amplified by PCR using primer pair of WRIF1 5 ATGACTCTC
ATGAAGAACTCT 3 and WRIR1 5 CTAGGCACCTTTGCTTGCA 3. PCR reactions were performed in a total
volume of 25 μL, containing 3 μL of cDNA product (end process of SMARTer PCR cDNA Synthesis Kit produced
100 μL cDNA product), 10 × PCR buffer, 1 mM MgCl2, 0.2 mM dNTPs, 5 pmol each primer and 1 unit DNA
polymerase. The amplification by using the designed primer was conducted with two PCR kits, which were Kapa
HiFi PCR kit (Kapa Biosystems) and Phire Plant Direct PCR kit (Thermo Scientific). The reactions were incubated
in thermocyler (Applied Biosystems, PCR System 9700). DNA amplification conditions were at 95 oC for 5 min
followed by 35 cycles of 30 s at 95 oC, 30 s at 55 oC and 30 s at 72 oC. Amplification concluded with a 10 min
extension step at 72 oC before cooling to 4 oC. The PCR products were analyzed by electrophoresis on a 1.5 %
agarose gel, visualized by UV light and measurement of DNA concentration by NanoDrop (Thermo Scientific).