MATERIALS AND METHODS
Construction of binary vector for rice
transformation
The OSB2 gene of 1,365 bp isolated from
cDNA prepared from total RNA of young leaves of
black rice variety Khum (collected from Nong-Tao-
Kham village, Sansai district, Chiang Mai, Thailand)
was revealed by our previous report (Inta et al.,
2013). The OSB2 gene was cloned in pGEM-T Easy
(Promega, USA) and digested by EcoRI. Then the
EcoRI-cut OSB2 gene was blunt ended by using
End-ItTM DNA End-Repair Kit (Epicentre, USA) and
inserted into p2CA (pUC19 containing a dual 35s
promoter and a nos terminator) to construct the
cassette of OSB2 gene under the control of a dual
35s promoter and a nos terminator. The gene
cassette (dual 35sP::OSB2::Tnos) was cloned into a
binary vector pCAMBIA1305.1 (Cambia, Australia)
at HindIII/EcoRI sites to construct pPI01_B2S which
contained hygromycin phosphotransferase (hptII) as
a selectable marker gene and β-glucuronidase
(GUSPlus) as a reporter gene (Figure 1). The
pPI01_B2S was introduced into Agrobacterium
tumefaciens strain AGL1 to be used for transformation
of rice.