TITLE:
Protocol optimization and evaluation of rice varieties response to in vitro regeneration
AUTHORS:
Puspasree Puhan, Ebrahimali Abubacker Siddiq
KEYWORDS:
Primary Culture; Secondary Culture; Growth Regulator; Mesocotyls; Indirect Organogenesis
JOURNAL NAME:
Advances in Bioscience and Biotechnology,
Vol.4 No.5,
May
30,
2013
ABSTRACT: Understanding the control of
related molecular mechanisms is impossible without efficient
and reproducible regeneration and stable genetic transformation. The key
factors for enhancing successful regeneration are genotypes, tissue source of
explants, combination and concentration of growth regulators, and culture conditions.
In the present study different methods of regeneration were tested in a set
of 12 rice accession representing indica, japonica, aromatic and wild groups. The highest frequency of shoot regeneration was
achieved using mesocotyls derived from in vitro grown seeds cultured on Murashige and Skoogs, basal medium
without growth regulators, when cultured on medium supplemented with Benzyl
Adenine (BA) 0.5 mg/l under subdued light at 25°C ± 2°C. Under these conditions
mesocotyls (Plurality of meristems) produced 3 to 4 tiller shoots in primary culture.
One seed/One single mesocotyls segment produced over 5 to 9 shoots, arising
primarily through direct organogenesis after 3 weeks of culture. Through
callusing phase different rice cultivars produced different percentage of callusing
however Basmati 370 gave high percentage in response to callussing,
organogenesis and root formation. In between these two methods, the direct
shoot regeneration gave 80% - 100% result besides the wild species in respect
with their genotype whereas the indirect organogenesis gave only 10% - 30% of
plantlets. So the direct multiplication from mesocotyls is an efficient
method for plantlet regeneration of rice cultivars through in vitro culture.
Tissue culture derived plants when
evaluated with rice markers no variability is found. For regeneration
genotypes and its trigger ing factors like medium composition, culture conditions
and type of explants are playing a combined role.