Pyramiding of thermosensitive genetic male sterility (TGMS) genes and in silico analysis of a candidate TGMS locos in rice
2004
Nas, T.M.S. | Sanchez, D.L.,International Rice Research Inst., Los Banos, Laguna (Philippines). Plant Breeding, Genetic and Biochemistry Div. | Diaz, M.G.Q. | Mendioro, M.S.
Thermosensitive genetic male sterility [TGMS] is an efficient system for hybrid seed production, wherein fertility-sterility alterations of TGMS lines are controlled by temperature. To further stabilize TGMS expression, the authors have pyramided three TGMS genes from TGMS lines Norin PL 12, SA2 and DQ 200047-21 through conventional hybridization. The three TGMS genes are complementary as shown by the segregation ratio of pollen sterility. Selection of progenies was aided by linked microsatellite markers RM11, RM257 and RM174. Selected plants that are homozygous for the linked microsatellite alleles were male sterile at high temperatures (greater than 27 deg C). These plants were then allowed to self-pollinate at low temperatures (less than 25 deg C) for generation advance. The authors are optimistic that commercial TGMS lines derived from the results of this study will someday be used in hybrid seed production in the Philippines and other countries. The authors partially sequenced and analyzed in silico a candidate TGMS locus based on its complete linkage with RM174. BLAST performed against sequence databases showed that the locus is similar to SF21 pollen specific gene of Arabidopsis and Helianthus. Pollen-specific regulatory sequences upstream of ATG codon and point mutations in the C-terminus exon of the TGMS locus, as compared with the standard rice genome sequence, were identified. These results will lead to cloning and proteomic studies to explore TGMS expression.
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