PCR Identification of Thermo-sensitive Genic Male Sterile Plants in Rice

Three PCR markers C365-1, S2-40, and InDel37, which were tightly linked with Thermo-sensitive Genetic Male Sterile (TGMS) genes reported, were used to identify TGMS gene in 146 individuals (including 126 TGMS and 20 fertile individuals) selected from F2 and F3 genetic segregated populations, which were derived from two indica hybrid combinations made by two TGMS lines, grown in the early-season in a rice field with 260 m low altitude in Yunnan, and 15 TGMS lines through selfing-crosses for many generations. The results showed that only marker C365-1 gave polymorphism between DNA pools of sterile and fertile plants from the two segregated populations. The DNA pool of sterile plants possessed two PCR fragments, one with 418 bp (reference as C365-418 bp), and another with 344 bp (reference as C365-344 bp). While the fertile plant DNA pools possessed only the PCR fragment with C365-418 bp. Sequencing and alignment analysis revealed the C365-344 bp fragment had 84% homology with a DNA sequence in a DNA clone, OJ1001_D05, located on chromosome 2 in rice, which had a 19.1 kb distance from two TGMS genes, ptgms2-1 and tms5. In the same time, this fragment also showed as high as 98% homology with a DNA sequence between OJ1001_B06.3 and OJ1001_B06.4 clones located on chromosome 6 in rice, and had about 1 cM distance from a TGMS gene, TMS. The correlation value between the genotypes of C365-1 locus and the fertile phenotypes in 146 individual plants is 0.944, had a highly significant correlation, and each lines of the 15 TGMS lines possessed the same genotype as that of sterile plants DNA pool. The results indicated that PCR marker C365-1 could be used to identify TGMS gene possessed by TGMS plants in rice effectively, which could be an effective marker in TGMS lines marker-assisted selection in rice.