The Research Of Genetic And Gene Mapping About Brittle Culm Mutants Of Rice(Oryza Sativa L.)

In this study, we mainly researched the agronomic characters, physiological and biochemical, genetic analysis and located the control gene of three rice brittle culm mutants were obtained by heavy ion irradiation. Through comparison with the other positioned brittle culm mutants’gene, we further researched the new brittle culm mutants’gene cloning and function analysis. The experiment conclusions as follows.1. Result of9311brittle culm mutantsWe obtained2brittle culm mutants from M2population of indica variety9311irradiated by heavy ion. One plant height is74.5cm, we called9311drwaf fragile rice, named drf. Another one plant height is115.5cm, we called9311high fragile rice, named bc9311-1. Cell wall composition analysis indicated that the cellulose, hemi-cellulose, lignin and SiO2content of culm, dfr mutant was22.3%,30.3%,3.2%and7.4%, respectively, bc9311-1mutant was24.7%,27.8%,3.7%and13.8%, respectively, while9311wild type was34.1%,18.6%,4.5%and9.1%, respectively; the content of those components of leaves, dfr mutant was13.8%,24.2%,4.9%and10.9%, respectively, bc9311-1mutant was17.6%,27.3%,6.4%and11.5%, respectively, while9311wild type was23.8%,20.6%,4.9%and11.7%, respectively. Compare with9311wild type, the cellulose content of these2brittle culm mutants decreased sharply, while hemi-cellulose increased evidently, no significant difference has been found in contents of lignin and SiO2.Genetic analysis showed that the mutated phenotype of these2brittle culm mutants were controlled by a recessive gene. The dfr and bc9311-1gene was mapped on rice chromosome2and1, respectively, by using a F2population developed from two crosses between the mutants and02428. The dfr genetic distances from the gene to the linked SSR markers RM5472and RM240were1.1cM and1.6cM, respectively, and the bc9311-1genetic distances from the gene to the linked SSR markers RM1095and RM3632were0.6cM and3.4cM, respectively. Through some predicted gene sequencing, we found the dfr mutant had one base deleted in Os02t0738900-01gene, and the bc9311-1mutant had two point mutations in Os02t0738900-01gene, CG changed AT, so these genes could not coded the integrated proteins, finally the two mutants showed the brittle characters.2. Result of bcl3(1) mutantThe bcl3(t) mutant was a special brittle culm mutant. Compare with its wild type, plant height had no obvious difference, the brittle character mianly show in its culm not in leaf. Cell wall components analysis showed that cellulose content of mutant leaf and culm decreased sharply, while hemi-cellulose increased evidently in culm but not in leaf, and significant difference has been found in contents of SiO2in leaf. Genetic analysis showed that the mutated phenotype of bcl3(t) was controlled by a recessive gene. The bcl3(t) gene was mapped on rice chromosome8by using a F2population developed from a cross between the mutant and NJ11, and the genetic distances from the gene to the linked SSR markers RM8018and RM5068were6.6cM and1.2cM, respectively. Because the distance between this two markers is about600Kb, and the inadequate F2populations, this mutant gene has not cloned.