OsMADS32 is a monocot specific MIKCc type MADS‐box gene that plays an important role in regulating rice floral meristem and organs identity, a crucial process for reproductive success and rice yield. However, its und...OsMADS32 is a monocot specific MIKCc type MADS‐box gene that plays an important role in regulating rice floral meristem and organs identity, a crucial process for reproductive success and rice yield. However, its underlying mechanism of action remains to be clarified. Here, we characterized a hypomorphic mutant allele of OsMADS32/CFO1, cfo1‐3 and identified its function in controlling rice flower development by bioinformatics and protein‐protein interaction analysis. The cfo1‐3 mutant produces defective flowers, including loss of lodicule identity, formation of ectopic lodicule or hull‐like organs and decreased stamen number, mimicking phenotypes related to the mutation of B class genes. Molecular characterization indicated that mis‐splicing of OsMADS32 transcripts in the cfo1‐3 mutant resulted in an extra eight amino acids in the K‐domain of OsMADS32 protein. By yeast two hybrid and bimolecular fluorescence comple-mentation assays, we revealed that the insertion of eight amino acids or deletion of the internal region in the K1 subdomain of OsMADS32 affects the interaction between OsMADS32 with PISTILLATA （PI）‐like proteins OsMADS2 and OsMADS4. This work provides new insight into the mecha-nism by which OsMADS32 regulates rice lodicule and stamen identity, by interaction with two PI‐like proteins via its K domain.展开更多
Grain shape and size are two key factors that determine rice yield and quality. In the present study, a rice triangular hull mutant (tri1) was obtained from the progeny of japonica rice variety Taipei 309 treated with...Grain shape and size are two key factors that determine rice yield and quality. In the present study, a rice triangular hull mutant (tri1) was obtained from the progeny of japonica rice variety Taipei 309 treated with 60Co γ-rays. Compared to the wild type, the tri1 mutant presents a triangular hull, and exhibits an increase in grain thickness and protein content, but with a slight decrease in plant height and grain weight. Genetic analysis indicated that the mutant phenotype was controlled by a recessive nuclear gene which is stably inherited. Using a map-based cloning strategy, we fine-mapped tri1 to a 47-kb region between the molecular markers CHR0122 and CHR0127 on the long arm of chromosome 1, and showed that it co-segregates with the molecular marker CHR0119. According to the rice genome sequence annotation there are six predicated genes within the mapped region. Sequencing analysis of the mutant and the wild type indicated that there was a deletion of an A nucleotide in exon 3 of the OsMADS32 gene, which could result in a downstream frameshift mutation and premature termination of the predicted polypeptide. Both semi-quantitative and real-time RT-PCR analyses showed that this gene expressed highly in young inflorescences, while expressed at very low levels in other tissues. These results implied that the OsMADS32 gene could be a candidate of TRI1. Taken together, the results of this study lay the foundation for further investigation into the molecular mechanisms regulating rice caryopsis development.展开更多
基金supported by the Funds from National Natural Science Foundation of China (30971739,31270222,31230051,and J1210047)Key Project on Basic Research from Science and Technology Commission of Shanghai (14JC1403900)the Innovation Program of Shanghai Municipal Education Commission (13ZZ018)
文摘OsMADS32 is a monocot specific MIKCc type MADS‐box gene that plays an important role in regulating rice floral meristem and organs identity, a crucial process for reproductive success and rice yield. However, its underlying mechanism of action remains to be clarified. Here, we characterized a hypomorphic mutant allele of OsMADS32/CFO1, cfo1‐3 and identified its function in controlling rice flower development by bioinformatics and protein‐protein interaction analysis. The cfo1‐3 mutant produces defective flowers, including loss of lodicule identity, formation of ectopic lodicule or hull‐like organs and decreased stamen number, mimicking phenotypes related to the mutation of B class genes. Molecular characterization indicated that mis‐splicing of OsMADS32 transcripts in the cfo1‐3 mutant resulted in an extra eight amino acids in the K‐domain of OsMADS32 protein. By yeast two hybrid and bimolecular fluorescence comple-mentation assays, we revealed that the insertion of eight amino acids or deletion of the internal region in the K1 subdomain of OsMADS32 affects the interaction between OsMADS32 with PISTILLATA （PI）‐like proteins OsMADS2 and OsMADS4. This work provides new insight into the mecha-nism by which OsMADS32 regulates rice lodicule and stamen identity, by interaction with two PI‐like proteins via its K domain.
基金supported by the National Key Basic Research and Development Project (2012CB944803)the National Natural Science Foundation of China (31071383)+1 种基金the Funds for Distinguished Young Scientists of Jiangsu Province (BK2012010)Priority Academic Program Development from Jiangsu Government, China
文摘Grain shape and size are two key factors that determine rice yield and quality. In the present study, a rice triangular hull mutant (tri1) was obtained from the progeny of japonica rice variety Taipei 309 treated with 60Co γ-rays. Compared to the wild type, the tri1 mutant presents a triangular hull, and exhibits an increase in grain thickness and protein content, but with a slight decrease in plant height and grain weight. Genetic analysis indicated that the mutant phenotype was controlled by a recessive nuclear gene which is stably inherited. Using a map-based cloning strategy, we fine-mapped tri1 to a 47-kb region between the molecular markers CHR0122 and CHR0127 on the long arm of chromosome 1, and showed that it co-segregates with the molecular marker CHR0119. According to the rice genome sequence annotation there are six predicated genes within the mapped region. Sequencing analysis of the mutant and the wild type indicated that there was a deletion of an A nucleotide in exon 3 of the OsMADS32 gene, which could result in a downstream frameshift mutation and premature termination of the predicted polypeptide. Both semi-quantitative and real-time RT-PCR analyses showed that this gene expressed highly in young inflorescences, while expressed at very low levels in other tissues. These results implied that the OsMADS32 gene could be a candidate of TRI1. Taken together, the results of this study lay the foundation for further investigation into the molecular mechanisms regulating rice caryopsis development.
