| Stem cells in the floral meristem are determinate. Once producing all floral organ primordiums, specification of the stem cell was lost. That means the maintenance of floral stem cells are terminated without the function as stem cells. The termination of floral stem cells required two kinds of transcription factors, WUSCHEL(WUS) and AGAMOUS(AG). WUS was specifically expressed in organization center of floral meristem that makes the above cells becoming stem cells. AG that belongs to MADS-box gene family negatively regulated WUS via direct and indirect ways, ending floral stem cell activity. Because the mechanism that the maintenance of floral stem cells are terminated has not been fully elucidated, further research was necessary.In this study, we isolated multiple targeted mutant by EMS mutagenesis on ag-10. The mutant genes were separated through map-based cloning and genome resequencing. The WUS expression period of mutants was also researched via introducing pWUS:GUS reporter gene. The main results are as follows:1. Multiple mutants like agen7, agen446, agen350, agen358, agen140, agen63, agen317, agen475, agen377, agen90 were isolated. All of them have bulged and short siliques that show serious flaws in floral determination. These prepared candidate materials for research the precisely termination of floral stem cells in a certain period of flower development.2. The results showed that the mutant gene of agen7 was a single recessive mutation and was located in chromosome 4. There are three candidate genes, respectively AT4G20910(HEN1), AT4G16280, AT4G29010.3. The mutant gene of agen446 was a single recessive mutation was located within the range between MGL6(2) and K1G2 in chromosome 3. The single mutant was also isolated. WUS of agen446 was expressed in stage 8 or stage 9 that indicated WUS expression was longer than in ag-10, influencing termination of flower stem cell activity.4. agen317 was mapped to chromosome 3 and agen358 was mapped to chromosome 5. |
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