Abstract: 【Objective】 In order to clarify the mechanism of cellular and molecular sterility characteristics, the flower morphology, anther abortion period and molecular mechanism of the thermos-sensitive male sterile line of cauliflower were studied, thus laying a theoretical foundation for further study of the male sterility. 【Method】 The thermo-sensitive male sterile line GS-19 was used as the experimental material, using morphological, cytological and high-throughput sequencing techniques, the morphological, cytological and molecular mechanism were studied with treatment at different temperatures (15℃ and 20℃). 【Result】 The fertility conversion of the thermo-sensitive male sterile line GS-19 was controlled by temperature, sterility at high temperature (20℃), and fertility at low temperature (15℃). The flower difference between sterile and fertile plants reached a significant level in GS-19, the flower was significantly smaller than that of fertile plants. The anthers abortive stages and manners were different between sterile and fertile plants of GS-19 by the microstructure observation. The anther development of GS-19 had differentiation of pollen mother cell, formed normal pollen sac, did not produce pollen grains or produce trace of pollen grains without viability, the development of anthers was blocked from pollen mother cell to the tetrad stage. The pollen mother cells could not pass the meiosis, with no dyads and tetrads formed in GS-19, insteading of some “pseudo microspores”, belong to an abortive type of pollen mother cell. The pollen exines of the “pseudo microspores” were abnormal. The “pseudo microspores” were decayed gradually and only empty shells remained at last. A total of 67 930 unigenes were generated in GS-19 alabastrum by sequence, Nt database compared to the largest number of similar sequences, for the 52 191, Nr database to similar sequence of times (46 447), KOG database than similar sequence of the least (13 198). By GO database the 25 336 unigenes were divided into 3 categories containing 55 function groups; by KOG databases the 13 198 unigenes were grouped into 26 functional categories; by KEGG database the 14 778 unigenes were divided into 19 metabolism pathways. Gene differential expression analysis revealed that there were 2 170 differentially expressed genes in the bud of GS-19 male sterile line and fertile plants, 1 078 genes up-regulated and 1 092 genes down regulated. 【Conclusion】 The fertility conversion of the thermo-sensitive male sterile line GS-19 is controlled by temperature, sterility at high temperature. The flower is significantly smaller than that of fertile plants. The filaments are significantly shortened, the anthers shrank, and dried. The development of anthers is blocked from pollen mother cell to the tetrad stage, belonging to an abortive type of pollen mother cell. A total of 67 930 unigenes were generated in GS-19 alabastrum by transcriptome analysis. Gene differential expression analysis reveals that there are 2 170 differentially expressed genes in the bud of GS-19 male sterile and fertile plants.

Key words: cauliflower (Brassica oleracea L.var.botrytis L.), thermo-sensitive genic male sterile, anther abortion, cytology, transcripiome analysis