Cytological and Molecular Characteristics of Pollen Abortion in Lily with Dysplastic Tapetum  

作　　者：Xueqian Wang Ze Wu Lanqing Wang Meijiao Wu Dehua Zhang Weimin Fang Fadi Chen Nianjun Teng 

机构地区：[1]College of Horticulture,Nanjing Agricultural University/Key Laboratory of Landscape Design,Ministry of Agriculture and Rural Affairs,Nanjing 210095,China [2]Baguazhou Science and Technology Innovation Center of Modern Horticultural Industry,Nanjing 210043,China

出　　处：《Horticultural Plant Journal》2019年第6期281-294,共14页园艺学报（英文版）

基　　金：supported by the Priority Academic Program Development of Jiangsu Higher Education Institutions;the Fundamental Research Funds for the Central Universities(Grant No.KYTZ201602);the High Level Talent Project of the Top Six Talents in Jiangsu(Grant No.NY-077);the earmarked fund for germplasm resources of Nanjing Agricultural University(Grant No.KYZZ201920)。

摘　　要：Lily was grown worldwide as a fresh cutting flower because of its colorful petals, but its anther contained a large number of pollen grains that cause serious pollen contamination, however, pollen abortion can effectively reduce the level of pollen pollution. Our analysis aims to use cytological observation to detect the critical stage when pollen abortion occurs and to provide comprehensive gene expression information at the transcriptional level. The result showed that pollen abortion in ‘Little Kiss’ began at the mononuclear stage and the callose that covers the microspores failed to degenerate when young pollens were released from the tetrads. In addition, compared with the normally developed one,the tapetum of ‘Little Kiss’ degraded in advance while the degradation of callose was delayed. Furthermore, 103 differentially expressed genes(DEGs) related to the advance degeneration of tapetum cells and callose were found in the expression levels, including 22 transcription factors(TFs). In particular, two β-glucanase genes(endo-1,3(4)-β-glucanase, exo-β-glucanase) responsible for callose degeneration were significantly down-regulated. These results suggested that pollen abortion may occur at mononuclear stage and that early degeneration of tapetum cells resulted in a significant down-regulation of β-glucanase genes. As a result, the callose to cover microspores impedes the formation of pollen walls, which may possibly lead to pollen abortion.Lily was grown worldwide as a fresh cutting flower because of its colorful petals, but its anther contained a large number of pollen grains that cause serious pollen contamination, however, pollen abortion can effectively reduce the level of pollen pollution. Our analysis aims to use cytological observation to detect the critical stage when pollen abortion occurs and to provide comprehensive gene expression information at the transcriptional level. The result showed that pollen abortion in ‘Little Kiss’ began at the mononuclear stage and the callose that covers the microspores failed to degenerate when young pollens were released from the tetrads. In addition, compared with the normally developed one,the tapetum of ‘Little Kiss’ degraded in advance while the degradation of callose was delayed. Furthermore, 103 differentially expressed genes(DEGs) related to the advance degeneration of tapetum cells and callose were found in the expression levels, including 22 transcription factors(TFs). In particular, two β-glucanase genes(endo-1,3(4)-β-glucanase, exo-β-glucanase) responsible for callose degeneration were significantly down-regulated. These results suggested that pollen abortion may occur at mononuclear stage and that early degeneration of tapetum cells resulted in a significant down-regulation of β-glucanase genes. As a result, the callose to cover microspores impedes the formation of pollen walls, which may possibly lead to pollen abortion.

关 键 词：Lilium Asiatic hybrids microspore development TAPETUM programmed cell death CALLOSE transcription factor 

分 类 号：Q945[生物学—植物学]