| 作者： | Chong Teng , Haili Dong , Lihua Shi , Yan Deng , Jinye Mu , Jian Zhang , Xiaohui Yang , and Jianru Zuo |
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| 刊物名称： | Plant Physiology Preview |
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| 摘要： | Sphingolipids are important signaling molecules involved in various cellular activities. De novo sphingolipid synthesis is initiated by a rate-limiting enzyme serine palmitoyltransferase (SPT), a heterodimer consisting of long-chain base1 (LCB1) and LCB2 subunits. A mutation in the Arabidopsis LCB1 gene, lcb1-1, was found to cause embryo lethality. However, the underpinning molecular and cellular mechanisms remain largely unclear. Here, we report the identification of the fumonisin B1 resistant11-2 (fbr11-2) mutant, an allele of lcb1-1. The fbr11-2 mutation, most likely an allele stronger than lcb1-1, was transmitted only through female gametophytes, and caused the formation of abortive microspores. During the second pollen mitosis, fbr11-2 initiated apoptotic cell death in binucleated microspores characteristic of nuclear DNA fragmentation, followed by cytoplasm shrinkage and organelle degeneration at the trinucleated stage. In addition, a double mutant with T-DNA insertions in two homologous LCB2 genes showed a phenotype similar to fbr11-2. Consistent with these observations, the FBR11/LCB1 expression was confined in microspores during microgametogenesis. These results suggest that SPT-modulated PCD plays an important role in the regulation of male gametophyte development. |
