ACOS5 is Required for Primexine Formation and Exine Pattern Formation During Microsporogenesis in Arabidopsis

作者:Xie, Hui-hui; Chen, Lin; Xu, Fa-qing; Guo, Wan-sheng; Wang, Shui; Yang, Zhong-nan; Zhang, Sen*
来源:Journal of Plant Biology, 2017, 60(4): 404-412.
DOI:10.1007/s12374-016-0523-4

摘要

Pollen exine, mainly composed of sporopollenin, plays important roles during microspore development. It has been reported that Acyl-CoA Synthetase5 (ACOS5) is required for sporopollenin biosynthesis in Arabidopsis. Here we show that ACOS5 is essential for primexine formation during Arabidopsis microspore development. Through genetic screen, we identified a point mutation of ACOS5 allele, acos5-2, showing abnormal microspore development. Its microspores were degenerated and aborted after released from the tetrads. Transmission electron microscopy showed that primexine formation was reduced in acos5-2 mutant as compared to that of the wild-type. Consequently, sporopollenin was aggregated and randomly deposited on the microspores. In situ hybridization indicated that the key regulators of tapetum development, DYT1 and TDF1, are required for the expression of ACOS5 in tapetum. Furthermore, the GUS reporter showed that the 593-bp promoter sequence was sufficient for the expression of ACOS5 in the anther. Our data provide evidence that ACOS5 is required for primexine formation and sporopollenin deposition during microspore development.