The Histone Deacetylase Inhibitor Trichostatin A Promotes Totipotency in the Male Gametophyte

• Published in: The Plant cell 2014-01, Vol.26 (1), p.195-209
• Main Authors: Li, Hui, Soriano, Mercedes, Cordewener, Jan, Muiño, Jose M., Riksen, Tjitske, Fukuoka, Hiroyuki, Angenent, Gerco C., Boutilier, Kim
• Format: Article
• Language: English
• Subjects: Acetylation; Anthers; Arabidopsis - cytology; Arabidopsis - drug effects; Arabidopsis - growth & development; Arabidopsis Proteins - metabolism; arabidopsis-thaliana; brassica-napus l; Cell Division - drug effects; Cell Proliferation - drug effects; Cell Wall - drug effects; Cultured cells; embryo development; Embryogenesis; Embryos; Gametophytes; Histone Deacetylase Inhibitors - pharmacology; Histones - metabolism; Hydroxamic Acids - pharmacology; in-vitro; Indoleacetic Acids - metabolism; microspore embryogenesis; Microspores; Microsporocytes; plant-cell cycle; Plants; Pollen; Pollen - cytology; Pollen - drug effects; Pollen - growth & development; pollen embryogenesis; polycomb-group proteins; retinoblastoma protein; Signal Transduction - drug effects; Somatic cells; somatic embryogenesis
• ISSN: 1040-4651; 1532-298X
• DOI: 10.1105/tpc.113.116491

The haploid male gametophyte, the pollen grain, is a terminally differentiated structure whose function ends at fertilization. Plant breeding and propagation widely use haploid embryo production from in vitro-cultured male gametophytes, but this technique remains poorly understood at the mechanistic level. Here, we show that histone deacetylases (HDACs) regulate the switch to haploid embryogenesis. Blocking HDAC activity with trichostatin A (TSA) in cultured male gametophytes of Brassica napus leads to a large increase in the proportion of cells that switch from pollen to embryogenie growth. Embryogenie growth is enhanced by, but not dependent on, the high-temperature stress that is normally used to induce haploid embryogenesis in B. napus. The male gametophyte of Arabidopsis thaliana, which is recalcitrant to haploid embryo development in culture, also forms embryogenic cell clusters after TSA treatment. Genetic analysis suggests that the HDAC protein HDA17 plays a role in this process. TSA treatment of male gametophytes is associated with the hyperacetylation of histones H3 and H4. We propose that the totipotency of the male gametophyte is kept in check by an HDAC-dependent mechanism and that the stress treatments used to induce haploid embryo development in culture impinge on this HDAC-dependent pathway.