A Novel Rice bHLH Transcription Factor, DTD, Acts Coordinately with TDR in Controlling Tapetum Function and Pollen Development

MS23, a master basic helix-loop-helix factor, regulates the specification and development of tapetum in maize

“…Mutant analysis demonstrates that several tapetal bHLHs are crucial for (1) pre-meiotic to meiotic stages: Arabidopsis DYSFUNCTIONAL TAPETUM1 (DYT1) Feng et al, 2012), its rice homolog UNDEVELOPED TAPETUM1 (UDT1) (Jung et al, 2005), and the maize homolog, Male Sterility32 (Ms32) (Moon et al, 2013); rice ETERNAL TAPETUM1 (EAT1 -OS04G0599300, also named DELAYED TAPETUM DEGENERATION or DTD) (Niu et al, 2013;Ji et al, 2013); rice TDR INTERACTING PARTNER2 (TIP2 -OS01T0293100; also named bHLH142) (Fu et al, 2014;Ko et al, 2014); Arabidopsis bHLH10, bHLH89 and bHLH91 (Zhu et al, 2015); as well as for (2) meiotic to post-meiotic stages: Arabidopsis ABORTED MICROSPORES (AMS) (Sorensen et al, 2003;Xu et al, 2010Xu et al, , 2014 and its rice homolog TAPETUM DEGENERATION RETARDATION (TDR) (Li et al, 2006;Zhang et al, 2008).…”

A Rice Ca2+ Binding Protein Is Required for Tapetum Function and Pollen Formation

“…The differentiation of the innermost tapetal cell layer is crucial for pollen formation (Kelliher and Walbot, 2012;Fu et al, 2014;Zhang and Yang, 2014). After the formation of tapetal cells, subsequent tapetal cell and callose degradation, as well as primexine formation, are vital for pollen development (Ma, 2005;Li et al, 2006;Wu and Cheun, 2000;Paxson-Sowders et al, 2001;Ariizumi et al, 2004;Li et al, 2011a;Chang et al, 2012;Ji et al, 2013;Niu et al, 2013;Sun et al, 2013).…”

“…Until now, several transcription factors and their associated targets have been reported to play role in tapetal cell death (Sorensen et al, 2003;Jung et al, 2005;Li et al, 2006;Aya et al, 2009;Xu et al, 2010;Li et al, 2011a;Niu et al, 2013;Ji et al, 2013;Fu et al, 2014;Ko et al, 2014). In rice (Oryza sativa), mutations in the basic helix-loop-helix (bHLH) transcription factor TDR Interacting Protein2 (TIP2), also called bHLH142, show compromised inner anther wall layer differentiation and defects in microspore development (Fu et al, 2014;Ko et al, 2014).…”

“…gamyb, which encodes a MYB transcription factor, shows aborted tapetum degradation (Aya et al, 2009). Another bHLH transcription factor, Eternal Tapetum1 (EAT1), also called DTD, as well as one PHD finger protein, Persistent Tapetal Cell1 (PTC1), regulate microspore development via controlling tapetal cell death (Li et al, 2011a;Ji et al, 2013;Niu et al, 2013). TDR and EAT1 directly regulate the expression of proteases, which are regarded as executors for programmed cell death (PCD) in animals (Li et al, 2006;Niu et al, 2013;Woltering, 2010).…”

“…Up to now, the progress made toward understanding tapetal cell death is mainly restricted to the level of transcription factors and their related regulatory effects (Sorensen et al, 2003;Li et al, 2006;Aya et al, 2009;Xu et al, 2010;Li et al, 2011a;Niu et al, 2013;Ji et al, 2013;Fu et al, 2014;Ko et al, 2014). Consequently, further approaches are needed to reveal additional details of tapetal cell death regulation.…”