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A G protein alpha mutation confers prolificacy potential in maize.

Urano D, Jackson D, Jones AM - J. Exp. Bot. (2015)

Bottom Line: The ct2 mutant partially compensated for a reduced shoot height by increased total leaf number, and had far more ears, even in the presence of pollination signals.The maize heterotrimeric G protein complex is important in some plastic developmental traits in maize.In particular, the maize Gα subunit is required to dampen the overproduction of female inflorescences.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology, The University of North Carolina, Chapel Hill, Coker Hall, NC 27599-3280, USA.

No MeSH data available.


Proposed function of Gα and pollination signals on prolificacy. There are two sequential events for conferring prolificacy; a Gα-mediated axillary ear formation/development and a Gα-independent ear outgrowth. Domesticated maize intrinsically suppresses axillary ear formation on a shank. Activation of the Gα pathway represses axillary ear formation or immature ear development, while a pollinated-apical ear inhibits subsequent ear outgrowth perhaps through auxin or an unknown mediator. The latter pathway is independent of the Gα subunit.
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Figure 4: Proposed function of Gα and pollination signals on prolificacy. There are two sequential events for conferring prolificacy; a Gα-mediated axillary ear formation/development and a Gα-independent ear outgrowth. Domesticated maize intrinsically suppresses axillary ear formation on a shank. Activation of the Gα pathway represses axillary ear formation or immature ear development, while a pollinated-apical ear inhibits subsequent ear outgrowth perhaps through auxin or an unknown mediator. The latter pathway is independent of the Gα subunit.

Mentions: Figure 4 shows a two-step model for conferring prolificacy. Genetics studies identified additional genes affecting the ear formation trait. Activation of a transcription factor, BARREN STALK1 (BA1), initiates the axillary ear shoot meristems, while another transcription factor gene, GRASSY TILLERS1 (GT1), suppresses the outgrowth of immature inflorescences (Ritter et al., 2002; Gallavotti et al., 2004; Whipple et al., 2011). A different expression profile of GT1 in the nodal plexus probably caused a distinct ear branching pattern between maize and teosinte (Wills et al., 2013). Our results prompt the speculation that the G protein network regulates axillary meristem initiation/transition of axillary buds to reproductive development and/or outgrowth of immature ear shoots (Fig. 4), so may control these transcription factors. Although the signalling mechanism regulating these and other genetic components remains poorly understood, it is empirically known that ear outgrowth requires ample energy resources—water, light, and nutrients (Lejeune and Bernier, 1996; Moulia et al., 1999; Markham and Stoltenberg, 2010). Multiple hormones—auxin, cytokinin, and strigolactones—also regulate the dormancy of axillary buds (Pautler et al., 2013). Maize and other plant G-protein networks couple those extracellular stimuli and modulate meristem activity, cell proliferation, and cellular senescence (Bommert et al., 2013; Urano et al., 2013; Sun et al., 2014), therefore G protein signalling may bridge these extracellular signals to ear development and outgrowth. The phenotypes described here, including root system and ear shoot architecture,are obvious plastic traits in plant development that have been selected during crop domestication and our results suggest that G protein signalling networks modulate the expression of these key agronomic traits. It will also be interesting to ask how natural variation in G protein signalling components has contributed to crop improvement.


A G protein alpha mutation confers prolificacy potential in maize.

Urano D, Jackson D, Jones AM - J. Exp. Bot. (2015)

Proposed function of Gα and pollination signals on prolificacy. There are two sequential events for conferring prolificacy; a Gα-mediated axillary ear formation/development and a Gα-independent ear outgrowth. Domesticated maize intrinsically suppresses axillary ear formation on a shank. Activation of the Gα pathway represses axillary ear formation or immature ear development, while a pollinated-apical ear inhibits subsequent ear outgrowth perhaps through auxin or an unknown mediator. The latter pathway is independent of the Gα subunit.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4507758&req=5

Figure 4: Proposed function of Gα and pollination signals on prolificacy. There are two sequential events for conferring prolificacy; a Gα-mediated axillary ear formation/development and a Gα-independent ear outgrowth. Domesticated maize intrinsically suppresses axillary ear formation on a shank. Activation of the Gα pathway represses axillary ear formation or immature ear development, while a pollinated-apical ear inhibits subsequent ear outgrowth perhaps through auxin or an unknown mediator. The latter pathway is independent of the Gα subunit.
Mentions: Figure 4 shows a two-step model for conferring prolificacy. Genetics studies identified additional genes affecting the ear formation trait. Activation of a transcription factor, BARREN STALK1 (BA1), initiates the axillary ear shoot meristems, while another transcription factor gene, GRASSY TILLERS1 (GT1), suppresses the outgrowth of immature inflorescences (Ritter et al., 2002; Gallavotti et al., 2004; Whipple et al., 2011). A different expression profile of GT1 in the nodal plexus probably caused a distinct ear branching pattern between maize and teosinte (Wills et al., 2013). Our results prompt the speculation that the G protein network regulates axillary meristem initiation/transition of axillary buds to reproductive development and/or outgrowth of immature ear shoots (Fig. 4), so may control these transcription factors. Although the signalling mechanism regulating these and other genetic components remains poorly understood, it is empirically known that ear outgrowth requires ample energy resources—water, light, and nutrients (Lejeune and Bernier, 1996; Moulia et al., 1999; Markham and Stoltenberg, 2010). Multiple hormones—auxin, cytokinin, and strigolactones—also regulate the dormancy of axillary buds (Pautler et al., 2013). Maize and other plant G-protein networks couple those extracellular stimuli and modulate meristem activity, cell proliferation, and cellular senescence (Bommert et al., 2013; Urano et al., 2013; Sun et al., 2014), therefore G protein signalling may bridge these extracellular signals to ear development and outgrowth. The phenotypes described here, including root system and ear shoot architecture,are obvious plastic traits in plant development that have been selected during crop domestication and our results suggest that G protein signalling networks modulate the expression of these key agronomic traits. It will also be interesting to ask how natural variation in G protein signalling components has contributed to crop improvement.

Bottom Line: The ct2 mutant partially compensated for a reduced shoot height by increased total leaf number, and had far more ears, even in the presence of pollination signals.The maize heterotrimeric G protein complex is important in some plastic developmental traits in maize.In particular, the maize Gα subunit is required to dampen the overproduction of female inflorescences.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology, The University of North Carolina, Chapel Hill, Coker Hall, NC 27599-3280, USA.

No MeSH data available.