sparse inflorescence1, barren
 inflorescence1 and barren stalk1 Promote Cell Elongation in Maize Inflorescence Development

Barazesh, Solmaz; Nowbakht, Cima; McSteen, Paula

doi:10.1534/genetics.108.099390

Cited by 13 publications

(11 citation statements)

References 17 publications

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“…Transgenic approaches to increase maize yields are also targeting the enhancement of INV activity and/or starch biosynthesis in florets (Tomes et al, 2011). These centrally important aspects of expansion are also mediated by auxin, which is critical to the earliest stages of sink strength development in flowers (Barazesh et al, 2009; Phillips et al, 2011; Reeves et al, 2012). …”

Section: Molecular Basis For Strong Sink Strength In Other Fruits Sementioning

confidence: 99%

Regulation of assimilate import into sink organs: update on molecular drivers of sink strength

et al. 2013

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Recent developments have altered our view of molecular mechanisms that determine sink strength, defined here as the capacity of non-photosynthetic structures to compete for import of photoassimilates. We review new findings from diverse systems, including stems, seeds, flowers, and fruits. An important advance has been the identification of new transporters and facilitators with major roles in the accumulation and equilibration of sugars at a cellular level. Exactly where each exerts its effect varies among systems. Sugarcane and sweet sorghum stems, for example, both accumulate high levels of sucrose, but may do so via different paths. The distinction is central to strategies for targeted manipulation of sink strength using transporter genes, and shows the importance of system-specific analyses. Another major advance has been the identification of deep hypoxia as a feature of normal grain development. This means that molecular drivers of sink strength in endosperm operate in very low oxygen levels, and under metabolic conditions quite different than previously assumed. Successful enhancement of sink strength has nonetheless been achieved in grains by up-regulating genes for starch biosynthesis. Additionally, our understanding of sink strength is enhanced by awareness of the dual roles played by invertases (INVs), not only in sucrose metabolism, but also in production of the hexose sugar signals that regulate cell cycle and cell division programs. These contributions of INV to cell expansion and division prove to be vital for establishment of young sinks ranging from flowers to fruit. Since INV genes are themselves sugar-responsive “feast genes,” they can mediate a feed-forward enhancement of sink strength when assimilates are abundant. Greater overall productivity and yield have thus been attained in key instances, indicating that even broader enhancements may be achievable as we discover the detailed molecular mechanisms that drive sink strength in diverse systems.

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Section: Molecular Basis For Strong Sink Strength In Other Fruits Sementioning

confidence: 99%

Regulation of assimilate import into sink organs: update on molecular drivers of sink strength

et al. 2013

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“…Reduction in tassel length in other barren inflorescence mutants has been shown to be caused by reduced cell size (Barazesh et al, 2009). To test whether the reduction in tassel length in vt2 was caused by a reduction in cell size, the length of cells in the epidermis of the mature tassel was measured.…”

Section: Vt2 Functions In Inflorescence Developmentmentioning

confidence: 99%

“…Both mutants have defects in axillary meristem formation during reproductive development, shorter inflorescences due to defects in cell elongation, and shorter plant height due to defects in leaf initiation during vegetative development (Gallavotti et al, 2008b;Barazesh et al, 2009). The vt2 mutant, however, has more severe defects than does spi1, although both are presumed to be null alleles.…”

Section: Auxin Biosynthesis Pathways In Maize and Arabidopsismentioning

confidence: 99%

“…For measurement of cell size, nail polish impressions were obtained from the basal region of five wild-type and vt2 field-grown tassels at maturity as previously described (Barazesh et al, 2009). Slides were analyzed at 320 magnification using a Nikon Eclipse 80i upright microscope on the brightfield setting and a Nikon DM1200F camera.…”

Section: Measurement Of Cell Sizementioning

confidence: 99%

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vanishing tassel2Encodes a Grass-Specific Tryptophan Aminotransferase Required for Vegetative and Reproductive Development in Maize

et al. 2011

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Auxin plays a fundamental role in organogenesis in plants. Multiple pathways for auxin biosynthesis have been proposed, but none of the predicted pathways are completely understood. Here, we report the positional cloning and characterization of the vanishing tassel2 (vt2) gene of maize (Zea mays). Phylogenetic analyses indicate that vt2 is a co-ortholog of TRYPTOPHAN AMINOTRANSFERASE OF ARABIDOPSIS1 (TAA1), which converts Trp to indole-3-pyruvic acid in one of four hypothesized Trp-dependent auxin biosynthesis pathways. Unlike single mutations in TAA1, which cause subtle morphological phenotypes in Arabidopsis thaliana, vt2 mutants have dramatic effects on vegetative and reproductive development. vt2 mutants share many similarities with sparse inflorescence1 (spi1) mutants in maize. spi1 is proposed to encode an enzyme in the tryptamine pathway for Trp-dependent auxin biosynthesis, although this biochemical activity has recently been questioned. Surprisingly, spi1 vt2 double mutants had only a slightly more severe phenotype than vt2 single mutants. Furthermore, both spi1 and vt2 single mutants exhibited a reduction in free auxin levels, but the spi1 vt2 double mutants did not have a further reduction compared with vt2 single mutants. Therefore, both spi1 and vt2 function in auxin biosynthesis in maize, possibly in the same pathway rather than independently as previously proposed.

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“…rum1 encodes ZmIAA10 and, unlike other described AUX/IAA mutants that have a missense mutation in the degron, rum1 carries a deletion that includes the GWPPV degron sequence in domain II (von Behrens et al, 2011). The Bif1 (ZmIAA27) and Bif4 (ZmIAA20) Aux/IAA mutants reduce the branching in male and female inflorescences (Barazesh et al, 2009; Galli et al, 2015), however, there is no effect on vegetative growth (Galli et al, 2015). Oja mutants have striking defects in leaf development but have normal roots and flowers if they make inflorescences.…”

Section: Discussionmentioning

confidence: 99%

The Hoja loca1 Mutant and AUX/IAA Function in Phytomer Development

Richardson

Sluis

Hake

2020

Preprint

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Auxin plays a vital role in plant organ development, influencing organ initiation and patterning across all axes. The diversity in auxin patterning results from changes in the activities and expression of auxin signaling components, including the AUX/IAA repressors. Higher land plants have multigene AUX/IAA families, which leads to functional redundancy and a lack of phenotype in loss of function mutants. Instead, dominant mutations, which prevent AUX/IAA degradation in response to auxin, have highlighted the importance of these proteins in organ development. Here we report a new dominant AUX/IAA mutant in maize, Hoja loca1 (Oja). Oja has a mutation in the degron motif of ZmIAA28 and affects aerial organ initiation and medio-lateral patterning in the leaf. These phenotypes contrast with other maize AUX/IAA mutants that affect the root or inflorescence only. Oja illustrates the role of auxin signaling in the tight coordination of phytomer unit development and provides evidence of species-specific sub-functionalization of the AUX/IAAs.One Line SummaryThe maize AUX/IAA ZmIAA38 is involved in phytomer coordination, aerial organ initiation and mediolateral patterning, and illustrates species specific sub-functionalization of the AUX/IAAs.

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sparse inflorescence1, barren inflorescence1 and barren stalk1 Promote Cell Elongation in Maize Inflorescence Development

Cited by 13 publications

References 17 publications

Regulation of assimilate import into sink organs: update on molecular drivers of sink strength

Regulation of assimilate import into sink organs: update on molecular drivers of sink strength

vanishing tassel2Encodes a Grass-Specific Tryptophan Aminotransferase Required for Vegetative and Reproductive Development in Maize

The Hoja loca1 Mutant and AUX/IAA Function in Phytomer Development

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