The Effects of Dwarfing Genes Rht1 and Rht2 on Cellular Dimensions and Rate of Leaf Elongation in Wheat*

Keyes, G. J.; Paolillo, Dominick J.; Sorrells, Mark E.

doi:10.1093/oxfordjournals.aob.a087894

Cited by 109 publications

(69 citation statements)

References 15 publications

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“…Cell depth was not affected by Rht gene dose while cell width was increased in dwarf types but not sufflciently to compensate for decreased length in determining projected surface area (14). Maximal leaf growth rates of tall types was sustained over a longer duration than corresponding double dwarftypes; however, the total duration of leaf elongation was constant across all levels of Rht gene dose (14). While there is known to be a developmental gradient in the region of elongation, variation for extensibility in that zone is uncharacterized and the Rht genes would be expected to affect extensibility uniformly over the region.…”

Section: Correlation Of Wall Plasticity With Sheath Expansionmentioning

confidence: 90%

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Gibberellic Acid Regulates Cell Wall Extensibility in Wheat (Triticum aestivum L.)

Keyes¹,

Sorrells²,

Setter³

1990

Plant Physiol.

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Mutations (Rht genes) blocking sensitivity to gibberellic acid (GA) were used to examine phytohormone mediated cell wall expansion in wheat (Triticum aestivum L.). Irreversible extensibility of immature leaf segments, as determined by stress/strain (instron) measurements, declined with Rht gene dose. Exogenous GA3 significantly increased wall extensibility in the nonmutant controls but had no effect on the near-isogenic GA-insensitive genotypes. Furthermore, ancymidol, an inhibitor of gibberellin biosynthesis, diminished wall extensibility in the nonmutant control. Extensibility of immature segments was highly correlated with mature leaf sheath length (R = +0.95). The results indicate that wall yielding properties of expanding wheat leaves are associated with leaf cell expansion potential and that GA is involved in the determination of those properties.The plane of cell division together with the rate and orientation of irreversible expansion determine cell size and shape. The rate of plant cell expansion may be further reduced to a few physical components including: (a) cell wall extensibility, which is the capacity of the wall to undergo irreversible (plastic) extension in response to a load; (b) the yield threshold of the wall, which is the minimum stress required to initiate extension; (c) hydraulic conductance, the capacity ofthe tissue to transport water to the expanding cell; and (d) the difference in water potential between the cell and extracellular space (16). Lockhart's (16) equations show that a change in the growth rate can take place with changes in wall structural/ mechanical properties which determine extensibility and/or changes in hydraulic processes and/or turgor changes.Heyn (9)

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Section: Correlation Of Wall Plasticity With Sheath Expansionmentioning

confidence: 90%

“…Rht genes have been reported to reduce organ length by reducing cell length, cell number, or both (8,14). Cell depth was not affected by Rht gene dose while cell width was increased in dwarf types but not sufflciently to compensate for decreased length in determining projected surface area (14).…”

Section: Correlation Of Wall Plasticity With Sheath Expansionmentioning

confidence: 97%

Gibberellic Acid Regulates Cell Wall Extensibility in Wheat (Triticum aestivum L.)

Keyes¹,

Sorrells²,

Setter³

1990

Plant Physiol.

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“…Reduced leaf and peduncle lengths of semidwarf cultivars carrying the gibberellic acid-insensitive mutant Rht dwarfing genes are due to a reduction in cell length (Keyes et al 1989;Hoogendoorn et al 1990). However, epidermal cell lengths in lines carrying even the strong dwarfing gene Rht3, relative to the wild type rht3, were similar in size when grown at LT (10°C) (Tonkinson et al 1997).…”

Section: Cell Sizementioning

confidence: 99%

Morphological and cytological characters associated with low-temperature tolerance in wheat (Triticum aestivum L. em Thell.)

Limin¹,

Fowler²

2000

Can. J. Plant Sci.

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. 2000. Morphological and cytological characters associated with low-temperature tolerance in wheat (Triticum aestivum L. em Thell.) Can. J. Plant Sci. 80: 687-692. Attempts to associate morphological or cytological characters with low-temperature (LT) tolerance in wheat (Triticum aestivum L. em. Thell.) and other members of the Triticeae group have met with ambiguous or contradictory results. Consequently no single character has emerged that can be considered a reliable predictor of LT tolerance. Twenty-six winter wheat cultivars of diverse origin were analyzed to determine the association among leaf length, width, area and cell size (guard cell length) and their association with LT stress tolerance. Measurements were made on plants grown at 4°C and at 17°C to determine if expression of LT tolerance associated characters was temperature dependent. At 4°C, all individual leaf characters measured, including cell size, were very highly correlated with LT tolerance and with each other. Undisturbed plant height was not significantly correlated with LT tolerance until 5 wk of growth at 4°C and reached its highest correlation at 10 wk when the plants were on average at their most prostrate state of growth. Growth at 17°C resulted in much weaker relationships among all characters. At 4°C short narrow leaves and small cell size were the best indicators of LT stress tolerance. Prostrate growth habit of plants grown at LT was also a good indicator of plant LT tolerance, but measurements of this character did not improve prediction equations based on leaf characters and cell size. Aucun caractère particulier ne peut donc être considéré comme un prédicteur fiable de la tolérance aux basses températures. Nous avons analysé 26 cultivars de blé d'hiver de provenances diverses pour établir le degré d'association entre longueur largeur et surface foliaire et la taille des cellules (longueur des cellules gardiennes) et le rapport de ces caractères avec la tolérance aux basses températures. Les mesures étaient prises sur les plantes cultivées à 4 et à 17°C afin de déterminer si l'expression des caractères liés à la tolérance était fonction de la température. À 4°C. tous les caractères foliaires mesurés, y compris les dimensions des cellules gardiennes, étaient très étroitement reliés avec la tolérance aux b.t. ainsi qu'entre eux. La hauteur des plantes (non perturbées) ne marquait une corrélation significative avec la tolérance qu'après 5 semaines de croissance à 4°C, pour atteindre sa plus forte corrélation à la dixième semaine lorsque la moyenne des plantes avaient un port prostre. La croissance sous régime de 17°C donnait lieu à des corrélations beaucoup plus faibles entre tous les caractères. À 4°C, des feuilles étroites et courtes et des cellules de petites dimensions étaient les meilleurs indicateurs de tolérance aux b.t. Le port prostré des plantes cultivées en régime de basses températures était également un bon indicateur, bien que l'inclusion des mesures de ce caractère n'améliorait pas les équations de pré-diction repos...

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“…Previous research leads us to the conclusion that Rht genes could reduce epidermal cell length without affecting cell width and division (Keyes et al, 1989;Hoogendoorn et al, 1990;Miralles et al, 1998;Botwright et al, 2005). The small cell sizes associated with Rht genes produce concomitant reductions in the length of internodes and coleoptiles, and leaf area of wheat seedlings (Allan, 1989;Botwright et al, 2001).…”

Section: Discussionmentioning

confidence: 99%

A new reduced height gene found in the tetraploid semi-dwarf wheat landrace Aiganfanmai

Peng¹,

Li²,

Yang³

et al. 2011

Genet. Mol. Res.

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ABSTRACT. Aiganfanmai is a dwarf tetraploid wheat landrace (Triticum turgidum var. turgidum) that stably produces the semi-dwarf trait. Plant height varies from 80-105 cm under cultivation. Compared with tall durum wheat (T. turgidum var. durum) variety Langdon, we found it to have short spikes and seeds, besides a semi-dwarf character. We crossed Aiganfanmai with Langdon to analyze the genetic basis of the semi-dwarf trait. The F 2 population segregated at a 1:3 ratio for the short trait to the normal, which demonstrates that Aiganfanmai carries a recessive reduced height (Rht) gene. This gene was found to be located between the molecular markers Xgwm471 and Xgwm350 on chromosome arm 7AS by microsatellite analysis. No Rht gene had been reported from this chromosome; we designated it as Rht22. Rht 22, unlike other previously reported Rht genes, does not reduce internodal cell length. Reduced cell numbers might explain the short stem trait.

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The Effects of Dwarfing Genes Rht1 and Rht2 on Cellular Dimensions and Rate of Leaf Elongation in Wheat*

Cited by 109 publications

References 15 publications

Gibberellic Acid Regulates Cell Wall Extensibility in Wheat (Triticum aestivum L.)

Gibberellic Acid Regulates Cell Wall Extensibility in Wheat (Triticum aestivum L.)

Morphological and cytological characters associated with low-temperature tolerance in wheat (Triticum aestivum L. em Thell.)

A new reduced height gene found in the tetraploid semi-dwarf wheat landrace Aiganfanmai

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