Alterations in sugar metabolism coincide with a transition of wheat seedlings to dehydration intolerance

Bogdan, Janusz; Zagdańska, Barbara

doi:10.1016/j.envexpbot.2009.02.013

Cited by 9 publications

(5 citation statements)

References 47 publications

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“…The objects of our studies were wheat seedlings at early stage of growth because they may be considered as carbon heterotrophs. Their development depends exclusively on seed reserves (Bogdan and Zagdańska 2009 ) and neither light nor the exogenously supplied sugars had statistically significant effects on accumulation of dry matter (Miazek et al 2001 ; Bogdan and Zagdańska 2006 ) since photosynthesis genes are expressed in the later phase of growth (Jang and Sheen 1994 ; Loza-Tavera et al 1990 ).…”

Section: Introductionmentioning

confidence: 99%

Differential regulation of alanine aminotransferase homologues by abiotic stresses in wheat (Triticum aestivum L.) seedlings

2012

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Wheat (Triticum aestivum L.) seedlings contain four alanine aminotransferase (AlaAT) homologues. Two of them encode AlaAT enzymes, whereas two homologues act as glumate:glyoxylate aminotransferase (GGAT). To address the function of the distinct AlaAT homologues a comparative examination of the changes in transcript level together with the enzyme activity and alanine and glutamate content in wheat seedlings subjected to low oxygen availability, nitrogen and light deficiency has been studied. Shoots of wheat seedlings were more tolerant to hypoxia than the roots as judging on the basis of enzyme activity and transcript level. Hypoxia induced AlaAT1 earlier in roots than in shoots, while AlaAT2 and GGAT were unaffected. The increase in AlaAT activity lagged behind the increase in alanine content. Nitrogen deficiency has little effect on the activity of GGAT. In contrast, lower activity of AlaAT and the level of mRNA for AlaAT1 and AlaAT2 in wheat seedlings growing on a nitrogen-free medium seems to indicate that AlaAT is regulated by the availability of nitrogen. Both AlaAT and GGAT activities were present in etiolated wheat seedlings but their activity was half of that observed in light-grown seedlings. Exposure of etiolated seedlings to light caused an increase in enzyme activities and up-regulated GGAT1. It is proposed that hypoxia-induced AlaAT1 and light-induced peroxisomal GGAT1 appears to be crucial for the regulation of energy availability in plants grown under unfavourable environmental conditions.Key message In young wheat seedlings, both AlaAT and GGAT are down-regulated by nitrogen deficiency, whereas AlaAT1 is upregulated by hypoxia and GGAT1 by light.

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Section: Introductionmentioning

confidence: 99%

Differential regulation of alanine aminotransferase homologues by abiotic stresses in wheat (Triticum aestivum L.) seedlings

2012

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“…The observed decline in the content of protein -SH groups because of the formation of disulfides plays a role in metabolic regulation (Møller et al 2011). Higher carbonylation, controlling protein quality and metabolism (Nyström 2005), results in the development of dehydration intolerance during the transition of wheat seedlings from heterotrophic to autotrophic growth (Bogdan and Zagdańska 2009;Lounifi et al 2013). …”

Section: Discussionmentioning

confidence: 99%

“…One of the main reason of seedlings transition from tolerance to dehydration to sensitivity is supposed to be change of the hexose/sucrose ratio i.e. ''cellular energy state'' in the developing seedlings of monocots and legumes (Koch 2004;Bogdan and Zagdańska 2009). Thus, questions have been raised whether the switch from dehydration tolerance to intolerance during the early growth of wheat seedlings may be linked to changes in the cellular redox state or to the more specific metabolic processes.…”

Section: Introductionmentioning

confidence: 99%

Changes in the reduction state of ascorbate and glutathione, protein oxidation and hydrolysis leading to the development of dehydration intolerance in Triticum aestivum L. seedlings

2015

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The present work demonstrates that the transition of wheat (Triticum aestivum L.) seedlings from dehydration tolerance to intolerance on the fifth day following imbibition is associated with a disturbance in cellular redox homeostasis. During germination the ratio of reduced (AsA) to oxidized ascorbate (DHA) was lower in the tolerant 4-day-old seedlings compared to the sensitive 6-day-old seedlings because of the lower ascorbate content in the former. The reduced glutathione (GSH) and total glutathione (GSH ? GSSG) pools were higher in tolerant seedlings and remained higher upon dehydration. The development of dehydration intolerance with a seedling age coincided with a 50 % loss of the total glutathione pool and a shift of GSH/GSSG to a more oxidized state. Activities of ascorbate peroxidase and glutathione reductase increased with water deficiency in both tolerant and sensitive seedlings but the three new activity bands appeared only in sensitive seedlings. The stable ratio of GSH/GSSG and a higher AsA/DHA ratio in sensitive seedlings did not prevent the enhanced production of H2O2 and the peroxidation of lipids with dehydration. As a result, an increase in the protein carbonyl group and a significant decrease in the thiol groups were observed in dehydrated sensitive seedlings. Water deficiency enhanced the total azocaseinolytic activity, mainly in sensitive seedlings. The highest increase in protein carbonylation and lowest azocaseinolytic activity was observed at the beginning of seedling dehydration (15-25 % WSD) being in a sensitive phase of growth. The presented results indicate that the development of dehydration intolerance during the transition of wheat seedlings from heterotrophic to autotrophic growth is associated with an alterations in protein oxidation.

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“…(2010) proposed that the accumulation of hexoses may partly be the result of the downregulation of enzymes involved in glycolysis, the central process of monosaccharide degradation for generating energy. Indeed, Bogdan and Zagdánska (2009) ascertained a reduction in hexokinase and fructokinase activity at the entry point of hexose sugars into glycolysis during water stress in wheat seedlings. According to Chaves and Oliveira (2004), further reasons for increased levels of hexoses in source tissues could be the inhibition of growth and export or the depression of starch synthesis.…”

Section: Discussionmentioning

confidence: 99%

Carbohydrate Dynamics in Leaves of Rapeseed (Brassica napus) Under Drought

Müller

Lentzsch

Müller

2012

J Agronomy Crop Science

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Until now, the carbohydrate dynamics in leaves of rapeseed under drought have largely been unknown. For this reason, a growth chamber study was conducted to examine whether the accumulation of carbohydrates under drought stress contributes to osmotic adjustment in leaf tissue. Plants of the cultivar Titan were subjected to temporary drought in the vegetative and reproductive stages. A third variant of long-term drought covered the period from leaf development to flowering. The level of sucrose decreased under moderate water deficit, but accumulated under severe long-term drought. Concentrations of glucose, fructose and trehalose were significantly enhanced and that of raffinose decreased in all the variants of drought. There was no evidence that any of the carbohydrates analysed in this study or the activities of soluble acid and cell wall invertases contributed to a drought-induced accumulation of osmolytes. The results of this study indicate that osmotic adjustment in response to drought in leaves of the rapeseed cultivar Titan is only limited. It is virtually impossible that carbohydrates function as osmoprotectants in leaves of this cultivar, rising above that of the frequently detected accumulation of proline in rapeseed under water deficit.

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Alterations in sugar metabolism coincide with a transition of wheat seedlings to dehydration intolerance

Cited by 9 publications

References 47 publications

Differential regulation of alanine aminotransferase homologues by abiotic stresses in wheat (Triticum aestivum L.) seedlings

Differential regulation of alanine aminotransferase homologues by abiotic stresses in wheat (Triticum aestivum L.) seedlings

Changes in the reduction state of ascorbate and glutathione, protein oxidation and hydrolysis leading to the development of dehydration intolerance in Triticum aestivum L. seedlings

Carbohydrate Dynamics in Leaves of Rapeseed (Brassica napus) Under Drought

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