Endo-β-Mannanase Activity Present in Cell Wall Extracts of Lettuce Endosperm prior to Radicle Emergence

Dutta, Sunil; Bradford, Kent J.; Nevins, Donald J.

doi:10.1104/pp.113.1.155

Cited by 38 publications

(27 citation statements)

References 16 publications

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“…These authors found that, even though there was an increase in β-mannanase activity in the seeds before the projection of the rootlet, the reduction in water potential either delayed or prevented the emergence of the rootlet. Dutta et al (1997) reported that this enzyme is expressed before germination, and it is regulated by the same conditions that control germination. Consequently, enzyme activity decreases with increases in seed germination rates.…”

Section: Discussionmentioning

confidence: 99%

Physiological quality and gene expression during the development of habanero pepper (Capsicum chinense Jacquin) seeds

Santos

Pinho

et al. 2015

Genet. Mol. Res.

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Section: Discussionmentioning

confidence: 99%

Physiological quality and gene expression during the development of habanero pepper (Capsicum chinense Jacquin) seeds

Santos

Pinho

et al. 2015

Genet. Mol. Res.

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“…Endo-β-mannanase was involved in weakening of the lettuce endosperm cell walls at high temperatures (Dutta et al, 1997). Therefore, endo-β-mannanase activity was assayed during seed germination at 35°C (Table 4).…”

Section: Resultsmentioning

confidence: 99%

“…They did not isolate or identify the enzyme. Dutta et al (1997) reported that a cell-wall-bound endo-β-mannanase was expressed in lettuce seed endosperm prior to radicle protrusion and was regulated by the same conditions that govern seed germination. These authors suggested that endo-β-mannanase was involved in weakening of the lettuce endosperm cell walls.…”

Section: Introductionmentioning

confidence: 99%

Ethylene evolution and endo-beta-mannanase activity during lettuce seed germination at high temperature

Nascimento

Cantliffe

Huber

2004

Sci. agric. (Piracicaba, Braz.)

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High temperatures during lettuce seed imbibition can delay or completely inhibit germination and the endosperm layer appears to restrict the radicle protrusion. The role of endo-β-mannanase during lettuce seed germination at 35°C and the influence of ethylene in endo-β-mannanase regulation were investigated. Seeds of 'Dark Green Boston' (DGB) and 'Everglades' (EVE) were germinated in water, or 10 mmol L -1 of 1-aminocyclopropane-1-carboxylic acid (ACC), or 10 mmol L -1 of aminoethoxyvinylglycine (AVG), or 20 mmol L -1 of silver thiosulphate (STS). Seeds were also primed in polyethylene glycol (PEG), or PEG + ACC, PEG + AVG, or PEG + STS. Untreated seeds germinated 100% at 20°C. At 35°C, EVE seeds germinated 100%, whereas DGB seeds germinated only 33%. Seed priming or adding ACC during incubation increased germination at 35°C. Higher ethylene evolution was detected in EVE than in DGB during germination at 35°C. AVG did not inhibit seed germination of DGB at 35°C, but STS did. Higher endo-β-mannanase activity was observed in EVE compared with DGB seeds. Providing ACC either during priming or during germination increased endo-β-mannanase activity, whereas AVG and STS led to decreased or no activity. Ethylene may overcome the inhibitory effect of high temperature in thermosensitive lettuce seeds due to increased endo-β-mannanase, possibly leading to weakening of the endosperm. Key words: Lactuca sativa, thermoinhibition, thermodormancy, endosperm weakening, seed priming EVOLUÇÃO DE ETILENO E ATIVIDADE DA ENZIMA ENDO-β-MANANASE DURANTE A GERMINAÇÃO DE SEMENTES DE ALFACE SOB ALTAS TEMPERATURASRESUMO: Altas temperaturas durante a embebição das sementes de alface podem atrasar ou inibir a germinação e o endosperma parece ser o responsável na restrição da protrusão da radícula. O envolvimento da enzima endo-β-mananase durante a germinação de sementes de alface a 35°C e a influência do etileno na regulagem desta enzima foram estudados. Sementes das cultivares Dark Green Boston (DGB) e Everglades (EVE) foram germinadas em água ou em soluções de 10 mmol L -1 de 1-aminociclopropano-1-ácido carboxilico (ACC), 10 mmol L -1 de amino-etoxi-vinil-glicina (AVG), ou 20 mmol L -1 de tiossulfato de prata (STS). Sementes foram ainda osmoticamente condicionadas em soluções de polietilenoglicol (PEG), ou PEG + ACC, PEG + AVG, ou PEG + STS. Sementes não tratadas germinaram 100% a 20°C. A 35°C, EVE germinou 100%, enquanto DGB germinou somente 33%. A germinação a 35°C aumentou em sementes osmoticamente condicionadas ou sementes que receberam ACC durante a incubação. Maior evolução de etileno foi detectada em EVE do que em DGB durante a germinação a 35°C. AVG não inibiu a germinação de DGB a 35°C, enquanto que STS inibiu. Maior atividade de endo-β-mananase nas sementes foi observada em EVE quando comparado com DGB. Fornecimento de ACC tanto durante o condicionamento osmótico como durante a germinação, aumentou a atividade de endo-β-mananase, enquanto que AVG e STS proporcionaram um decréscimo ou ausência da atividade enzimática. O...

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“…The latter experiment included only a single time point at 72 h of imbibition; therefore, it is possible that by that time mannanase activity had already declined below the sensitivity of the assay used. On the other hand, ABA inhibits development of mannanase synthesis or activity in lettuce (Dulson et al, 1988;Dutta et al, 1996) and fenugreek (Trigonella foenum-graecum L.; Malek and Bewley, 1991) endosperm. Groot and Karssen (1992) showed that ABA inhibits mechanical weakening of the tomato endosperm cap, but we found no inhibition of mannanase activity at a time when seeds that were allowed to imbibe in water would have completed radicle emergence.…”

Section: T5 Seeds Cerminating At Reduced +mentioning

confidence: 99%

Endo-β-Mannanase Activity from Individual Tomato Endosperm Caps and Radicle Tips in Relation to Germination Rates

Still

Bradford

1997

Plant Physiology

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~ ~ ~~Endo-P-mannanase is hypothesized to be a rate-limiting enzyme in endosperm weakening, which is a prerequisite for radicle emergente from tomato (Lycopersicon esculentum Mill.) seeds. Using a sensitive, single-seed assay, we have measured mannanase activity diffusing from excised tomato endosperm caps following treatments that alter the rate or percentage of radicle emergence. Most striking was the 100-to more than 10,000-fold range of mannanase activity detected among individual seeds of highly inbred tomato lines, which would not be detected in pooled samples. In some cases a threshold-type relationship between mannanase activity and radicle emergence was observed. However, when radicle emergence was delayed or prevented by osmoticum or abscisic acid, the initial increase in mannanase activity was unaffected or even enhanced. Partially dormant seed lots displayed a bimodal distribution of activity, with low activity apparently associated with dormant seeds in the population. Gibberellin-and abscisic acid-deficient mutant seeds exhibited a wide range of mannanase activity, consistent with their variation in hormonal sensitivity. Although the presence of mannanase activity in the endosperm cap is consistently associated with radicle emergence, it is not the sole or limiting factor under all conditions.Even though tomato (Lycopersicon esculentum Mill.) is self-pollinating and cultivars are highly homozygous genetically, germination behavior varies considerably among individual seeds. We have developed a population-based hydrotime model that accurately describes germination time courses in response to environmental and hormonal factors (Bradford, 1990(Bradford, , 1995(Bradford, , 1996 Bradford, 1990, 1994; Bradford, 1992, 1993). This model is based on the assumption that individual seeds vary in their sensitivity to these factors and particularly in the sensitivity of radicle emergence to +. If the +, , is higher (more positive) than the actual seed +, radicle emergence will not occur. The lower (more negative) the & for radicle emergente relative to the ambient +, the more rapid germination will be. The distribution of Ic., values within the seed population therefore determines both the rate and final percentage of germination. Environmental and hormonal fac- (Ni and Bradford, 1993;Dutta and Bradford, 1994;Bradford, 1995Bradford, , 1996.The population-based hydrotime model can quantify and describe seed germination patterns, but it does not identify the physiological or biochemical basis of +, , .

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Endo-β-Mannanase Activity Present in Cell Wall Extracts of Lettuce Endosperm prior to Radicle Emergence

Cited by 38 publications

References 16 publications

Physiological quality and gene expression during the development of habanero pepper (Capsicum chinense Jacquin) seeds

Physiological quality and gene expression during the development of habanero pepper (Capsicum chinense Jacquin) seeds

Ethylene evolution and endo-beta-mannanase activity during lettuce seed germination at high temperature

Endo-β-Mannanase Activity from Individual Tomato Endosperm Caps and Radicle Tips in Relation to Germination Rates

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