Phytochrome mediates germination responses to multiple seasonal cues

Donohue, Kathleen; Heschel, M. Shane; Chiang, George C. K.; Butler, C.; Barua, Deepak

doi:10.1111/j.1365-3040.2006.01619.x

Cited by 62 publications

(51 citation statements)

References 71 publications

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“…Thermoinhibition of lettuce seed germination is both temperature-and light-dependent Temperature and light are important factors for seed germination that largely determine the expression of dormancy and the seasonality of germination and emergence in the field (Allen et al 2007;Donohue et al 2007). The germination of 'JX1' lettuce seeds was inhibited by temperatures at C17°C in darkness and at C23°C in light, the optimal temperature for 'JX1' lettuce seed germination was much higher in light than in darkness (Table 1).…”

Section: Discussionmentioning

confidence: 99%

Nitrate, abscisic acid and gibberellin interactions on the thermoinhibition of lettuce seed germination

et al. 2011

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Germination of lettuce seeds has obvious thermoinhibition, but the mechanism for thermoinhibition of seed germination is poorly understood. Here, we investigated the interactions of nitrate, abscisic acid (ABA) and gibberellin on seed germination at high temperatures to understand further the mechanism for thermoinhibition of seed germination. Our results showed that lettuce (Lactuca sativa L. 'Jianye Xianfeng No. 1') seeds exhibited notable thermoinhibiton of germination at C17°C in darkness, and at C23°C in light, but the thermoinhibited seeds did not exhibit secondary dormancy. Thermoinhibition of seed germination at 23 or 25°C in light was notably decreased by 5 and 10 mM nitrate, and the stimulatory effects were markedly prevented by nitric oxide (NO) scavenger 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide. The sensitivity of seed germination to exogenous ABA increased with increasing temperature. Thermoinhibition of seed germination was markedly decreased by fluridone (an inhibitor of ABA biosynthesis) and GA 3 , and was increased by diniconazole (an inhibitor of the ABA-catabolizing enzyme ABA 8 0 -hydroxylase) and paclobutrazol (an inhibitor of GA biosynthetic pathway). The effect of fluridone in decreasing thermoinhibition of seed germination was obviously antagonized by paclobutrazol, and that of GA 3 was notably added to by fluridone, and that of nitrate was antagonized by paclobutrazol, diniconazole and ABA and was added to by GA 3 and fluridone. Our data show that thermoinhibition of lettuce seed germination is decreased by nitrate in a NO-dependent manner, which is antagonized by ABA, diniconazole and paclobutrazol and added by fluridone.

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Section: Discussionmentioning

confidence: 99%

Nitrate, abscisic acid and gibberellin interactions on the thermoinhibition of lettuce seed germination

et al. 2011

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“…Sensitivity of Lettuce Seed Germination to Light, Temperature, GA, and ABA Light and temperature are critical regulators of seed germination that largely determine the expression of dormancy and the seasonality of germination and emergence in the field (Allen et al, 2007;Donohue et al, 2007). There is considerable evidence that light and temperature interact through the phytochromes in regulating germination and that a major effect of Pfr is to promote GA biosynthesis (Toyomasu et al, 1998).…”

Section: Discussionmentioning

confidence: 99%

Genetic Variation for Lettuce Seed Thermoinhibition Is Associated with Temperature-Sensitive Expression of Abscisic Acid, Gibberellin, and Ethylene Biosynthesis, Metabolism, and Response Genes

et al. 2008

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Lettuce (Lactuca sativa ‘Salinas’) seeds fail to germinate when imbibed at temperatures above 25°C to 30°C (termed thermoinhibition). However, seeds of an accession of Lactuca serriola (UC96US23) do not exhibit thermoinhibition up to 37°C in the light. Comparative genetics, physiology, and gene expression were analyzed in these genotypes to determine the mechanisms governing the regulation of seed germination by temperature. Germination of the two genotypes was differentially sensitive to abscisic acid (ABA) and gibberellin (GA) at elevated temperatures. Quantitative trait loci associated with these phenotypes colocated with a major quantitative trait locus (Htg6.1) from UC96US23 conferring germination thermotolerance. ABA contents were elevated in Salinas seeds that exhibited thermoinhibition, consistent with the ability of fluridone (an ABA biosynthesis inhibitor) to improve germination at high temperatures. Expression of many genes involved in ABA, GA, and ethylene biosynthesis, metabolism, and response was differentially affected by high temperature and light in the two genotypes. In general, ABA-related genes were more highly expressed when germination was inhibited, and GA- and ethylene-related genes were more highly expressed when germination was permitted. In particular, LsNCED4, a gene encoding an enzyme in the ABA biosynthetic pathway, was up-regulated by high temperature only in Salinas seeds and also colocated with Htg6.1. The temperature sensitivity of expression of LsNCED4 may determine the upper temperature limit for lettuce seed germination and may indirectly influence other regulatory pathways via interconnected effects of increased ABA biosynthesis.

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“…It would be interesting to test whether the balance of DAG1 repression and DAG2 promotion of germination changes as a function of environmental factors known to be associated with maternal environmental effects on germinationespecially phytochrome-mediated maternal effects such as those mentioned above (e.g. Donohue et al 2007Donohue et al , 2008.…”

Section: Maternal Effects and The Genetic Basis Of Germination (A) Mamentioning

confidence: 99%

Completing the cycle: maternal effects as the missing link in plant life histories

Donohue

2009

Phil. Trans. R. Soc. B

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374

417

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Maternal effects on seed traits such as germination are important components of the life histories of plants because they represent the pathway from adult to offspring: the pathway that completes the life cycle. Maternal environmental effects on germination influence basic life-history expression, natural selection on germination, the expression of genetic variation for germination and even the genes involved in germination. Maternal effects on seed traits can even influence generation time and projected population growth rates. Whether these maternal environmental effects are imposed by the maternal genotype, the endosperm genotype or the embryonic genotype, however, is as yet unknown. Patterns of gene expression and protein synthesis in seeds indicate that the maternal genotype has the opportunity to influence its progeny's germination behaviour. Investigation of the phenotypic consequences of maternal environmental effects, regardless of its genetic determination, is relevant for understanding the variation in plant life cycles. Distinguishing the genotype(s) that control them is relevant for predicting the evolutionary trajectories and patterns of selection on progeny phenotypes and the genes underlying them.

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Phytochrome mediates germination responses to multiple seasonal cues

Cited by 62 publications

References 71 publications

Nitrate, abscisic acid and gibberellin interactions on the thermoinhibition of lettuce seed germination

Nitrate, abscisic acid and gibberellin interactions on the thermoinhibition of lettuce seed germination

Genetic Variation for Lettuce Seed Thermoinhibition Is Associated with Temperature-Sensitive Expression of Abscisic Acid, Gibberellin, and Ethylene Biosynthesis, Metabolism, and Response Genes

Completing the cycle: maternal effects as the missing link in plant life histories

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