Phytochrome–induced Germination, Endosperm Softening and Embryo Growth Potential in Datura ferox Seeds: Sensitivity to Low Water Potential and Time to Escape to FR Reversal

Miguel, Lucila de; Sánchez, Rodolfo A.

doi:10.1093/jxb/43.7.969

Cited by 30 publications

(19 citation statements)

References 24 publications

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“…These remaining structures of the panicoid spikelet would act as filters of red light, maintaining a pool of cis‐isomers of the phytochrome molecule and, therefore, a greater proportion of non‐active phytochrome (Pr). It is known that the phytochrome acts positively on embryo development potential under moderate osmotic stress (between −0.5 and −0.3 MPa), potentiating improvement of early plant development of species such as Datura ferox L. (see Miguel & Sánchez), as also observed for our results on uncovered caryopses. On the other hand, recent studies have demonstrated a slight relationship between phytochrome and PIL5 expression (see Oh et al .…”

Section: Discussionsupporting

confidence: 86%

An integrative insight on dormancy alleviation in diaspores of Urochloa humidicola (Rendle) Morrone & Zuloaga, a tropical grass with great economic and ecological impact

et al. 2017

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Even though exhaustively studied, dormancy alleviation in diaspores of Urochloa humidicola (Rendle) Morrone & Zuloaga remains a mystery. To clarify this, we asked the following question: could dormancy alleviation in diaspores of this species be associated with ageing, GA/ABA balance and remaining structures of the panicoid spikelet? We answer this question using diaspores of U. humidicola cv. BRS Tupi as a biological model, a cultivar with a wide edaphoclimatic range in Neotropical areas and whose diaspores possess 'deep dormancy' when dispersed. We analysed both germination and early plant development using a split-plot model. Our findings demonstrate that dormancy alleviation in diaspores of U. humidicola is a synergic phenomenon driven by crosstalk between age, GA/ABA balance and remaining structures of the panicoid spikelet covering caryopses, since this interaction acts on the dynamics of germination and early plant development. We demonstrate that: (i) spreading germination time is a maternal survival mechanism of this species, which has repercussions for occupational aggressiveness of the species; (ii) remaining structures of the panicoid spikelet covering caryopses are the main modulator of embryo development. These structures control the after-ripening process, which is modulated by some molecular factor. We also highlight that it is necessary to review concepts about dormancy of dispersal units in this grass species.

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Section: Discussionsupporting

confidence: 86%

An integrative insight on dormancy alleviation in diaspores of Urochloa humidicola (Rendle) Morrone & Zuloaga, a tropical grass with great economic and ecological impact

et al. 2017

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“…1,2a). The EGP was measured after dark incubation for 24 h, as described in de Miguel and Sa´nchez (1992).…”

Section: Egp Measurementsmentioning

confidence: 99%

“…Endosperm hardness is related to the b1-4mannan content of the cell walls, and the softening mediated by phytochrome includes an increment in the activity of two enzymes involved in mannan degradation (endo-bmannanase and b-mannosidase) (Sa´nchez et al 1990;de Miguel and Sa´nchez 1992) as well as an increment in the transcripts of DfMan (endo-b-mannanase) and DfExpa1 (expansin) Mella et al 2004). In D. ferox, these light-induced changes in mannan-degrading activities and ME softening involve embryo-endosperm interactions, in which the embryo, in response to R, provides the GAs required for endosperm softening (Sa´nchez and de Miguel 1997;Mella et al 2000).…”

Section: Introductionmentioning

confidence: 99%

A phytochrome-dependent embryonic factor modulates gibberellin responses in the embryo and micropylar endosperm of Datura ferox seeds

Arana

Miguel

Sánchez

2005

Planta

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The promotion of germination by phytochrome is associated with extensive changes both in the embryo and in the micropylar region of the endosperm (ME) of Datura ferox seeds. These changes require de novo gibberellins (GAs) biosynthesis in the embryo, the site where the light stimulus is perceived. GAs stimulate embryo growth potential and move to ME, promoting the expression of genes related with weakening. We report here that, in addition, phytochrome stimulates the sensitivity of the seeds to gibberellic acid (GA). The phytochrome-induced signal is produced in the embryo and enhances the stimulus by GA of embryo growth potential (EGP) and the promotion of the expression of proteins thought to participate in ME weakening: endo-beta-mannanase (EC 3.2.1.78), endo-beta-mannosidase (EC 3.2.1.25) and expansin. Our results suggest that the cytokinins may be a component of the embryonic signal. Phytochrome also modulates DfPHOR and DfMYB transcript levels in ME. These genes show a high identity with components of GAs signaling identified in other species. Expression of DfPHOR in the ME is apparently regulated by phytochrome through the supply of GAs from the embryo to ME, whereas DfMYB expression is regulated by an embryonic factor with some of the characteristics of the one that modulates seed sensitivity to GAs.

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“…As in LFR, VLFR induces EW after light stimulation (de Miguel and Sánchez, 1992). Endosperm softening is led by the degradation of the main cell wall component, a 4-linked mannose (b-1,4-mannan), by endo-b-mannanase and b-mannosidase activities (Sánchez et al, 1990).…”

Section: Introductionmentioning

confidence: 96%

Dynamics of the processes leading to the acquisition of sensitivity to very low fluence of photons inDatura feroxseeds

Auge

Miguel

2013

Seed Sci. Res.

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Soil tillage operations stimulate germination of buried seeds in cultivated lands, allowing them to perceive light as a germination-promoting factor. The time of burial and the effect of changing environmental factors affect the physiological state of the seeds, which may lead to an extreme light-sensitivity and very low fluence response (VLFR) through phytochrome A. This paper describes the influence of the progressive process of dormancy breakage, which is accompanied by the acquisition of extreme light-sensitivity, on processes associated with endosperm weakening and embryo growth potential in the VLFR-mediated promotion ofDatura feroxseed germination. Our results show that endosperm weakening is mainly limited by β-mannosidase enzyme activity after far-red light stimulation, which is highly dependent on the dormancy level of the seeds. In addition, stimulation of the embryo growth potential by far-red irradiation did not require an extreme light-sensitivity to very low fluence of photons to reach its maximum response, and it was not completely correlated with expansin gene expression in the embryo. Our work indicates that responses of endosperm weakening and embryo growth potential to far-red irradiation, dependent on dormancy level, have different requirements for stimulation by the signalling network initiated by phytochrome A during the course of the very low fluence response inDatura feroxseeds.

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Phytochrome–induced Germination, Endosperm Softening and Embryo Growth Potential in Datura ferox Seeds: Sensitivity to Low Water Potential and Time to Escape to FR Reversal

Cited by 30 publications

References 24 publications

An integrative insight on dormancy alleviation in diaspores of Urochloa humidicola (Rendle) Morrone & Zuloaga, a tropical grass with great economic and ecological impact

An integrative insight on dormancy alleviation in diaspores of Urochloa humidicola (Rendle) Morrone & Zuloaga, a tropical grass with great economic and ecological impact

A phytochrome-dependent embryonic factor modulates gibberellin responses in the embryo and micropylar endosperm of Datura ferox seeds

Dynamics of the processes leading to the acquisition of sensitivity to very low fluence of photons inDatura feroxseeds

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