Timing seed germination under changing salinity: a key role of the ERECTA receptor-kinases

ERECTA receptor-kinases play a key role in the appropriate timing of seed germination under changing salinity

Journal of Experimental Botany ◽

10.1093/jxb/erz385 ◽

2019 ◽

Vol 70 (21) ◽

pp. 6417-6435 ◽

Cited By ~ 4

Author(s):

Amrit K Nanda ◽

Abdeljalil El Habti ◽

Charles H Hocart ◽

Josette Masle

Keyword(s):

Seed Germination ◽

Seed Coat ◽

Soil Conditions ◽

Primary Role ◽

Triple Mutant ◽

Receptor Kinases ◽

Increased Sensitivity ◽

Aba Insensitive ◽

Salt And Osmotic Stress

Abstract Appropriate timing of seed germination is crucial for the survival and propagation of plants, and for crop yield, especially in environments prone to salinity or drought. However, the exact mechanisms by which seeds perceive changes in soil conditions and integrate them to trigger germination remain elusive, especially once the seeds are non-dormant. In this study, we determined that the Arabidopsis ERECTA (ER), ERECTA-LIKE1 (ERL1), and ERECTA-LIKE2 (ERL2) leucine-rich-repeat receptor-like kinases regulate seed germination and its sensitivity to changes in salt and osmotic stress levels. Loss of ER alone, or in combination with ERL1 and/or ERL2, slows down the initiation of germination and its progression to completion, or arrests it altogether under saline conditions, until better conditions return. This function is maternally controlled via the tissues surrounding the embryo, with a primary role being played by the properties of the seed coat and its mucilage. These relate to both seed-coat expansion and subsequent differentiation and to salinity-dependent interactions between the mucilage, subtending seed coat layers and seed interior in the germinating seed. Salt-hypersensitive er105, er105 erl1.2, er105 erl2.1 and triple-mutant seeds also exhibit increased sensitivity to exogenous ABA during germination, and under salinity show an enhanced up-regulation of the germination repressors and inducers of dormancy ABA-insensitive-3, ABA-insensitive-5, DELLA-encoding RGL2, and Delay-Of-Germination-1. These findings reveal a novel role of the ERECTA receptor-kinases in the sensing of conditions at the seed surface and the integration of developmental, dormancy and stress signalling pathways in seeds. They also open novel avenues for the genetic improvement of plant adaptation to changing drought and salinity patterns.

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Dispersal of mimetic seeds of three species of Ormosia (Leguminosae)

Journal of Tropical Ecology ◽

10.1017/s0266467498000303 ◽

1998 ◽

Vol 14 (4) ◽

pp. 389-411 ◽

Cited By ~ 18

Author(s):

Mercedes S. Foster ◽

Linda S. Delay

Keyword(s):

Seed Germination ◽

Seed Dispersal ◽

Seed Coat ◽

Seed Predation ◽

The Other ◽

Frugivorous Birds ◽

Hard Seed ◽

Seed Surface ◽

Mutualistic Relationship

ABSTRACT. Seeds with ‘imitation arils’ appear wholly or partially covered by pulp or aril but actually carry no fleshy material. The mimetic seed hypothesis to explain this phenomenon proposes a parasitic relationship in which birds are deceived into dispersing seeds that resemble bird-dispersed fruits, without receiving a nutrient reward. The hard-seed for grit hypothesis proposes a mutualistic relationship in which large, terrestrial birds swallow the exceptionally hard mimetic seeds as grit for grinding the softer seeds on which they feed. They defecate, dispersing the seeds, and abrade the seed surface, enhancing germination. Any fruit mimicry is incidental. Fruiting trees of Ormosia spp. (Leguminosae: Papilionoideae) were observed to ascertain mechanisms of seed dispersal and the role of seemingly mimetic characteristics of the seeds in that dispersal. Seed predation and seed germination were also examined. Ormosia isthamensis and O. macrocalyx (but not O. bopiensis) deceived arboreally-foraging frugivorous birds into taking their mimetic seeds, although rates of seed dispersal were low. These results are consistent with the mimetic seed hypothesis. On the other hand, the rates of disappearance of seeds from the ground under the Ormosia trees, hardness of the seeds, and enhancement of germination with the abrasion of the seed coat are all consistent with the hard-seed for grit hypothesis. RESUMEN. Semillas con arilos falsos aparecen estar cubiertas en parte o completamente por pulpa o arilo, pero en realidad no llevan ninguna materia carnosa. El hipótesis semilla mímica propone que las semillas parecen frutos carnosos cuyas semillas están dispersadas por aves y que engañan las aves a dispersar sus semillas sin recibir una recompensa nutritiva — una relación parasítica. El hipótesis semilla dura para arenisca propone que aves grandes y terrestres tragan las semillas mímicas y excepcionalmente duras como arenisca para moler las semillas más suaves en que se alimentan; las aves defecan y dispersan las semillas, y las rascan, lo cual mejora la germinación — una relación mutua. Cualquier mimetismo es incidente. Se observaron árboles de Ormosia espp. (Leguminosae: Papilionoideae) con frutos para averiguar los mecanismos de dispersión de semillas y el papel que hacen las características aparentemente mímicas de sus semillas en esa dispersión. Se examinaron también la depredación y germinación de semillas. Las semillas mímicas de Ormosia isthamensis y O. macrocalyx (pero no O. bopiensis), engañaron aves frugivoras y arbóreas en comerlas, aunque las tasas de dispersión eran bajas. Estos resultados son consistente con el hipótesis semilla mímica. En cambio, las tasas de desaparición de semillas caídas de Ormosia, dureza de las semillas, y mejoramiento de germinación con la raedura de las capas de las semillas son consistente con el hipótesis semilla dura para arenisca.

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Proanthocyanidins in seed coat tegmen and endospermic cap inhibit seed germination in Sapium sebiferum

PeerJ ◽

10.7717/peerj.4690 ◽

2018 ◽

Vol 6 ◽

pp. e4690 ◽

Cited By ~ 8

Author(s):

Faheem Afzal Shah ◽

Jun Ni ◽

Jing Chen ◽

Qiaojian Wang ◽

Wenbo Liu ◽

...

Keyword(s):

Seed Germination ◽

Seed Coat ◽

Nordihydroguaiaretic Acid ◽

Potassium Nitrate ◽

Sapium Sebiferum ◽

Exogenous Application ◽

Catabolic Genes ◽

Long Time ◽

Aba Biosynthesis

Sapium sebiferum, an ornamental and bio-energetic plant, is propagated by seed. Its seed coat contains germination inhibitors and takes a long time to stratify for germination. In this study, we discovered that the S. sebiferum seed coat (especially the tegmen) and endospermic cap (ESC) contained high levels of proanthocyanidins (PAs). Seed coat and ESC removal induced seed germination, whereas exogenous application with seed coat extract (SCE) or PAs significantly inhibited this process, suggesting that PAs in the seed coat played a major role in regulating seed germination in S. sebiferum. We further investigated how SCE affected the expression of the seed-germination-related genes. The results showed that treatment with SCE upregulated the transcription level of the dormancy-related gene, gibberellins (GAs) suppressing genes, abscisic acid (ABA) biosynthesis and signalling genes. SCE decreased the transcript levels of ABA catabolic genes, GAs biosynthesis genes, reactive oxygen species genes and nitrates-signalling genes. Exogenous application of nordihydroguaiaretic acid, gibberellic acid, hydrogen peroxide and potassium nitrate recovered seed germination in seed-coat-extract supplemented medium. In this study, we highlighted the role of PAs, and their interactions with the other germination regulators, in the regulation of seed dormancy in S. sebiferum.

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Role of seed coat in regulation of seed dormancy in houndstongue (Cynoglossum officinale)

Weed Science ◽

10.1017/s0043174500089529 ◽

1998 ◽

Vol 46 (3) ◽

pp. 344-350 ◽

Cited By ~ 7

Author(s):

Elisa Stabell ◽

Mahesh K. Upadhyaya ◽

Brian E. Ellis

Keyword(s):

Seed Germination ◽

Seed Dormancy ◽

Seed Coat ◽

Elevated Level ◽

Quantitative Relationship ◽

Total Phenolic ◽

Cynoglossum Officinale ◽

Saturated Water ◽

Stimulation Of

To understand the role of the seed coat in regulation of houndstongue seed dormancy, the effects of manipulation of seed coat integrity on seed germination and O2uptake were studied. The results suggest that the seed coat of this weed regulates dormancy in part by interfering with the diffusion of O2to the embryo. Scanning electron microscopy showed a network of ridges on the seed coat surface that were partially dissolved following 1.5 min of sulphuric acid scarification. Mechanical scarification removed fragments of the seed coat surface. Both scarification treatments stimulated seed germination. Supply of an elevated level of O2also stimulated seed germination. O2uptake by seeds imbibed in O2-saturated water was 150% higher than that for seeds imbibed in air-saturated water. Although all treatments that stimulated seed germination also stimulated O2uptake, there was a lack of a consistent, quantitative relationship between increases in O2uptake and seed germination in various experiments. This suggests that limitation of O2availability to the embryo is not the only factor involved in regulation of houndstongue seed dormancy by the seed coat. Mechanical restriction of embryo expansion by the seed coat may also be important. Methanol-insoluble phenolics constituted < 1% of the total phenolic pool in the embryo. Their potential oxidation could not account for more than a small fraction of the previously reported massive stimulation of O2uptake by the embryo upon decoating. The present O2uptake and seed germination studies indicate that not all of the large increase in O2uptake following decoating is essential for houndstongue seed germination.

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Proanthocyanidins in seed coat’s tegmen and endospermic cap inhibit seed germination in the bioenergy plant Sapium sebiferum

10.7287/peerj.preprints.3514v1 ◽

2018 ◽

Author(s):

Faheem Afzal Shah ◽

Jun Ni ◽

Jing Chen ◽

Qiaojian Wang ◽

Wenbo Liu ◽

...

Keyword(s):

Seed Germination ◽

Seed Coat ◽

Nordihydroguaiaretic Acid ◽

Potassium Nitrate ◽

Sapium Sebiferum ◽

Exogenous Application ◽

Bioenergy Plant ◽

Long Time ◽

Aba Biosynthesis

Sapium sebiferum, a highly ornamental and bioenergy plant, is propagated by seed. Its seed coat contains germination inhibitors and needs long time stratification for germination. In this experiment, we discovered that S. Sebiferum seed coat (especially tegmen) and endospermic cap contained high levels of proanthocyanidins (PAs). Seed coat and endospermic cap removal induced seed germination whereas exogenous application with seed coat extract (SCE) or PAs significantly inhibited this process, suggesting that PAs in the seed coat played a major role in regulating seed germination in S. sebiferum. We further investigated how seed coat extract affected the expression of the seed germination-related genes. The results showed that SCE treatment upregulated the transcription level of the dormancy-related gene, abscisic acid (ABA) biosynthesis and signalling genes and gibberellins (GA) suppressing genes. SCE decreased the transcript levels of ABA catabolic, GA biosynthesis, reactive oxygen species (ROS) and nitrates signalling genes. Exogenous application of nordihydroguaiaretic acid (NDGA), gibberellic acid (GA3), hydrogen peroxide (H2O2) and potassium nitrate (KNO3) recovered seed germination in SCE supplemented medium. In this experiment, we highlighted the role of PAs, and its interactions with the other germination regulators, in the regulation of seed dormancy in S. Sebiferum.

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The role of seed coat in the germination and early stages of growth of bean (Phaseolus vulgaris L.) in the presence of chickweed (Stellaria media (L.) Vill.)

Annales Universitatis Paedagogicae Cracoviensis Studia Naturae ◽

10.24917/25438832.4.6 ◽

2019 ◽

pp. 103-118 ◽

Cited By ~ 1

Author(s):

Aleksandra Mazur

Keyword(s):

Phaseolus Vulgaris ◽

Seed Germination ◽

Seedling Growth ◽

Seed Coat ◽

Dry Mass ◽

Control Group ◽

Aqueous Extracts ◽

Phaseolus Vulgaris L ◽

Stellaria Media

The aim of the study was to determine the role of the seed coat in the presence of aqueous extracts from Stellaria media (L.) Vill. on germination and early growth stages of bean seeds Phaseolus vulgaris L. Dry shoots of the chickweed aqueous extracts were prepared, with which the bean seeds with coat and without coat were treated. The control group was seeds watered only with distilled water. After 7 days of the experiment, seed germination parameters, seed germination rate (SE), seed vitality index (SVI), seedling growth inhibition index (IP), fresh and dry mass values and percentage water content were determined. The experiment showed the germination capacity of bean seeds was varied, in relation to seeds from the control. With increasing concentrations of extracts, a significant reduction in the seed germination rate was observed, both for those with seed coat and without seed coat. The seed vitality index increased only in seeds with coat, and decreased in each of the applied concentrations of extracts in seeds without seed coat. The seedling growth inhibition index reached negative values in both groups of seeds tested only at a concentration of 5%. In comparison to the control, IP was positive for seedlings watered with 15% extracts. For P. vulgaris seedlings grown on 5% of extracts the highest increase in the fresh mass was observed, in relation to the value of control mass. For seedlings grown from seeds with seed coat the diferences in the dry mass values primarily were noted. The percentage of water content in bean seedlings varied depending on the group of seeds studied and the concentration of allelopathic substances in the chickweed aqueous extracts. The examined indexes of seed germination and seedling growth showed that in the case of P. vulgaris seeds without seed coat. The role of seed coat in the germination and early stages of growth of bean (Phaseolus vulgaris L.) in the presence of chickweed (Stellaria media (L.) Vill.) were more sensitive to aqueous extracts from dry shoots of S. media. Compared to the control group, in low concentrations of allelopathic substances the seeds germinated similarly to the distilled water, and at higher concentrations, the seeds germination, the seedlings growth and fresh and dry mass values were inhibited.

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Proanthocyanidins in seed coat’s tegmen and endospermic cap inhibit seed germination in the bioenergy plant Sapium sebiferum

10.7287/peerj.preprints.3514 ◽

2018 ◽

Author(s):

Faheem Afzal Shah ◽

Jun Ni ◽

Jing Chen ◽

Qiaojian Wang ◽

Wenbo Liu ◽

...

Keyword(s):

Seed Germination ◽

Seed Coat ◽

Nordihydroguaiaretic Acid ◽

Potassium Nitrate ◽

Sapium Sebiferum ◽

Exogenous Application ◽

Bioenergy Plant ◽

Long Time ◽

Aba Biosynthesis

Sapium sebiferum, a highly ornamental and bioenergy plant, is propagated by seed. Its seed coat contains germination inhibitors and needs long time stratification for germination. In this experiment, we discovered that S. Sebiferum seed coat (especially tegmen) and endospermic cap contained high levels of proanthocyanidins (PAs). Seed coat and endospermic cap removal induced seed germination whereas exogenous application with seed coat extract (SCE) or PAs significantly inhibited this process, suggesting that PAs in the seed coat played a major role in regulating seed germination in S. sebiferum. We further investigated how seed coat extract affected the expression of the seed germination-related genes. The results showed that SCE treatment upregulated the transcription level of the dormancy-related gene, abscisic acid (ABA) biosynthesis and signalling genes and gibberellins (GA) suppressing genes. SCE decreased the transcript levels of ABA catabolic, GA biosynthesis, reactive oxygen species (ROS) and nitrates signalling genes. Exogenous application of nordihydroguaiaretic acid (NDGA), gibberellic acid (GA3), hydrogen peroxide (H2O2) and potassium nitrate (KNO3) recovered seed germination in SCE supplemented medium. In this experiment, we highlighted the role of PAs, and its interactions with the other germination regulators, in the regulation of seed dormancy in S. Sebiferum.

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An R2R3-type myeloblastosis transcription factor MYB103 is involved in phosphorus remobilization

Food Production, Processing and Nutrition ◽

10.1186/s43014-020-00038-6 ◽

2020 ◽

Vol 2 (1) ◽

Author(s):

Fangwei Yu ◽

Shenyun Wang ◽

Wei Zhang ◽

Hong Wang ◽

Li Yu ◽

...

Keyword(s):

Cell Wall ◽

Transcription Factor ◽

Abiotic Stresses ◽

Myb Transcription Factor ◽

Ethylene Signaling ◽

Biotic And Abiotic Stresses ◽

P Deficiency ◽

P Concentration ◽

Increased Sensitivity

Abstract The members of myeloblastosis transcription factor (MYB TF) family are involved in the regulation of biotic and abiotic stresses in plants. However, the role of MYB TF in phosphorus remobilization remains largely unexplored. In the present study, we show that an R2R3 type MYB transcription factor, MYB103, is involved in phosphorus (P) remobilization. MYB103 was remarkably induced by P deficiency in cabbage (Brassica oleracea var. capitata L.). As cabbage lacks the proper mutant for elucidating the mechanism of MYB103 in P deficiency, another member of the crucifer family, Arabidopsis thaliana was chosen for further study. The transcript of its homologue AtMYB103 was also elevated in response to P deficiency in A. thaliana, while disruption of AtMYB103 (myb103) exhibited increased sensitivity to P deficiency, accompanied with decreased tissue biomass and soluble P concentration. Furthermore, AtMYB103 was involved in the P reutilization from cell wall, as less P was released from the cell wall in myb103 than in wildtype, coinciding with the reduction of ethylene production. Taken together, our results uncover an important role of MYB103 in the P remobilization, presumably through ethylene signaling.

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Richness of Rhizosphere Organisms Affects Plant P Nutrition According to P Source and Mobility

Agriculture ◽

10.3390/agriculture11020157 ◽

2021 ◽

Vol 11 (2) ◽

pp. 157

Author(s):

Jean Trap ◽

Patricia Mahafaka Ranoarisoa ◽

Usman Irshad ◽

Claude Plassard

Keyword(s):

Careful Consideration ◽

Soil Conditions ◽

Organic P ◽

P Nutrition ◽

Soil P ◽

P Acquisition ◽

Complex Interactions ◽

Experimental Trials ◽

The Relationship

Plants evolve complex interactions with diverse soil mutualist organisms to enhance P mobilization from the soil. These strategies are particularly important when P is poorly available. It is still unclear how the soil P source (e.g., mineral P versus recalcitrant organic P) and its mobility in the soil (high or low) affect soil mutualist biological (ectomycorrhizal fungi, bacteria and bacterial-feeding nematodes) richness—plant P acquisition relationships. Using a set of six microcosm experiments conducted in growth chamber across contrasting P situations, we tested the hypothesis that the relationship between the increasing addition of soil mutualist organisms in the rhizosphere of the plant and plant P acquisition depends on P source and mobility. The highest correlation (R2 = 0.70) between plant P acquisition with soil rhizosphere biological richness was found in a high P-sorbing soil amended with an organic P source. In the five other situations, the relationships became significant either in soil conditions, with or without mineral P addition, or when the P source was supplied as organic P in the absence of soil, although with a low correlation coefficient (0.09 < R2 < 0.15). We thus encourage the systematic and careful consideration of the form and mobility of P in the experimental trials that aim to assess the role of biological complexity on plant P nutrition.

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RAD50 and RAD51 Define Two Pathways That Collaborate to Maintain Telomeres in the Absence of Telomerase

Genetics ◽

10.1093/genetics/152.1.143 ◽

1999 ◽

Vol 152 (1) ◽

pp. 143-152 ◽

Cited By ~ 12

Author(s):

Siyuan Le ◽

J Kent Moore ◽

James E Haber ◽

Carol W Greider

Keyword(s):

Cell Death ◽

Telomere Length ◽

Gene Conversion ◽

De Novo ◽

Dna Recombination ◽

Telomere Maintenance ◽

Triple Mutant ◽

Yeast Telomerase ◽

Telomere Lengthening

Abstract Telomere length is maintained by the de novo addition of telomere repeats by telomerase, yet recombination can elongate telomeres in the absence of telomerase. When the yeast telomerase RNA component, TLC1, is deleted, telomeres shorten and most cells die. However, gene conversion mediated by the RAD52 pathway allows telomere lengthening in rare survivor cells. To further investigate the role of recombination in telomere maintenance, we assayed telomere length and the ability to generate survivors in several isogenic DNA recombination mutants, including rad50, rad51, rad52, rad54, rad57, xrs2, and mre11. The rad51, rad52, rad54, and rad57 mutations increased the rate of cell death in the absence of TLC1. In contrast, although the rad50, xrs2, and mre11 strains initially had short telomeres, double mutants with tlc1 did not affect the rate of cell death, and survivors were generated at later times than tlc1 alone. While none of the double mutants of recombination genes and tlc1 (except rad52 tlc1) blocked the ability to generate survivors, a rad50 rad51 tlc1 triple mutant did not allow the generation of survivors. Thus RAD50 and RAD51 define two separate pathways that collaborate to allow cells to survive in the absence of telomerase.

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