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1.
PLoS One ; 15(7): e0235896, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32730265

RESUMO

Mature sorghum herbage is known to contain several water-soluble secondary metabolites (allelochemicals). In this study, we investigated quantitative trait loci (QTLs) associated with allelochemical characteristics in sorghum using linkage mapping and linkage disequilibrium (LD)-based association mapping. A sorghum diversity research set (SDRS) of 107 accessions was used in LD mapping whereas, F2:3 lines derived from a cross between Japanese and African landraces were used in linkage mapping. The QTLs were further confirmed by positional (targeted) association mapping with Q+K model. The inhibitory effect of water-soluble extracts (WSE) was tested on germination and root length of lettuce seedlings in four concentrations (25%, 50%, 75% and 100%). A Significant range of variations was observed among genotypes in both types of mapping populations (P < 0.05). A total of 181 simple sequence repeats (SSRs) derived from antecedently reported map have been used for genotyping of SDRS. A genetic linkage map of 151 sorghum SSR markers was also developed on 134 F2 individuals. The total map length was 1359.3 cM, with an average distance of 8.2 cM between adjacent markers. LD mapping identified three QTLs for inhibition effect on germination and seven QTLs for root length of lettuce seedlings. Whereas, a total of six QTLs for inhibition of germination and ten QTLs for root length were detected in linkage mapping approach. The percent phenotypic variation explained by individual QTL ranged from 6.9% to 27.3% in SDRS and 9.9% to 35.6% in F2:3 lines. Regional association analysis identified four QTLs, three of them are common in other methods too. No QTL was identified in the region where major gene for sorgoleone (SOR1) has been cloned previously on chromosome 5.


Assuntos
Locos de Características Quantitativas , Sorghum/genética , Ligação Genética , Germinação/genética , Repetições de Microssatélites , Raízes de Plantas/genética , Raízes de Plantas/crescimento & desenvolvimento , Plântula/genética , Plântula/crescimento & desenvolvimento , Sorghum/crescimento & desenvolvimento , Sorghum/fisiologia
2.
Gene ; 753: 144803, 2020 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-32446917

RESUMO

R2R3-type MYBs are a key group of regulatory factors that control diverse developmental processes and stress tolerance in plants. Soybean is a major legume crop with the richness of seed protein and edible vegetable oil, and 244 R2R3-type MYBs have been identified in soybean. However, the knowledge regarding their functional roles has been greatly limited as yet. In this study, a novel R2R3-type MYB (GmMYB81) was functionally characterized in soybean, and it is closely related to two abiotic stress-associated regulators (AtMYB44 and AtMYB77). GmMYB81 transcripts not only differentially accumulated in soybean tissues and during embryo development, but also were significantly enhanced by drought, salt and cold stress. Histochemical GUS assay in Arabidopsis indicated that GmMYB81 promoter showed high activity in seedlings, rosette leaves, inflorescences, silique wall, mature anthers, roots, and germinating seeds. Further investigation indicated that over-expression of GmMYB81 in Arabidopsis caused auxin-associated phenotypes, including small flower and silique, more branch, and weakened apical dominance. Moreover, over-expression of GmMYB81 significantly elevated the rates of seed germination and green seedling under salt and drought stress, indicating that GmMYB81 might confer plant tolerance to salt and drought stress during seed germination. Additionally, protein interaction analysis showed that GmMYB81 interacts with the abiotic stress regulator GmSGF14l. Further observation indicated that they displayed similar expression patterns under drought and salt stress, suggesting GmMYB81 and GmSGF14l might cooperatively affect stress tolerance. These findings will facilitate future investigations of the regulatory mechanisms of GmMYB81 in response to plant stress tolerance, especially seed germination under abiotic stresses.


Assuntos
Proteínas de Arabidopsis/genética , Soja/genética , Estresse Fisiológico/genética , Fatores de Transcrição/genética , Ácido Abscísico/metabolismo , Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Secas , Fabaceae/genética , Flores/metabolismo , Regulação da Expressão Gênica de Plantas/genética , Genes de Plantas/genética , Germinação/genética , Folhas de Planta/metabolismo , Proteínas de Plantas/genética , Raízes de Plantas/metabolismo , Plantas Geneticamente Modificadas/genética , Estresse Salino/genética , Tolerância ao Sal/genética , Sementes/metabolismo , Fatores de Transcrição/metabolismo
3.
Artigo em Inglês | MEDLINE | ID: mdl-32289638

RESUMO

Chenopodium quinoa, a halophytic crop belonging to the Amaranthaceae, has remarkable resistance to harsh growth conditions and produces seed with excellent nutritional value. This makes it a suitable crop for marginal soils. However, to date most of the commercial cultivars are susceptible to preharvest sprouting (PHS). Meanwhile, understanding of the PHS regulatory mechanisms is still limited. Abscisic acid (ABA) has been demonstrated to be tightly associated with seed dormancy and germination regulation in many crops. Whether ABA metabolism pathway could be manipulated to prevent PHS in quinoa is worth investigating. In the present study, we tested the inhibitory effects of exogenous ABA on quinoa seed germination. By RNA-seq analysis we investigated the global gene expression changes during seed germination, and obtained 1066 ABA-repressed and 392 ABA-induced genes. Cis-elements enrichment analysis indicated that the promoters of these genes were highly enriched in motifs "AAAAAAAA" and "ACGTGKC (K = G/T)", the specific binding motifs of ABI3/VP1 and ABI5. Transcription factor annotation showed that 13 genes in bHLH, MADS-box, G2-like and NF-YB, and five genes in B3, bZIP, GATA and LBD families were specifically ABA-repressed and -induced, respectively. Furthermore, expression levels of 53 key homologs involved in seed dormancy and germination regulation were markedly changed. Hence, we speculated that the 18 transcription factors and the homologs were potential candidates involved in ABA-mediated seed dormancy and germination regulation, which could be manipulated for molecular breeding of quinoa elites with PHS tolerance in future.


Assuntos
Chenopodium quinoa , Perfilação da Expressão Gênica , Germinação , Dormência de Plantas , Sementes , Fatores de Transcrição , Ácido Abscísico/farmacologia , Chenopodium quinoa/genética , Chenopodium quinoa/crescimento & desenvolvimento , Regulação da Expressão Gênica de Plantas , Germinação/efeitos dos fármacos , Germinação/genética , Dormência de Plantas/genética , Reguladores de Crescimento de Planta/farmacologia , Sementes/efeitos dos fármacos , Sementes/genética , Sementes/crescimento & desenvolvimento , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
4.
Artigo em Inglês | MEDLINE | ID: mdl-32114250

RESUMO

Potassium homeostasis is essential for pollen development and pollen-pistil interactions during the sexual reproduction of flowering plants. Here, we described the role of a Shaker K+ channel, OsAKT1.2, in rice pollen germination and growth. OsAKT1.2 is specifically expressed in the tricellular pollen, mature pollen grains and growing pollen tubes. Using CRISPR gene editing, we found that knockout lines did not differ from wildtype in vegetative growth, but showed decreased pollen germination rate both in the germination medium and in vivo. OsAKT1.2-GFP fusion protein was localized in the plasma membrane and enriched at the pollen tube tip. OsAKT1.2 could complement the yeast strain which is deficient in K+ intake. These findings suggest that OsAKT1.2 is associated with pollen germination and tube elongation in rice.


Assuntos
Germinação/genética , Oryza/fisiologia , Proteínas de Plantas/genética , Pólen/crescimento & desenvolvimento , Canais de Potássio/genética , Sequência de Bases , Oryza/genética , Proteínas de Plantas/metabolismo
5.
Sci Adv ; 6(6): eaax0384, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-32076636

RESUMO

Germination of 2000-year-old seeds of Phoenix dactylifera from Judean desert archaeological sites provides a unique opportunity to study the Judean date palm, described in antiquity for the quality, size, and medicinal properties of its fruit, but lost for centuries. Microsatellite genotyping of germinated seeds indicates that exchanges of genetic material occurred between the Middle East (eastern) and North Africa (western) date palm gene pools, with older seeds exhibiting a more eastern nuclear genome on a gradient from east to west of genetic contributions. Ancient seeds were significantly longer and wider than modern varieties, supporting historical records of the large size of the Judean date. These findings, in accord with the region's location between east and west date palm gene pools, suggest that sophisticated agricultural practices may have contributed to the Judean date's historical reputation. Given its exceptional storage potentialities, the date palm is a remarkable model for seed longevity research.


Assuntos
Estudos de Associação Genética , Germinação/genética , Phoeniceae/anatomia & histologia , Phoeniceae/genética , Locos de Características Quantitativas , Característica Quantitativa Herdável , Sementes/crescimento & desenvolvimento , Sementes/genética , Evolução Molecular , Técnicas de Genotipagem , Repetições de Microssatélites , Phoeniceae/classificação , Datação Radiométrica
6.
Int J Mol Sci ; 21(4)2020 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-32074988

RESUMO

Among all cereals, rice is highly sensitive to cold stress, especially at the germination stage, which adversely impacts its germination ability, seed vigor, crop stand establishment, and, ultimately, grain yield. The dissection of novel quantitative trait loci (QTLs) or genes conferring a low-temperature germination (LTG) ability can significantly accelerate cold-tolerant rice breeding to ensure the wide application of rice cultivation through the direct seeding method. In this study, we identified 11 QTLs for LTG using 144 recombinant inbred lines (RILs) derived from a cross between a cold-tolerant variety, Lijiangxintuanheigu (LTH), and a cold-sensitive variety, Shennong265 (SN265). By resequencing two parents and RIL lines, a high-density bin map, including 2,828 bin markers, was constructed using 123,859 single-nucleotide polymorphisms (SNPs) between two parents. The total genetic distance corresponding to all 12 chromosome linkage maps was 2,840.12 cm. Adjacent markers were marked by an average genetic distance of 1.01 cm, corresponding to a 128.80 kb physical distance. Eight and three QTL alleles had positive effects inherited from LTH and SN265, respectively. Moreover, a pleiotropic QTL was identified for a higher number of erected panicles and a higher grain number on Chr-9 near the previously cloned DEP1 gene. Among the LTG QTLs, qLTG3 and qLTG7b were also located at relatively small genetic intervals that define two known LTG genes, qLTG3-1 and OsSAP16. Sequencing comparisons between the two parents demonstrated that LTH possesses qLTG3-1 and OsSAP16 genes, and SN-265 owns the DEP1 gene. These comparison results strengthen the accuracy and mapping resolution power of the bin map and population. Later, fine mapping was done for qLTG6 at 45.80 kb through four key homozygous recombinant lines derived from a population with 1569 segregating plants. Finally, LOC_Os06g01320 was identified as the most possible candidate gene for qLTG6, which contains a missense mutation and a 32-bp deletion/insertion at the promoter between the two parents. LTH was observed to have lower expression levels in comparison with SN265 and was commonly detected at low temperatures. In conclusion, these results strengthen our understanding of the impacts of cold temperature stress on seed vigor and germination abilities and help improve the mechanisms of rice breeding programs to breed cold-tolerant varieties.


Assuntos
Ligação Genética , Germinação/genética , Oryza/genética , Estresse Fisiológico , Mapeamento Cromossômico , Temperatura Baixa , DNA de Plantas/química , DNA de Plantas/metabolismo , Genótipo , Oryza/crescimento & desenvolvimento , Fenótipo , Proteínas de Plantas/genética , Polimorfismo de Nucleotídeo Único , Regiões Promotoras Genéticas , Locos de Características Quantitativas , Sementes/genética , Sementes/crescimento & desenvolvimento , Sequenciamento Completo do Genoma
7.
Sci Rep ; 10(1): 1677, 2020 02 03.
Artigo em Inglês | MEDLINE | ID: mdl-32015470

RESUMO

Plant seed germination is a crucial developmental event that has significant effects on seedling establishment and yield production. This process is controlled by multiple intrinsic signals, particularly phytohormones. The gaseous hormone ethylene stimulates seed germination; however, the genetic basis of ethylene production in maize during seed germination remains poorly understood. In this study, we quantified the diversity of germination among 14 inbred lines representing the parental materials corresponding to multiple recombinant inbred line (RIL) mapping populations. Quantitative trait loci (QTLs) controlling ethylene production were then identified in germinating seeds from an RIL population constructed from two parental lines showing differences in both germination speed and ethylene production during germination. To explore the possible genetic correlations of ethylene production with other traits, seed germination and seed weight were evaluated using the same batch of samples. On the basis of high-density single nucleotide polymorphism-based genetic linkage maps, we detected three QTLs for ethylene production in germinating seeds, three QTLs for seed germination, and four QTLs for seed weight, with each QTL explaining 5.8%-13.2% of the phenotypic variation of the trait. No QTLs were observed to be co-localized, suggesting that the genetic bases underlying the three traits are largely different. Our findings reveal three chromosomal regions responsible for ethylene production during seed germination, and provide a valuable reference for the future investigation of the genetic mechanism underlying the role of the stress hormone ethylene in maize germination control under unfavourable external conditions.


Assuntos
Etilenos/metabolismo , Germinação/genética , Locos de Características Quantitativas/genética , Sementes/genética , Zea mays/genética , Mapeamento Cromossômico/métodos , Cromossomos de Plantas/genética , Ligação Genética/genética , Genótipo , Fenótipo , Plântula/genética
8.
Plant Sci ; 293: 110435, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32081273

RESUMO

Seed germination is essential for ensuring grain yield and quality. Germination rate, uniformity, and post-germination growth all contribute to cultivation. Although the phytohormones gibberellin (GA) and brassinosteroid (BR) are known to regulate germination, the underlying mechanism of their crosstalk in co-regulating rice seed germination remains unclear. In this study, the isobaric tags for relative and absolute quantitation (iTRAQ) proteomic approach was employed to identify target proteins responsive to GA during recovery of germination in BR-deficient and BR-insensitive rice. A total of 42 differentially abundant proteins were identified in both BR-deficient and BR-insensitive plants, and most were altered consistently in the two groups. Gene Ontology (GO) analysis revealed enrichment in proteins with binding and catalytic activity. A potential protein-protein interaction network was constructed using STRING analysis, and five Late Embryogenesis Abundant (LEA) family members were markedly down-regulated at both mRNA transcript and protein levels. These LEA genes were specifically expressed in rice seeds, especially during the latter stages of seed development. Mutation of LEA33 affected rice grain size and seed germination, possibly by reducing BR accumulation and enhancing GA biosynthesis. The findings improve our knowledge of the mechanisms by which GA and BR coordinate seed germination.


Assuntos
Brassinosteroides/metabolismo , Germinação/fisiologia , Giberelinas/metabolismo , Oryza/metabolismo , Sementes/metabolismo , Transdução de Sinais/fisiologia , Sistemas CRISPR-Cas , Regulação da Expressão Gênica de Plantas , Ontologia Genética , Germinação/genética , Oryza/genética , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Mapas de Interação de Proteínas , Proteômica , RNA Mensageiro/metabolismo , Sementes/genética , Sementes/crescimento & desenvolvimento
9.
Int J Mol Sci ; 21(3)2020 Feb 04.
Artigo em Inglês | MEDLINE | ID: mdl-32033113

RESUMO

Inositol polyphosphate 5-phosphatases (5PTases) function in inositol signaling by regulating the catabolism of phosphoinositol derivatives. Previous reports showed that 5PTases play a critical role in plant development and stress responses. In this study, we identified a novel 5PTase gene, Gs5PTase8, from the salt-tolerance locus of chromosome 3 in wild soybean (Glycine soja). Gs5PTase8 is highly up-regulated under salt treatment. It is localized in the nucleus and plasma membrane with a strong signal in the apoplast. Ectopic expression of Gs5PTase8 significantly increased salt tolerance in transgenic BY-2 cells, soybean hairy roots and Arabidopsis, suggesting Gs5PTase8 could increase salt tolerance in plants. The overexpression of Gs5PTase8 significantly enhanced the activities of catalase and ascorbate peroxidase under salt stress. The seeds of Gs5PTase8-transgenic Arabidopsis germinated earlier than the wild type under abscisic acid treatment, indicating Gs5PTase8 would alter ABA sensitivity. Besides, transcriptional analyses showed that the stress-responsive genes, AtRD22, AtRD29A and AtRD29B, were induced with a higher level in the Gs5PTase8-transgenic Arabidopsis plants than in the wild type under salt stress. These results reveal that Gs5PTase8 play a positive role in salt tolerance and might be a candidate gene for improving soybean adaptation to salt stress.


Assuntos
Expressão Ectópica do Gene/genética , Inositol Polifosfato 5-Fosfatases/genética , Proteínas de Plantas/genética , Tolerância ao Sal/genética , Soja/genética , Arabidopsis/genética , Ascorbato Peroxidases/genética , Catalase/genética , Membrana Celular/genética , Regulação da Expressão Gênica de Plantas/genética , Germinação/genética , Raízes de Plantas/genética , Plantas Geneticamente Modificadas/genética , Sementes/genética , Estresse Fisiológico/genética , Regulação para Cima/genética
10.
Int J Mol Sci ; 21(4)2020 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-32075313

RESUMO

WRKY transcription factors play central roles in developmental processes and stress responses of wheat. Most WRKY proteins of the same group (Group III) have a similar function in abiotic stress responses in plants. TaWRKY46, a member of Group III, was up-regulated by PEG treatment. TaWRKY46-GFP fusion proteins localize to the nucleus in wheat mesophyll protoplasts. Overexpression of TaWRKY46 enhanced osmotic stress tolerance in transgenic Arabidopsis thaliana plants, which was mainly demonstrated by transgenic Arabidopsis plants forming higher germination rate and longer root length on 1/2 Murashige and Skoog (MS) medium containing mannitol. Furthermore, the expression of several stress-related genes (P5CS1, RD29B, DREB2A, ABF3, CBF2, and CBF3) was significantly increased in TaWRKY46-overexpressing transgenic Arabidopsis plants after mannitol treatment. Taken together, these findings proposed that TaWRKY46 possesses vital functions in improving drought tolerance through ABA-dependent and ABA-independent pathways when plants are exposed to adverse osmotic conditions. TaWRKY46 can be taken as a candidate gene for transgenic breeding against osmotic stress in wheat. It can further complement and improve the information of the WRKY family members of Group III.


Assuntos
Proteínas de Arabidopsis/genética , Pressão Osmótica/fisiologia , Plantas Geneticamente Modificadas/genética , Fatores de Transcrição/genética , Triticum/genética , Arabidopsis/genética , Secas , Regulação da Expressão Gênica de Plantas , Germinação/genética , Plantas Geneticamente Modificadas/crescimento & desenvolvimento , Protoplastos/metabolismo , Estresse Fisiológico/genética
11.
DNA Cell Biol ; 39(4): 533-547, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32031882

RESUMO

Brassica napus embryos contain precursor tissues for the leaves, stem, and root, as well as the cotyledons, and these precursor tissues play key roles in seed germination, seedling survival, and subsequent seedling growth. Abscisic acid (ABA) plays a prominent role in the inhibition of seed germination. The underlying molecular mechanisms of the embryo responses to ABA stress followed by inhibited seed germination have not been reported in B. napus to date. In this study, we conducted quantitative trait locus (QTL) analysis of B. napus seed in response to ABA stress using 170 recombinant inbred lines. Furthermore, we performed transcriptome sequencing (RNA-seq) analyses by using B. napus ZS11 embryos under sterile deionized water (control) and 10 mg/L (10A), 20 mg/L (20A), and 30 mg/L (30A) ABA treatment conditions. In total, 10 QTLs were screened for explaining 2.70-6.73% of the phenotypic variation under ABA stress. In addition, 1495, 3332, and 3868 differentially expressed genes (DEGs) were identified in the "control vs 10A," "control vs 20A," and "control vs 30A" comparisons, respectively. Gene Ontology (GO) enrichment analysis indicated that DEG functions are mainly related to response to stimuli, response to oxygen-containing compounds, response to lipids, and the transport and seed dormancy processes. These DEGs mainly participated in the response to plant hormone signal transduction, starch and sucrose metabolism, cutin, suberine, and wax biosynthesis, and phenylpropanoid biosynthesis processes pathways. Our results provide a foundation for further explorations of the molecular regulatory mechanisms of B. napus embryos in response to abiotic stress during the seed germination stage.


Assuntos
Ácido Abscísico/metabolismo , Brassica napus/embriologia , Germinação/genética , Plântula/crescimento & desenvolvimento , Sementes/fisiologia , Sequência de Bases , Mapeamento Cromossômico , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Locos de Características Quantitativas , Sementes/genética , Análise de Sequência de RNA , Transcriptoma/genética
12.
Int J Mol Sci ; 21(2)2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31952322

RESUMO

Cellular autophagy is a widely-occurring conserved process for turning over damaged organelles or recycling cytoplasmic contents in cells. Although autophagy-related genes (ATGs) have been broadly identified from many plants, little is known about the potential function of autophagy in mediating plant growth and development, particularly in recycling cytoplasmic contents during seed development and germination. Castor bean (Ricinus communis) is one of the most important inedible oilseed crops. Its mature seed has a persistent and large endosperm with a hard and lignified seed coat, and is considered a model system for studying seed biology. Here, a total of 34 RcATG genes were identified in the castor bean genome and their sequence structures were characterized. The expressional profiles of these RcATGs were examined using RNA-seq and real-time PCR in a variety of tissues. In particular, we found that most RcATGs were significantly up-regulated in the later stage of seed coat development, tightly associated with the lignification of cell wall tissues. During seed germination, the expression patterns of most RcATGs were associated with the decomposition of storage oils. Furthermore, we observed by electron microscopy that the lipid droplets were directly swallowed by the vacuoles, suggesting that autophagy directly participates in mediating the decomposition of lipid droplets via the microlipophagy pathway in germinating castor bean seeds. This study provides novel insights into understanding the potential function of autophagy in mediating seed development and germination.


Assuntos
Proteínas Relacionadas à Autofagia/genética , Semente de Rícino/genética , Perfilação da Expressão Gênica/métodos , Regulação da Expressão Gênica de Plantas , Genoma de Planta/genética , Genômica/métodos , Autofagia/genética , Proteínas Relacionadas à Autofagia/classificação , Proteínas Relacionadas à Autofagia/metabolismo , Semente de Rícino/metabolismo , Óleo de Rícino/metabolismo , Endosperma/genética , Endosperma/metabolismo , Germinação/genética , Sequenciamento de Nucleotídeos em Larga Escala , Gotículas Lipídicas/metabolismo , Filogenia , Sementes/genética , Sementes/metabolismo
13.
Biochem J ; 477(2): 305-323, 2020 01 31.
Artigo em Inglês | MEDLINE | ID: mdl-31967650

RESUMO

Seed longevity is a central pivot of the preservation of biodiversity, being of main importance to face the challenges linked to global climate change and population growth. This complex, quantitative seed quality trait is acquired on the mother plant during the second part of seed development. Understanding what factors contribute to lifespan is one of the oldest and most challenging questions in plant biology. One of these challenges is to recognize that longevity depends on the storage conditions that are experimentally used because they determine the type and rate of deleterious conditions that lead to cell death and loss of viability. In this review, we will briefly review the different storage methods that accelerate the deteriorative reactions during storage and argue that a minimum amount of information is necessary to interpret the longevity data. Next, we will give an update on recent discoveries on the hormonal factors regulating longevity, both from the ABA signaling pathway but also other hormonal pathways. In addition, we will review the effect of both maternal and abiotic factors that influence longevity. In the last section of this review, we discuss the problems in unraveling cause-effect relationship between the time of death during storage and deteriorative reactions leading to seed ageing. We focus on the three major types of cellular damage, namely membrane permeability, lipid peroxidation and RNA integrity for which germination data on seed stored in dedicated seed banks for long period times are now available.


Assuntos
Germinação/genética , Longevidade/genética , Desenvolvimento Vegetal/genética , Sementes/genética , Peroxidação de Lipídeos/genética , Plantas/genética , RNA/genética , Sementes/crescimento & desenvolvimento , Transdução de Sinais
14.
BMC Genet ; 21(1): 6, 2020 01 17.
Artigo em Inglês | MEDLINE | ID: mdl-31952473

RESUMO

BACKGROUND: Anaerobic germination is one of the most important traits for rice under direct-seeded conditions. The trait reduces risk of crop failure due to waterlogged conditions after seeding and allows water to be used as a means of weed control. The identification of QTLs and causal genes for anaerobic germination will facilitate breeding for improved direct-seeded rice varieties. In this study, we explored a BC1F2:3 population developed from a cross between BJ1, an indica landrace, and NSIC Rc222, a high-yielding recurrent parent. The population was phenotyped under different screening methods (anaerobic screenhouse, anaerobic tray, and aerobic screenhouse) to establish the relationship among the methods and to identify the most suitable screening method, followed by bulk segregant analysis (BSA) to identify large-effect QTLs. RESULTS: The study showed high heritability for survival (SUR) under all three phenotyping conditions. Although high correlation was observed within screening environments between survival at 14 and 21 days after seeding, the correlation across environments was low. Germination under aerobic and anaerobic conditions showed very low correlation, indicating the independence of their genetic control. The results were further confirmed through AMMI analysis. Four significant markers with an effect on anaerobic germination were identified through BSA. CIM analysis revealed qAG1-2, qAG6-2, qAG7-4, and qAG10-1 having significant effects on the trait. qAG6-2 and qAG10-1 were consistent across screening conditions and seedling age while qAG1-2 and qAG7-4 were specific to screening methods. All QTLs showed an effect when survival across all screening methods was analyzed. Together, the QTLs explained 39 to 55% of the phenotypic variation for survival under anaerobic conditions. No QTL effects were observed under aerobic conditions. CONCLUSIONS: The study helped us understand the effect of phenotyping method on anaerobic germination, which will lead to better phenotyping for this trait in future studies. The QTLs identified through this study will allow the improvement of breeding lines for the trait through marker-assisted selection or through forward breeding approaches such as genomic selection. The high frequency of the BJ1 allele of these QTLs will enhance the robustness of germination under anaerobic conditions in inbred and hybrid rice varieties.


Assuntos
Anaerobiose/genética , Mapeamento Cromossômico , Germinação/genética , Oryza/genética , Locos de Características Quantitativas , Característica Quantitativa Herdável , Variação Biológica da População , Interação Gene-Ambiente , Oryza/metabolismo , Fenótipo
15.
PLoS One ; 15(1): e0219413, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31899920

RESUMO

Seed dormancy and germination are the two important traits related to plant survival, reproduction and crop yield. To understand the regulatory mechanisms of these traits, it is crucial to clarify which genes or pathways participate in the regulation of these processes. However, little information is available on seed dormancy and germination in peanut. In this study, seeds of the variety Luhua No.14, which undergoes nondeep dormancy, were selected, and their transcriptional changes at three different developmental stages, the freshly harvested seed (FS), the after-ripening seed (DS) and the newly germinated seed (GS) stages, were investigated by comparative transcriptomic analysis. The results showed that genes with increased transcription in the DS vs FS comparison were overrepresented for oxidative phosphorylation, the glycolysis pathway and the tricarboxylic acid (TCA) cycle, suggesting that after a period of dry storage, the intermediates stored in the dry seeds were rapidly mobilized by glycolysis, the TCA cycle, the glyoxylate cycle, etc.; the electron transport chain accompanied by respiration was reactivated to provide ATP for the mobilization of other reserves and for seed germination. In the GS vs DS pairwise comparison, dozens of the upregulated genes were related to plant hormone biosynthesis and signal transduction, including the majority of components involved in the auxin signal pathway, brassinosteroid biosynthesis and signal transduction as well as some GA and ABA signal transduction genes. During seed germination, the expression of some EXPANSIN and XYLOGLUCAN ENDOTRANSGLYCOSYLASE genes was also significantly enhanced. To investigate the effects of different hormones during seed germination, the contents and differential distribution of ABA, GAs, BRs and IAA in the cotyledons, hypocotyls and radicles, and plumules of three seed sections at different developmental stages were also investigated. Combined with previous data in other species, it was suggested that the coordination of multiple hormone signal transduction nets plays a key role in radicle protrusion and seed germination.


Assuntos
Arachis/genética , Regulação da Expressão Gênica no Desenvolvimento , Regulação da Expressão Gênica de Plantas , Germinação/genética , Proteínas de Plantas/genética , Sementes/genética , Transcriptoma , Ácido Abscísico/metabolismo , Trifosfato de Adenosina/biossíntese , Arachis/crescimento & desenvolvimento , Arachis/metabolismo , Brassinosteroides/metabolismo , Ciclo do Ácido Cítrico/genética , Ontologia Genética , Redes Reguladoras de Genes , Glicólise/genética , Glicosiltransferases/genética , Glicosiltransferases/metabolismo , Ácidos Indolacéticos/metabolismo , Anotação de Sequência Molecular , Fosforilação Oxidativa , Dormência de Plantas , Proteínas de Plantas/metabolismo , Característica Quantitativa Herdável , Sementes/crescimento & desenvolvimento , Sementes/metabolismo , Transdução de Sinais
16.
Plant Mol Biol ; 102(6): 615-624, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31997111

RESUMO

KEY MESSAGE: PTR2 in Arabidopsis thaliana is negatively regulated by ABI4 and plays a key role in water uptake by seeds, ensuring that imbibed seeds proceed to germination. Peptide transporters (PTRs) transport nitrogen-containing substrates in a proton-dependent manner. Among the six PTRs in Arabidopsis thaliana, the physiological role of the tonoplast-localized, seed embryo abundant PTR2 is unknown. In the present study, a molecular physiological analysis of PTR2 was conducted using ptr2 mutants and PTR2CO complementation lines. Compared with the wild type, the ptr2 mutant showed ca. 6 h delay in testa rupture and consequently endosperm rupture because of 17% lower water content and 10% higher free abscisic acid (ABA) content. Constitutive overexpression of the PTR2 gene under the control of the Cauliflower mosaic virus (CaMV) 35S promoter in ptr2 mutants rescued the mutant phenotypes. After cold stratification, a transient increase in ABA INSENSITIVE4 (ABI4) transcript levels during induction of testa rupture was followed by a similar increase in PTR2 transcript levels, which peaked prior to endosperm rupture. The PTR2 promoter region containing multiple CCAC motifs was recognized by ABI4 in electrophoretic mobility shift assays, and PTR2 expression was repressed by 67% in ABI4 overexpression lines compared with the wild type, suggesting that PTR2 is an immediate downstream target of ABI4. Taken together, the results suggest that ABI4-dependent temporal regulation of PTR2 expression may influence water status during seed germination to promote the post-germinative growth of imbibed seeds.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Transporte Biológico/fisiologia , Germinação/fisiologia , Proteínas de Membrana Transportadoras/metabolismo , Sementes/metabolismo , Água/metabolismo , Ácido Abscísico/metabolismo , Arabidopsis/genética , Arabidopsis/crescimento & desenvolvimento , Proteínas de Arabidopsis/genética , Regulação da Expressão Gênica no Desenvolvimento , Regulação da Expressão Gênica de Plantas , Germinação/genética , Mutação , Fenótipo , Regiões Promotoras Genéticas , Fatores de Transcrição/metabolismo
17.
Artigo em Inglês | MEDLINE | ID: mdl-31779892

RESUMO

A. racemosus is a rich source of pharmacologically active steroidal saponins. Most of the studies are related to its chemistry and pharmacology, but the pathway involved in the biosynthesis of steroidal saponin is not much emphasized. Squalene epoxidase acts as a rate-limiting enzyme in this biosynthesis. In this study, we have selected root specific squalene epoxidase ArSQE from A. racemosus for its characterization. ArSQE was able to complement ergosterol auxotrophy in erg1 yeast mutants. Mutants were sensitive to the antifungal drug terbinafine, whereas ArSQE complementation made them tolerant to the same drug. ArSQE plays a significant role in early germination in transgenic tobacco. The transgenic tobacco seedlings overexpressing ArSQE were tolerant to terbinafine and abiotic stress. Expression analysis of transcripts in ArSQE transgenic lines suggests that it mostly affects ABA, GA, stress, and sterol related functions in transgenic tobacco. Further, root specific MeJA responsive A. racemosus bZIP transcription factors (TFs), ArTGA1 and ArTGA2, were identified that bind to MeJA responsive cis-element present in the promoter region of ArSQE. Characterization of ArSQE of A. racemosus provides new information about its regulation through MeJA responsive bZIP TF along with its role in the development and abiotic stress response in transgenic tobacco.


Assuntos
Asparagus (Planta)/fisiologia , Fatores de Transcrição de Zíper de Leucina Básica/genética , Regulação da Expressão Gênica de Plantas , Germinação/genética , Proteínas de Plantas/genética , Esqualeno Mono-Oxigenase/genética , Sequência de Aminoácidos , Asparagus (Planta)/enzimologia , Asparagus (Planta)/genética , Fatores de Transcrição de Zíper de Leucina Básica/metabolismo , Filogenia , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/metabolismo , Alinhamento de Sequência , Esqualeno Mono-Oxigenase/metabolismo , Estresse Fisiológico , Tabaco/genética , Tabaco/fisiologia
18.
Planta ; 251(1): 26, 2019 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-31797121

RESUMO

MAIN CONCLUSION: Silencing of CI-sHsps by RNAi negatively affected the seed germination process and heat stress response of rice seedlings. Seed size of RNAiCI-sHsp was reduced as compared to wild-type plants. Small heat shock proteins (sHsps) are the ATP-independent chaperones ubiquitously expressed in response to diverse environmental and developmental cues. Cytosolic sHsps constitute the major repertoire of sHsp family. Rice cytosolic class I (CI)-sHsps consists of seven members (Hsp16.9A, Hsp16.9B, Hsp16.9C, Hsp17.4, Hsp17.7, Hsp17.9A and Hsp18). Purified OsHsp17.4 and OsHsp17.9A proteins exhibited chaperone activity by preventing formation of large aggregates with model substrate citrate synthase. OsHsp16.9A and OsHsp17.4 showed nucleo-cytoplasmic localization, while the localization of OsHsp17.9A was preferentially in the nucleus. Transgenic tobacco plants expressing OsHsp17.4 and OsHsp17.9A proteins and Arabidopsis plants ectopically expressing OsHsp17.4 protein showed improved thermotolerance to the respective trans-hosts during the post-stress recovery process. Single hairpin construct was designed to generate all CI-sHsp silenced (RNAiCI-sHsp) rice lines. The major vegetative and reproductive attributes of the RNAiCI-sHsp plants were comparable to the wild-type rice plants. Basal and acquired thermotolerance response of RNAiCI-sHsp seedlings of rice was mildly affected. The seed length of RNAiCI-sHsp rice plants was significantly reduced. The seed germination process was delayed and seed thermotolerance of RNAiCI-sHsp was negatively affected than the non-transgenic seeds. We, thus, implicate that sHsp genes are critical in seedling thermotolerance and seed physiology.


Assuntos
Inativação Gênica , Proteínas de Choque Térmico Pequenas/metabolismo , Oryza/genética , Oryza/fisiologia , Proteínas de Plantas/metabolismo , Plântula/fisiologia , Sementes/fisiologia , Termotolerância/fisiologia , Arabidopsis/genética , Arabidopsis/fisiologia , Citrato (si)-Sintase/metabolismo , Regulação da Expressão Gênica de Plantas , Germinação/genética , Proteínas de Choque Térmico Pequenas/genética , Fenótipo , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas , Ligação Proteica , Multimerização Proteica , Protoplastos/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Sementes/genética , Termotolerância/genética , Tabaco/genética , Transcriptoma/genética
19.
BMC Plant Biol ; 19(1): 549, 2019 Dec 11.
Artigo em Inglês | MEDLINE | ID: mdl-31829135

RESUMO

BACKGROUND: In the Brassicaceae, the early stages of compatible pollen-stigma interactions are tightly controlled with early checkpoints regulating pollen adhesion, hydration and germination, and pollen tube entry into the stigmatic surface. However, the early signalling events in the stigma which trigger these compatible interactions remain unknown. RESULTS: A set of stigma-expressed pseudokinase genes, termed BRASSIKINs (BKNs), were identified and found to be present in only core Brassicaceae genomes. In Arabidopsis thaliana Col-0, BKN1 displayed stigma-specific expression while the BKN2 gene was expressed in other tissues as well. CRISPR deletion mutations were generated for the two tandemly linked BKNs, and very mild hydration defects were observed for wild-type Col-0 pollen when placed on the bkn1/2 mutant stigmas. In further analyses, the predominant transcript for the stigma-specific BKN1 was found to have a premature stop codon in the Col-0 ecotype, but a survey of the 1001 Arabidopsis genomes uncovered three ecotypes that encoded a full-length BKN1 protein. Furthermore, phylogenetic analyses identified intact BKN1 orthologues in the closely related outcrossing Arabidopsis species, A. lyrata and A. halleri. Finally, the BKN pseudokinases were found to be plasma-membrane localized through the dual lipid modification of myristoylation and palmitoylation, and this localization would be consistent with a role in signaling complexes. CONCLUSION: In this study, we have characterized the novel Brassicaceae-specific family of BKN pseudokinase genes, and examined the function of BKN1 and BKN2 in the context of pollen-stigma interactions in A. thaliana Col-0. Additionally, premature stop codons were identified in the predicted stigma specific BKN1 gene in a number of the 1001 A. thaliana ecotype genomes, and this was in contrast to the out-crossing Arabidopsis species which carried intact copies of BKN1. Thus, understanding the function of BKN1 in other Brassicaceae species will be a key direction for future studies.


Assuntos
Arabidopsis/genética , Tubo Polínico/genética , Pólen/genética , Arabidopsis/metabolismo , Germinação/genética , Germinação/fisiologia , Filogenia , Pólen/metabolismo , Tubo Polínico/metabolismo
20.
Curr Biol ; 29(24): R1326-R1338, 2019 12 16.
Artigo em Inglês | MEDLINE | ID: mdl-31846685

RESUMO

Global warming is one of the most detrimental aspects of climate change, affecting plant growth and development across the entire life cycle. This Review explores how different stages of development are influenced by elevated temperature in both wild plants and crops. Starting from seed development and germination, global warming will influence morphological adjustments, termed thermomorphogenesis, and photosynthesis primarily during the vegetative phase, as well as flowering and reproductive development. Where applicable, we distinguish between moderately elevated temperatures that affect all stages of plant development and heat waves that often occur during the reproductive phase when they can have devastating consequences for fruit development. The parallel occurrence of elevated temperature with other abiotic and biotic stressors, particularly the combination of global warming and drought or increased pathogen pressure, will potentiate the challenges for both wild and cultivated plant species. The key components of the molecular networks underlying the physiological processes involved in thermal responses in the model plant Arabidopsis thaliana are highlighted. In crops, temperature-sensitive traits relevant for yield are illustrated for winter wheat (Triticum aestivum L.) and soybean (Glycine max L.), representing cultivated species adapted to temperate vs. warm climate zones, respectively. While the fate of wild plants depends on political agendas, plant breeding approaches informed by mechanistic understanding originating in basic science can enable the generation of climate change-resilient crops.


Assuntos
Agricultura/métodos , Agricultura/tendências , Mudança Climática/economia , Produtos Agrícolas/genética , Produtos Agrícolas/crescimento & desenvolvimento , Secas , Germinação/genética , Aquecimento Global/economia , Aquecimento Global/estatística & dados numéricos , Desenvolvimento Vegetal/genética , Plântula/crescimento & desenvolvimento , Sementes/crescimento & desenvolvimento , Temperatura , Triticum/crescimento & desenvolvimento
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