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1.
Plant Sci ; 311: 110994, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34482907

RESUMO

Drought is a pivotal cause for crop yield reductions. When subjected to recurrent external stimuli, plants can develop memory of stress responses that, eventually, enables improved plant tolerance to environmental changes. In addition, despite causal relationships, these responses may vary according to hierarchical levels of observation. Thus, this study aims to check the responses of recurrent and non-recurrent stresses in two rice genotypes observing their drought memory responses at different levels of organization, that is, on a physiological, biochemical and metabolomic scale and for end in global PCA. For this, seventy variables were measured on the scales described in order to obtain a large number of observations. The memory responses were evident in almost all scales observed. The lowland genotype, especially plants not subjected to recurrent water shortage, showed higher damage to the photosynthetic apparatus under drought conditions, although it has exhibited more evident memory response effect after rehydration. On the other hand, the upland genotype appears to be more tolerant to drought insofar lower biochemical damage was observed. Specific behaviors of each genotype at biochemical and metabolomics levels and similar behavior at physiological level were observed. This study demonstrates the importance of observation at different hierarchical levels.


Assuntos
Adaptação Fisiológica/genética , Desidratação/genética , Desidratação/fisiopatologia , Secas , Oryza/genética , Oryza/fisiologia , Água/metabolismo , Brasil , Produtos Agrícolas/genética , Produtos Agrícolas/fisiologia , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Variação Genética , Genótipo , Estresse Fisiológico/genética
2.
Plant Sci ; 311: 111009, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34482912

RESUMO

Weeds, pests, and pathogens are among the pre-harvest constraints in rice farming across rice-growing countries. For weed management, manual weeding and herbicides are widely practiced. Among the herbicides, glyphosate [N-(phosphonomethyl) glycine] is a broad-spectrum systemic chemical extensively used in agriculture. Being a competitive structural analog to phosphoenolpyruvate, it selectively inhibits the conserved 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) enzyme required for the biosynthesis of aromatic amino acids and essential metabolites in eukaryotes and prokaryotes. In the present study, we investigated the antifungal and defense elicitor activity of glyphosate against Magnaporthe oryzae on transgenic-rice overexpressing a glyphosate-resistance OsEPSPS gene (T173I + P177S; TIPS OsmEPSPS) for blast disease management. The glyphosate foliar spray on OsmEPSPS transgenic rice lines showed both prophylactic and curative suppression of blast disease comparable to a blasticide, tricyclazole. The glyphosate displayed direct antifungal activity on Magnaporthe oryzae as well as enhanced the levels of antioxidant enzymes and photosynthetic pigments in rice. However, the genes associated with phytohormones-mediated defense (OsPAD4, OsNPR1.3, and OsFMO) and innate immunity pathway (OsCEBiP and OsCERK1) were found repressed upon glyphosate spray. Altogether, the current study is the first report highlighting the overexpression of a crop-specific TIPS mutation in conjugation with glyphosate application showing potential for blast disease management in rice cultivation.


Assuntos
Antifúngicos/farmacologia , Ascomicetos/patogenicidade , Resistência a Herbicidas/genética , Herbicidas/farmacocinética , Oryza/genética , Oryza/microbiologia , Oryza/fisiologia , Doenças das Plantas/prevenção & controle , Ascomicetos/efeitos dos fármacos , Produtos Agrícolas/genética , Produtos Agrícolas/microbiologia , Produtos Agrícolas/fisiologia , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Variação Genética , Genótipo , Doenças das Plantas/genética , Plantas Geneticamente Modificadas/genética
3.
Plant Physiol Biochem ; 167: 198-209, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34365290

RESUMO

Two pepper methionine sulfoxide reductase B2 (CaMsrB2) gene expressing transgenic rice lines (L-8 and L-23) were interrogated with respect to their physiological and photochemical attributes along with control (WT, Ilmi) as a standard against varying levels of salt concentration which are 75 mM, 150 mM and 225 mM. Against various levels of salt (NaCl) concentration, recurring detrimental effects of extreme salt stress was observed and more pronounced in the wild type plants as compared to our transgenic lines. As the exacerbated effects of salinity is responsible for pushing the plants to their ecological tolerance, our transgenic lines performed well uplifted in different realms of physiology and photochemistry such as relative water content (RWC = 60-75%), stomatal conductance (gs = 70-190 mmolm-2s-1), performance index (PIABS = 1.0-4.5), maximal photochemical yield of PSII (FV/FM = 0.48-0.72) and chlorophyll content index (CCI = 5-7.2 au) in comparison to the control. Relative gene expression, ion analysis and antioxidants activity were analyzed in all treatments to ensure the hypothesis obtained from data of physiology and photochemistry. Photosynthetic apparatus is known to lose energy in various forms such as NPQ, DIO/CS, damages of reaction center (FV/FO) which are the markers of poor health were clearly decreased in the L-23 line as compared to L-8 and WT. Present study revealed the protruding tolerance of L-23 and L-8 transgenic lines with L-23 line in the lead in comparison to control and L-8 transgenic lines.


Assuntos
Metionina Sulfóxido Redutases , Oryza , Capsicum/enzimologia , Clorofila , Ecossistema , Metionina Sulfóxido Redutases/genética , Oryza/genética , Oryza/fisiologia , Fotossíntese , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/fisiologia , Estresse Fisiológico
4.
Int J Mol Sci ; 22(15)2021 Jul 25.
Artigo em Inglês | MEDLINE | ID: mdl-34360691

RESUMO

Two-line hybrid rice systems represent a new technical approach to utilizing the advantages of rice hybrids. However, the mechanism underlying the male sterile-line fertility transition in rice remains unclear. Peiai 64S (PA64S) is a photoperiod- and thermo-sensitive genic male sterile (PTGMS) line in which male sterility manifests at an average temperature above 23.5 °C under long-day (LD) conditions. Nongken 58S (NK58S) is a LD-sensitive genic male sterile (PGMS) rice that is sterile under LD conditions (above 13.75 h-day). In contrast, D52S is a short-day (SD)-PGMS line that manifests male sterility under SD conditions (below 13.5 h-day). In this study, we obtained fertile and sterile plants from all three lines and performed transcriptome analyses on the anthers of the plants. Gene ontology (GO) analysis suggested that the differentially expressed genes identified were significantly enriched in common terms involved in the response to jasmonic acid (JA) and in JA biosynthesis. On the basis of the biochemical and molecular validation of dynamic, tissue-specific changes in JA, indole-3-acetic acid (IAA) levels, gibberellin (GA) levels, and JA biosynthetic enzyme activities and expression, we proposed that JA could play a pivotal role in viable pollen production through its initial upregulation, constant fluctuation and leaf-spikelet signaling under certain fertility-inducing conditions. Furthermore, we also sprayed methyl jasmonate (MEJA) and salicylhydroxamic acid (SHAM) on the plants, thereby achieving fertility reversal in the PGMS lines NK58S and D52S, with 12.91-63.53% pollen fertility changes. Through qPCR and enzyme activity analyses, we identified two key enzymes-allene oxide synthase (AOS) and allene oxide cyclase (AOC)-that were produced and upregulated by 20-500-fold in PGMS in response to spraying; the activities of these enzymes reversed pollen fertility by influencing the JA biosynthetic pathway. These results provide a new understanding of hormone interactions and networks in male-sterile rice based on the role of JA that will help us to better understand the potential regulatory mechanisms of fertility development in rice in the future.


Assuntos
Ciclopentanos/metabolismo , Oxirredutases Intramoleculares/genética , Oryza/metabolismo , Oxilipinas/metabolismo , Pólen/crescimento & desenvolvimento , Transdução de Sinais , Acetatos/farmacologia , Ciclopentanos/farmacologia , Fertilidade , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Oryza/genética , Oryza/fisiologia , Oxilipinas/farmacologia , Proteínas de Plantas/genética , Pólen/metabolismo , Salicilamidas/farmacologia
5.
J Genet ; 1002021.
Artigo em Inglês | MEDLINE | ID: mdl-34282732

RESUMO

Rice is one of the most important cereals of the world, with a substantial amount of genetic variation, and a staple food for more than half of the world's population. Salinity is the second most important abiotic stress after drought that adversely affects rice production globally. Both the seedling and reproductive stages are extremely sensitive to salinity but tolerant at the reproductive stage which is most crucial, as it translates into grain yield. Therefore, it is more important to identify the underlying factors of tolerance at the reproductive stage as a necessary step towards improving varieties for salinity environments. However, because of the difficulties in phenotyping protocols of salinity tolerance screening at the reproductive stage, only a few studies exist on this aspect. In view of this, a study involving 188 F4 rice lines derived from a cross CSR28 × Sadri along with the parents was carried out for phenotyping using a novel screening approach for the reproductive stage in salinity conditions and genotyping by SNP markers (Infinium Illumina 6K SNP chip) to construct a high-saturation linkage map. Quantitative trait loci analysis in an F4 population for physiological traits (chlorophyll a, chlorophyll b and carotenoid) and agronomic traits (plant height, filled grain number, grain yield and spikelet fertility percentage) led to the identification of 14 QTLs with an LOD range of 2.72-4.46 explaining phenotypic variation of 5.29-24.86% on chromosomes 1, 2, 3, 5, 6, 7 and 8. Tolerant alleles were contributed by both CSR28 and Sadri. The results indicated that both physiological and agronomic traits were involved in salinity tolerance at the reproductive stage and majority of the QTLs identified in this study are reported for the first time.


Assuntos
Oryza/genética , Locos de Características Quantitativas/genética , Estresse Salino/genética , Tolerância ao Sal/genética , Alelos , Mapeamento Cromossômico/métodos , Cromossomos de Plantas , Genótipo , Oryza/crescimento & desenvolvimento , Oryza/fisiologia , Fenótipo , Reprodução/genética , Reprodução/fisiologia , Plântula/genética
6.
Nat Plants ; 7(8): 1065-1077, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34294907

RESUMO

Microbial symbioses can mitigate drought stress in crops but harnessing these beneficial interactions will require an in-depth understanding of root microbiome responses to drought cycles. Here, by detailed temporal characterization of root-associated microbiomes of rice plants during drought stress and recovery, we find that endosphere communities remained compositionally altered after rewatering, with prolonged droughts leading to decreased resilience. Several endospheric Actinobacteria were significantly enriched during drought and for weeks after rewatering. Notably, the most abundant endosphere taxon during this period was a Streptomyces, and a corresponding isolate promoted root growth. Additionally, drought stress disrupted the temporal dynamics of late-colonizing microorganisms, permanently altering the normal successional trends of root microbiota. These findings reveal that severe drought results in enduring impacts on rice root microbiomes, including enrichment of taxonomic groups that could shape the recovery response of the host, and have implications relevant to drought protection strategies using root microbiota.


Assuntos
Desidratação/microbiologia , Secas , Microbiota , Oryza/microbiologia , Oryza/fisiologia , Raízes de Plantas/microbiologia , Simbiose/fisiologia , Bactérias , Fungos
7.
Int J Mol Sci ; 22(12)2021 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-34203082

RESUMO

Ideal Plant Architecture 1 (IPA1) encodes SQUAMOSA PROMOTER BINDING PROTEIN-LIKE 14 (SPL14) with a pleiotropic effect on regulating rice development and biotic stress responses. To investigate the role of IPA1 in early seedling development, we developed a pair of IPA1/ipal-NILs and found that seed germination and early seedling growth were retarded in the ipa1-NIL. Analysis of the soluble sugar content, activity of amylase, and expression of the α-amylase genes revealed that the starch metabolism was weakened in the ipa1-NIL germinating seeds. Additionally, the content of bioactive gibberellin (GA) was significantly lower than that in the IPA1-NIL seeds at 48 h of imbibition. Meanwhile, the expression of GA synthesis-related gene OsGA20ox1 was downregulated, whereas the expression of GA inactivation-related genes was upregulated in ipa1-NIL seeds. In addition, the expression of OsWRKY51 and OsWRKY71 was significantly upregulated in ipa1-NIL seeds. Using transient dual-luciferase and yeast one-hybrid assays, IPA1 was found to directly activate the expression of OsWRKY51 and OsWRKY71, which would interfere with the binding affinity of GA-induced transcription factor OsGAMYB to inhibit the expression of α-amylase genes. In summary, our results suggest that IPA1 negatively regulates seed germination and early seedling growth by interfering with starch metabolism via the GA and WRKY pathways.


Assuntos
Proteínas de Ligação a DNA/metabolismo , Giberelinas/metabolismo , Oryza/fisiologia , Desenvolvimento Vegetal , Plântula/crescimento & desenvolvimento , Transdução de Sinais , Amido/metabolismo , Fatores de Transcrição/metabolismo , Regulação da Expressão Gênica de Plantas , Germinação/genética , Fenótipo , Ligação Proteica , alfa-Amilases/metabolismo
8.
BMC Plant Biol ; 21(1): 308, 2021 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-34193032

RESUMO

BACKGROUND: Rice (Oryza sativa L.) Chalkiness, the opaque part in the kernel endosperm formed by loosely piled starch and protein bodies. Chalkiness is a complex quantitative trait regulated by multiple genes and various environmental factors. Phytohormones play important roles in the regulation of chalkiness formation but the underlying molecular mechanism is still unclear at present. RESULTS: In this research, Xiangzaoxian24 (X24, pure line of indica rice with high-chalkiness) and its origin parents Xiangzaoxian11 (X11, female parent, pure line of indica rice with high-chalkiness) and Xiangzaoxian7 (X7, male parent, pure line of indica rice with low-chalkiness) were used as materials. The phenotype, physiological and biochemical traits combined with transcriptome analysis were conducted to illustrate the dynamic process and transcriptional regulation of rice chalkiness formation. Impressively, phytohormonal contents and multiple phytohormonal signals were significantly different in chalky caryopsis, suggesting the involvement of phytohormones, particularly ABA and auxin, in the regulation of rice chalkiness formation, through the interaction of multiple transcription factors and their downstream regulators. CONCLUSION: These results indicated that chalkiness formation is a dynamic process associated with multiple genes, forming a complex regulatory network in which phytohormones play important roles. These results provided informative clues for illustrating the regulatory mechanisms of chalkiness formation in rice.


Assuntos
Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Oryza/genética , Oryza/fisiologia , Reguladores de Crescimento de Plantas/farmacologia , Transcrição Genética/efeitos dos fármacos , Endosperma/efeitos dos fármacos , Endosperma/metabolismo , Endosperma/ultraestrutura , Perfilação da Expressão Gênica , Ontologia Genética , Oryza/efeitos dos fármacos , Fenótipo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Reprodutibilidade dos Testes , Amido/metabolismo , Amido/ultraestrutura , Sacarose/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
9.
Int J Mol Sci ; 22(11)2021 Jun 04.
Artigo em Inglês | MEDLINE | ID: mdl-34199720

RESUMO

The underground reserve (root) has been an uncharted research territory with its untapped genetic variation yet to be exploited. Identifying ideal traits and breeding new rice varieties with efficient root system architecture (RSA) has great potential to increase resource-use efficiency and grain yield, especially under direct-seeded rice, by adapting to aerobic soil conditions. In this review, we tried to mine the available research information on the direct-seeded rice (DSR) root system to highlight the requirements of different root traits such as root architecture, length, number, density, thickness, diameter, and angle that play a pivotal role in determining the uptake of nutrients and moisture at different stages of plant growth. RSA also faces several stresses, due to excess or deficiency of moisture and nutrients, low or high temperature, or saline conditions. To counteract these hindrances, adaptation in response to stress becomes essential. Candidate genes such as early root growth enhancer PSTOL1, surface rooting QTL qSOR1, deep rooting gene DRO1, and numerous transporters for their respective nutrients and stress-responsive factors have been identified and validated under different circumstances. Identifying the desired QTLs and transporters underlying these traits and then designing an ideal root architecture can help in developing a suitable DSR cultivar and aid in further advancement in this direction.


Assuntos
Adaptação Fisiológica/fisiologia , Oryza/fisiologia , Raízes de Plantas/anatomia & histologia , Raízes de Plantas/fisiologia , Sementes/fisiologia , Germinação/fisiologia , Oryza/genética , Oryza/crescimento & desenvolvimento , Locos de Características Quantitativas/genética , Sementes/genética , Sementes/crescimento & desenvolvimento
10.
Int J Mol Sci ; 22(13)2021 Jun 29.
Artigo em Inglês | MEDLINE | ID: mdl-34209672

RESUMO

Gene editing by use of clustered regularly interspaced short palindromic repeats (CRISPR) has become a powerful tool for crop improvement. However, a common bottleneck in the application of this approach to grain crops, including rice (Oryza sativa), is efficient vector delivery and calli regeneration, which can be hampered by genotype-dependent requirements for plant regeneration. Here, methods for Agrobacterium-mediated and biolistic transformation and regeneration of indica rice were optimized using CRISPR-Cas9 gene-editing of the submergence tolerance regulator SUBMERGENCE 1A-1 gene of the cultivar Ciherang-Sub1. Callus induction and plantlet regeneration methods were optimized for embryogenic calli derived from immature embryos and mature seed-derived calli. Optimized regeneration (95%) and maximal editing efficiency (100%) were obtained from the immature embryo-derived calli. Phenotyping of T1 seeds derived from the edited T0 plants under submergence stress demonstrated inferior phenotype compared to their controls, which phenotypically validates the disruption of SUB1A-1 function. The methods pave the way for rapid CRISPR-Cas9 gene editing of recalcitrant indica rice cultivars.


Assuntos
Genes de Plantas , Oryza/fisiologia , Regeneração , Transformação Genética , Sistemas CRISPR-Cas , Proteínas de Ligação ao Cálcio/genética , Edição de Genes , Fenótipo , Desenvolvimento Vegetal/genética , Plantas Geneticamente Modificadas , Reprodutibilidade dos Testes , Sementes/genética , Sementes/crescimento & desenvolvimento
11.
Nat Plants ; 7(7): 888-892, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-34112987

RESUMO

Base-editing-library-induced high density nucleotide substitutions have been applied to screen functional mutations in plants. However, due to limitations in the scope and conversion specificity of base editors, many desired mutations at pivotal protein sites may be overlooked. Here, we developed a prime-editing-library-mediated saturation mutagenesis (PLSM) method to substantially increase the diversity of amino acid substitutions at target sites for in planta screening. At six conserved residues of OsACC1, 16 types of herbicide-resistance-endowing mutations were identified. Most of these mutations exhibit reliable tolerance to aryloxyphenoxypropionate herbicides and have not been reported or applied in rice breeding. In addition, the advantage of PLSM was further shown by comparing the base-editing-mediated mutagenesis at the selected targets. The PLSM method established in this study has great potential for the direct evolution of genes related to agronomically important traits for crop improvement.


Assuntos
Edição de Genes , Biblioteca Gênica , Resistência a Herbicidas/genética , Resistência a Herbicidas/fisiologia , Oryza/genética , Oryza/fisiologia , Produtos Agrícolas/genética , Produtos Agrícolas/fisiologia , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Mutação , Plantas Geneticamente Modificadas/genética
12.
Int J Mol Sci ; 22(11)2021 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-34073070

RESUMO

Although recent studies suggest that the plant cytoskeleton is associated with plant stress responses, such as salt, cold, and drought, the molecular mechanism underlying microtubule function in plant salt stress response remains unclear. We performed a comparative proteomic analysis between control suspension-cultured cells (A0) and salt-adapted cells (A120) established from Arabidopsis root callus to investigate plant adaptation mechanisms to long-term salt stress. We identified 50 differentially expressed proteins (45 up- and 5 down-regulated proteins) in A120 cells compared with A0 cells. Gene ontology enrichment and protein network analyses indicated that differentially expressed proteins in A120 cells were strongly associated with cell structure-associated clusters, including cytoskeleton and cell wall biogenesis. Gene expression analysis revealed that expressions of cytoskeleton-related genes, such as FBA8, TUB3, TUB4, TUB7, TUB9, and ACT7, and a cell wall biogenesis-related gene, CCoAOMT1, were induced in salt-adapted A120 cells. Moreover, the loss-of-function mutant of Arabidopsis TUB9 gene, tub9, showed a hypersensitive phenotype to salt stress. Consistent overexpression of Arabidopsis TUB9 gene in rice transgenic plants enhanced tolerance to salt stress. Our results suggest that microtubules play crucial roles in plant adaptation and tolerance to salt stress. The modulation of microtubule-related gene expression can be an effective strategy for developing salt-tolerant crops.


Assuntos
Proteínas de Arabidopsis/fisiologia , Arabidopsis , Microtúbulos/fisiologia , Oryza , Tolerância ao Sal , Arabidopsis/fisiologia , Regulação da Expressão Gênica de Plantas , Oryza/fisiologia , Plantas Geneticamente Modificadas/fisiologia
13.
Plant Mol Biol ; 106(4-5): 419-432, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34129189

RESUMO

KEY MESSAGE: Coordinated regulation of amylose and amylopectin synthesis via manipulation of SSII-2, SSII-3 and Wx expression in endosperm can improve rice eating and cooking quality. With increasing rice consumption worldwide, many researchers are working to increase the yield and improve grain quality, especially eating and cooking quality (ECQ). The rice ECQ is mainly controlled by the expression of starch synthesis-related genes (SSRGs) in endosperm. Although the Wx and SSII-3/SSIIa/ALK genes, two major SSRGs, have been manipulated to improve rice ECQ via various breeding approaches, new methods to further improve ECQ are desired. In our previous study, we enhanced rice ECQ by knocking down SSII-2 expression in the japonica Nipponbare cultivar (carrying the Wxb allele) via RNA interference. Herein, the SSII-2 RNAi was introduced into two Nipponbare-derived near-isogenic lines (NILs), Nip(Wxa) and Nip(wx), carrying Wxa and wx alleles respond for high and no amylose levels, respectively. Analysis of physicochemical properties revealed that the improved grain quality of SSII-2 RNAi transgenic lines was achieved by coordinated downregulating the expression of SSII-2, SSII-3 and Wx. To further confirm this conclusion, we generated ssii-2, ssii-3 and ssii-2ssii-3 mutants via CRISPR/Cas9 technique. The amylopectin structure of the resulting ssii-2sii-3 mutants was similar to that in SSII-2 RNAi transgenic lines, and the absence of SSII-2 decreased the amylose content, gelatinisation temperature and rapid visco-analyser profile, indicating essential roles for SSII-2 in the regulation of amylopectin biosynthesis and amylose content in rice endosperm. The effect of SSII-2 was seen only when the activity of SSII-3 was very low or lacking. Our study provides novel approaches and valuable germplasm resources for improving ECQ via plant breeding.


Assuntos
Grão Comestível/genética , Endosperma/genética , Regulação da Expressão Gênica de Plantas , Oryza/genética , Amido/biossíntese , Culinária , Grão Comestível/enzimologia , Grão Comestível/fisiologia , Qualidade dos Alimentos , Oryza/enzimologia , Oryza/fisiologia , Proteínas de Plantas/genética , Interferência de RNA , Amido/genética , Sintase do Amido/genética
14.
BMC Plant Biol ; 21(1): 278, 2021 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-34147069

RESUMO

BACKGROUND: Cold stress caused by low temperatures is an important factor restricting rice production. Identification of cold-tolerance genes that can stably express in cold environments is crucial for molecular rice breeding. RESULTS: In this study, we employed high-throughput quantitative trait locus sequencing (QTL-seq) analyses in a 460-individual F2:3 mapping population to identify major QTL genomic regions governing cold tolerance at the seedling stage in rice. A novel major QTL (qCTS6) controlling the survival rate (SR) under low-temperature conditions of 9°C/10 days was mapped on the 2.60-Mb interval on chromosome 6. Twenty-seven single-nucleotide polymorphism (SNP) markers were designed for the qCST6 region based on re-sequencing data, and local QTL mapping was conducted using traditional linkage analysis. Eventually, we mapped qCTS6 to a 96.6-kb region containing 13 annotated genes, of which seven predicted genes contained 13 non-synonymous SNP loci. Quantitative reverse transcription PCR analysis revealed that only Os06g0719500, an OsbZIP54 transcription factor, was strongly induced by cold stress. Haplotype analysis confirmed that +376 bp (T>A) in the OsbZIP54 coding region played a key role in regulating cold tolerance in rice. CONCLUSION: We identified OsbZIP54 as a novel regulatory gene associated with rice cold-responsive traits, with its Dongfu-104 allele showing specific cold-induction expression serving as an important molecular variation for rice improvement. This result is expected to further exploration of the genetic mechanism of rice cold tolerance at the seedling stage and improve cold tolerance in rice varieties by marker-assisted selection.


Assuntos
Aclimatação/genética , Genes de Plantas , Oryza/genética , Mapeamento Cromossômico , Oryza/crescimento & desenvolvimento , Oryza/fisiologia , Polimorfismo de Nucleotídeo Único , Locos de Características Quantitativas , Plântula/genética , Plântula/fisiologia , Sequenciamento Completo do Genoma
15.
BMC Plant Biol ; 21(1): 263, 2021 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-34098898

RESUMO

BACKGROUND: Recent temperature increases due to rapid climate change have negatively affected rice yield and grain quality. Particularly, high temperatures during right after the flowering stage reduce spikelet fertility, while interfering with sugar energy transport, and cause severe damage to grain quality by forming chalkiness grains. The effect of high-temperature on spikelet fertility and grain quality during grain filling stage was evaluated using a double haploid line derived from another culture of F1 by crossing Cheongcheong and Nagdong cultivars. Quantitative trait locus (QTL) mapping identifies candidate genes significantly associated with spikelet fertility and grain quality at high temperatures. RESULTS: Our analysis screened OsSFq3 that contributes to spikelet fertility and grain quality at high-temperature. OsSFq3 was fine-mapped in the region RM15749-RM15689 on chromosome 3, wherein four candidate genes related to the synthesis and decomposition of amylose, a starch component, were predicted. Four major candidate genes, including OsSFq3, and 10 different genes involved in the synthesis and decomposition of amylose and amylopectin, which are starch constituents, together with relative expression levels were analyzed. OsSFq3 was highly expressed during the initial stage of high-temperature treatment. It exhibited high homology with FLOURY ENDOSPERM 6 in Gramineae plants and is therefore expected to function similarly. CONCLUSION: The QTL, major candidate genes, and OsSFq3 identified herein could be effectively used in breeding rice varieties to improve grain quality, while tolerating high temperatures, to cope with climate changes. Furthermore, linked markers can aid in marker-assisted selection of high-quality and -yield rice varieties tolerant to high temperatures.


Assuntos
Mapeamento Cromossômico , Grão Comestível/crescimento & desenvolvimento , Genes de Plantas , Temperatura Alta , Oryza/fisiologia , Locos de Características Quantitativas , Amilose/metabolismo , Grão Comestível/genética , Endosperma/metabolismo , Fertilidade , Oryza/genética , Melhoramento Vegetal
16.
Plant Cell Rep ; 40(9): 1751-1772, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34173048

RESUMO

KEY MESSAGE: Early induction of OsFEX was insufficient for fluoride adaptation in IR-64. Overexpression of OsFEX in yeast and Nicotiana benthamiana enhanced fluoride tolerance. The present study delineates the regulation of fluoride exporter (FEX) in the fluoride-sensitive rice cultivar, IR-64 and its efficacy in generating high fluoride tolerance in transgenic Nicotiana benthamiana. Gene and protein expression profiling revealed that OsFEX exhibited early induction during fluoride stress in the vegetative and reproductive tissues of IR-64, although the expression was suppressed upon prolonged stress treatment. Analysis of OsFEX promoter in transgenic N. benthamiana, using ß-glucuronidase reporter assay confirmed its early inducible nature, since the reporter expression and activity peaked at 12 h of NaF stress, after which it was lowered. OsFEX expression was up regulated in the presence of gibberellic acid (GA) and melatonin, while it was suppressed by abscisic acid (ABA). Complementation of ΔFEX1ΔFEX2 yeast mutants with OsFEX enabled high fluoride tolerance, thus validating the functional efficiency of the transgene. Bioassay of transgenic N. benthamiana lines, expressing OsFEX either under its own promoter or under CaMV35S promoter, established that constitutive overexpression, rather than early induction of OsFEX was essential and crucial for generating fluoride tolerance in the transgenics. Overall, the suppression of OsFEX in the later growth phases of stressed IR-64 due to enhanced ABA conservation and lowered synthesis of GA, as supported by the application of the respective phytohormone biosynthetic inhibitors, such as sodium tungstate and paclobutrazol, accounted for the fluoride-hyperaccumulative nature of the rice cultivar.


Assuntos
Fluoretos/toxicidade , Oryza/efeitos dos fármacos , Oryza/fisiologia , Proteínas de Plantas/genética , Tabaco/genética , Ácido Abscísico/farmacologia , Adaptação Fisiológica/efeitos dos fármacos , Adaptação Fisiológica/genética , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Fluoretos/metabolismo , Regulação da Expressão Gênica de Plantas , Teste de Complementação Genética , Giberelinas/farmacologia , Proteínas de Membrana/genética , Microrganismos Geneticamente Modificados , Mutação , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas , Regiões Promotoras Genéticas , Saccharomyces cerevisiae/efeitos dos fármacos , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/genética , Estresse Fisiológico/efeitos dos fármacos , Estresse Fisiológico/fisiologia
17.
Plant Cell Rep ; 40(8): 1495-1512, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34089089

RESUMO

KEY MESSAGE: Expression pattern indicates that JA biosynthesis pathway via regulating JA levels might control root system architecture to improve nutrient use efficiency (NUE) and N, P, K+ deficiency tolerance in rice. Deficiencies of macronutrients (N, P and K+) and consequent excessive use of fertilizers have dramatically reduced soil fertility. It calls for development of nutrient use efficient plants. Plants combat nutrient deficiencies by altering their root system architecture (RSA) to enhance the acquisition of nutrients from the soil. Amongst various phytohormones, Jasmonic acid (JA) is known to regulate plant root growth and modulate RSA. Therefore, to understand the role of JA in macronutrient deficiency in rice, expression pattern of JA biosynthesis genes was analyzed under N, P and K+ deficiencies. Several members belonging to different families of JA biosynthesis genes (PLA1, LOX, AOS, AOC, OPR, ACX and JAR1) showed differential expression exclusively in one nutrient deficiency or in multiple nutrient deficiencies. Expression analysis during developmental stages showed that several genes expressed significantly in vegetative tissues, particularly in root. In addition, JA biosynthesis genes were found to have significant expression under the treatment of different phytohormones, including Auxin, cytokinin, gibberellic acid (GA), abscisic acid (ABA), JA and abiotic stresses, such as drought, salinity and cold. Analysis of promoters of these genes revealed various cis-regulatory elements associated with hormone response, plant development and abiotic stresses. These findings suggest that JA biosynthesis pathway by regulating the level of JA might control the RSA thus, it may help rice plant in combating macronutrient deficiency.


Assuntos
Ciclopentanos/metabolismo , Oryza/fisiologia , Oxilipinas/metabolismo , Proteínas de Plantas/genética , Regulação da Expressão Gênica de Plantas , Redes e Vias Metabólicas/genética , Nitrogênio/metabolismo , Oryza/efeitos dos fármacos , Fósforo/metabolismo , Reguladores de Crescimento de Plantas/metabolismo , Reguladores de Crescimento de Plantas/farmacologia , Proteínas de Plantas/metabolismo , Potássio/metabolismo , Regiões Promotoras Genéticas , Estresse Fisiológico/fisiologia
18.
Genes (Basel) ; 12(5)2021 05 11.
Artigo em Inglês | MEDLINE | ID: mdl-34064770

RESUMO

Lodging reduces rice yield, but increasing lodging resistance (LR) usually limits yield potential. Stem strength and leaf type are major traits related to LR and yield, respectively. Hence, understanding the genetic basis of stem strength and leaf type is of help to reduce lodging and increase yield in LR breeding. Here, we carried out an association analysis to identify quantitative trait locus (QTLs) affecting stem strength-related traits (internode length/IL, stem wall thickness/SWT, stem outer diameter/SOD, and stem inner diameter/SID) and leaf type-associated traits (Flag leaf length/FLL, Flag leaf angle/FLA, Flag leaf width/FLW, leaf-rolling/LFR and SPAD/Soil, and plant analyzer development) using a diverse panel of 550 accessions and evaluated over two years. Genome-wide association study (GWAS) using 4,076,837 high-quality single-nucleotide polymorphisms (SNPs) identified 89 QTLs for the nine traits. Next, through "gene-based association analysis, haplotype analysis, and functional annotation", the scope was narrowed down step by step. Finally, we identified 21 candidate genes in 9 important QTLs that included four reported genes (TUT1, OsCCC1, CFL1, and ACL-D), and seventeen novel candidate genes. Introgression of alleles, which are beneficial for both stem strength and leaf type, or pyramiding stem strength alleles and leaf type alleles, can be employed for LR breeding. All in all, the experimental data and the identified candidate genes in this study provide a useful reference for the genetic improvement of rice LR.


Assuntos
Oryza/genética , Caules de Planta/genética , Polimorfismo de Nucleotídeo Único , Característica Quantitativa Herdável , Oryza/fisiologia , Locos de Características Quantitativas
19.
Ecotoxicol Environ Saf ; 220: 112401, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34118747

RESUMO

Cadmium (Cd) is a trace element causing severe toxicity symptoms in plants, besides posing hazardous fitness issue due to its buildup in the human body through food chain. Nanoparticles (NPs) are recently employed as a novel strategy to directly ameliorate the Cd stress and acted as nano-fertilizers. The intend of the current study was to explore the effects of zinc oxide nanoparticles (ZnO-NPs; 50 mg/L) on plant growth, photosynthetic activity, elemental status and antioxidant activity in Oryza sativa (rice) under Cd (0.8 mM) stress. To this end, the rice plants are treated by Cd stress at 15 days after sowing (DAS), and the treatment was given directly into the soil. Supply of ZnO-NPs as foliar spray was given for five consecutive days from 30 to 35 DAS, and sampling was done at 45 DAS. However, rice plants supplemented with ZnO-NPs under the Cd toxicity revealed significantly increased shoot length (SL; 34.0%), root fresh weight (RFW; 30.0%), shoot dry weight (SDW; 23.07%), and root dry weight (RDW; 12.24%). Moreover, the ZnO-NPs supplement has also positive effects on photosynthesis related parameters, SPAD value (40%), chloroplast structure, and qualitatively high fluorescence observed by confocal microscopy even under Cd stress. ZnO-NPs also substantially prevented the increases of hydrogen peroxide (H2O2) and malondialdehyde (MDA) triggered by Cd. Physiological and biochemical analysis showed that ZnO-NPs increased enzymatic activities of superoxide dismutase (SOD; 59%), catalase (CAT; 52%), and proline (17%) that metabolize reactive oxygen species (ROS); these increases coincided with the changes observed in the H2O2 and MDA accumulation after ZnO-NPs application. In conclusion, ZnO-NPs application to foliage has great efficiency to improve biomass, photosynthesis, protein, antioxidant enzymes activity, mineral nutrient contents and reducing Cd levels in rice. This can be attributed mainly from reduced oxidative damage resulted due to the ZnO-NPs application.


Assuntos
Antioxidantes/metabolismo , Cádmio/efeitos adversos , Nanopartículas , Oryza/efeitos dos fármacos , Fotossíntese/efeitos dos fármacos , Poluentes do Solo/efeitos adversos , Óxido de Zinco/farmacologia , Biomassa , Catalase/metabolismo , Produtos Agrícolas/efeitos adversos , Produtos Agrícolas/fisiologia , Fertilizantes , Humanos , Peróxido de Hidrogênio/metabolismo , Malondialdeído/metabolismo , Oryza/crescimento & desenvolvimento , Oryza/metabolismo , Oryza/fisiologia , Estresse Oxidativo/efeitos dos fármacos , Folhas de Planta , Solo/química , Superóxido Dismutase/metabolismo , Óxido de Zinco/administração & dosagem
20.
Ecotoxicol Environ Saf ; 217: 112100, 2021 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-33933890

RESUMO

Studies focusing on arsenic methylation and volatilization in paddy soil, aiming to limit bioaccumulation of arsenic (As) in rice grains, have attracted global attention. In this study, we explored three aspects of these topics. First, rainwater and trace H2O2 were compared for their influence on the arsenic methylation and volatilization of paddy soil in different rice growth stages. Second, the arsenic accumulation in different parts of rice was affected by rainwater and trace H2O2. Third, we determined whether rice fields were affected by rainwater and trace H2O2. The result showed that the rainwater or trace H2O2 irrigation caused As(III) to significantly decrease and As(V) to significantly increase in soil. A similar consequence occurred in the filling stage and mature stage of rice. The arsenic volatilization rates of the rainwater and trace H2O2 irrigation were significantly higher than the control, and the arsenic volatilization of rainwater irrigation was the highest (51.0 µg m-2 d-1) in the filling stage. Compared to the control, the total arsenic and iAs of treatments decreased by 14-41% and 12-32% respectively. Finally, we found that rainwater and trace H2O2 irrigation likely increased rice fields.


Assuntos
Poluentes Atmosféricos/química , Arsênio/toxicidade , Peróxido de Hidrogênio/química , Oryza/fisiologia , Poluentes do Solo/toxicidade , Arsênio/química , Arsênio/metabolismo , Metilação , Oryza/crescimento & desenvolvimento , Solo , Poluentes do Solo/análise , Poluentes do Solo/química , Poluentes do Solo/metabolismo , Volatilização
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