Precise Editing of the OsPYL9 Gene by RNA-Guided Cas9 Nuclease Confers Enhanced Drought Tolerance and Grain Yield in Rice (Oryza sativa L.) by Regulating Circadian Rhythm and Abiotic Stress Responsive Proteins

Abscisic acid (ABA) is involved in regulating drought tolerance, and pyrabactin resistance-like (PYL) proteins are known as ABA receptors. To elucidate the role of one of the ABA receptors in rice, OsPYL9 was mutagenized through CRISPR/Cas9 in rice. Homozygous and heterozygous mutant plants lacking any off-targets and T-DNA were screened based on site-specific sequencing and used for morpho-physiological, molecular, and proteomic analysis. Mutant lines appear to accumulate higher ABA, antioxidant activities, chlorophyll content, leaf cuticular wax, and survival rate, whereas a lower malondialdehyde level, stomatal conductance, transpiration rate, and vascular bundles occur under stress conditions. Proteomic analysis found a total of 324 differentially expressed proteins (DEPs), out of which 184 and 140 were up and downregulated, respectively. The OsPYL9 mutants showed an increase in grain yield under both drought and well watered field conditions. Most of the DEPs related to circadian clock rhythm, drought response, and reactive oxygen species were upregulated in the mutant plants. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis revealed that DEPs were only involved in circadian rhythm and Gene Ontology (GO) analysis showed that most of the DEPs were involved in response to abiotic stimulus, and abscisic acid-activated signaling pathways. Protein GIGANTEA, Adagio-like, and Pseudo-response regulator proteins showed higher interaction in protein–protein interaction (PPI) network. Thus, the overall results showed that CRISPR/Cas9-generated OsPYL9 mutants have potential to improve both drought tolerance and the yield of rice. Furthermore, global proteome analysis provides new potential biomarkers and understandings of the molecular mechanism of rice drought tolerance.

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Genotype by environment analysis of rice (Oryza sativa L.) populations under drought stressed and well-watered environments

Australian Journal of Crop Science ◽

10.21475/ajcs.20.14.02.p2112 ◽

2020 ◽

pp. 259-262

Author(s):

Lourine Chebet Bii ◽

Kahiu Ngugi ◽

John M. Kimani ◽

George N. Chemining’ wa

Keyword(s):

Oryza Sativa ◽

Drought Stress ◽

Drought Tolerance ◽

Grain Yield ◽

Oryza Sativa L ◽

Phenotypic Traits ◽

Yield Data ◽

Physiological Maturity ◽

Lattice Design ◽

Gge Biplots

In Kenya, the key abiotic stress affecting rice production is drought stress which is experienced mainly during reproductive phase of the crop. This study evaluated the performance of Kenyan rice populations including 19 generation of crosses, 6 parental and 5 checks under well-watered and drought stressed environment with the aim of identifying the phenotypic traits that confer drought tolerance in rice. The 19 generation of crosses were in F3 when they were evaluated in the short rains season and later advanced to F4 in the long rains season. Nineteen generation of crosses rice (Oryza sativa L.) lines, six parental and five check lines were evaluated for response to drought under drought stressed and well-watered environment. The study was conducted over two seasons in the year 2016/2017 at Kenya Agricultural Livestock Research Organization (KALRO) -Mwea Centre. The experiment was set up in an alpha lattice design with three replications. Drought stress was imposed at panicle initiation by withholding irrigation till physiological maturity meanwhile the well-watered environment continued to enjoy the recommended irrigation regime from planting to physiological maturity. Yield data were scored for drought tolerance. AMMI analysis of variance for grain yield showed that genotypes from crosses of crosses of SARO5XNERICA11, NERICA2XSARO5 and NERICA15XSARO5 expressed high grain yield. AMMI stability Variance (ASV) showed genotypes NERICA15, Duorado Precoce and progenies from crosses of NERICA11XNERICA2, SARO5XKomboka and NERICA2XNERICA11 expressed high stability in both well-watered and drought-stressed environment. GGE analysis showed that Principal Components (PC1) and PC2 accounted for 96.46% and 3.54%, respectively. GGE biplots showed that genotypes from crosses SARO5XNERICA11 and NERICA15XSARO5 were the most stable and high yielding. GGE biplots ranked the rice lines as follows: those above average in performance, the stable ones, unstable and those below average in performance. SARO5XNERICA11 is worth of selection due to its high mean yield value and is stable across the mega-environments.

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Genetic studies for drought tolerance under contrasting moisture regimes in rice (Oryza sativa L.)

ORYZA- An International Journal on Rice ◽

10.35709/ory.2020.57.2.4 ◽

2020 ◽

Vol 57 (2) ◽

pp. 108-115

Author(s):

D Shoba ◽

S Robin ◽

P Jeyaprakash ◽

M Arumugam Pillai

Keyword(s):

Drought Tolerance ◽

Grain Yield ◽

Plant Height ◽

Leaf Senescence ◽

Oryza Sativa L ◽

Flowering Plant ◽

Genetic Advance ◽

Leaf Rolling ◽

Panicle Length ◽

Stress Regime

Twenty six genotypes and four check varieties were studied for drought tolerance in rice. The experiment was conducted under both irrigated and stress regimes. Ten different drought tolerant contributing traits were evaluated under stress regime and five yield contributing traits were evaluated under irrigated regime. Among the studied genotypes, IR 87651-26-1-1-3 possessed desirable mean performance under stress for grain yield with other studied traits except number of panicles per plant. Under irrigated regime, the genotypes IR 87753-13-1-1-3, IR 87638-10-1-1-3, IR 87759-5-2-1-3 and IR 83381-B-B-137-3 were advantageous for grain yield and other studied traits except number of panicles per plant. From the variability studies under stress, the traits viz., leaf rolling, leaf senescence, leaf drying, panicle exsertion and grain yield exhibited high genetic advance indicated additive gene action and selection is desirable for these traits. High heritability with advantageous genetic advance was recorded for plant height and grain yield under non-stress regime. From the association analysis, grain yield had positive correlation with plant height, number of panicles per plant and panicle length and negative correlation with days to fifty per cent flowering, leaf rolling, leaf senescence, leaf drying and panicle exsertion under stress. Grain yield was positively correlated with days to fifty per cent flowering, plant height and panicle length under non stress. The desirable genotypes recognized from this study may be utilized as donors and the desirable traits identified may be exploited for drought tolerance rice breeding programs.

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Priming of rice ( Oryza sativa L.) seedlings with abscisic acid enhances seedling survival, plant growth, and grain yield in saline-alkaline paddy fields

Field Crops Research ◽

10.1016/j.fcr.2016.12.024 ◽

2017 ◽

Vol 203 ◽

pp. 86-93 ◽

Cited By ~ 19

Author(s):

Li-Xing Wei ◽

Bing-Sheng Lv ◽

Xiao-Wei Li ◽

Ming-Ming Wang ◽

Hong-Yuan Ma ◽

...

Keyword(s):

Oryza Sativa ◽

Abscisic Acid ◽

Plant Growth ◽

Grain Yield ◽

Oryza Sativa L ◽

Seedling Survival ◽

Paddy Fields

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Programmed Editing of Rice (Oryza sativa L.) OsSPL16 Gene Using CRISPR/Cas9 Improves Grain Yield by Modulating the Expression of Pyruvate Enzymes and Cell Cycle Proteins

International Journal of Molecular Sciences ◽

10.3390/ijms22010249 ◽

2020 ◽

Vol 22 (1) ◽

pp. 249

Author(s):

Babar Usman ◽

Gul Nawaz ◽

Neng Zhao ◽

Shanyue Liao ◽

Baoxiang Qin ◽

...

Keyword(s):

Oryza Sativa ◽

Grain Yield ◽

Pyruvate Dehydrogenase ◽

Agronomic Traits ◽

Oryza Sativa L ◽

Pyruvate Dehydrogenase Complex ◽

Gene Mutations ◽

Proteome Analysis ◽

Mendelian Inheritance ◽

Dynamic Regulation

Rice (Oryza sativa L.) is one of the major crops in the world and significant increase in grain yield is constant demand for breeders to meet the needs of a rapidly growing population. The size of grains is one of major components determining rice yield and a vital trait for domestication and breeding. To increase the grain size in rice, OsSPL16/qGW8 was mutagenized through CRISPR/Cas9, and proteomic analysis was performed to reveal variations triggered by mutations. More specifically, mutants were generated with two separate guide RNAs targeting recognition sites on opposite strands and genomic insertions and deletions were characterized. Mutations followed Mendelian inheritance and homozygous and heterozygous mutants lacking any T-DNA and off-target effects were screened. The mutant lines showed a significant increase in grain yield without any change in other agronomic traits in T0, T1, and T2 generations. Proteomic screening found a total of 44 differentially expressed proteins (DEPs), out of which 33 and 11 were up and downregulated, respectively. Most of the DEPs related to pyruvate kinase, pyruvate dehydrogenase, and cell division and proliferation were upregulated in the mutant plants. Pathway analysis revealed that DEPs were enriched in the biosynthesis of secondary metabolites, pyruvate metabolism, glycolysis/gluconeogenesis, carbon metabolism, ubiquinone and other terpenoid-quinone biosynthesis, and citrate cycle. Gene Ontology (GO) analysis presented that most of the DEPs were involved in the pyruvate metabolic process and pyruvate dehydrogenase complex. Proteins related to pyruvate dehydrogenase E1 component subunit alpha-1 displayed higher interaction in the protein-protein interaction (PPI) network. Thus, the overall results revealed that CRISPR/Cas9-guided OsSPL16 mutations have the potential to boost the grain yield of rice. Additionally, global proteome analysis has broad applications for discovering molecular components and dynamic regulation underlying the targeted gene mutations.

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Utilize of genetic diversity and marker-trait association to improve drought tolerance in rice (Oryza sativa L.)

10.21203/rs.3.rs-29383/v1 ◽

2020 ◽

Author(s):

Mohamed I. Ghazy ◽

Khaled. F. Salem ◽

Ahmed Sallam

Keyword(s):

Genetic Diversity ◽

Drought Tolerance ◽

Grain Yield ◽

Oryza Sativa L ◽

Phenotypic Correlation ◽

Phenotypic Traits ◽

Yield Traits ◽

Drought Tolerant ◽

Drought Conditions ◽

Rice Genotypes

Abstract Drought stress in one of the main problems for rice crop as it reduces the production and productivity of the grain yield significantly. In Egypt, many restrictions were made on the cultivation of rice due to its high water demand. Producing promising drought-tolerant rice cultivars in a combination with high yielding is one of the main targets for rice breeders. To address this challenge, a set of 22 highly diverse rice genotypes were evaluated under normal and drought conditions. Morphological, physiological, yield traits were recorded on each genotype. Drought susceptibility index (DSI) was estimated for six yield traits to identify the most drought-tolerant rice genotypes. High genetic variation was found among genotypes tested in the experiment. Under normal conditions, the highest phenotypic correlation was found between grain yield (GY) and sterility percentage (SP) (- 0.73**), while, it was among GY and chlorophyll content (CC) (0.82**) under drought conditions. To identify quantitative trait loci (QTL) controlling yielding traits under drought and normal, single marker analysis was performed between all yield traits under both condition and a set of 106 simple sequence repeat (SSR) marker alleles. The genetic association analysis revealed 14 and 17 QTL under drought and normal conditions, respectively. The most drought-tolerant genotypes were selected based on DSI, the number of QTL in each selected genotypes, and the level of genetic diversity. As a result, five genotypes (Giza 178, IET1444, GZ1368-S-5-4, Nahda, Giza 14) were identified as the most promising drought-tolerant rice genotypes. Eight QTL controlling drought tolerance were identified in Giza 178, Nahda, and GZ1368-S-5-4, while, four QTL were found in IET1444. The number of different QTLs were estimated among the five selected genotypes. Giza 178 and GZ1368-S-5-4 shared the same QTLs. Seven different QTLs were found among Nahda, IET1444, GZ1368-S-5-4, and Giza 14. Combining information from phenotypic traits, genetic diversity analysis, and QTL identification was very useful in identifying the true drought-tolerant rice genotypes that can be used for crossing in the future breeding program.

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The abscisic acid receptor OsPYL6 confers drought tolerance to indica rice through dehydration avoidance and tolerance mechanisms

Journal of Experimental Botany ◽

10.1093/jxb/eraa509 ◽

2020 ◽

Author(s):

V V Santosh Kumar ◽

Shashank Kumar Yadav ◽

Rakesh Kumar Verma ◽

Sanya Shrivastava ◽

Omprakash Ghimire ◽

...

Keyword(s):

Abscisic Acid ◽

Drought Tolerance ◽

Grain Yield ◽

Stress Tolerance ◽

Plant Development ◽

Indica Rice ◽

Stress Conditions ◽

Wild Type ◽

Rnai Silencing ◽

Dehydration Avoidance

Abstract Abscisic acid (ABA) is a key regulator of plant development and stress tolerance. Here we report functional validation of the ABA receptor OsPYL6 by constitutive and stress-inducible overexpression and RNAi silencing, in an indica rice cultivar ‘Pusa Sugandh 2’. Overexpression of OsPYL6 conferred ABA hypersensitivity during germination and promoted total root length. Overexpression and RNAi silencing of OsPYL6 resulted in enhanced accumulation of ABA in seedlings under non-stress conditions, at least, in part through up-regulation of different 9-cis epoxycarotenoid dioxygenase (NCED )genes. This suggests that PYL6 expression is crucial for ABA homeostasis. Analysis of drought tolerance of OsPYL6 transgenic and wild type plants showed that OsPYL6 overexpression enhanced the expression of stress-responsive genes and dehydration tolerance. Transgenic rice plants overexpressing OsPYL6 with AtRD29A (Arabidopsis thaliana Responsive to Dehydration 29A) promoter also exhibited about 25% less whole plant transpiration, compared with wild type plants under drought, confirming its role in activation of dehydration avoidance mechanisms. However, overexpression of PYL6 reduced grain yield under non-stress conditions due to reduction in height, biomass, panicle branching and spikelet fertility. RNAi silencing of OsPYL6 also reduced grain yield under drought. These results showed that rice OsPYL6 is a key regulator of plant development and drought tolerance, and fine-tuning of its expression is critical for improving yield and stress tolerance.

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Efficacy of some insecticide modules against major insect pests and spider population of rice, Oryza sativa L.

ENTOMON ◽

10.33307/entomon.v43i4.405 ◽

2018 ◽

Vol 43 (4) ◽

pp. 257-262

Author(s):

Atanu Seni ◽

Bhimasen Naik

Keyword(s):

Oryza Sativa ◽

Grain Yield ◽

Untreated Control ◽

Insect Pests ◽

Oryza Sativa L ◽

Gall Midge ◽

Stem Borer ◽

The Other ◽

The Third ◽

Treated Plot

Experiments were carried out to assess some insecticide modules against major insect pests of rice. Each module consists of a basal application of carbofuran 3G @ 1 kg a.i ha-1 at 20 DAT and Rynaxypyr 20 SC @ 30 g a.i ha-1 at 45 DAT except untreated control. All modules differ with each other only in third treatment which was applied in 65 DAT. The third treatment includes: Imidacloprid 17.8 SL @ 27 g a.i ha-1, Pymetrozine 50 WG @ 150 g a.i ha-1, Triflumezopyrim 106 SC @ 27 g a.i ha-1, Buprofezin 25 SC @ 250 g a.i ha-1; Glamore (Imidacloprid 40+Ethiprole 40% w/w) 80 WG @ 100 g a.i. ha-1, Thiacloprid 24 SC @ 60 g a.i ha-1, Azadirachtin 0.03 EC @ 8 g a.i ha-1, Dinotefuran 20 SG@ 40 g a.i ha-1 and untreated control. All the treated plots recorded significantly lower percent of dead heart, white ear- head caused by stem borer and silver shoot caused by gall midge. Module with Pymetrozine 50 WG @ 150 g a.i ha-1 treated plot recorded significantly higher per cent reduction of plant hoppers (>80% over untreated control) and produced higher grain yield (50.75 qha-1) than the other modules. Among the different treated modules the maximum number of spiders was found in Azadirachtin 0.03 EC @ 8 g a.i ha-1 treated module plot followed by other treatments.

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