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1.
PLoS One ; 15(6): e0234088, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32559183

RESUMO

Bacterial blight (BB) and fungal blast diseases are the major biotic constraints that limit rice productivity. To sustain yield improvement in rice, it is necessary to developed yield potential of the rice varieties by incorporation of biotic stress resistance genes. Tellahamsa is a well-adapted popular high yielding rice variety in Telangana state, India. However, the variety is highly susceptible to BB and blast. In this study, simultaneous stepwise transfer of genes through marker-assisted backcross breeding (MABB) strategy was used to introgress two major BB (Xa21 and xa13) and two major blast resistance genes (Pi54 and Pi1) into Tellahamsa. In each generation (from F1 to ICF3) foreground selection was done using gene-specific markers viz., pTA248 (Xa21), xa13prom (xa13), Pi54MAS (Pi54) and RM224 (Pi1). Two independent BC2F1 lines of Tellahamsa/ISM (Cross-I) and Tellahamsa/NLR145 (Cross-II) possessing 92% and 94% recurrent parent genome (RPG) respectively were intercrossed to develop ICF1-ICF3 generations. These gene pyramided lines were evaluated for key agro-morphological traits, quality, and resistance against blast at three different hotspot locations as well as BB at two locations. Two ICF3 gene pyramided lines viz., TH-625-159 and TH-625-491 possessing four genes exhibited a high level of resistance to BB and blast. In the future, these improved Tellahamsa lines could be developed as mega varieties for different agro-climatic zones and also as potential donors for different pre-breeding rice research.


Assuntos
Resistência à Doença/genética , Genoma de Planta , Oryza/genética , Doenças das Plantas/genética , DNA de Plantas/metabolismo , Grão Comestível/fisiologia , Marcadores Genéticos , Genótipo , Oryza/crescimento & desenvolvimento , Doenças das Plantas/microbiologia
2.
PLoS One ; 15(5): e0232974, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32401803

RESUMO

Heat stress along with low water availability at reproductive stage (terminal growth phase of wheat crop) is major contributing factor towards less wheat production in tropics and sub-tropics. Flag leaf plays a pivotal role in assimilate partitioning and stress tolerance of wheat during terminal growth phase. However, limited is known about biochemical response of flag leaf to combined and individual heat and drought stress during terminal growth phase. Therefore, current study investigated combined and individual effect of terminal drought and heat stress on water relations, photosynthetic pigments, osmolytes accumulation and antioxidants defense mechanism in flag leaf of bread wheat. Experimental treatments comprised of control, terminal drought stress alone (50% field capacity during reproductive phase), terminal heat stress alone (wheat grown inside plastic tunnel during reproductive phase) and terminal drought stress + terminal heat stress. Individual and combined imposition of drought and heat stresses significantly (p≤0.05) altered water relations, osmolyte contents, soluble proteins and sugars along with activated antioxidant defensive system in terms of superoxide dismutase (SOD), peroxidase (POD) and ascorbate peroxidase (APX). Turgor potential, POD and APX activities were lowest under individual heat stress; however, these were improved when drought stress was combined with heat stress. It is concluded that combined effect of drought and heat stress was more detrimental than individual stresses. The interactive effect of both stresses was hypo-additive in nature, but for some traits (like turgor potential and APX) effect of one stress neutralized the other. To best of our knowledge, this is the first report on physiological and biochemical response of flag leaf of wheat to combine heat and drought stress. These results will help future studies dealing with improved stress tolerance in wheat. However, detailed studies are needed to fully understand the genetic mechanisms behind these physiological and biochemical changes in flag leaf in response to combined heat and drought stress.


Assuntos
Triticum/crescimento & desenvolvimento , Triticum/fisiologia , Antioxidantes/metabolismo , Pão , Clorofila/metabolismo , Secas , Grão Comestível/crescimento & desenvolvimento , Grão Comestível/fisiologia , Resposta ao Choque Térmico/fisiologia , Fotossíntese , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/fisiologia , Água/metabolismo
3.
PLoS One ; 15(3): e0230689, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32214360

RESUMO

Wheat grain yield is usually decomposed in the yield components: number of spikes / m2, number of grains / spike, number of grains / m2 and thousand kernel weight (TKW). These are correlated one with another due to yield component compensation. Under optimal conditions, the number of grains per m2 has been identified as the main determinant of yield. However, with increasing occurrences of post-flowering abiotic stress associated with climate change, TKW may become severely limiting and hence a target for breeding. TKW is usually studied at the plot scale as it represents the average mass of a grain. However, this view disregards the large intra-genotypic variance of individual grain mass and its effect on TKW. The aim of this study is to investigate the determinism of the variance of individual grain size. We measured yield components and individual grain size variances of two large genetic wheat panels grown in two environments. We also carried out a genome-wide association study using a dense SNPs array. We show that the variance of individual grain size partly originates from the pre-flowering components of grain yield; in particular it is driven by canopy structure via its negative correlation with the number of spikes per m2. But the variance of final grain size also has a specific genetic basis. The genome-wide analysis revealed the existence of QTL with strong effects on the variance of individual grain size, independently from the other yield components. Finally, our results reveal some interesting drivers for manipulating individual grain size variance either through canopy structure or through specific chromosomal regions.


Assuntos
Grão Comestível/fisiologia , Triticum/genética , Produção Agrícola , Grão Comestível/genética , Determinismo Genético , Estudo de Associação Genômica Ampla , Genótipo , Modelos Lineares , Fenótipo , Polimorfismo de Nucleotídeo Único , Locos de Características Quantitativas , Triticum/crescimento & desenvolvimento
4.
BMC Plant Biol ; 20(1): 57, 2020 Feb 04.
Artigo em Inglês | MEDLINE | ID: mdl-32019504

RESUMO

BACKGROUND: High yielding rice varieties are usually low in grain iron (Fe) and zinc (Zn) content. These two micronutrients are involved in many enzymatic activities, lack of which cause many disorders in human body. Bio-fortification is a cheaper and easier way to improve the content of these nutrients in rice grain. RESULTS: A population panel was prepared representing all the phenotypic classes for grain Fe-Zn content from 485 germplasm lines. The panel was studied for genetic diversity, population structure and association mapping of grain Fe-Zn content in the milled rice. The population showed linkage disequilibrium showing deviation of Hardy-Weinberg's expectation for Fe-Zn content in rice. Population structure at K = 3 categorized the panel population into distinct sub-populations corroborating with their grain Fe-Zn content. STRUCTURE analysis revealed a common primary ancestor for each sub-population. Novel quantitative trait loci (QTLs) namely qFe3.3 and qFe7.3 for grain Fe and qZn2.2, qZn8.3 and qZn12.3 for Zn content were detected using association mapping. Four QTLs, namely qFe3.3, qFe7.3, qFe8.1 and qFe12.2 for grain Fe content were detected to be co-localized with qZn3.1, qZn7, qZn8.3 and qZn12.3 QTLs controlling grain Zn content, respectively. Additionally, some Fe-Zn controlling QTLs were co-localized with the yield component QTLs, qTBGW, OsSPL14 and qPN. The QTLs qFe1.1, qFe3.1, qFe5.1, qFe7.1, qFe8.1, qZn6, qZn7 and gRMm9-1 for grain Fe-Zn content reported in earlier studies were validated in this study. CONCLUSION: Novel QTLs, qFe3.3 and qFe7.3 for grain Fe and qZn2.2, qZn8.3 and qZn12.3 for Zn content were detected for these two traits. Four Fe-Zn controlling QTLs and few yield component QTLs were detected to be co-localized. The QTLs, qFe1.1, qFe3.1, qFe5.1, qFe7.1, qFe8.1, qFe3.3, qFe7.3, qZn6, qZn7, qZn2.2, qZn8.3 and qZn12.3 will be useful for biofortification of the micronutrients. Simultaneous enhancement of Fe-Zn content may be possible with yield component traits in rice.


Assuntos
Grão Comestível/fisiologia , Ferro/metabolismo , Desequilíbrio de Ligação , Oryza/genética , Zinco/metabolismo , Grão Comestível/genética , Variação Genética , Nutrientes/metabolismo , Melhoramento Vegetal , Locos de Características Quantitativas
5.
PLoS One ; 15(1): e0227739, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31986164

RESUMO

Climate change is posing severe challenges in Africa, where resilient crops are urgently needed to withstand drought periods and unreliable rainfall. Multi-purpose legume species, such as lablab (Lablab purpureus (L.) Sweet), have been under-utilized yet have the potential to overcome climate challenges. While lablab is native to Africa, there are few characterized varieties and it is under-utilized by smallholder farmers due to a lack of information and access to varieties. Knowledge is especially lacking on the performance of this crop by genotype, management, and environment. We conducted a two-year field study at two sites to evaluate 29 lablab cultivars under sole and maize intercrop management, with 14 cultivars selected for in-depth study. Cultivars were evaluated on vegetative biomass and grain yield production, with N fixation assessed for one site year. Biomass and grain production differed across environments and cultivars, with only biomass affected by intercropping. Average grain yield was substantially reduced to only 37 kg ha-1 in environments with maximum temperatures greater than 33°C, but biomass production yielded comparable amounts across high temperatures and in dry (<500 mm rainfall) environments. Tradeoffs were found between biomass and grain yield across high yielding cultivars, with the top three grain accessions averaging 612 kg ha-1 of grain and 1.97 Mg ha-1 biomass whereas the top three biomass accessions produced 327 kg ha-1 grain and 2.52 Mg ha-1 biomass across all environments. In a comparison of production and N fixation measurements, cultivars were identified which may have high performance in both. Suitability of lablab for grain and biomass production were visualized across Tanzania in a map comparing max temperature thresholds for grain and biomass against average regional livestock populations. This provides a way forward for identifying potential areas for lablab cultivation as a novel means to enhance fodder and pulse production with smallholder farmers.


Assuntos
Aclimatação , Mudança Climática , Produção Agrícola/métodos , Grão Comestível/fisiologia , Fabaceae/fisiologia , Biomassa , Secas , Chuva , Estações do Ano , Tanzânia , Zea mays/fisiologia
6.
FEMS Microbiol Ecol ; 96(2)2020 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-31851310

RESUMO

In view of their key roles in many soil- and plant-related processes, we hypothesized that soil microorganisms could play a larger role in determining wheat baking quality than nitrogen fertilization. A field experiment was conducted under bread wheat production conditions, where different fertilization treatments, ranging from 0-120 kg/ha NH4NO3, were applied. Soil samples were taken in May, June and July. Functional genes in the nitrogen cycle were quantified and amplicons of the 16S rRNA gene and the ITS region were sequenced. Wheat yields were measured, and the grain baking quality was analysed for each plot. Fertilisation did not significantly influence the yields and the grain quality. Many bacterial and fungal Amplicon Sequence Variants showed significant positive or negative correlations with yield and grain baking quality parameters. Among the functional gene quantified, the archaeal amoA showed strong negative correlations with the wheat yields and many grain and flour quality parameters. Regression models were able to explain up to 81% of the variability in grain quality based on the microbial data from the May sampling. A better understanding of the microbiology of wheat fields could lead to an optimized management of the N fertilization to maximize yields and grain quality.


Assuntos
Fertilizantes/análise , Nitrogênio/análise , Microbiologia do Solo , Triticum/fisiologia , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Grão Comestível/crescimento & desenvolvimento , Grão Comestível/fisiologia , Fungos/classificação , Fungos/genética , Fungos/isolamento & purificação , Ciclo do Nitrogênio/genética , RNA Ribossômico/genética , Solo/química , Triticum/crescimento & desenvolvimento
7.
PLoS One ; 14(12): e0225383, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31800595

RESUMO

Genome wide association studies (GWAS) are important in discerning the genetic architecture of complex traits such as biomass allocation for improving drought tolerance and carbon sequestration potential of wheat. The objectives of this study were to deduce the population structure and marker-trait association for biomass traits in wheat under drought-stressed and non-stressed conditions. A 100-wheat (Triticum aestivum L.) genotype panel was phenotyped for days to heading (DTH), days to maturity (DTM), shoot biomass (SB), root biomass (RB), root to shoot ratio (RS) and grain yield (GY). The panel was sequenced using 15,600 single nucleotide polymorphism (SNPs) markers and subjected to genetic analysis using the compressed mixed linear model (CMLM) at false discovery rate (FDR < 0.05). Population structure analysis revealed six sub-clusters with high membership ancestry coefficient of ≤0.65 to their assigned sub-clusters. A total of 75 significant marker-trait associations (MTAs) were identified with a linkage disequilibrium threshold of 0.38 at 5cM. Thirty-seven of the MTAs were detected under drought-stressed condition and 48% were on the B genome, where most quantitative trait loci (QTLs) for RB, SB and GY were previously identified. There were seven pleiotropic markers for RB and SB that may facilitate simultaneous selection. Thirty-seven putative candidate genes were mined by gene annotation on the IWGSC RefSeq 1.1. The significant MTAs observed in this study will be useful in devising strategies for marker-assisted breeding for simultaneous improvement of drought tolerance and to enhance C sequestration capacity of wheat.


Assuntos
Grão Comestível/genética , Polimorfismo de Nucleotídeo Único , Estresse Fisiológico , Triticum/genética , Biomassa , Secas , Grão Comestível/crescimento & desenvolvimento , Grão Comestível/fisiologia , Locos de Características Quantitativas , Triticum/crescimento & desenvolvimento , Triticum/fisiologia
8.
PLoS One ; 14(9): e0222639, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31539409

RESUMO

The adverse effects of heat on plant yield strongly depend on its duration and the phenological stage of the crops when the heat occurs. To clarify the effects of these two aspects of heat stress, systematic research was conducted under controlled conditions on 101 wheat cultivars of various geographic origin. Different durations of heat stress (5, 10 and 15 days) were applied starting from three developmental stages (ZD49: booting stage, ZD59: heading, ZD72: 6th day after heading). Various morphological, yield-related traits and physiological parameters were measured to determine the stress response patterns of the wheat genotypes under combinations of the duration and the timing of heat stress. Phenological timing significantly influenced the thousand-kernel weight and reproductive tiller number. The duration of heat stress was the most significant component in determining both seed number and seed weight, as well as the grain yield consequently, explaining 51.6% of its phenotypic variance. Irrespective of the developmental phase, the yield-related traits gradually deteriorated over time, and even a 5-day heat stress was sufficient to cause significant reductions. ZD59 was significantly more sensitive to heat than either ZD49 or ZD72. The photosynthetic activity of the flag leaf was mostly determined by heat stress duration. No significant associations were noted between physiological parameters and heat stress response as measured by grain yield. Significant differences were observed between the wheat genotypes in heat stress responses, which varied greatly with developmental phase. Based on the grain yield across developmental phases and heat stress treatments, eight major response groups of wheat genotypes could be identified, and among them, three clusters were the most heat-tolerant. These cultivars are currently included in crossing schemes, partially for the identification of the genetic determinants of heat stress response and partially for the development of new wheat varieties with better heat tolerance.


Assuntos
Triticum/fisiologia , Grão Comestível/crescimento & desenvolvimento , Grão Comestível/fisiologia , Estudos de Associação Genética , Resposta ao Choque Térmico , Temperatura Alta/efeitos adversos , Fatores de Tempo , Triticum/genética , Triticum/crescimento & desenvolvimento
9.
BMC Plant Biol ; 19(1): 392, 2019 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-31500559

RESUMO

BACKGROUND: Utilization of heterosis in maize could be critical in maize breeding for boosting grain yield. However, the genetic architecture of heterosis is not fully understood. To dissect the genetic basis of yield-related traits and heterosis in maize, 301 recombinant inbred lines derived from 08 to 641 × YE478 and 298 hybrids from the immortalized F2 (IF2) population were used to map quantitative trait loci (QTLs) for nine yield-related traits and mid-parent heterosis. RESULTS: We observed 156 QTLs, 28 pairs of loci with epistatic interaction, and 10 significant QTL × environment interactions in the inbred and hybrid mapping populations. The high heterosis in F1 and IF2 populations for kernel weight per ear (KWPE), ear weight per ear (EWPE), and kernel number per row (KNPR) matched the high percentages of QTLs (over 50%) for those traits exhibiting overdominance, whereas a notable predominance of loci with dominance effects (more than 70%) was observed for traits that show low heterosis such as cob weight per ear (CWPE), rate of kernel production (RKP), ear length (EL), ear diameter (ED), cob diameter, and row number (RN). The environmentally stable QTL qRKP3-2 was identified across two mapping populations, while qKWPE9, affecting the trait mean and the mid-parent heterosis (MPH) level, explained over 18% of phenotypic variations. Nine QTLs, qEWPE9-1, qEWPE10-1, qCWPE6, qEL8, qED2-2, qRN10-1, qKWPE9, qKWPE10-1, and qRKP4-3, accounted for over 10% of phenotypic variation. In addition, QTL mapping identified 95 QTLs that were gathered together and integrated into 33 QTL clusters on 10 chromosomes. CONCLUSIONS: The results revealed that (1) the inheritance of yield-related traits and MPH in the heterotic pattern improved Reid (PA) × Tem-tropic I (PB) is trait-dependent; (2) a large proportion of loci showed dominance effects, whereas overdominance also contributed to MPH for KNPR, EWPE, and KWPE; (3) marker-assisted selection for markers at genomic regions 1.09-1.11, 2.04, 3.08-3.09, and 10.04-10.05 contributed to hybrid performance per se and heterosis and were repeatedly reported in previous studies using different heterotic patterns is recommended.


Assuntos
Grão Comestível/genética , Vigor Híbrido/genética , Locos de Características Quantitativas , Zea mays/genética , Mapeamento Cromossômico , Grão Comestível/fisiologia , Epistasia Genética/genética , Zea mays/fisiologia
10.
PLoS One ; 14(9): e0223107, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31557241

RESUMO

Globally, gains in sweet corn [Zea mays L.var. rugosa (or saccharata)] are a fraction of the yield advances made in field corn (Zea mays L.) in the last half-century. Grain yield improvement of field corn is associated with increased tolerance to higher plant densities (i.e., crowding stress). Processing sweet corn hybrids that tolerate crowding stress have been identified; however, such hybrids appear to be under-planted in the processing sweet corn. Using crowding stress tolerant (CST) hybrids, the objectives of this study were to: (1) identify optimum plant densities for a range of growing conditions; (2) quantify gaps in production between current and optimum plant densities; and (3) enumerate changes in yield and ear traits when shifting from current to optimum plant densities. Using a CST shrunken-2 (sh2) processing sweet corn hybrid, on-farm plant density trials were conducted in thirty fields across the states of Illinois, Minnesota and Wisconsin, from 2013 to 2017 in order to capture a wide variety of growing conditions. Linear mixed-effects models were used to identify the optimum plant density corresponding to maximum ear mass (Mt ha-1), case production (cases ha-1), and profitability to the processor ($ ha-1). Kernel moisture, indicative of plant development, was unaffected by plant density. Ear traits, such as ear number and ear mass per plant, average ear length, and filled ear length declined linearly with increasing plant density. Nonetheless, there was a large economic benefit to the grower and processor by shifting to higher plant densities in most environments. This research shows that increasing plant densities of CST hybrids from current (58,475 plants ha-1) to optimum (73,075 plants ha-1) could improve processing sweet corn green ear yield and processor profitability on average of 1.13 Mt ha-1 and $525 ha-1, respectively.


Assuntos
Adaptação Fisiológica , Produção Agrícola/métodos , Grão Comestível/fisiologia , Dispersão Vegetal , Zea mays/fisiologia , Illinois , Minnesota , Estresse Fisiológico , Wisconsin
11.
Plant Physiol Biochem ; 142: 440-451, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31419646

RESUMO

Drought stress during the grain filling stage severely affects the quality and quantity of starch in rice grains. The enzymes such as ADP-glucose pyrophosphorylase (AGPase, EC 2.7.7.27) and starch synthase (SS, EC 2.4.1.21) are the key regulatory enzymes involved in the starch biosynthesis. In this study, the activity of the AGPase and starch synthase (SS) was correlated with the qualitative and quantitative parameters such as sucrose, starch, amylose, amylopectin, and resistant starch in leaves, roots, and grains of drought tolerant (N22) and drought susceptible (IR64) cultivars under applied water deficit stress (WDS). Drought stress enhanced the remobilization of stored starch from leaves to developing rice grains which was positively correlated with a decrease in the starch and starch synthase activity in leaves. Starch accumulation in developing grains was positively correlated with an increase in the AGPase and SS activity under drought. It was found that starch, amylopectin, and sucrose content in developing grains increased under water deficit stress (WDS), while amylose content decreased in both the varieties. However, in leaves, the SS activity decreased while AGPase activity was found to be increased under WDS in both varieties. Decreased starch content in matured grains was due to shortening of grain filling stage as drought stress caused early plant senescence. Yield reduction under drought was more in susceptible variety IR64 as compared to tolerant genotype N22.


Assuntos
Grão Comestível/metabolismo , Oryza/metabolismo , Amido/metabolismo , Amilopectina/metabolismo , Amilose/metabolismo , Desidratação , Grão Comestível/fisiologia , Oryza/fisiologia , Fotossíntese , Folhas de Planta/metabolismo , Sacarose/metabolismo
12.
Nat Commun ; 10(1): 3822, 2019 08 23.
Artigo em Inglês | MEDLINE | ID: mdl-31444356

RESUMO

The widespread agricultural problem of pre-harvest sprouting (PHS) could potentially be overcome by improving seed dormancy. Here, we report that miR156, an important grain yield regulator, also controls seed dormancy in rice. We found that mutations in one MIR156 subfamily enhance seed dormancy and suppress PHS with negligible effects on shoot architecture and grain size, whereas mutations in another MIR156 subfamily modify shoot architecture and increase grain size but have minimal effects on seed dormancy. Mechanistically, mir156 mutations enhance seed dormancy by suppressing the gibberellin (GA) pathway through de-represssion of the miR156 target gene Ideal Plant Architecture 1 (IPA1), which directly regulates multiple genes in the GA pathway. These results provide an effective method to suppress PHS without compromising productivity, and will facilitate breeding elite crop varieties with ideal plant architectures.


Assuntos
Giberelinas/metabolismo , MicroRNAs/metabolismo , Oryza/fisiologia , Dormência de Plantas/genética , Proteínas de Plantas/genética , Vias Biossintéticas/genética , Sistemas CRISPR-Cas/genética , Grão Comestível/fisiologia , Regulação da Expressão Gênica de Plantas , MicroRNAs/genética , Mutagênese , Mutação , Melhoramento Vegetal , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas
13.
BMC Plant Biol ; 19(1): 335, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31370805

RESUMO

BACKGROUND: Drought is a serious causal factor of reduced crop yields than any other abiotic stresses. As one of the most widely distributed crops, maize plants frequently suffer from drought stress, which causes great losses in the final kernel yield. Drought stress response in plants showed tissue- and developmental stage-specific characteristics. RESULTS: In this study, the ears at the V9 stage, kernels and ear leaf at the 5DAP (days after pollination) stage of maize were used for morphological, physiological and comparative transcriptomics analysis to understand the different features of "sink" or "source" organs and the effects on kernel yield under drought stress conditions. The ABA-, NAC-mediate signaling pathway, osmotic protective substance synthesis and protein folding response were identified as common drought stress response in the three organs. Tissue-specific drought stress responses and the regulators were identified, they were highly correlated with growth, physiological adaptation and yield loss under drought stress. For ears, drought stress inhibited ear elongation, led to the abnormal differentiation of the paired spikelet, and auxin signaling involved in the regulation of cell division and growth and primordium development changes. In the kernels, reduced kernel size caused by drought stress was observed, and the obvious differences of auxin, BR and cytokine signaling transduction appeared, which indicated the modification in carbohydrate metabolism, cell differentiation and growth retardation. For the ear leaf, dramatically and synergistically reduced the expression of photosynthesis genes were observed when suffered from drought stress, the ABA- and NAC- mediate signaling pathway played important roles in the regulation of photosynthesis. CONCLUSIONS: Transcriptomic changes caused by drought were highly correlated with developmental and physiological adaptation, which was closely related to the final yield of maize, and a sketch of tissue- and developmental stage-specific responses to drought stress in maize was drafted.


Assuntos
Zea mays/fisiologia , Produção Agrícola , Desidratação , Grão Comestível/crescimento & desenvolvimento , Grão Comestível/fisiologia , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas/fisiologia , Fotossíntese , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/fisiologia , Zea mays/crescimento & desenvolvimento , Zea mays/metabolismo
14.
BMC Plant Biol ; 19(1): 306, 2019 Jul 11.
Artigo em Inglês | MEDLINE | ID: mdl-31296169

RESUMO

BACKGROUND: Phosphorus (P) deficiency in soil is a worldwide issue and a major constraint on the production of sorghum, which is an important staple food, forage and energy crop. The depletion of P reserves and the increasing price of P fertilizer make fertilizer application impractical, especially in developing countries. Therefore, identifying sorghum accessions with low-P tolerance and understanding the underlying molecular basis for this tolerance will facilitate the breeding of P-efficient plants, thereby resolving the P crisis in sorghum farming. However, knowledge in these areas is very limited. RESULTS: The 29 sorghum accessions used in this study demonstrated great variability in their tolerance to low-P stress. The internal P content in the shoot was correlated with P tolerance. A low-P-tolerant accession and a low-P-sensitive accession were chosen for RNA-seq analysis to identify potential underlying molecular mechanisms. A total of 2089 candidate genes related to P starvation tolerance were revealed and found to be enriched in 11 pathways. Gene Ontology (GO) enrichment analyses showed that the candidate genes were associated with oxidoreductase activity. In addition, further study showed that malate affected the length of the primary root and the number of tips in sorghum suffering from low-P stress. CONCLUSIONS: Our results show that acquisition of P from soil contributes to low-P tolerance in different sorghum accessions; however, the underlying molecular mechanism is complicated. Plant hormone (including auxin, ethylene, jasmonic acid, salicylic acid and abscisic acid) signal transduction related genes and many transcriptional factors were found to be involved in low-P tolerance in sorghum. The identified accessions will be useful for breeding new sorghum varieties with enhanced P starvation tolerance.


Assuntos
Fósforo/deficiência , Reguladores de Crescimento de Planta/metabolismo , Transdução de Sinais/genética , Sorghum/genética , Grão Comestível/genética , Grão Comestível/fisiologia , Perfilação da Expressão Gênica , Solo/química , Sorghum/fisiologia
15.
BMC Plant Biol ; 19(1): 302, 2019 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-31291890

RESUMO

BACKGROUND: Nitrogen (N) and potassium (K) are two important mineral nutrients in regulating leaf photosynthesis. Studying the interactive effects of N and K on regulating N allocation and photosynthesis (Pn) of rice leaves will be of great significance for further increasing leaf Pn, photosynthetic N use efficiency (PNUE) and grain yield. We measured the gas exchange of rice leaves in a field experiment and tested different kinds of leaf N based on N morphology and function, and calculated the interactive effects of N and K on N allocation and the PNUE. RESULTS: Compared with N0 (0 kg N ha- 1) and K0 (0 kg K2O ha- 1) treatments, the Pn was increased by 17.1 and 12.2% with the supply of N and K. Compared with N0K0 (0 kg N and 0 kg K2O ha- 1), N0K120 (0 kg N and 120 kg K2O ha- 1) and N0K180 (0 kg N and 180 kg K2O ha- 1), N supply increased the absolute content of photosynthetic N (Npsn) by 15.1, 15.5 and 10.5% on average, and the storage N (Nstore) was increased by 32.7, 64.9 and 72.7% on average. The relative content of Npsn was decreased by 5.6, 12.1 and 14.5%, while that of Nstore was increased by 8.7, 27.8 and 33.8%. Supply of K promoted the transformation of Nstore to Npsn despite the leaf N content (Na) was indeed decreased. Compared with N0K0, N180K0 (180 kg N and 0 kg K2O ha- 1) and N270K0 (270 kg N and 0 kg K2O ha- 1), K supply increased the relative content of Npsn by 17.7, 8.8 and 7.3%, and decreased the relative content of Nstore by 24.2, 11.4 and 8.7% respectively. CONCLUSIONS: This study indicated the mechanism that K supply decreased the Na but increased the Npsn content and then increased leaf Pn and PNUE from a new viewpoint of leaf N allocation. The supply of K promoted the transformation of Nstore to Npsn and increased the PNUE. The decreased Nstore mainly resulted from the decrease of non-protein N. Combined use of N and K could optimize leaf N allocation and maintain a high leaf Npsn content and PNUE.


Assuntos
Nitrogênio/metabolismo , Oryza/fisiologia , Potássio/metabolismo , Grão Comestível/genética , Grão Comestível/crescimento & desenvolvimento , Grão Comestível/fisiologia , Oryza/genética , Oryza/crescimento & desenvolvimento , Fotossíntese , Folhas de Planta/genética , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/fisiologia
16.
Int J Mol Sci ; 20(11)2019 Jun 04.
Artigo em Inglês | MEDLINE | ID: mdl-31167420

RESUMO

Grasses represent a major family of monocots comprising mostly cereals. When compared to their eudicot counterparts, cereals show a remarkable morphological diversity. Understanding the molecular basis of floral organ identity and inflorescence development is crucial to gain insight into the grain development for yield improvement purposes in cereals, however, the exact genetic mechanism of floral organogenesis remains elusive due to their complex inflorescence architecture. Extensive molecular analyses of Arabidopsis and other plant genera and species have established the ABCDE floral organ identity model. According to this model, hierarchical combinatorial activities of A, B, C, D, and E classes of homeotic genes regulate the identity of different floral organs with partial conservation and partial diversification between eudicots and cereals. Here, we review the developmental role of A, B, C, D, and E gene classes and explore the recent advances in understanding the floral development and subsequent organ specification in major cereals with reference to model plants. Furthermore, we discuss the evolutionary relationships among known floral organ identity genes. This comparative overview of floral developmental genes and associated regulatory factors, within and between species, will provide a thorough understanding of underlying complex genetic and molecular control of flower development and floral organ identity, which can be helpful to devise innovative strategies for grain yield improvement in cereals.


Assuntos
Grão Comestível/fisiologia , Evolução Molecular , Flores/fisiologia , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Biodiversidade , Grão Comestível/classificação , Filogenia , Desenvolvimento Vegetal/genética
17.
Int J Biol Macromol ; 134: 316-329, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31078592

RESUMO

Cysteine-rich receptor-like kinases (CRK) constitute one of the largest subfamily of receptor-like kinases, which play crucial roles in plant development and stress response. In total, 43, 37, 36, 38 and 170 CRK genes including duplicated genes were identified in the genome of Brachypodium distachyon, Hordeum vulgare, Oryza sativa, Sorghum bicolor and Triticum aestivum, respectively. These CRK proteins were tightly clustered into four phylogenetic groups and exhibited close syntenic relationship among orthologous genes. Majority of CRK proteins contain a transmembrane domain for plasma membrane localization. The organization of exon/intron, domains and motifs were variably conserved. Tissue-specific expression suggested the involvement of certain CRK genes in plant development. Modulated expression revealed their specific stress-responsive functions. Co-expression and interaction analysis indicated their role in signaling. Ks value and divergence time analysis suggested duplication of TaCRK genes before the hybridization of T. aestivum sub-genomes. Expression comparison of duplicated TaCRK genes revealed functional retention, neofunctionalization or pseudo-functionalization. Recombinant expression of a stress-responsive gene TaCRK68-A in Escherichia coli and Saccharomyces cerevisiae displayed enhanced tolerance against heat, drought, cold and salinity stresses. The study suggested vital functions of CRKs during development and stresses, and provides the basis for functional characterization of each gene in future studies.


Assuntos
Grão Comestível/enzimologia , Grão Comestível/genética , Perfilação da Expressão Gênica , Genômica , Proteínas Quinases/genética , Duplicação Cromossômica , Grão Comestível/fisiologia , Filogenia , Estresse Fisiológico/genética , Sintenia
18.
PLoS One ; 14(5): e0215066, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31112545

RESUMO

Stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), is an airborne fungal disease which always destructs leaf and leads to stagnation of grain filling, decreasing of kernel weight, thin seed and yield loss. Winter wheat Huixianhong is a special germplasm with special characteristics of tolerance or resistance against stripe rust. In order to understand the effect on Huixianhong from stripe rust, we designed two kinds of treatment, inoculation of stripe rust fungi (IH) and artificial immune by bactericide (CK) to study the dynamic of disease process, the grain filling and the thousand-kernel weight (TKW). Our results showed that the incubation period of Hongxinahui was 13.5 days. The prevalence increased from 32.9% at 15 days after jointing to 80.0% at 9 days after booting, and reached to 97.0% at the heading stage. The infection type (IT) was 7 to 9 at the beginning of anthesis. The severity, leaf withered area ratio and disease index at the 15th day after anthesis were 67.17%, 98.17% and 0.6717, respectively. The IH maximum increasing rate of leaf necrosis and chlorosis area was from heading beginning stage to anthesis beginning stage, which increased from 18.66 mm2·d-1 to 21.04 mm2·d-1. The maximum rate of grain filling was 1.25 mg·d-1 at the 18th day after anthesis, which was earlier than that of CK by 3.3 days. The IH thousand-kernel weight Loss (TKWL) was more than that of CK by 6.19%, the stage of heading and amature were 3.0 days and 4.5 days earlier than CK, respectively. The stripe rust infection seriously destructed the photosynthetic function of leaf at the earlier stage of grain filling, i.e. at the beginning of anthesis, which led to the most important biomass loss and the grain filling rate decrease. As far as stripe rust is concerned, Huixianhong is a high susceptible, easily been infected, seriously showing symptoms and most quickly epidemic type but can successfully complete grain filling in high quality. It is a very useful germplasm for creating and selecting special breeding materials against stripe rust.


Assuntos
Basidiomycota/patogenicidade , Grão Comestível/fisiologia , Doenças das Plantas/microbiologia , Triticum/crescimento & desenvolvimento , Anti-Infecciosos/farmacologia , Basidiomycota/efeitos dos fármacos , Biomassa , Fotossíntese , Doenças das Plantas/estatística & dados numéricos , Folhas de Planta/metabolismo , Folhas de Planta/microbiologia , Sementes/microbiologia , Sementes/fisiologia , Triticum/metabolismo , Triticum/microbiologia
19.
Int J Mol Sci ; 20(8)2019 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-30991628

RESUMO

Access to adequate irrigation resources is critical for sustained agricultural production, and rice, a staple cereal grain for half of the world population, is one of the biggest users of irrigation. To reduce water use, several water saving irrigation systems have been developed for rice production, but a reliable system to evaluate cultivars for water stress tolerance is still lacking. Here, seven rice cultivars that have diverse yield potential under water stress were evaluated in a field study using four continuous irrigation regimes varying from saturation to wilting point. To understand the relationship between water stress and yield potential, the physiological and leaf metabolic responses were investigated at the critical transition between vegetative and reproductive growth stages. Twenty-nine metabolite markers including carbohydrates, amino acids and organic acids were found to significantly differ among the seven cultivars in response to increasing water stress levels with amino acids increasing but organic acids and carbohydrates showing mixed responses. Overall, our data suggest that, in response to increasing water stress, rice cultivars that do not show a significant yield loss accumulate carbohydrates (fructose, glucose, and myo-inositol), and this is associated with a moderate reduction in stomatal conductance (gs), particularly under milder stress conditions. In contrast, cultivars that had significant yield loss due to water stress had the greatest reduction in gs, relatively lower accumulation of carbohydrates, and relatively high increases in relative chlorophyll content (SPAD) and leaf temperature (Tm). These data demonstrate the existence of genetic variation in yield under different water stress levels which results from a suite of physiological and biochemical responses to water stress. Our study, therefore, suggests that in rice there are different physiological and metabolic strategies that result in tolerance to water stress that should be considered in developing new cultivars for deficit irrigation production systems that use less water.


Assuntos
Grão Comestível/fisiologia , Metaboloma , Oryza/fisiologia , Solo/química , Estresse Fisiológico , Água/metabolismo , Aclimatação , Agricultura , Secas , Fotossíntese , Água/análise
20.
Chemosphere ; 227: 109-116, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30986592

RESUMO

ZnO nanoparticles (NPs) are studied as a potential solution to alleviate Zn deficiency in human diet due to their special physicochemical properties. However, information for food quality and safety in NP-treated crops is limited. The effects of ZnO NPs and ZnSO4 on germination and growth of wheat (Triticum aestivum L.) were studied in germination and pot experiments. Zn content increased significantly, ZnO NPs were more effective than ZnSO4 at increasing grain Zn content, but less effective at increasing leaf Zn, and no ZnO NPs were detected in the wheat tissues by NP-treatments, indicated by XRD. Both ZnO NPs and ZnSO4 at moderate doses increased grain yield and biomass. Compared with control, the maximum grain yield and biomass of wheat treated with ZnO NPs and ZnSO4 were increased by 56%, 63% and 55%, 72%, respectively. ZnSO4 was more toxic than ZnO NPs at high doses as measured by the inhibitory effects in seed germination, root length, shoot length and dry biomass of seedlings. Structural damage in roots and variation in enzyme activities were greater with ZnSO4 than with ZnO NPs. ZnO NPs did not cause toxicity different from that of ZnSO4, which indicates that ZnO NPs used under the current experimental conditions did not cause Nano specific risks.


Assuntos
Nanopartículas Metálicas/análise , Triticum/crescimento & desenvolvimento , Sulfato de Zinco/metabolismo , Biofortificação , Biomassa , Grão Comestível/fisiologia , Germinação/fisiologia , Folhas de Planta/química , Raízes de Plantas/fisiologia , Plântula/efeitos dos fármacos , Zinco/análise , Óxido de Zinco/química
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