Assessing the leaf shape dynamic through marker–trait association under drought stress in a rice germplasm panel

Abstract The flag leaf acts as a functional leaf in rice, Oryza sativa L., primarily supplying photosynthate to the developing grains and influencing yields to a certain extent. Drought stress damages the leaf physiology, severely affecting grain fertility. Autumn rice of northeast India is called locally as ‘ahu’ rice, and is known for its drought tolerance. Exploring diverse germplasm resources at the morphological level using an association mapping approach can aid in identifying the genomic regions influencing leaf shape dynamics. A marker–trait association (MTA) study was carried out using 95 polymorphic SSR markers and a panel of 273 ahu rice germplasm accessions in drought stress and irrigated conditions. The trials suggest that at the vegetative stage, drought stress significantly affects leaf morphology. The leaf physiology of some tolerant accessions was relatively little affected by stress and these can be considered as ideal varieties for drought conditions. The phenotypic coefficient of variance and genotypic coefficient of variance values implied moderate to high variability for the leaf traits studied. Analysis of molecular variance inferred that 11% of variation in the germplasm panel was due to differences between populations, while the remaining 89% may be attributed to a difference within subgroups formed through STRUCTURE analysis. Using the mixed linear model approach revealed 11 MTAs explaining between 4.5 and 20.0% of phenotypic variance at P > 0.001 for all the leaf traits. The study concludes that ahu rice germplasm is extremely diverse and can serve as a valuable resource for mining desirable alleles for drought tolerance.

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Evaluation of the tolerance of Thai indigenous upland rice germplasm to early drought stress using multiple selection criteria

Plant Genetic Resources ◽

10.1017/s1479262115000428 ◽

2015 ◽

Vol 15 (2) ◽

pp. 109-118 ◽

Cited By ~ 1

Author(s):

Kittichai Narenoot ◽

Tidarat Monkham ◽

Sompong Chankaew ◽

Patcharin Songsri ◽

Wattana Pattanagul ◽

...

Keyword(s):

Drought Stress ◽

Drought Tolerance ◽

Selection Criteria ◽

Upland Rice ◽

Block Design ◽

Rice Variety ◽

Tolerance Index ◽

Rice Varieties ◽

Rice Germplasm ◽

Drought Tolerance Index

Drought remains the most important factor that affects rice productivity, especially in rainfed areas, worldwide. Upland rice is one of the crop choices of farmers in the rainfed environment. Although upland rice varieties require less water than lowland rice varieties, yields often remain limited by drought, particularly in the period of early growth. The aims of this study were to identify the traits related to early drought tolerance in upland rice varieties, and to identify the potential sources of germplasm for early drought tolerance. A total of sixty upland rice varieties were planted in a factorial experiment with a randomized complete block design with 3 replications in the rainy seasons of 2011 and 2012, under greenhouse conditions. Based on the drought tolerance index (DTI), the test germplasm sources were classified into three groups: (i) susceptible; (ii) moderately tolerant; (iii) tolerant to drought stress. Grain yield (GY) showed significant negative correlations with the leaf rolling score (r= − 0.623, P< 0.01), the leaf death score (LDS) (r= − 0.673, P< 0.01) and the recovery score (r= − 0.746, P< 0.01), while leaf dry matter (r= 0.698, P< 0.01) and leaf water potential (r= 0.618, P< 0.01) had significant positive correlations with GY. These findings indicate the suitability of the DTI as the selection criteria for early drought tolerance in a breeding programme. In addition, the upland rice germplasm accessions KKU-ULR011, KKU-ULR012, KKU-ULR125, KKU-ULR199 and KKU-ULR292 were identified as having high levels of stability for drought tolerance in both the 2011 and 2012 experiments, suggesting their potential for further use for rice variety improvement for drought tolerance.

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The Effects of Drought on Leaf Gas Exchange and Growth of Three Species of Herbaceous Perennials

HortScience ◽

10.21273/hortsci.33.3.540a ◽

1998 ◽

Vol 33 (3) ◽

pp. 540a-540

Author(s):

K.J. Prevete ◽

R.T. Fernandez

Keyword(s):

Drought Stress ◽

Stomatal Conductance ◽

Gas Exchange ◽

Drought Tolerance ◽

Transpiration Rate ◽

Leaf Gas Exchange ◽

Gas Analysis ◽

Herbaceous Perennials ◽

Effects Of Drought ◽

Analysis System

Three species of herbaceous perennials were tested on their ability to withstand and recover from drought stress periods of 2, 4, and 6 days. Eupatorium rugosum and Boltonia asteroides `Snowbank' were chosen because of their reported drought intolerance, while Rudbeckia triloba was chosen based on its reported drought tolerance. Drought stress began on 19 Sept. 1997. Plants were transplanted into the field the day following the end of each stress period. The effects of drought on transpiration rate, stomatal conductance, and net photosynthetic rate were measured during the stress and throughout recovery using an infrared gas analysis system. Leaf gas exchange measurements were taken through recovery until there were no differences between the stressed plants and the control plants. Transpiration, stomatal conductance, and photosynthesis of Rudbeckia and Boltonia were not affected until 4 days after the start of stress. Transpiration of Eupatorium decreased after 3 days of stress. After rewatering, leaf gas exchange of Boltonia and Rudbeckia returned to non-stressed levels quicker than Eupatorium. Growth measurements were taken every other day during stress, and then weekly following transplanting. Measurements were taken until a killing frost that occurred on 3 Nov. There were no differences in the growth between the stressed and non-stressed plants in any of the species. Plants will be monitored throughout the winter, spring, and summer to determine the effects of drought on overwintering capability and regrowth.

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Flavonoids improve drought tolerance of maize seedlings by regulating the homeostasis of reactive oxygen species

Plant and Soil ◽

10.1007/s11104-020-04814-8 ◽

2021 ◽

Author(s):

Baozhu Li ◽

Ruonan Fan ◽

Guiling Sun ◽

Ting Sun ◽

Yanting Fan ◽

...

Keyword(s):

Free Radicals ◽

Drought Stress ◽

Drought Tolerance ◽

Infrared Imaging ◽

Oxygen Free Radicals ◽

Transcriptome Profiling ◽

Far Infrared ◽

Drought Treatment ◽

Physiological Characterization ◽

Oxidative Damages

Abstract Background and aims As drought threatens the yield and quality of maize (Zea mays L.), it is important to dissect the molecular basis of maize drought tolerance. Flavonoids, participate in the scavenging of oxygen free radicals and alleviate stress-induced oxidative damages. This study aims to dissect the function of flavonoids in the improvement of maize drought tolerance. Methods Using far-infrared imaging screening, we previously isolated a drought overly insensitivity (doi) mutant from an ethyl methanesulfonate (EMS)-mutagenized maize library and designated it as doi57. In this study, we performed a physiological characterization and transcriptome profiling of doi57 in comparison to corresponding wild-type B73 under drought stress. Results Under drought stress, doi57 seedlings displayed lower leaf-surface temperature (LST), faster water loss, and better performance in growth than B73. Transcriptome analysis reveals that key genes involved in flavonoid biosynthesis are enriched among differentially expressed genes in doi57. In line with these results, more flavonols and less hydrogen peroxide (H2O2) were accumulated in guard cells of doi57 than in those of B73 with the decrease of soil water content (SWC). Moreover, the capacity determined from doi57 seedling extracts to scavenge oxygen free radicals was more effective than that of B73 under the drought treatment. Additionally, doi57 seedlings had higher photosynthetic rates, stomatal conductance, transpiration rates, and water use efficiency than B73 exposed to drought stress, resulting in high biomass and greater root/shoot ratios in doi57 mutant plants. Conclusion Flavonoids may facilitate maize seedling drought tolerance by lowering drought-induced oxidative damage as well regulating stomatal movement.

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Surprising Drought Tolerance of Fir (Abies) Species between Past Climatic Adaptation and Future Projections Reveals New Chances for Adaptive Forest Management

Forests ◽

10.3390/f12070821 ◽

2021 ◽

Vol 12 (7) ◽

pp. 821

Author(s):

Csaba Mátyás ◽

František Beran ◽

Jaroslav Dostál ◽

Jiří Čáp ◽

Martin Fulín ◽

...

Keyword(s):

Drought Stress ◽

Drought Tolerance ◽

Test Site ◽

Species Differentiation ◽

Silver Fir ◽

Growth And Survival ◽

Future Performance ◽

Moisture Deficit ◽

Climatic Scenarios ◽

Unique Potential

Research Highlights: Data of advanced-age provenance tests were reanalyzed applying a new approach, to directly estimate the growth of populations at their original sites under individually generated future climates. The results revealed the high resilience potential of fir species. Background and Objectives: The growth and survival of silver fir under future climatic scenarios are insufficiently investigated at the xeric limits. The selective signature of past climate determining the current and projected growth was investigated to analyze the prospects of adaptive silviculture and assisted transfer of silver fir populations, and the introduction of non-autochthonous species. Materials and Methods: Hargreaves’ climatic moisture deficit was selected to model height responses of adult populations. Climatic transfer distance was used to assess the relative drought stress of populations at the test site, relating these to the past conditions to which the populations had adapted. ClimateEU and ClimateWNA pathway RCP8.5 data served to determine individually past, current, and future moisture deficit conditions. Besides silver fir, other fir species from South Europe and the American Northwest were also tested. Results: Drought tolerance profiles explained the responses of transferred provenances and predicted their future performance and survival. Silver fir displayed significant within-species differentiation regarding drought stress response. Applying the assumed drought tolerance limit of 100 mm relative moisture deficit, most of the tested silver fir populations seem to survive their projected climate at their origin until the end of the century. Survival is likely also for transferred Balkan fir species and for grand fir populations, but not for the Mediterranean species. Conclusions: The projections are less dramatic than provided by usual inventory assessments, considering also the resilience of populations. The method fills the existing gap between experimentally determined adaptive response and the predictions needed for management decisions. It also underscores the unique potential of provenance tests.

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Improving Drought Tolerance in Mungbean (Vigna radiata L. Wilczek): Morpho-Physiological, Biochemical and Molecular Perspectives

Agronomy ◽

10.3390/agronomy11081534 ◽

2021 ◽

Vol 11 (8) ◽

pp. 1534

Author(s):

Chandra Mohan Singh ◽

Poornima Singh ◽

Chandrakant Tiwari ◽

Shalini Purwar ◽

Mukul Kumar ◽

...

Keyword(s):

Drought Stress ◽

Drought Tolerance ◽

Crop Production ◽

Mitigation Strategies ◽

Theoretical Research ◽

Whole Genome Sequence ◽

Complex Nature ◽

Drought Tolerant ◽

Breeding Programmes ◽

The Impact

Drought stress is considered a severe threat to crop production. It adversely affects the morpho-physiological, biochemical and molecular functions of the plants, especially in short duration crops like mungbean. In the past few decades, significant progress has been made towards enhancing climate resilience in legumes through classical and next-generation breeding coupled with omics approaches. Various defence mechanisms have been reported as key players in crop adaptation to drought stress. Many researchers have identified potential donors, QTLs/genes and candidate genes associated to drought tolerance-related traits. However, cloning and exploitation of these loci/gene(s) in breeding programmes are still limited. To bridge the gap between theoretical research and practical breeding, we need to reveal the omics-assisted genetic variations associated with drought tolerance in mungbean to tackle this stress. Furthermore, the use of wild relatives in breeding programmes for drought tolerance is also limited and needs to be focused. Even after six years of decoding the whole genome sequence of mungbean, the genome-wide characterization and expression of various gene families and transcriptional factors are still lacking. Due to the complex nature of drought tolerance, it also requires integrating high throughput multi-omics approaches to increase breeding efficiency and genomic selection for rapid genetic gains to develop drought-tolerant mungbean cultivars. This review highlights the impact of drought stress on mungbean and mitigation strategies for breeding high-yielding drought-tolerant mungbean varieties through classical and modern omics technologies.

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Applying RGB- and Thermal-Based Vegetation Indices from UAVs for High-Throughput Field Phenotyping of Drought Tolerance in Forage Grasses

Remote Sensing ◽

10.3390/rs13010147 ◽

2021 ◽

Vol 13 (1) ◽

pp. 147

Author(s):

Tom De Swaef ◽

Wouter H. Maes ◽

Jonas Aper ◽

Joost Baert ◽

Mathias Cougnon ◽

...

Keyword(s):

Drought Stress ◽

Drought Tolerance ◽

Lolium Perenne ◽

High Throughput ◽

Festuca Arundinacea ◽

Stress Index ◽

Forage Grasses ◽

Crop Water Stress Index ◽

Ploidy Levels ◽

Field Phenotyping

The persistence and productivity of forage grasses, important sources for feed production, are threatened by climate change-induced drought. Breeding programs are in search of new drought tolerant forage grass varieties, but those programs still rely on time-consuming and less consistent visual scoring by breeders. In this study, we evaluate whether Unmanned Aerial Vehicle (UAV) based remote sensing can complement or replace this visual breeder score. A field experiment was set up to test the drought tolerance of genotypes from three common forage types of two different species: Festuca arundinacea, diploid Lolium perenne and tetraploid Lolium perenne. Drought stress was imposed by using mobile rainout shelters. UAV flights with RGB and thermal sensors were conducted at five time points during the experiment. Visual-based indices from different colour spaces were selected that were closely correlated to the breeder score. Furthermore, several indices, in particular H and NDLab, from the HSV (Hue Saturation Value) and CIELab (Commission Internationale de l’éclairage) colour space, respectively, displayed a broad-sense heritability that was as high or higher than the visual breeder score, making these indices highly suited for high-throughput field phenotyping applications that can complement or even replace the breeder score. The thermal-based Crop Water Stress Index CWSI provided complementary information to visual-based indices, enabling the analysis of differences in ecophysiological mechanisms for coping with reduced water availability between species and ploidy levels. All species/types displayed variation in drought stress tolerance, which confirms that there is sufficient variation for selection within these groups of grasses. Our results confirmed the better drought tolerance potential of Festuca arundinacea, but also showed which Lolium perenne genotypes are more tolerant.

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Comparing transcriptional responses to Fusarium crown rot in wheat and barley identified an important relationship between disease resistance and drought tolerance

BMC Plant Biology ◽

10.1186/s12870-020-02818-1 ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Z. Y. Su ◽

J. J. Powell ◽

S. Gao ◽

M. Zhou ◽

C. Liu

Keyword(s):

Drought Stress ◽

Drought Tolerance ◽

Crown Rot ◽

Differentially Expressed ◽

Transcriptional Responses ◽

Drought Treatment ◽

Crop Species ◽

Fusarium Crown Rot ◽

Important Relationship ◽

The Impact

Abstract Background Fusarium crown rot (FCR) is a chronic disease in cereal production worldwide. The impact of this disease is highly environmentally dependant and significant yield losses occur mainly in drought-affected crops. Results In the study reported here, we evaluated possible relationships between genes conferring FCR resistance and drought tolerance using two approaches. The first approach studied FCR induced differentially expressed genes (DEGs) targeting two barley and one wheat loci against a panel of genes curated from the literature based on known functions in drought tolerance. Of the 149 curated genes, 61.0% were responsive to FCR infection across the three loci. The second approach was a comparison of the global DEGs induced by FCR infection with the global transcriptomic responses under drought in wheat. This analysis found that approximately 48.0% of the DEGs detected one week following drought treatment and 74.4% of the DEGs detected three weeks following drought treatment were also differentially expressed between the susceptible and resistant isolines under FCR infection at one or more timepoints. As for the results from the first approach, the vast majority of common DEGs were downregulated under drought and expressed more highly in the resistant isoline than the sensitive isoline under FCR infection. Conclusions Results from this study suggest that the resistant isoline in wheat was experiencing less drought stress, which could contribute to the stronger defence response than the sensitive isoline. However, most of the genes induced by drought stress in barley were more highly expressed in the susceptible isolines than the resistant isolines under infection, indicating that genes conferring drought tolerance and FCR resistance may interact differently between these two crop species. Nevertheless, the strong relationship between FCR resistance and drought responsiveness provides further evidence indicating the possibility to enhance FCR resistance by manipulating genes conferring drought tolerance.

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Overexpression of the pitaya phosphoethanolamine N-methyltransferase gene (HpPEAMT) enhanced simulated drought stress in tobacco

Plant Cell Tissue and Organ Culture (PCTOC) ◽

10.1007/s11240-021-02040-3 ◽

2021 ◽

Author(s):

Ai-Hua Wang ◽

Lan Yang ◽

Xin-Zhuan Yao ◽

Xiao-Peng Wen

Keyword(s):

Drought Stress ◽

Stress Response ◽

Transgenic Plants ◽

Drought Tolerance ◽

Transgenic Tobacco ◽

Sequence Similarity ◽

Amino Acid Sequence Similarity ◽

Transgenic Tobacco Plants ◽

Wild Type ◽

Tobacco Plants

AbstractPhosphoethanolamine N-methyltransferase (PEAMTase) catalyzes the methylation of phosphoethanolamine to produce phosphocholine and plays an important role in the abiotic stress response. Although the PEAMT genes has been isolated from many species other than pitaya, its role in the drought stress response has not yet been fully elucidated. In the present study, we isolated a 1485 bp cDNA fragment of HpPEAMT from pitaya (Hylocereus polyrhizus). Phylogenetic analysis showed that, during its evolution, HpPEAMT has shown a high degree of amino acid sequence similarity with the orthologous genes in Chenopodiaceae species. To further investigate the function of HpPEAMT, we generated transgenic tobacco plants overexpressing HpPEAMT, and the transgenic plants accumulated significantly more glycine betaine (GB) than did the wild type (WT). Drought tolerance trials indicated that, compared with those of the wild-type (WT) plants, the roots of the transgenic plants showed higher drought tolerance ability and exhibited improved drought tolerance. Further analysis revealed that overexpression of HpPEAM in Nicotiana tabacum resulted in upregulation of transcript levels of GB biosynthesis-related genes (NiBADH, NiCMO and NiSDC) in the leaves. Furthermore, compared with the wild-type plants, the transgenic tobacco plants displayed a significantly lower malondialdehyde (MDA) accumulation and higher activities of the superoxide dismutase (SOD) and peroxidase (POD) antioxidant enzymes under drought stress. Taken together, our results suggested that HpPEAMT enhanced the drought tolerance of transgenic tobacco.

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Drought Tolerant near Isogenic Lines (NILs) of Pusa 44 Developed through Marker Assisted Introgression of qDTY2.1 and qDTY3.1 Enhances Yield under Reproductive Stage Drought Stress

Agriculture ◽

10.3390/agriculture11010064 ◽

2021 ◽

Vol 11 (1) ◽

pp. 64

Author(s):

Priyanka Dwivedi ◽

Naleeni Ramawat ◽

Gaurav Dhawan ◽

Subbaiyan Gopala Krishnan ◽

Kunnummal Kurungara Vinod ◽

...

Keyword(s):

Drought Stress ◽

Drought Tolerance ◽

Grain Quality ◽

Reproductive Stage ◽

Recurrent Parent ◽

Near Isogenic Lines ◽

Improvement Project ◽

Isogenic Lines ◽

Drought Tolerant ◽

Rice Improvement

Reproductive stage drought stress (RSDS) is detrimental for rice, which affects its productivity as well as grain quality. In the present study, we introgressed two major quantitative trait loci (QTLs), namely, qDTY2.1 and qDTY3.1, governing RSDS tolerance in a popular high yielding non-aromatic rice cultivar, Pusa 44, through marker-assisted backcross breeding (MABB). Pusa 44 is highly sensitive to RSDS, which restricts its cultivation across drought-prone environments. Foreground selection was carried out using markers, RM520 for qDTY3.1 and RM 521 for qDTY2.1. Background selection was achieved with 97 polymorphic SSR markers in tandem with phenotypic selection to achieve faster recurrent parent genome (RPG) recovery. Three successive backcrosses followed by three selfings aided RPG recoveries of 98.6% to 99.4% among 31 near isogenic lines (NILs). Fourteen NILs were found to be significantly superior in yield and grain quality under RSDS with higher drought tolerance efficiency (DTE) than Pusa 44. Among these, the evaluation of two promising NILs in the multilocational trial during Kharif 2019 showed that they were significantly superior to Pusa 44 under reproductive stage drought stress, while performing on par with Pusa 44 under normal irrigated conditions. These di-QTL pyramided drought-tolerant NILs are in the final stages of testing the All India Coordinated Rice Improvement Project varietal trials for cultivar release. Alternately, the elite drought-tolerant Pusa 44 NILs will serve as an invaluable source of drought tolerance in rice improvement.

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Penconazole and calcium ameliorate drought stress in canola by upregulating the antioxidative enzymes

Functional Plant Biology ◽

10.1071/fp19341 ◽

2020 ◽

Vol 47 (9) ◽

pp. 825 ◽

Cited By ~ 1

Author(s):

Maryam Rezayian ◽

Vahid Niknam ◽

Hassan Ebrahimzadeh

Keyword(s):

Oxidative Stress ◽

Lipid Peroxidation ◽

Drought Stress ◽

Drought Tolerance ◽

Antioxidative Enzymes ◽

Proline Content ◽

Fresh Weight ◽

Negative Effects ◽

Mda Content ◽

Effects Of Drought

The aim of this research was to gauge the alternations in the lipid peroxidation and antioxidative enzyme activity in two cultivars (cv. RGS003 and cv. Sarigol) of canola under drought stress and drought tolerance amelioration by penconazole (PEN) and calcium (Ca). Plants were treated with different polyethylene glycol (PEG) concentrations (0, 5, 10 and 15%) without or with PEN (15 mg L–1) and Ca (15 mM). The Ca treatment prevented the negative effects of drought on fresh weight (FW) in RGS003 and Sarigol at 5 and 15% PEG respectively. Ca and PEN/Ca treatments caused significant induction in the proline content in Sarigol at 15% PEG; the latter treatment was accompanied by higher glycine betaine (GB), lower malondialdehyde (MDA) and growth recovery. Hydrogen peroxide (HO2) content in Sarigol was proportional to the severity of drought stress and all PEN, Ca and PEN/Ca treatments significantly reduced the H2O2 content. PEN and PEN/Ca caused alleviation of the drought-induced oxidative stress in RGS003. RGS003 cultivar exhibited significantly higher antioxidative enzymes activity at most levels of drought, which could lead to its drought tolerance and lower MDA content. In contrast to that of Sarigol, the activity of catalase and superoxide dismutase (SOD) increased with Ca and PEN/Ca treatments in RGS003 under low stress. The application of PEN and Ca induced significantly P5CS and SOD expression in RGS003 under drought stress after 24 h. Overall, these data demonstrated that PEN and Ca have the ability to enhance the tolerance against the drought stress in canola plants.

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