Responses of Sphagneticola trilobata, Sphagneticola calendulacea and Their Hybrid to Drought Stress

Sphagneticola trilobata is an invasive plant in South China. A hybrid between S. trilobata and Sphagneticola calendulacea (a native related species) has also been found in South China. The drought resistance of S. calendulacea, S. trilobata and their hybrid was studied in this paper. Under drought stress, the leaves of S. trilobata synthesized more abscisic acid (ABA) than those of the other species to reduce stomatal opening and water loss. The activities of antioxidant enzymes were the highest in S. trilobata and the lowest in S. calendulacea. The leaves of S. calendulacea suffered the most serious damage, and their maximum photochemical efficiency was the lowest. RNA-sequencing ware used to analyze the expression levels of genes in ABA, antioxidant enzyme, sugar and proline synthesis and photosynthesis pathways. Further real-time PCR detection verified the RNA-sequence results, and the results were in accordance with the physiological data. The results showed that S. trilobata was the most drought tolerant, and the drought tolerance of the hybrid did not show heterosis but was higher than S. calendulacea. Therefore, compared with S. trilobata and the hybrid, the population number and distribution of S. calendulacea may be less in arid areas.

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Physiological and Proteomic Analysis Revealed the Response Mechanisms of two Different Grought-resistant Maize Varieties

10.21203/rs.3.rs-630007/v1 ◽

2021 ◽

Author(s):

Hongjie Li ◽

Mei Yang ◽

Chengfeng Zhao ◽

Yifan Wang ◽

Renhe Zhang

Keyword(s):

Drought Stress ◽

Drought Tolerance ◽

Stress Responses ◽

Molecular Chaperones ◽

Electron Flow ◽

Photochemical Efficiency ◽

Growth And Yield ◽

Protective Mechanism ◽

Drought Tolerant ◽

Maize Varieties

Abstract Background: Drought stress seriously limits the seedling growth and yield of maize. Despite previous studies on drought resistance mechanisms by which maize cope with water deficient, the link between physiological and molecular variations are largely unknown. To reveal the complex regulatory mechanisms, comparative physiology and proteomic analyses were conducted to investigate the stress responses of two maize cultivars with contrasting tolerance to drought stress. Results: Physiological results showed that SD609 (drought-tolerant) maintains higher photochemical efficiency by enhancing CEF (cyclic electron flow) protective mechanism and antioxidative enzymes activities. Proteomics analysis revealed a total of 198 and 102 proteins were differentially expressed in SD609 and SD902, respectively. Further enrichment analysis indicated that drought-tolerant ‘SD609’ increased the expression of proteins related to photosynthesis, antioxidants/detoxifying enzymes, molecular chaperones and metabolic enzymes. The up-regulation proteins related to PSII repair and photoprotection mechanisms resulted in more efficient photochemical capacity in tolerant variety under moderate drought. However, the drought-sensitive ‘SD902’ only induced molecular chaperones and sucrose synthesis pathways, and failed to protect the impaired photosystem. Further analysis indicated that proteins related to the electron transport chain, redox homeostasis and heat shock proteins (HSPs) could be important in protecting plants from drought stress. Conclusions: Our experiments explored the mechanism of drought tolerance, and obtained detailed information about the interconnection of physiological research and protein research. In summary, our findings could provide new clues into further understanding of drought tolerance mechanisms in maize.

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Proteins Involved in Energy Metabolism and Oxidative Regulation Associated with Genotypic Variations in Drought Tolerance for Tall Fescue

Journal of the American Society for Horticultural Science ◽

10.21273/jashs04385-18 ◽

2018 ◽

Vol 143 (3) ◽

pp. 207-212

Author(s):

Jianming Sun ◽

Yiming Liu ◽

Xianglin Li ◽

Bingru Huang

Keyword(s):

Drought Stress ◽

Drought Tolerance ◽

Tall Fescue ◽

Photochemical Efficiency ◽

Grass Species ◽

Drought Treatment ◽

Drought Tolerant ◽

Oxidative Regulation ◽

Tolerant Genotype ◽

Adaptation To Drought

Protein metabolism plays an important role in plant adaptation to drought stress. The objective of this study was to identify drought-responsive proteins associated with differential drought tolerance for a tolerant genotype (RU9) and a sensitive genotype (RU18) of tall fescue (Lolium arundinacea). Plants of both genotypes were grown under well-watered conditions or subjected to drought stress by withholding irrigation for 12 days in a growth chamber controlled at the optimal growth temperatures of 23/18 °C (day/night). Physiological analysis demonstrated that RU9 was relatively more drought tolerant than RU18, as shown by the higher leaf net photosynthetic rate (Pn) and photochemical efficiency at 12 days of drought treatment. Differentially expressed proteins between RU9 and RU18 exposed to drought stress were identified by two-dimensional electrophoresis and mass spectrometry (MS). Several proteins [photosystem I reaction center subunit II, Rubisco small subunit, and Glyceraldehyde-3-phosphate dehydrogenase (GADPH)] in photosynthesis, respiration, or oxidative regulation exhibited higher abundance in RU9 than RU18 under drought stress. These results suggested the critical importance of energy and oxidative metabolism in tall fescue adaptation to drought stress. Those abundant proteins in the drought-tolerant genotype could be used as biomarkers or developed to molecular markers to develop elite drought-tolerant germplasm in tall fescue and other cool-season perennial grass species.

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Response of Yellow Quality Protein Maize Inbred Lines to Drought stress at Seedling Stage

Agronomy ◽

10.3390/agronomy8120287 ◽

2018 ◽

Vol 8 (12) ◽

pp. 287 ◽

Cited By ~ 3

Author(s):

Nyasha Chiuta ◽

Charles Mutengwa

Keyword(s):

Drought Stress ◽

Block Design ◽

Photochemical Efficiency ◽

Field Capacity ◽

Inbred Lines ◽

Proline Content ◽

The Other ◽

Quality Protein Maize ◽

Ps Ii ◽

Drought Tolerant

This study seeks to evaluate the response of 17 yellow Quality Protein Maize (QPM) inbred line seedlings to drought stress (DS), using different morphophysiological traits (plant height (PH), chlorophyll content (CC), stem diameter (SD), proline content (Pro), photochemical efficiency of photosystem II (PS II), canopy temperature (CT) and substomatal carbon dioxide concentration (Ci). The experiment was laid out in a randomized complete block design (RCBD) and replicated three times in a growth chamber. The seedlings were exposed to DS treatment by growing them at 20% field capacity. The control/well-watered (WW) treatments were kept at 80% field capacity throughout the experiment. Highly significant differences (p < 0.001) were observed for PH, SD, and Pro across environments. On the other hand, significant differences (p < 0.05) were observed for CC and PS II, while DS had no significant effects on Ci and CT. Proline content increased under DS compared to WW conditions. Inbred lines L34, L7, L5, L2, L16, and L6 had approximately equal or more Pro than the drought tolerant check (ZM1523). As such, these lines were regarded as drought tolerant. Taking all measured parameters into consideration, L7 performed notably better than the other inbred lines under DS.

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Important Physiological Changes Due to Drought Stress on Oat

Frontiers in Ecology and Evolution ◽

10.3389/fevo.2021.644726 ◽

2021 ◽

Vol 9 ◽

Author(s):

Hongying Xie ◽

Mengran Li ◽

Youjun Chen ◽

Qingping Zhou ◽

Wenhui Liu ◽

...

Keyword(s):

Drought Stress ◽

Drought Resistance ◽

Comprehensive Evaluation ◽

Photochemical Efficiency ◽

Damage Index ◽

Principal Component ◽

Drought Tolerant ◽

Gray Correlation ◽

Relative Electrical Conductivity ◽

The Impact

As temperatures rise and water availability decreases, the water decit is gaining attention regarding future agricultural production. Drought stress is a global issue and adversely affects the productivity of different crops. In this study, drought-tolerant varieties of oats were screened to determine drought-tolerant varieties that may be employed in drought-prone areas to achieve sustainable development and mitigate the impact of climate change. To do so, the growth and stress adaptive mechanism of 15 domestic and overseas oat cultivars at the seedling stage were analyzed. Water stress was simulated using 20% polyethylene glycol (PEG-6000). The results showed that the soluble protein content and superoxide dismutase activity of variety DY2 significantly increased under drought stress, whereas the photochemical efficiency and relative water content decreased slightly. The relative electrical conductivity (REC) and drought damage index of the QH444 and DY2 varieties increased the least. The peroxidase content of Q1 and DY2 significantly increased, and the catalase activity of Q1, QH444, and DY2 also substantially increased. Principal component analysis revealed that nine physiological and biochemical parameters were transformed into three independent comprehensive indexes. The comprehensive evaluation results showed that DY2, LN, and Q1 exhibited a strong drought resistance capacity and could be used as a reference material for a drought-resistant oat breeding program. The gray correlation analysis also indicated that Fv/Fm, chlorophyll, REC, and malondialdehyde could be used as key indexes for evaluating the drought resistance of oat.

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Mitigation of drought stress in maize through inoculation with drought tolerant ACC deaminase containing PGPR under axenic conditions

Pakistan Journal of Botany ◽

10.30848/pjb2020-1(7) ◽

2019 ◽

Vol 52 (1) ◽

Cited By ~ 6

Author(s):

Subhan Danish ◽

Muhammad Zafar-Ul-Hye ◽

Shahid Hussain ◽

Muhammad Riaz ◽

Muhammad Farooq Qayyum

Keyword(s):

Drought Stress ◽

Acc Deaminase ◽

Drought Tolerant ◽

Axenic Conditions

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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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Genome wide identification and characterization of light-harvesting Chloro a/b binding (LHC) genes reveals their potential role in enhancing drought tolerance in Gossypium hirsutum

Journal of Cotton Research ◽

10.1186/s42397-021-00090-8 ◽

2021 ◽

Vol 4 (1) ◽

Author(s):

Teame Gereziher MEHARI ◽

Yanchao XU ◽

Richard Odongo MAGWANGA ◽

Muhammad Jawad UMER ◽

Joy Nyangasi KIRUNGU ◽

...

Keyword(s):

Drought Stress ◽

Gossypium Hirsutum ◽

Abiotic Stresses ◽

Substitution Rate ◽

Synonymous Substitution ◽

Synonymous Substitution Rate ◽

Drought Tolerant ◽

Genome Wide ◽

Identification And Characterization

Abstract Background Cotton is an important commercial crop for being a valuable source of natural fiber. Its production has undergone a sharp decline because of abiotic stresses, etc. Drought is one of the major abiotic stress causing significant yield losses in cotton. However, plants have evolved self-defense mechanisms to cope abiotic factors like drought, salt, cold, etc. The evolution of stress responsive transcription factors such as the trihelix, a nodule-inception-like protein (NLP), and the late embryogenesis abundant proteins have shown positive response in the resistance improvement to several abiotic stresses. Results Genome wide identification and characterization of the effects of Light-Harvesting Chloro a/b binding (LHC) genes were carried out in cotton under drought stress conditions. A hundred and nine proteins encoded by the LHC genes were found in the cotton genome, with 55, 27, and 27 genes found to be distributed in Gossypium hirsutum, G. arboreum, and G. raimondii, respectively. The proteins encoded by the genes were unevenly distributed on various chromosomes. The Ka/Ks (Non-synonymous substitution rate/Synonymous substitution rate) values were less than one, an indication of negative selection of the gene family. Differential expressions of genes showed that majority of the genes are being highly upregulated in the roots as compared with leaves and stem tissues. Most genes were found to be highly expressed in MR-85, a relative drought tolerant germplasm. Conclusion The results provide proofs of the possible role of the LHC genes in improving drought stress tolerance, and can be explored by cotton breeders in releasing a more drought tolerant cotton varieties.

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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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Genetic Diversity of Selected Rice Genotypes under Water Stress Conditions

Plants ◽

10.3390/plants10010027 ◽

2020 ◽

Vol 10 (1) ◽

pp. 27

Author(s):

Mahmoud M. Gaballah ◽

Azza M. Metwally ◽

Milan Skalicky ◽

Mohamed M. Hassan ◽

Marian Brestic ◽

...

Keyword(s):

Genetic Diversity ◽

Water Stress ◽

Drought Stress ◽

Drought Tolerance ◽

Ssr Markers ◽

Similarity Index ◽

Stress Conditions ◽

Yield Potential ◽

Drought Tolerant ◽

Rice Genotypes

Drought is the most challenging abiotic stress for rice production in the world. Thus, developing new rice genotype tolerance to water scarcity is one of the best strategies to achieve and maximize high yield potential with water savings. The study aims to characterize 16 rice genotypes for grain and agronomic parameters under normal and drought stress conditions, and genetic differentiation, by determining specific DNA markers related to drought tolerance using Simple Sequence Repeats (SSR) markers and grouping cultivars, establishing their genetic relationship for different traits. The experiment was conducted under irrigated (normal) and water stress conditions. Mean squares due to genotype × environment interactions were highly significant for major traits. For the number of panicles/plants, the genotypes Giza179, IET1444, Hybrid1, and Hybrid2 showed the maximum mean values. The required sterility percentage values were produced by genotypes IET1444, Giza178, Hybrid2, and Giza179, while, Sakha101, Giza179, Hybrid1, and Hybrid2 achieved the highest values of grain yield/plant. The genotypes Giza178, Giza179, Hybrid1, and Hybrid2, produced maximum values for water use efficiency. The effective number of alleles per locus ranged from 1.20 alleles to 3.0 alleles with an average of 1.28 alleles, and the He values for all SSR markers used varied from 0.94 to 1.00 with an average of 0.98. The polymorphic information content (PIC) values for the SSR were varied from 0.83 to 0.99, with an average of 0.95 along with a highly significant correlation between PIC values and the number of amplified alleles detected per locus. The highest similarity coefficient between Giza181 and Giza182 (Indica type) was observed and are susceptible to drought stress. High similarity percentage between the genotypes (japonica type; Sakha104 with Sakha102 and Sakha106 (0.45), Sakha101 with Sakha102 and Sakha106 (0.40), Sakha105 with Hybrid1 (0.40), Hybrid1 with Giza178 (0.40) and GZ1368-S-5-4 with Giza181 (0.40)) was also observed, which are also susceptible to drought stress. All genotypes are grouped into two major clusters in the dendrogram at 66% similarity based on Jaccard’s similarity index. The first cluster (A) was divided into two minor groups A1 and A2, in which A1 had two groups A1-1 and A1-2, containing drought-tolerant genotypes like IET1444, GZ1386-S-5-4 and Hybrid1. On the other hand, the A1-2 cluster divided into A1-2-1 containing Hybrid2 genotype and A1-2-2 containing Giza179 and Giza178 at coefficient 0.91, showing moderate tolerance to drought stress. The genotypes GZ1368-S-5-4, IET1444, Giza 178, and Giza179, could be included as appropriate materials for developing a drought-tolerant variety breeding program. Genetic diversity to grow new rice cultivars that combine drought tolerance with high grain yields is essential to maintaining food security.

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Genetic Dissection of Epistatic Interactions Contributing Grain Yield Variability in Rice under Drought

Current Genomics ◽

10.2174/1386207324666210713112127 ◽

2021 ◽

Vol 22 ◽

Author(s):

Ratna Rani Majumder ◽

Nitika Sandhu ◽

Shailesh Yadav ◽

Margaret Catolos ◽

Ma. Teresa Sta. Cruz ◽

...

Keyword(s):

Drought Stress ◽

Grain Yield ◽

Genetic Background ◽

Reproductive Stage ◽

Yield Variability ◽

Marker Interval ◽

Negative Interaction ◽

Epistatic Interactions ◽

Lattice Design ◽

Drought Tolerant

Aims: The aim of the present study was to evaluate the performance of ‘high’-‘low’ yielding pyramided lines (PLs) with the same combinations of qDTYs in Samba Mahsuri, MR219 and IR64-Sub1 genetic backgrounds and understand the genetic interactions of QTL and with genetic background affecting grain yield. Background: Epistasis regulates the expression of traits governed by several major/minor genes/QTL. Multiple pyramided lines (PLs) with the same grain yield QTL (qDTYs) combinations but possessing grain yield variability under different levels of reproductive stage drought stress were identified in different rice genetic backgrounds at International Rice Research Institute (IRRI). Objectives: The objectives of the present study were to evaluate the performance pyramided lines (PLs) with drought QTL in the backgrounds of Samba Mahsuri, MR219 and IR64-Sub1 under reproductive stage drought stress (RS) and NS (non-stress) conditions ii) to understand the effect of epistatic interactions of qDTYs and with genetic background on GY under the differential level of stress iii) to identify the promising drought-tolerant lines with high yield under drought and higher background recovery in different genetic backgrounds. Results: Several digenic interactions were found in different genetic backgrounds, 13 interactions in Samba Mahsuri, 11 in MR219 and 20 in IR64-Sub1 backgrounds. Among all digenic interactions, one QTL × QTL interaction, 17 QTL × background and 26 background × background interactions resulted in GY reduction in low yielding PLs in different genetic backgrounds under LSS or LMS. Negative interaction of qDTY3.1, qDTY4.1 and qDTY9.1 with background markers and background × background interactions caused up to 15% GY reduction compared to the high yielding PLs under LMS in the Samba Mahsuri PLs. In MR219 PLs, the negative interaction of qDTY2.2, qDTY3.2, qDTY4.1 and qDTY12.1 with the background marker interval RM314-RM539, RM273-RM349 and RM445-RM346, RM473D-RM16, respectively resulted in 52% GY reduction compared to the high yielding PLs under LSS. In IR64-Sub1 PLs, qDTY6.1 interacted with background loci at RM16-RM135, RM228-RM333, RM202-RM287 and RM415-RM558A marker interval under LSS; and at RM475-RM525 marker interval under LMS, causing GY reduction to 58% compared to the high yielding PLs. Conclusion: High yielding PLs in Samba Mahsuri (IR 99734:1-33-69-1-22-6), MR219 (IR 99784-156-87-2-4-1) and IR64-Sub1 (IR 102784:2-89-632-2-1-2) backgrounds without any negative interactions were identified. The identified selected promising PLs may be used as potential drought-tolerant donors or may be released as varieties for drought-prone ecosystems in different countries. Methods: The experiments were conducted in 2015DS (dry season), 2015WS (wet season) and 2017 DS at IRRI, Los Baños, Philippines, in a transplanted lowland ecosystem under lowland severe stress (LSS), moderate lowland stress (LMS) and lowland non-stress (LNS). The experiments were laid out in alpha lattice design with two replications.

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