Use of DArT molecular markers for QTL analysis of drought-stress responses in soybean. II. Marker identification and QTL analyses

2015 ◽  
Vol 66 (8) ◽  
pp. 817 ◽  
Author(s):  
Hang T. T. Vu ◽  
A. Kilian ◽  
A. T. James ◽  
L. M. Bielig ◽  
R. J. Lawn

This study applied newly developed Diversity Arrays Technology (DArT) and soybean and mungbean DArT libraries for quantitative trait locus (QTL) linkage analysis in recombinant inbred lines (RILs) from three soybean crosses that had previously been assessed for physiological response to severe drought stress. The phenotypic assessments had identified statistically significant genetic variation among and within the RIL populations and their parents for three drought-related responses: epidermal conductance (ge) and relative water content (RWC) during stress, and plant recovery after stress. The new linkage maps containing only DArT markers for the three populations individually contained 196–409 markers and 15–22 linkage groups (LGs), with an aggregate length ranging from 409.4 to 516.7 cM. An integrated map constructed by using the marker data from all three RIL populations comprised 759 DArT markers, 27 LGs and an expanded length of 762.2 cM. Two populations with the landrace accession G2120 as a parent, CPI 26671 × G2120 (CG) and Valder × G2120 (VG), respectively contained 106 and 34 QTLs. In each of these populations, 10 LGs harboured QTLs associated with RWC, ge and recovery ability, of which six similar LGs were associated with drought tolerance. A BLAST (Basic Local Alignment Search Tool) search for sequences of 19 selected DArT markers linked to QTLs conditioning the drought-response traits indicated that 18 DArT markers were unique and aligned to 12 soybean chromosomes. Comparison of these sequenced DArT markers with other markers associated with drought-related QTLs in previously reported studies using other marker types confirmed that five of them overlapped, whereas the remaining 13 were new. Except for chromosome 15, the chromosomes with which the DArT QTLs in the CG and VG populations were associated were those that had been shown to harbour drought-related QTLs in previous studies. A BLASTx protein database search identified soPt-856602 as being associated with the gene for a probable glycosyltransferase At5g03795-like isoform X1 on chromosome 6. Although the several QTLs identified in the study were all of relatively minor effect, it was concluded that, because the DArT technology involves large numbers of markers and enables many lines to be genotyped simultaneously, it should help the process of manipulating multiple QTLs and so enhance their likely cumulative effect.


2015 ◽  
Vol 66 (8) ◽  
pp. 802 ◽  
Author(s):  
Hang T. T. Vu ◽  
A. T. James ◽  
R. J. Lawn ◽  
L. M. Bielig ◽  
A. Kilian

Physiological drought stress responses were assessed in recombinant inbred lines (RILs) from three soybean (Glycine max (L.) Merr.) crosses, in preparation for quantitative trait locus (QTL) analyses using Diversity Arrays Technology (DArT) markers. The three RIL populations were derived from pairwise crosses between three genotypes, cv. Valder, CPI 26671 and G2120, which in previous studies had differed in drought-stress response. Of particular interest was the landrace variety G2120, which in the previous reports had recovered better after severe drought. To assess drought-stress response, the plants were grown in deep cylindrical pots in the glasshouse and exposed to severe water deficit followed by re-watering. Two plants to be genotyped were grown in each pot, together with one plant of G2120, which served as a reference plant against which the responses of the two other plants were assessed. Traits recorded included measures of relative water content (RWC), epidermal conductance (ge) and recovery in growth following re-watering. The responses in the reference and parental plants and the RIL populations were broadly consistent with previous studies. As plant-available water in the soil declined, both RWC and ge declined, although the relation between RWC and ge was exponential, rather than linear as in previous studies. Analysis of variance revealed large environmental effects on most of the traits, which resulted in high coefficients of variation and low estimates of broad-sense heritability. However, there were significant differences at both the population and genotype levels for all key traits, confirming the presence of genetic variation for drought-stress response. Some opportunities for enhancing the observed genetic differences and reducing the environmental noise in future studies are canvassed. Application of the observed phenotypic data reported in this paper in subsequent QTL analyses based on DArT markers is reported in the companion paper.



Cells ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 261
Author(s):  
Md. Mahadi Hasan ◽  
Milan Skalicky ◽  
Mohammad Shah Jahan ◽  
Md. Nazmul Hossain ◽  
Zunaira Anwar ◽  
...  

In recent years, research on spermine (Spm) has turned up a lot of new information about this essential polyamine, especially as it is able to counteract damage from abiotic stresses. Spm has been shown to protect plants from a variety of environmental insults, but whether it can prevent the adverse effects of drought has not yet been reported. Drought stress increases endogenous Spm in plants and exogenous application of Spm improves the plants’ ability to tolerate drought stress. Spm’s role in enhancing antioxidant defense mechanisms, glyoxalase systems, methylglyoxal (MG) detoxification, and creating tolerance for drought-induced oxidative stress is well documented in plants. However, the influences of enzyme activity and osmoregulation on Spm biosynthesis and metabolism are variable. Spm interacts with other molecules like nitric oxide (NO) and phytohormones such as abscisic acid, salicylic acid, brassinosteroids, and ethylene, to coordinate the reactions necessary for developing drought tolerance. This review focuses on the role of Spm in plants under severe drought stress. We have proposed models to explain how Spm interacts with existing defense mechanisms in plants to improve drought tolerance.



2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Ying Liang ◽  
Kunhua Wei ◽  
Fan Wei ◽  
Shuangshuang Qin ◽  
Chuanhua Deng ◽  
...  

Abstract Background Sophora tonkinensis Gagnep is a traditional Chinese medical plant that is mainly cultivated in southern China. Drought stress is one of the major abiotic stresses that negatively impacts S. tonkinensis growth. However, the molecular mechanisms governing the responses to drought stress in S. tonkinensis at the transcriptional and posttranscriptional levels are not well understood. Results To identify genes and miRNAs involved in drought stress responses in S. tonkinensis, both mRNA and small RNA sequencing was performed in root samples under control, mild drought, and severe drought conditions. mRNA sequencing revealed 66,476 unigenes, and the differentially expressed unigenes (DEGs) were associated with several key pathways, including phenylpropanoid biosynthesis, sugar metabolism, and quinolizidine alkaloid biosynthesis pathways. A total of 10 and 30 transcription factors (TFs) were identified among the DEGs under mild and severe drought stress, respectively. Moreover, small RNA sequencing revealed a total of 368 miRNAs, including 255 known miRNAs and 113 novel miRNAs. The differentially expressed miRNAs and their target genes were involved in the regulation of plant hormone signal transduction, the spliceosome, and ribosomes. Analysis of the regulatory network involved in the response to drought stress revealed 37 differentially expressed miRNA-mRNA pairs. Conclusion This is the first study to simultaneously profile the expression patterns of mRNAs and miRNAs on a genome-wide scale to elucidate the molecular mechanisms of the drought stress responses of S. tonkinensis. Our results suggest that S. tonkinensis implements diverse mechanisms to modulate its responses to drought stress.



2020 ◽  
Author(s):  
Li Wei ◽  
Ziwen Geng ◽  
Zhang Cuiping ◽  
Wang Kuiling ◽  
Jiang Xinqiang

Abstract Background: Rose (Rosa chinensis) is a traditional famous flower with valuable ornamental characteristics. However, drought stress restricts its growth and development, leading to abnormal phenotype. APETALA2/ethylene-responsive factor (AP2/ERF) proteins are a kind of transcription factor (TF) protein groups in the plant kingdom, which are crucially involved in the growth and stress responses of most plants. Results: Our investigation focused on exploring the genome of rose and we discovered 135 apparent AP2/ERF TFs. Phylogenic analyses revealed that RcAP2/ERF genes are categorized into DREB, Soloist, AP2, and ERF subfamilies, and further classified these into 17 groups. Analysis of the gene structure revealed that the introns ranged from 0 to 9 in number. Pattern examination demonstrated that the RcAP2/ERF predominantly had typical AP2 domains, of which the 2nd motif is the most ubiquitous. Distributions of cis-acting elements showed members of the AP2/ERF family are involved in growth development and stress response in rose species. We carried out a distribution mapping of the seven rose chromosomes which revealed that AP2/ERF class genes are dispersed among all seven chromosomes. Additionally, we isolated a novel DREB A-2 subgroup gene and named it RcDREB2B. RcDREB2B transcript accumulation was repressed under mild drought and severe drought stress in the root samples of rose. RcDREB2B was targeted to the nucleus and exhibited transactivation in yeast cells. Overexpression of RcDREB2B resulted in enhanced sensitivity to high salt concentration, ABA, and PEG at the germination and post-germination stages. Twelve putative osmotic and ABA-related genes were impaired in RcDREB2B-overexpressing plants. Conclusion: The results provide comprehensive information regarding the gene structure, phylogenic, and distribution of rose AP2/ERF family and shed insight into the complex transcriptional gene regulation of RcAP2/ERF. Findings in this study would also contribute to further understanding of the RcDREB2B gene in rose.



2021 ◽  
Author(s):  
Maryam Mehmood ◽  
Muhammad Jadoon Khan ◽  
Muhammad Jawad Khan ◽  
Nadeem Akhtar ◽  
Fizza Mughal ◽  
...  

Abstract Sesame is a very ancient oilseed crop. Sesame sensitivity to drought stress at early seedling stage is one of the limiting factors affecting its growth and yield in the world. HD-ZIP transcription factors family is one of the most important families involved in drought stress responses in plants. In this study, total sixty one sesame HD-ZIP (SiHZ) proteins were identified in sesame, based on protein sequence homology with Arabidopsis and protein domain(s) architectures were predicted by Hidden Markov model (HMM). HD-ZIP proteins were then classified into four classes (HD-ZIP Class I-IV) according to the phylogenetic, conserved domain(s) motifs and gene structure analyses in sesame. Based on comparative phylogenetic analysis of sesame with Arabidopsis and maize HD-ZIP protein sequences, HD-ZIP Class I was subdivided into four subgroups α (SiHZ25, SiHZ43, SiHZ9 and SiHZ16), β1 (SiHZ10, SiHZ30, SiHZ32 and SiHZ26), β2 (SiHZ42 and SiHZ45) and (SiHZ17, SiHZ7 and SiHZ35). Twenty-one days old Sesame seedling were exposed to severe drought stress by withholding water for 7 days. Gene expression of 13 members of HD-ZIP Class I was performed in well- watered (control) and water stressed (treatment) seedlings. The results of gene expression analysis showed that, SiHZ7 (6.8 fold) and SiHZ35 (2.6 fold) from subgroup showed significantly high gene expression levels under drought stress in sesame seedlings. Thus, this study provides useful molecular information pinpointing the role SiHD-ZIP Class I in drought stress responses at early seedling stage and to develop sesame novel varieties with improved drought tolerance in sesame.



2019 ◽  
Author(s):  
Julia C. Haas ◽  
Alexander Vergara ◽  
Vaughan Hurry ◽  
Nathaniel R. Street

AbstractDrought stress impacts on seedling establishment, survival and whole-plant productivity. Drought stress responses have been extensively studied at the physiological and molecular level in angiosperms, particularly in agricultural species and the model Arabidopsis thaliana, with the vast majority of work performed on aboveground tissues. Boreal forests are dominated by coniferous tree species and cover vast areas of the terrestrial surface. These areas are predicted to be particularly influenced by ongoing climate change and will be exposed to more frequent and acute drought. The associated impact at all stages of the forest tree life cycle is expected to have large-scale ecological and economic impacts. To provide a comprehensive understanding of the drought response mechanisms of Picea abies seedlings, we assayed the physiological response of needles and transcriptional responses of roots and needles after exposure to mild and severe drought. Shoots and needles showed extensive reversible plasticity for physiological measures indicative of drought response mechanisms, including stomatal conductance (gs) and shoot water potential. Root and needle transcriptional responses contrasted, with an extensive root-specific down-regulation of growth. When we compared the responses of P. abies with previously-characterised A. thaliana drought response genes, we found that the majority of the genes were conserved across lineages. However, in P. abies, transcription factors (TFs) previously identified as belonging to the ABA-dependent pathway had a more limited role and most differentially expressed genes were specific to the stress response of P. abies. These results highlight the importance of profiling both above- and below-ground tissues and provide a comprehensive framework to advance understanding of the drought response mechanism of P. abies.One sentence summaryAnalysis of the drought transcriptome of Norway spruce reveals divergent molecular response pathways in conifers.



HortScience ◽  
2010 ◽  
Vol 45 (3) ◽  
pp. 409-413 ◽  
Author(s):  
Nicole L. Waterland ◽  
Craig A. Campbell ◽  
John J. Finer ◽  
Michelle L. Jones

Drought stress is a major cause of postproduction decline in bedding plants. The plant hormone abscisic acid (ABA) regulates drought stress responses by mediating stomatal closure, thereby reducing transpirational water loss. Exogenous ABA applications delay wilting and allow plants to survive short periods of severe drought. The effectiveness of the ABA biochemical, s-ABA (ConTego™; Valent BioSciences Corp., Libertyville, IL), at delaying wilting and extending shelf life during drought stress was evaluated in six bedding plant species. Spray and drench applications of 0 or 500 mg·L−1 s-ABA were applied to Impatiens walleriana (impatiens), Pelargonium ×hortorum (seed geranium), Petunia ×hybrida (petunia), Tagetes patula (marigold), Salvia splendens (salvia), and Viola ×wittrockiana (pansy). Water was subsequently withheld and wilting symptoms were compared between treated and control plants. s-ABA applications delayed wilting in all crops by 1.7 to 4.3 days. Leaf chlorosis was observed after s-ABA application in drought-stressed seed geraniums, marigolds, and pansies. In seed geraniums and marigolds, the drought stress itself resulted in leaf chlorosis that was equivalent to or more severe than the s-ABA application alone. In pansies, s-ABA applications induced leaf chlorosis that was more severe than the drought treatment. Overall, s-ABA was consistently effective at reducing water loss and extending shelf life for all species treated. Applications of s-ABA to bedding plants before shipping and retailing would allow plants to maintain marketability even under severe drought stress conditions.



Forests ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 332
Author(s):  
Min Li ◽  
Haoyun Wang ◽  
Xizhou Zhao ◽  
Zhongke Lu ◽  
Xueguang Sun ◽  
...  

Masson pine is an important afforestation species in southern China, where seasonal drought is common. The present study focused on the effects of Suillus placidus, an ectomycorrhizal fungus, inoculation on the growth and physiological and biochemical performance of masson pine seedlings under four different watering treatments (well-watered, mild drought, moderate drought, and severe drought) to evaluate the symbiotic relationship between S. placidus and masson pine seedlings. Ectomycorrhizal-inoculated (ECM) and non-inoculated (NM) seedlings were grown in pots and maintained for 60 days using the weighing method. Results showed that seedlings’ growth, dry weight, RWC, chlorophyll content, PSII efficiency, and photosynthesis decreased as drought stress intensified in both ECM and NM plants. This suggests that drought stress significantly limits the growth and photosynthetic performance of masson pine seedlings. Nevertheless, increased An/gs and proline contents in both NM and ECM prevented oxidative damage caused by drought stress. In addition, increased peroxidase (POD) activity is an essential defense mechanism of ECM seedling under drought stress. Compared with NM, ECM seedlings showed faster growth, higher RWC, and photosynthetic performance, and lower lipid peroxidation in cell membranes under drought stress, as indicated by higher POD activity and lower proline and malondialdehyde (MDA). Our experiment found that S. placidus inoculation can enhance the drought resistance of masson pine seedlings by increasing antioxidant enzyme activity, water use efficiency, and proline content, thereby enhancing growth under water-deficiency conditions. S. placidus can be used to cultivate high-quality seedlings and improve their survival in regions that experience seasonal droughts.



2021 ◽  
Author(s):  
Garima Singroha ◽  
Pradeep Sharma ◽  
Ramanjulu Sunkur


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