Transcriptional responses to water stress and recovery in a drought-tolerant fescue wild grass (Festuca ovina; Poaceae)

Genome ◽  
2021 ◽  
Vol 64 (1) ◽  
pp. 15-27
Author(s):  
Fan Qiu ◽  
Seton Bachle ◽  
Ryan Estes ◽  
Melvin R. Duvall ◽  
Jesse B. Nippert ◽  
...  

Water stress associated with drought-like conditions is a major factor limiting plant growth and impacts productivity of natural plant communities and agricultural crops. Molecular responses of plants to water stress have been studied most extensively in model species and crops, few of which have evolved natural drought tolerance. In the current study, we examined physiological and transcriptomic responses at multiple timepoints during increasing water stress and following initial recovery from stress in a drought-tolerant C3 species, Festuca ovina. Results demonstrated non-linear transcriptomic changes during increasing stress, but largely linear declines in physiological measurements during this same period. Transcription factors represented approximately 12.7% of all differentially expressed genes. In total, 117 F. ovina homologs of previously identified and molecularly characterized drought-responsive plant genes were identified. This information will be valuable for further investigations of the molecular mechanisms involved in drought tolerance in C3 plants.

Plants ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 27
Author(s):  
Mahmoud M. Gaballah ◽  
Azza M. Metwally ◽  
Milan Skalicky ◽  
Mohamed M. Hassan ◽  
Marian Brestic ◽  
...  

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.


2019 ◽  
Vol 02 ◽  
pp. 65-70
Author(s):  
Tin Q. Huynh

Drought has been a big problem and damaged seriously to rice cultivation and production in Vietnam and the Mekong Delta region; evaluating drought tolerance of rice is a major objective for the rice improvement programmes in Can Tho University. Fifty-two collected rice varieties including resistant and susceptible control varieties were screened for water stress under the artificial drought condition. Marker RM223 was used to identify the drought tolerance genotypes for some selected varieties with good and moderate tolerant scores. After 30 days of water stress, the results were 6 varieties of good tolerant, 8 varieties of moderate tolerance, 36 varieties of moderately susceptible and 2 varieties of susceptible to drought. Analyses of PCR showed that 10 varieties expressed the similar bands with the resistant control variety. Four varieties (LH8, MTL812, Lua Canh and VB1) with good tolerant to drought were recommended to use for genetic materials of rice breeding program and applying in alternative wetting and drying irrigation technique for rice cultivation.


2018 ◽  
Author(s):  
Ivan D. Mateus ◽  
Frédéric G. Masclaux ◽  
Consolée Aletti ◽  
Edward C. Rojas ◽  
Romain Savary ◽  
...  

AbstractArbuscular mycorrhizal fungi (AMF) impact plant growth and are a major driver of plant diversity and productivity. We quantified the contribution of intra-specific genetic variability in cassava (Manihot esculenta) and Rhizophagus irregularis to gene reprogramming in symbioses using dual RNA-sequencing. A large number of cassava genes exhibited altered transcriptional responses to the fungus but transcription of most of these plant genes (72%) responded in a different direction or magnitude depending on the plant genotype. Two AMF isolates displayed large differences in their transcription, but the direction and magnitude of the transcriptional responses for a large number of these genes was also strongly influenced by the genotype of the plant host. This indicates that unlike the highly conserved plant genes necessary for the symbiosis establishment, plant and fungal gene transcriptional responses are not conserved and are greatly influenced by plant and fungal genetic differences, even at the within-species level. The transcriptional variability detected allowed us to identify an extensive gene network showing the interplay in plant-fungal reprogramming in the symbiosis. Key genes illustrated that the two organisms jointly program their cytoskeleton organisation during growth of the fungus inside roots. Our study reveals that plant and fungal genetic variation plays a strong role in shaping the genetic reprograming in response to symbiosis, indicating considerable genotype x genotype interactions in the mycorrhizal symbiosis. Such variation needs to be considered in order to understand the molecular mechanisms between AMF and their plant hosts in natural communities.


2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Josefat Gregorio Jorge ◽  
Miguel Angel Villalobos-López ◽  
Karen Lizeth Chavarría-Alvarado ◽  
Selma Ríos-Meléndez ◽  
Melina López-Meyer ◽  
...  

Abstract Background Common bean (Phaseolus vulgaris L.) is a relevant crop cultivated over the world, largely in water insufficiency vulnerable areas. Since drought is the main environmental factor restraining worldwide crop production, efforts have been invested to amend drought tolerance in commercial common bean varieties. However, scarce molecular data are available for those cultivars of P. vulgaris with drought tolerance attributes. Results As a first approach, Pinto Saltillo (PS), Azufrado Higuera (AH), and Negro Jamapa Plus (NP) were assessed phenotypically and physiologically to determine the outcome in response to drought on these common bean cultivars. Based on this, a Next-generation sequencing approach was applied to PS, which was the most drought-tolerant cultivar to determine the molecular changes at the transcriptional level. The RNA-Seq analysis revealed that numerous PS genes are dynamically modulated by drought. In brief, 1005 differentially expressed genes (DEGs) were identified, from which 645 genes were up-regulated by drought stress, whereas 360 genes were down-regulated. Further analysis showed that the enriched categories of the up-regulated genes in response to drought fit to processes related to carbohydrate metabolism (polysaccharide metabolic processes), particularly genes encoding proteins located within the cell periphery (cell wall dynamics). In the case of down-regulated genes, heat shock-responsive genes, mainly associated with protein folding, chloroplast, and oxidation-reduction processes were identified. Conclusions Our findings suggest that secondary cell wall (SCW) properties contribute to P. vulgaris L. drought tolerance through alleviation or mitigation of drought-induced osmotic disturbances, making cultivars more adaptable to such stress. Altogether, the knowledge derived from this study is significant for a forthcoming understanding of the molecular mechanisms involved in drought tolerance on common bean, especially for drought-tolerant cultivars such as PS.


2018 ◽  
Vol 69 (5) ◽  
pp. 515 ◽  
Author(s):  
Fatemeh Saeidnia ◽  
Mohammad Mahdi Majidi ◽  
Aghafakhr Mirlohi ◽  
Benyamin Ahmadi

The genetic basis of physiological responses to drought and its association with productivity, persistence and summer dormancy is not clear in orchardgrass (Dactylis glomerata L.). Thirty-six orchardgrass genotypes were evaluated under water stress and non-stressed conditions during 2 years (2013–14). High genotypic variation was observed for all of the agronomic and physiological traits. Water stress reduced dry matter yield, relative water content and chlorophyll content while significantly increasing carotenoids, water-soluble carbohydrates, proline and chlorophyll a : b ratio. The results indicated that carotenoids and proline accumulation could not be used for discriminating drought-tolerant genotypes of orchardgrass, whereas water-soluble carbohydrates may be used to achieve this purpose. Moreover, the results showed that the stable genotypes that have lower changes in productivity from normal to water-stress environments also have more persistence. No association was found between summer dormancy and drought tolerance measured by both physiological and yield-based drought-tolerance indices. Some of the drought-tolerant genotypes had relatively high persistence and better autumn recovery, a characteristic useful for the development of new synthetic varieties.


HortScience ◽  
2007 ◽  
Vol 42 (7) ◽  
pp. 1695-1699 ◽  
Author(s):  
Erin Alvarez ◽  
S.M. Scheiber ◽  
Richard C. Beeson ◽  
David R. Sandrock

Nonnative Miscanthus sinensis Anderss ‘Adagio’ and native Eragrostis spectabilis (Pursh) Steud. were evaluated for drought tolerance in a rain-excluded landscape setting in sandy soil in response to irrigation application volumes of 0 L, 0.25 L, 0.5 L, or 0.75 L. As irrigation rates increased, plant mass, canopy size, and shoot-to-root ratios increased for both species, being greatest at the 0.75-L rate. Shoot dry weight, root dry weight, total biomass, and shoot-to-root ratios were greater for E. spectabilis than M. sinensis. Cumulative water stress integral was also greater for E. spectabilis. Greater growth in conjunction with higher cumulative water stress indicates the native E. spectabilis is anisohydric and more drought-tolerant than the isohydric nonnative M. sinensis.


Agriculture ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 6
Author(s):  
Tzu-Ya Weng ◽  
Taiken Nakashima ◽  
Antonio Villanueva-Morales ◽  
J. Ryan Stewart ◽  
Erik J. Sacks ◽  
...  

Miscanthus, a high-yielding, warm-season C4 grass, shows promise as a potential bioenergy crop in temperate regions. However, drought may restrain productivity of most genotypes. In this study, total 29 Miscanthus genotypes of East-Asian origin were screened for drought tolerance with two methods, a dry-down treatment in two locations and a system where soil moisture content (SMC) was maintained at fixed levels using an automatic irrigation system in one location. One genotype, Miscanthus sinensis PMS-285, showed relatively high drought-tolerance capacity under moderate drought stress. Miscanthus sinensis PMS-285, aligned with the M. sinensis ‘Yangtze-Qinling’ genetic cluster, had relatively high principal component analysis ranking values in both two locations experiments, Hokkaido University and Brigham Young University. Genotypes derived from the ‘Yangtze-Qinling’ genetic cluster showed relatively greater photosynthetic performance than other genetic clusters, suggesting germplasm from this group could be a potential source of drought-tolerant plant material. Diploid genotypes showed stronger drought tolerance than tetraploid genotypes, suggesting ploidy could be an influential factor for this trait. Of the two methods, the dry-down treatment appears more suitable for selecting drought-tolerant genotypes given that it reflects water-stress conditions in the field. However, the fixed-SMC experiment may be good for understanding the physiological responses of plants to relatively constant water-stress levels.


2021 ◽  
Vol 12 ◽  
Author(s):  
Alexander M. C. Bowles ◽  
Jordi Paps ◽  
Ulrike Bechtold

It is commonly known that drought stress is a major constraint limiting crop production. Drought stress and associated drought tolerance mechanisms are therefore under intense investigation with the view to future production of drought tolerant crops. With an ever-growing population and variable climate, novel approaches need to be considered to sustainably feed future generations. In this context, definitions of drought tolerance are highly variable, which poses a major challenge for the systematic assessment of this trait across the plant kingdom. Furthermore, drought tolerance is a polygenic trait and understanding the evolution of this complex trait may inform us about patterns of gene gain and loss in relation to diverse drought adaptations. We look at the transition of plants from water to land, and the role of drought tolerance in enabling this transition, before discussing the first drought tolerant plant and common drought responses amongst vascular plants. We reviewed the distribution of a combined “drought tolerance” trait in very broad terms to encompass different experimental systems and definitions used in the current literature and assigned a binary trait “tolerance vs. sensitivity” in 178 extant plant species. By simplifying drought responses of plants into this “binary” trait we were able to explore the evolution of drought tolerance across the wider plant kingdom, compared to previous studies. We show how this binary “drought tolerance/sensitivity” trait has evolved and discuss how incorporating this information into an evolutionary genomics framework could provide insights into the molecular mechanisms underlying extreme drought adaptations.


2012 ◽  
Vol 151 (5) ◽  
pp. 630-647 ◽  
Author(s):  
R. SANKARAPANDIAN ◽  
S. AUDILAKSHMI ◽  
V. SHARMA ◽  
K. GANESAMURTHY ◽  
H. S. TALWAR ◽  
...  

SUMMARYRecent trends in climate change resulting in global warming and extreme dry spells during rainy seasons are having a negative impact on grain and fodder production in rain-fed crops in India. Understanding the mechanisms of drought tolerance at various growth stages will help in developing tolerant genotypes. Crosses were made between elite and drought-tolerant sorghums, and F2and F3progenies were evaluated for drought tolerance in multiple locations. Twenty-five F4/F5derivatives along with drought-tolerant check plants (two high-yielding genotypes showing moderate drought tolerance: C43 (male parent of the commercial hybrid CSH 16, tolerant to drought) and CSV 17, (a pure line commercial cultivar released for drought-prone areas) were screened for drought tolerance under a factorial randomized block design with three replications during the rain-free months of April–June in 2007 and 2008 at Tamil Nadu Agricultural University, Kovilpatti, India. In each generation/year, four trials were conducted and water stress at different phases of crop growth,viz. vegetative, flowering and post-flowering (maturity), was imposed by withholding irrigation. Observations were recorded on grain and straw yields, plant height, number of roots, root length, leaf relative water content (LRWC), chlorophyll content and stomatal conductance under all treatments. The traits, grain yield, plant height, average root length and stomatal conductance showed significant mean sums of squares (SSs) for genotype × environment (G × E), suggesting that genotypes had significant differential response to the changing environments. Significant mean SSs due to G × E (linear) were obtained for straw yield, LRWC and chlorophyll content, indicating that the variability is partly genetic and partly influenced by environment. Grain yield was correlated with chlorophyll content (r = 0·43) at the vegetative stage, with number of roots (r = 0·49), LRWC (r = 0·51), chlorophyll content (r = 0·46) and stomatal conductance (r = −0·51) at the pre-flowering stage, and with LRWC (r = 0·50) and stomatal conductance (r = −0·40) at the post-flowering stage, under water stress. Partial least square (PLS) analysis showed that different traits were important for grain yield under water stress at different growth stages. Pyramiding the genes for the traits responsible for high grain yield under stress will help in developing stable genotypes at different stages of plant growth.


Author(s):  
A. M. M. Al-Naggar ◽  
M. M. Shafik ◽  
M. O. A. Elsheikh

Identifying maize genotypes with favorable root architecture traits for drought tolerance is prerequisite for initiating a successful breeding program for developing high yielding and drought tolerant varieties of maize. The aims of the present study were: (i) to identify drought tolerant genotypes of maize at flowering and grain filling, (ii) to interpret the correlations between the drought tolerance and root architecture traits and (iii) to identify the putative mechanisms of drought tolerance via root system traits. An experiment was carried out in two years using a split plot design with three replications. The main plots were assigned to three water stress levels, namely: well watering (WW), water stress at flowering (WSF) and water stress at grain filling (WSG), and sub-plots to 22 maize cultivars and populations. Drought tolerance index (DTI) had strong and positive associations with crown root length (CRL), root circumference (RC) and root dry weight (DRW) under both WSF and WSG, a negative correlation with brace root whorls (BW), and positive correlations with crown root number (CN) under WSF and brace root branching (BB) and crown root branching (CB) under WSG. These root traits are therefore considered as putative mechanisms of drought tolerance. The cultivars Pioneer-3444, SC-128, Egaseed-77, SC-10 and TWC-324 showed the most drought tolerant and the highest yielding in a descending order; each had a number of such drought tolerance mechanisms. Further investigation should be conducted to determine the underlying root mechanisms contributing to the selection of water-efficient hybrids of maize.


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