Drought Tolerance Traits Research Articles

Dissecting genomic regions and underlying candidate genes in groundnut MAGIC population for drought tolerance

BackgroundGroundnut is mainly grown in the semi-arid tropic (SAT) regions worldwide, where abiotic stress like drought is persistent. However, a major research gap exists regarding exploring the genetic and genomic underpinnings of tolerance to drought. In this study, a multi-parent advanced generation inter-cross (MAGIC) population was developed and evaluated for five seasons at two locations for three consecutive years (2018–19, 2019–20 and 2020–21) under drought stress and normal environments.ResultsPhenotyping data of drought tolerance related traits, combined with the high-quality 10,556 polymorphic SNPs, were used to perform multi-locus model genome-wide association study (GWAS) analysis. We identified 37 significant marker-trait associations (MTAs) (Bonferroni-corrected) accounting, 0.91- 9.82% of the phenotypic variance. Intriguingly, 26 significant MTAs overlap on four chromosomes (Ah03, Ah07, Ah10 and Ah18) (harboring 70% of MTAs), indicating genomic hotspot regions governing drought tolerance traits. Furthermore, important candidate genes associated with leaf senescence (NAC transcription factor), flowering (B3 domain-containing transcription factor, Ulp1 protease family, and Ankyrin repeat-containing protein), involved in chlorophyll biosynthesis (FAR1 DNA-binding domain protein), stomatal regulation (Rop guanine nucleotide exchange factor; Galacturonosyltransferases), and associated with yield traits (Fasciclin-like arabinogalactan protein 11 and Fasciclin-like arabinogalactan protein 21) were found in the vicinity of significant MTAs genomic regions.ConclusionThe findings of our investigation have the potential to provide a basis for significant MTAs validation, gene discovery and development of functional markers, which could be employed in genomics-assisted breeding to develop climate-resilient groundnut varieties.

Bacterial population-level trade-offs between drought tolerance and resource acquisition traits impact decomposition.

Microbes drive fundamental ecosystem processes such as decomposition. Environmental stressors are known to affect microbes, their fitness, and the ecosystem functions that they perform, yet understanding the causal mechanisms behind this influence has been difficult. We used leaf litter on soil surface as a model in situ system to assess changes in bacterial genomic traits and decomposition rates over 18months with drought as a stressor. We hypothesized that genome-scale trade-offs due to investment in stress tolerance traits under drought reduce the capacity for bacterial populations to carry out decomposition, and that these population-level trade-offs scale up to impact emergent community traits thereby reducing decomposition rates. We observed drought tolerance mechanisms that were heightened in bacterial populations under drought, identified as higher gene copy numbers in metagenome-assembled genomes. A subset of populations under drought had reduced carbohydrate-active enzyme genes which suggested - as a trade-off - a decline in decomposition capabilities. These trade-offs were driven by community succession and taxonomic shifts as distinct patterns appeared in populations. We show that trait-tradeoffs in bacterial populations under drought could scale up to reduce overall decomposition capabilities and litter decay rates. Using a trait-based approach to assess the population ecology of soil bacteria, we demonstrate genome-level trade-offs in response to drought with consequences for decomposition rates.

Agricultural innovation for climate change: limited but positive impacts of commercialized drought-tolerant corn

Abstract The extent to which new technologies can countervail the risks posed by climate change is a critical element for designing adaptation strategies. This study uses new experimental data spanning 17 US states from 2008 to 2023 to examine the potential impact of recently commercialized drought tolerant (DT) traits on both yield and yield resilience in US corn production. We find that there is no yield advantage for DT hybrids under average weather conditions, but they improve yield resilience, particularly with respect to precipitation. These effects are spatially heterogeneous, such that DT has a positive yield impact in the droughty, western US, but a small, or even negative, impact in the central and eastern US. In addition, the presence of DT reduces yield variance and kurtosis, and increases skewness, all of which imply a reduction in yield risk. Using the statistical model estimates, we project the impact of DT on corn yields under future climate conditions obtained from 20 general circulation models with two representative concentration pathways. The projected ensemble means of yield gains are 6.34 bu/acre and 5.39 bu/acre under moderate and extreme warming scenarios, respectively, by the mid-twenty-first century. These gains compensate for 23% and 13.5% of total yield loss due to climate change. Our results indicate that current commercial DT hybrids reduce yield risk, improve resilience with respect to precipitation, and have the potential to offer moderate benefits under climate change warming scenarios.

Unlocking nature’s drought resilience: a focus on the parsimonious root phenotype and specialised root metabolism in wild Medicago populations

Abstract Background and aims Crop wild relatives, exposed to strong natural selection, exhibit effective tolerance traits against stresses. While an aggressive root proliferation phenotype has long been considered advantageous for a range of stresses, it appears to be counterproductive under drought due to its high metabolic cost. Recently, a parsimonious root phenotype, metabolically more efficient, has been suggested to be better adapted to semiarid environments, although it is not clear that this phenotype is a trait exhibited by crop wild relatives. Methods Firstly, we analysed the root phenotype and carbon metabolism in four Medicago crop wild relatives adapted to a semiarid environment and compared them with the cultivated M. truncatula Jemalong (A17). Secondly, we exposed the cultivated (probably the least adapted genotype to aridity) and the wild (the most common one in arid zones) M. truncatula genotypes to water deficit. The carbon metabolism response in different parts of their roots was analysed. Results A reduced carbon investment per unit of root length was a common trait in the four wild genotypes, indicative of an evolution towards a parsimonious root phenotype. During the water deficit experiment, the wild M. truncatula showed higher tolerance to drought, along with a superior ability of its taproot to partition sucrose and enhanced capacity of its fibrous roots to maintain sugar homeostasis. Conclusion A parsimonious root phenotype and the spatial specialization of root carbon metabolism represent two important drought tolerance traits. This work provides relevant findings to understand the response of Medicago species roots to water deficit.

Genome-wide study of drought tolerance traits in wild jujube

BackgroundWild jujube trees in Ningxia, China, demonstrate exceptional drought tolerance. The identification of quantitative trait loci (QTLs) associated with drought resistance and linked genes could significantly enhance molecular breeding efforts for this species. This study involved the measurement of nine drought resistance indicators were measured in 150 wild jujube trees from five regions in Ningxia. Genome-wide association studies (GWAS) were carried out using a range of mixed linear models to pinpoint SNP markers linked to drought resistance.ResultsThe coefficients of variation for the nine leaf traits in wild jujube trees ranged from 14.76 to 62.17%, with broad-sense heritability estimates falling between 0.84 and 0.99. Through GWAS analysis, a total of 12 significant SNPs and 162 potential genes associated with drought resistance were detected. This SNPs explained phenotypic variance ranging from 20.74 to 50.37%. Gene Ontology (GO) functional annotation highlighted five crucial candidate genes‒ZjMYB44, ZjUCLOC, ZjDnaJ50, ZjUCHL22 and ZjHSFB‒linked to drought tolerance in wild jujube. These genes demonstrated a positive correlation with drought tolerance within the wild jujube population.ConclusionsOur findings indicate that these five genes likely play a pivotal role in conferring drought tolerance in wild jujubes. This study offers new insights to support the development of drought-resistant jujube varieties, thereby contributing to sustainable agricultural practices and bolstering food security in arid regions.

Fixing active sand dune by native grasses in the desert of Northwest China

BackgroundDesertification is the most severe environmental problem in arid and semi-arid regions and has caused great economic loss every year. However, artificial sand fixation barriers function on sand fixation for only 10–20 years. Searching for a native species with long-term sand fixation effect and strong environmental adaptive capacity, and low water consumption is needed. In this study, we investigated the environmental adaption and sand fixation effect of a grass from Poaceae family (Psammochloa villosa) that is indigenous to the desert of Northwest China.ResultsThe results showed that P. villosa has a streamlined leaf form, strong mechanical strength, and flexibility to adapt to wind. Leaf curling of P. villosa under drought decreased water loss rate through decreased evaporation area to adapt to drought. Significant negative relationship between adventitious root length and horizontal root burial depth indicates that adventitious roots help P. villosa absorb water and nutrients from soil under shallow sand burial condition, which enables P. villosa to adapt to different sand burial conditions. P. villosa fixed sand dunes through the distribution of the population at the top of the dune and the vertical relationship between the direction of windblown sand and the direction of growth of P. villosa, which stopped the expansion of the dune.ConclusionsGrowth characteristics of wind and drought tolerant leaf traits and adventitious roots under sand burial indicate that P. villosa is well adapted to dry sandy desert conditions and burial by sand. The distribution of the P. villosa population on the sand dune is a “brake” on its expansion. These findings provide new insight for active sand dune fixation and desertification control using native grass in the desertified regions.

A functional trait-based assessment of urban street tree selection for Ethiopia

Urbanization in Ethiopia is rapidly reducing green space and biodiversity, and placing ecological stress on trees. Urban street trees (UST) can provide multiple ecosystem services, but need to cope with challenging street ecology and future climate risks. However, UST selection in Ethiopia is poor, and conventional trials and modern breeding are costly and time consuming to apply in Ethiopia. The main objective of the study was to identify potential UST species for two Ethiopian cities; Addis Ababa, and Arba Minch, by studying interspecific differences in functional traits. For the purpose, we created a database with list of 120 candidate UST gathered from multi-stakeholder workshop, literature review, and senior experts survey, and their ecological with their phenological and morphological features. Then we filtered 25 potential UST through framework analysis considering eco-morphological features of the trees. For the 25 species, we measured three types of plant functional traits: conservative traits (leaf mass per area and leaf dry matter content), acquisitive traits (leaf area, specific leaf area and leaf water content) and drought tolerance traits (leaf turgor pressure loss point, and leaf succulence index). Our results showed a strong trade-off between conservative and acquisitive traits, particularly between leaf dry matter content (LDMC) and specific leaf area (SLA) (r = −0.71), consistent with plant economic spectrum theory. Using PCA analysis, we identified three groups of potential USTs (Type I, II and III) that exhibit different adaptation strategies, consistent with Grime’s trait-based classification of universal plant adaptation strategies (CSR). Compared to species with high acquisitive traits (Type II and Type III), Type I species have high conservative and drought-tolerant traits shows better adaptation to harsh road environments, whereas Type II and Type III species may be more advantageous for urban parks and other resource-rich components of urban ecology. We also found significant variation in conservative, acquisitive and drought-tolerant traits among different species, indicating their different adaptation strategies. Our research advances the knowledge of plant adaptation in urban environments and provides a useful method for UST selection.

The ubiquitin E3 ligase RZFP1 affects drought tolerance in poplar by mediating the degradation of the protein phosphatase PP2C-9.

Abscisic acid signaling has been implicated in plant responses to water deficit-induced osmotic stress. However, the underlying molecular mechanism remains unelucidated. This study identified the RING-type E3 ubiquitin ligase RING ZINC FINGER PROTEIN1 (PtrRZFP1) in poplar (Populus trichocarpa), a woody model plant. PtrRZFP1 encodes a ubiquitin E3 ligase that participates in protein ubiquitination. PtrRZFP1 mainly functions in the nucleus and endoplasmic reticulum and is activated by drought and abscisic acid. PtrRZFP1-overexpressing transgenic poplars (35S:PtrRZFP1) showed greater tolerance to drought, whereas PtrRZFP1-knockdown lines (KD-PtrRZFP1) showed greater sensitivity to drought. Under treatment with polyethylene glycol and abscisic acid, PtrRZFP1 promoted the production of NO and H2O2 in stomatal guard cells, ultimately enhancing stomatal closure and improving drought tolerance. Additionally, PtrRZFP1 physically interacted with the clade A Protein Phosphatase 2C protein PtrPP2C-9, a core regulator of abscisic acid signaling, and mediated its ubiquitination and eventual degradation through the ubiquitination-26S proteasome system, indicating that PtrRZFP1 positively regulates the abscisic acid signaling pathway. Furthermore, the PtrPP2C-9-overexpression line was insensitive to abscisic acid and more sensitive to drought than the wild-type plants, whereas the opposite phenotype was observed in 35S:PtrRZFP1 plants. In general, PtrRZFP1 negatively regulates the stability of PtrPP2C-9 to mediate poplar drought tolerance. The results of this study provide a theoretical framework for the targeted breeding of drought-tolerant traits in perennial woody plants.

Multi-locus genome-wide association study for grain yield and drought tolerance indices in sorghum accessions.

Drought is a significant factor that causes yield loss in essential cereal crops such as sorghum [Sorghum bicolor (L.) Moench], necessitating the development of drought-tolerant varieties adaptable to various water conditions. This study aimed to pinpoint drought-tolerant sorghum lines and genomic regions for tolerance by utilizing 216 sorghum accessions in stressed and non-stressed environments at two locations. Genetic diversity was evident among accessions in terms of grain yield under different watering regimes. Drought stress indices such as the stress tolerance index, mean productivity, geometric mean productivity, harmonic mean productivity, yield stability index, and yield index were identified as effective measures for selecting drought-tolerant sorghum. Cluster analysis classified genotypes into four groups based on their association with grain yield, highlighting Acc. #28546 and Acc. #216739 as highly drought tolerant across environments. This study identified 32 and 22 quantitative trait nucleotides (QTNs) for drought indices and grain yield under stress and non-stress conditions, respectively, at two locations, with five common QTNs linked to multiple drought indices. Colocation analysis revealed that these QTNs were associated with known stay-green-related quantitative trait loci (QTLs), and 47 putative genes near these QTNs potentially influenced drought tolerance traits. It is suggested that accession selection considers multiple indices for robust evaluation. Understanding the identified genes and their functions provides insights into the genetic mechanisms governing plant responses to drought stress, offering prospects for developing improved drought-resistant sorghum varieties through further genetic research.

Responses of leaf gas exchange and metabolites to drought stress in different organs of sugarcane and its closely related species Erianthus arundinaceus

Main conclusionThe high intrinsic water-use efficiency of Erianthus may be due to the low abaxial stomatal density and the accumulation of leaf metabolites such as betaine and gamma-aminobutyric acid.Sugarcane is an important crop that is widely cultivated in tropical and subtropical regions of the world. Because drought is among the main impediments limiting sugarcane production in these regions, breeding of drought-tolerant sugarcane varieties is important for sustainable production. Erianthus arundinaceus, a species closely related to sugarcane, exhibits high intrinsic water-use efficiency (iWUE), the underlying mechanisms for which remain unknown. To improve the genetic base for conferring drought tolerance in sugarcane, in the present study, we performed a comprehensive comparative analysis of leaf gas exchange and metabolites in different organs of sugarcane and Erianthus under wet and dry soil-moisture conditions. Erianthus exhibited lower stomatal conductance under both conditions, which resulted in a higher iWUE than in sugarcane. Organ-specific metabolites showed gradations between continuous parts and organs, suggesting linkages between them. Cluster analysis of organ-specific metabolites revealed the effects of the species and treatments in the leaves. Principal component analysis of leaf metabolites confirmed a rough ordering of the factors affecting their accumulations. Compared to sugarcane leaf, Erianthus leaf accumulated more raffinose, betaine, glutamine, gamma-aminobutyric acid, and S-adenosylmethionine, which function as osmolytes and stress-response compounds, under both the conditions. Our extensive analyses reveal that the high iWUE of Erianthus may be due to the specific accumulation of such metabolites in the leaves, in addition to the low stomatal density on the abaxial side of leaves. The identification of drought-tolerance traits of Erianthus will benefit the generation of sugarcane varieties capable of withstanding drought stress.Graphical abstract

Responses to drought of two Mediterranean ring-porous, deciduous species: Searching for climate smart trees and shrubs

Drought-tolerant tree species with high growth rates and a good capacity for carbon storage in woody tissues (dense wood) are searched for due to aridification. Deciduous, ring-porous tree and shrub species could show such drought tolerance and growth traits, thus representing good candidates for climate-smart rewilding. However, we still do not know the long-term growth rates of these species and how they respond to drought, particularly in climate change hotspots such as the Mediterranean Basin. We analysed these issues at the site and individual levels in two ring-porous, deciduous species (Pistacia terebinthus, Celtis australis) using dendroecology and wood anatomy. The ring width, earlywood vessel diameter, vessel density (VD) and area (%) were measured in two focal sites, one per species, and then growth data were compared with two secondary sites to test if site-to-site synchrony changed through time. Ring-width indices (RWI) and the hydraulic diameter (Dh) of earlywood were calculated. Growth rates (ring width), Dh and vessel area were higher in C. australis (1.03−2.26 mm, 269 μm, 33.9 %) than in P. terebinthus (0.57−0.72 mm, 146 μm, 21.5 %). Consequently, VD was higher in P. terebinthus than in C. australis (104 vs. 61 vessels mm−2). The ring width and Dh were more coupled in P. terebinthus (r = 0.43) than in C. australis (r = 0.32). RWI series of the focal and secondary sites have been synchronized since the 1990s as temperatures rose. Precipitation during the growing season (May, June) enhanced growth and VD of both species. P. terebinthus was more responsive to a drought index than C. australis. The two study species show high growth rates and tolerate drought being thus suitable candidates for climate-smart rewilding.

African Cultivated, Wild and Weedy Rice (Oryza spp.): Anticipating Further Genomic Studies.

Rice is a staple crop in sub-Saharan Africa, and it is mostly produced by Asian cultivars of Oryza sativa that were introduced to the continent around the fifteenth or sixteenth century. O. glaberrima, the native African rice, has also been planted due to its valuable traits of insect and drought tolerance. Due to competition and resistance evolution, weedy rice has evolved from O. sativa and O. glaberrima, posing an increasing threat to rice production. This paper provides an overview of current knowledge on the introduction and domestication history of cultivated rice in Africa, as well as the genetic properties of African weedy rice that invades paddy fields. Recent developments in genome sequencing have made it possible to uncover findings about O. glaberrima's population structure, stress resilience genes, and domestication bottleneck. Future rice genomic research in Africa should prioritize producing more high-quality reference genomes, quantifying the impact of crop-wild hybridization, elucidating weed adaptation mechanisms through resequencing, and establishing a connection between genomic variation and stress tolerance phenotypes to accelerate breeding efforts.

Essential traits for reproductive drought and heat stress tolerance of Sabour Ardhjal rice: Implication for agricultural improvement

Essential traits for reproductive drought and heat stress tolerance of Sabour Ardhjal rice: Implication for agricultural improvement

Genome-wide identification and characterization of FORMIN gene family in potato (Solanum tuberosum L.) and their expression profiles in response to drought stress condition.

Formin proteins, characterized by the FH2 domain, are critical in regulating actin-driven cellular processes and cytoskeletal dynamics during abiotic stress. However, no genome-wide analysis of the formin gene family has yet to be conducted in the economically significant plant potato (Solanum tuberosum L.). In this study, 26 formin genes were identified and characterized in the potato genome (named as StFH), each containing the typical FH2 domain and distributed across the ten chromosomes. The StFH was categorized into seven subgroups (A-G) and the gene structure and motif analysis demonstrated higher structural similarities within the subgroups. Besides, the StFH exhibited ancestry and functional similarities with Arabidopsis. The Ka/Ks ratio indicated that StFH gene pairs were evolving through purifying selection, with five gene pairs exhibiting segmental duplications and two pairs exhibiting tandem duplications. Subcellular localization analysis suggested that most of the StFH genes were located in the chloroplast and plasma membrane. Moreover, 54 cis-acting regulatory elements (CAREs) were identified in the promoter regions, some of which were associated with stress responses. According to gene ontology analysis, the majority of the StFH genes were involved in biological processes, with 63 out of 74 GO terms affecting actin polymerization. Six major transcription factor families, including bZIP, C2H2, ERF, GATA, LBD, NAC, and HSF, were identified that were involved in the regulation of StFH genes in various abiotic stresses, including drought. Further, the 60 unique microRNAs targeted 24 StFH by regulating gene expression in response to drought stress were identified. The expression of StFH genes in 14 different tissues, particularly in drought-responsive tissues such as root, stem, shoot apex, and leaf, underscores their significance in managing drought stress. RNA-seq analysis of the drought-resistant Qingshu No. 9 variety revealed the potential role of up-regulated genes, including StFH2, StFH10, StFH19, and StFH25, in alleviating drought stress. Overall, these findings provide crucial insights into the response to drought stress in potatoes and can be utilized in breeding programs to develop potato cultivars with enhanced drought-tolerant traits.

Lentil adaptation to drought stress: response, tolerance, and breeding approaches.

Lentil (Lens culinaris Medik.) is a cool season legume crop that plays vital roles in food and nutritional security, mostly in the least developed countries. Lentil is often cultivated in dry and semi-dry regions, where the primary abiotic factor is drought, which negatively impacts lentil growth and development, resulting in a reduction of yield. To withstand drought-induced multiple negative effects, lentil plants evolved a variety of adaptation strategies that can be classified within three broad categories of drought tolerance mechanisms (i.e., escape, avoidance, and tolerance). Lentil adapts to drought by the modulation of various traits in the root system, leaf architecture, canopy structure, branching, anatomical features, and flowering process. Furthermore, the activation of certain defensive biochemical pathways as well as the regulation of gene functions contributes to lentil drought tolerance. Plant breeders typically employ conventional and mutational breeding approaches to develop lentil varieties that can withstand drought effects; however, little progress has been made in developing drought-tolerant lentil varieties using genomics-assisted technologies. This review highlights the current understanding of morpho-physiological, biochemical, and molecular mechanisms of lentil adaptation to drought stress. We also discuss the potential application of omics-assisted breeding approaches to develop lentil varieties with superior drought tolerance traits.

Predictive Analytics in Genetic Engineering as an Optimization Problem

In genetic engineering, developing a breed with a desired trait is a search and optimization problem that sometimes requires many generations of field and laboratory experiments for an optimal solution to be found. The nature of the problem requires that a stochastic optimization algorithm be applied in the metaheuristic search rather than using a deterministic or mathematical approach. In the search for drought-tolerant cowpea, this study applied a genetic algorithm as a predictive analytics tool in the genetic engineering of three native cowpea landraces (Dan muzakkari, Gidigiwa, and Dan mesera) selected from Northern Nigeria (specifically from Kontagora in Niger State of Nigeria). The three cowpea species were subjected to mutagenic treatments using gamma irradiation and Ethyl Methane Sulphonate (EMS). Doses applied include 200, 400, 600, and 800 Gray of gamma irradiation and 0.372% v/v of EMS. Both treated and untreated cowpea landraces were planted and observed. Mutation-induced breeding aims to deepen the drought-tolerant trait of the cowpea mutants to survive conditions in drought-prone Northern Nigeria. The statistical analysis of the agro-morphological and yield parameters of the first mutant generation (M1 generation) indicates that mutagenic treatments have a positive impact on both the yield and the survival of the three landraces as all the treated landraces yielded better than the control, particularly the treatments combination of 600gray and 372% v/v of EMS. Also, the predictive outcomes of the computational simulation that was implemented in Python programming indicate that these local cultivars are developing drought-tolerant genetic variability. For the three computational experiments, the stochastic optimizer (genetic algorithm) converged at the 9412th, 9717th, and 14338th generations respectively. Such predictive analytics information is useful for guiding decision-making by researchers and breeders in the crop improvement program.

Drought tolerance and species abundance mediate dry season negative density dependence in a tropical forest.

Conspecific negative density dependence (CNDD) is thought to be a key process in maintaining plant diversity. However, the strength of CNDD is highly variable in space and time as well as among species, and correlates of this variation that might help to understand and explain it remain largely unquantified. Using Bayesian hierarchical models, we took advantage of 10-year seedling monitoring data that were collected annually in every dry and rainy season in a seasonal tropical forest. We quantified the interspecific variation in the strength of CNDD and its temporal variation. We also examined potential correlates of this interspecific and temporal variation, including species functional traits (such as drought-tolerant traits, defense-related traits, and recourse acquisition traits) and species abundances. In the dry season, we found a negative relationship between the density of neighboring conspecific seedlings on seedling survival, while in the rainy season, there was a negative relationship between the density of neighboring conspecific adults on seedling survival. In addition, we found that interspecific variation in CNDD was related to drought-tolerant traits in the dry season but not in the rainy season. Across years, we found that drought-intolerant species suffer less CNDD during the dry seasons that have higher rainfall, whereas drought-tolerant species suffer less CNDD when the dry season has lower rainfall. We also found that rare species suffered stronger CNDD in the dry season. Overall, our study highlights that CNDD is highly variable among species and through time, necessitating a deeper appreciation of the environmental and functional contexts of CNDD and their interactions.

Prediction and validation of putative candidate genes underlying drought‐tolerant QTLs through in silico and RT‐PCR approaches in rice (Oryza sativa)

AbstractIn the present study, the aim was to predict and validate putative candidate genes underlying drought‐tolerant quantitative trait loci (QTLs) in rice crop using in silico approaches and real‐time polymerase chain reaction (RT‐PCR). The genes underlying major drought‐tolerant QTLs which have been reported by data mining, sequence variation, gene ontology analysis, quantitative traits gene finder and gene expression analysis were subjected to RiceVarmap software to design primers, and only a few variants gave the SNP/InDel primers; thus, finally, 15 primers were ultimately selected, which were used in identification of differentially expressed genes (DEGs) among contrasting rice genotypes IR 64 and N 22 for drought tolerance trait using quantitative RT‐PCR studies by providing drought stress treatment during panicle initiation stage. In this investigation, we predicted 11 genes as candidate genes underlying drought‐tolerant QTLs. Out of these, only four QTLs were found responsible for the major effect in drought tolerance regions such as QTL‐Qsn‐4b, QTL‐rn7a, QTL‐Qtgw‐2a and QTL‐phc4.1 and 11 prioritized candidates were identified that expressed in leaf tissues. Only four primers belong to two QTLs, primer vg0712623096 from QTL‐rn7a (LOC_Os07g22450) located on chromosome‐7 encoding NAC domain‐containing protein and the primers vg0431750843(LOC_Os04g53310) encoding soluble starch synthase 3‐ chloroplast precursor, vg0432626757 (LOC_Os04g54850) encoding pectin acetylesterase domain‐containing protein and vg0433031562 (LOC_Os04g55520) encoding AP2 domain‐containing protein, from QTL‐Qsn‐4b, located on chromosome‐4 found to have higher differential expression in N 22 in comparison with IR 64 during drought stress as per quantitative RT‐PCR 2–ΔΔCt values. Considering the overall study, these four primers/genes were identified as candidate genes underlying genomic regions governing drought tolerance. Therefore, these putative candidate genes could be focussed for further functional analysis to exploit in rice breeding.

Climate interacts with the trait structure of tree communities to influence forest productivity

Abstract Tree functional diversity can increase forest productivity by enhancing species interactions and providing greater growth stability. However, very few studies have examined the influence of tree community trait structure on survivor growth, recruitment and mortality simultaneously, which are the main drivers of forest population dynamics. Here, we explore the interactions among functional diversity, productivity and climate to investigate the role of the trait structure of communities on forest productivity and to determine under what circumstances functional diversity should be promoted to ensure forest adaptive capacity under future climate. Using random‐forest modelling and a network of permanent sample plots covering a broad gradient of climatic conditions, we isolated the effects of functional diversity—described as the distribution of trait values in a community—and climate variables on net forest productivity (NFP), survivor growth, recruitment and mortality. Based on our findings, community‐level trait structure affects forest productivity in different ways. NFP was influenced by three traits from three different plant strategy dimensions, whereas survivor growth and recruitment were strongly correlated with leaf and resource acquisition traits, and tree mortality with a mix of traits reflecting various plant strategies. We also observed climate interactions with the functional trait structure of tree communities. For instance, we observed an interaction between drought tolerance and mean annual temperature: At low temperatures, NFP biomass accumulation increased with the value of the drought tolerance trait; however, at higher temperatures, the opposite pattern was observed. However, we found contrasting patterns of population response to climate variability, depending on their functional diversity. Greater functional diversity does not necessarily increase biomass accumulation under different climatic conditions. Synthesis. As all components of forest productivity contribute to NFP, studies on forest productivity should consider not only survivor growth but also recruitment and mortality. Each component responds differently in terms of biomass changes in climatic variation, according to the trait structure of tree communities. This study provides a framework to identify the trait structure that should be targeted under different climate scenarios to anticipate change and help strengthen forest response capacity to climate change.

Drought-tolerant peanut (Arachis hypogaea L.) varieties can mitigate negative impacts of climate change on yield in the Southeastern U.S.

Rising temperatures and varying precipitation patterns in future climates pose huge challenges to the peanut (Arachis hypogaea L.) production in Southeastern U.S. (SEUS), which was characterized by hot summers and mild winters. This will require genetic improvement of peanut varieties for adapting to future climates for higher yields. Recently, several novel peanut varieties were found to exhibit higher yield and maintain photosynthesis during drought. Thus, this study aimed to investigate the spatial and temporal patterns of peanut yield response to future climate changes for peanut varieties with and without the drought tolerant trait of maintaining photosynthesis (MPh) under drought in the SEUS and evaluate the relative importance of yield related traits for enhancing yield advantage of peanut under future climate conditions. A modified version of the CROPGRO-Peanut model incorporating the drought tolerant factor was developed and validated using field trail data collected from distinct experimental sites under both rainfed and irrigated conditions. Yield was then simulated for the historical baseline period (1990–2021) and future (mid-century/2050s, late-century/2080s) climate scenarios across the SEUS. The results showed that peanut yield in the Northern SEUS was expected to benefit from climate change in the 2050s (RCP4.5 and RCP8.5), but Middle SEUS and Southern SEUS would experience high probability of yield loss in the future. Comparing to the reference variety (C4), the drought tolerant peanut varieties (C1, C2 and C3) with the trait of MPh under drought could enhance the yield gains due to future climates in the 2050s (RCP4.5 and RCP8.5) in Northern SEUS (yield increases from 5% to 10% for C1-C3, and 2% to 3% for C4) and mitigate the negative impacts of climate change in the 2080s (RCP4.5 and RCP8.5) in the Middle (yield changes from −26% to −1% for C1-C3, and −37% to −11% for C4) and Southern SEUS (yield changes from −24% to 1% for C1-C3, and −35% to −7% for C4). The yield advantage of the drought tolerant peanut varieties in future climates was strongly associated with the higher water use efficiency (WUE), harvest index (HI), seed size, seed number, and biomass with significant P values (p < 0.001). These findings are important for local breeding and management programs to mitigate the potential impacts of climate change on peanut yield in SEUS.