Proline accumulation and varietal adaptability to drought in barley: a potential metabolic measure of drought resistance.
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Breeding↗
SEARCH · PubMed Health
Results for “Droughts”
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Mosquito immatures in drought-prone and drought-resistant bamboo stumps in Flores, Indonesia.
Mosquito species in water-filled bamboo stumps were compared with those emerged from dormant eggs in dry stumps. Tripteroides spp. was more abundant than Aedes (Stegomyia) spp. (mainly annandalei and albopictus) in water-filled stumps, whereas the latter was more abundant than the former in dry stumps. During 5 days after inundation, Aedes (Stegomyia) spp. developed faster than Tripteroides spp. Density of Tripteroides spp. was high in narrow and deep stumps. Both taxa of mosquitoes were at low densities in water-filled stumps with large detritivores (Tipulidae and Oligochaeta).
Aedes↗
Demographic aspects of drought: an examination of the African drought of 1970-74.
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Africa↗
Carbon allocation, gas exchange, and needle morphology of Pinus ponderosa genotypes known to differ in growth and survival under imposed drought.
Seedlings from 27 open-pollinated families of ponderosa pine representing nine geographically diverse origins were screened for drought tolerance based on survival and growth under imposed drought. Seedlings that had been preconditioned to drought survived 14 days longer than seedlings that had been well watered before being subjected to drought. Seed sources varied in their ability to survive drought and this variation was accentuated by drought preconditioning. Seedlings from a South Dakota source and a Nebraska source generally survived the longest under drought. Seedlings from a Montana source and a New Mexico source succumbed the fastest after water was withheld. Significant family within source variation in drought survival was observed for some sources. In general, drought survival was poorly correlated to climate indices of the seed sources. Allocation of biomass to roots, stems, and needles varied significantly among the seed sources with the most drought-sensitive sources (Montana and New Mexico) showing the most divergent allocation patterns. The relation between drought survival and shoot/root ratio suggested that there is an optimum pattern of allocation for drought survival. A comparison of the most and least drought-tolerant sources indicated that needle gas exchange (net photosynthesis and needle conductance to water vapor) and predawn needle water potential were similar among the sources regardless of their relative ability to survive drought. Needle morphology traits often associated with variation in drought tolerance, such as stomatal density and specific leaf area, did not differ among the seed sources. However, seedlings from the drought-tolerant sources had shorter needles, less surface area per needle, and fewer stomata per needle than seedlings from the drought-sensitive sources. The results suggest that drought tolerance of ponderosa pine may be improved through seed source selection and, within certain sources, family selection. Allocation patterns and needle morphology appear to play a larger role than needle gas exchange patterns in determining drought tolerance in this species.
Journal Article↗
Multi-Omics insights into OsZFP252-OsGA20ox5 mediated drought tolerance in rice through stomatal and vascular regulation.
Rice growth is highly dependent on water availability, and drought stress significantly impacts its entire life cycle. However, previous studies lack systematic investigations into drought-responsive candidate genes across the full life cycle of rice. This study integrates transcriptomic and phenotypic data from two rice lines, IR64 (drought-sensitive) and DK151 (drought-tolerant), under varied environmental conditions at distinct growth stages. Using k-means clustering, 13 369 genes were categorized into 17 distinct expression patterns, revealing drought-responsive genes specifically upregulated or downregulated under drought stress. Weighted co-expression network analysis (WGCNA) further identified four gene modules strongly correlated with drought-related phenotypes, co-localizing 2859 drought-responsive genes through both approaches. Proteomics and metabolomics were supplemented at the booting stage, where phenotypic and transcriptomic differences under drought were most pronounced. Integrated omics results demonstrate gibberellin (GA) and abscisic acid (ABA) pathways play a key role during drought tolerance in rice, and 79 high-confidence drought-resistant candidate genes were prioritized from the 2859 drought-responsive genes. Among these, Gibberellin 20-oxidase 5 (OsGA20ox5) was identified as a key negative regulator of drought tolerance. Furthermore, the transcription factor zinc finger protein 252 (OsZFP252) directly binds to the OsGA20ox5 promoter, repressing its expression and enhancing ABA biosynthesis, thereby improving drought tolerance by increasing stomatal closure and expanding vascular bundle water transport capacity. Notably, the drought-tolerant haplotype 2-4 (Hap2-4) of OsGA20ox5 provides valuable insights for drought-resistant breeding.
Oryza↗
Comparison of Sources and Lines Selected for Drought Resistance in Common Bean.
Drought is a major constraint to common bean (Phaseolus vulgaris L.) production worldwide. Our objectives were to (i) identify sources of drought resistant germplasm in common bean cultivars and (ii) compare drought resistant germplasm with lines selected from interracial and intergene pool populations. We included in this study 12 of the most promising drought resistant cultivars from race Durango and 11 from race Jalisco, nine drought resistant lines selected from interracial or intergene pool populations, and two drought resistant and two susceptible checks. The 36 genotypes were evaluated in drought-stressed (DS) and nonstressed (NS) environments in four cropping seasons between 1996 and 1998 at the International Center for Tropical Agriculture (CIAT), Palmira, Colombia. Drought stress reduced seed yield by 53%, 100-seed weight by 13%, and days to maturity by 3%. Race Durango cultivars had higher yield, larger seed weight, and earlier maturity than race Jalisco cultivars in DS and NS environments. Large variations within the two races were found for the three traits. Drought resistant selected lines out-yielded drought resistant checks by 44% in DS and 15% in NS and cultivars from race Durango by 48% in DS and 30% in NS and race Jalisco by 96% in DS and 46% in NS environments. Seed yield in DS was correlated negatively with the percent reduction (PR) because of drought stress and drought susceptibility index (DSI), whereas a positive correlation existed between PR and DSI. Drought resistant selected lines and race Durango cultivars had similar maturity. Mean 100-seed weight of selected lines (23 g) was less than race Durango (34 g) and race Jalisco cultivars (29 g). While new sources of drought resistance could be identified in races Durango and Jalisco, these drought resistant germplasm and selected lines derived from interracial and intergene pool populations should be utilized for improvement of drought resistance in common bean.
Journal Article↗
Drought responses of conifers in ecotone forests of northern Arizona: tree ring growth and leaf delta13C.
We sought to understand differences in tree response to meteorological drought among species and soil types at two ecotone forests in northern Arizona, the pinyon-juniper woodland/ponderosa pine ecotone, and the higher elevation, wetter, ponderosa pine/mixed conifer ecotone. We used two approaches that provide different information about drought response: the ratio of standardized radial growth in wet years to dry years (W:D) for the period between years 1950 and 2000 as a measure of growth response to drought, and delta13C in leaves formed in non-drought (2001) and drought (2002) years as a measure of change in water use efficiency (WUE) in response to drought. W:D and leaf delta13C response to drought for Pinus edulis and P. ponderosa did not differ for trees growing on coarse-texture soils derived from cinders compared with finer textured soils derived from flow basalts or sedimentary rocks. P. ponderosa growing near its low elevation range limit at the pinyon-juniper woodland/ponderosa pine ecotone had a greater growth response to drought (higher W:D) and a larger increase in WUE in response to drought than co-occurring P. edulis growing near its high elevation range limit. P. flexilis and Pseudotsuga menziesii growing near their low elevation range limit at the ponderosa pine/mixed conifer ecotone had a larger growth response to drought than co-occurring P. ponderosa growing near its high elevation range limit. Increases in WUE in response to drought were similar for all species at the ponderosa pine/mixed conifer ecotone. Low elevation populations of P. ponderosa had greater growth response to drought than high-elevation populations, whereas populations had a similar increase in WUE in response to drought. Our findings of different responses to drought among co-occurring tree species and between low- and high-elevation populations are interpreted in the context of drought impacts on montane coniferous forests of the southwestern USA.
Arizona↗
Protein Alterations in Tall Fescue in Response to Drought Stress and Abscisic Acid.
Drought stress may alter protein synthesis in turfgrasses. The objectives of this study were to investigate physiological changes associated with the synthesis of dehydrin and a cytosolic-heat shock protein (HSC 70) in response to drought stress in two tall fescue (Festuca arundinacea L.) cultivars, 'Southeast' and 'Rebel Jr.'. The effects of abscisic acid (ABA) application on the drought tolerance of the cultivars also were evaluated. The cultivars were subjected to three treatments in growth chambers: well-watered control, drought stress, and drought stress following ABA treatment. Turf quality and leaf relative water content (RWC) decreased and electrolyte leakage (EL) increased during drought stress for both cultivars. The ABA-treated plants maintained higher turf quality and RWC, and lower EL than untreated plants under drought stress conditions. Levels of 20- and 29-kDa polypeptides increased during drought stress, and a 35-kDa polypeptide was noted in both cultivars only when subjected to drought stress either with or without ABA treatment. Immunoblot analysis indicated that dehydrin-like polypeptides of about 23-60 kDa were induced by progressive water deficit in both cultivars. The 53 kDa dehydrin polypeptide was present in Southeast with or without ABA treatment at 10 d of drought stress, whereas the 40 kDa dehydrin polypeptide accumulated in Rebel Jr. in both treatment. The 23- and 27-kDa dehydrin polypeptides were present at 10 d in drought-stressed and ABA-treated plants in both cultivars, but were more pronounced in the drought-stressed plants without ABA. A cytosolic-heat shock protein (HSC 70) was detected in plants in all treatments including well-watered plants of both cultivars, but its levels were higher in drought-stressed and ABA-treated plants. No single dehydrin polypeptide was induced by ABA treatment under drought stress, however, the promotive effects of ABA on the reduced drought stress paralleled the delayed induction of protein synthesis in tall fescue.
Journal Article↗
Multi-season analysis reveals hundreds of drought-responsive genes in sorghum.
Persistent drought affects global crop production and is becoming more severe in many parts of the world in recent decades. Deciphering how plants respond to drought will facilitate the development of flexible mitigation strategies. Sorghum bicolor L. Moench (sorghum), a major cereal crop and an emerging bioenergy crop, exhibits remarkable resilience to drought. To better understand the molecular traits that underlie sorghum's remarkable drought tolerance, we undertook a large-scale sorghum gene expression profiling effort, totaling nearly 1500 transcriptome profiles, across a 3-year field study with replicated plots in California's Central Valley. This study included time-resolved gene expression data from roots and leaves of two sorghum genotypes, BTx642 and RTx430, with different pre-flowering and post-flowering drought-tolerance adaptations under control and drought conditions. Quantification of genotype-specific drought tolerance effects was enabled by de novo sequencing, assembly, and annotation of both BTx642 and RTx430 genomes. These reference-quality genomes were used to construct a pangene set for characterizing conserved and genotype-specific expression. By integrating time-resolved transcriptomic responses to drought in the field across three consecutive years, we identified a set of 726 drought-responsive genes that responded similarly in all 3 years of our field study. Functional enrichment analysis identified abiotic stress, secondary cell wall-related processes and metabolism as particularly affected under both types of drought stress. We also found that some glyoxylate cycle pathway genes, including malate synthase and isocitrate lyase, are differentially regulated particularly during post-flowering drought stress, implicating this pathway as potentially important for drought responsiveness. This expansive dataset represents a unique resource for sorghum and drought research communities and provides a methodological framework for the integration of multi-faceted time-resolved transcriptomic datasets.
Sorghum↗
Genetic analysis for drought resistance of rice at reproductive stage in field with different types of soil.
Drought resistance of rice is a complex trait and is mainly determined by mechanisms of drought avoidance and drought tolerance. The present study was conducted to characterize the genetic basis of drought resistance at reproductive stage in field by analyzing the QTLs for drought response index (DRI, normalized by potential yield and flowering time), relative yield, relative spikelet fertility, and four traits of plant water status and their relationships with root traits using a recombinant inbred population derived from a cross between an indica rice and upland rice. A total of 39 QTLs for these traits were detected with individual QTL explained 5.1-32.1% of phenotypic variation. Only two QTLs for plant water status were commonly detected in two environments, suggesting different mechanisms might exist in two types of soil conditions. DRI has no correlation with potential yield and flowering time under control, suggesting that it can be used as a good drought resistance index in field conditions. The co-location of QTLs for canopy temperature and delaying in flowering time suggested a usefulness of these two traits as indexes in drought resistance screening. Correlation and QTL congruence between root traits and putative drought tolerance traits revealed that drought avoidance (via thick and deep root traits) was the main genetic basis of drought resistance in sandy soil condition, while drought tolerance may play more role in the genetic basis of drought resistance in paddy soil condition. Therefore, both drought mechanisms and soil textures must be considered in the improvement of drought resistance at reproductive stage in rice.
Adaptation, Physiological↗
Effects of drought during grain filling on PS II activity in rice.
The Rice varieties Araure 4 (A4) and Fonaiap 2000 (F2000) were grown in the glasshouse under natural sunlight and subjected to drought at heading. The drought induced changes in chlorophyll a fluorescence parameters, pigment composition, D1 contents and carbohydrate accumulation were investigated. Drought decreased phiPS II, FV'/FM' and qP, and increased qN in both varieties. F2000 had larger values of phiPS II and FV'/FM' at a lower RWC than A4. With the onset of drought only A4 increased the xanthophyll cycle pool, F2000 remaining constant throughout the drought cycle. Irrigated plants of A4 had a Larger de-epoxidation state (DEPS) of the xanthophyll cycle than F2000. A 40% increase in DEPS was induced by drought in both varieties but in A4 it was attained at a larger RWC than in F2000. Drought increased glucose and fructose contents of leaves 8-fold in A4 and 3-fold in F2000. Contrarily, sucrose contents decreased with drought but the effects were larger in A4 than in F2000. Sugars accumulation preceded and was proportional to the decrease in PS II activity elicited by drought in both varieties. In F2000 a decrease in D1 content smaller than 20% occurred at 70% of RWC, whereas droughted plants of A4 had lost 80% of D1 protein at 77% of RWC. Our data show that drought severely affected PS II activity and its main regulatory mechanisms in rice. There are genotypic differences in the response of PS II activity to drought that could be exploited as traits for selection to drought tolerance. There is a possible link between the drought-induced sugars accumulation in the flag leaf and the response of PS II to water deficit.
Carbohydrate Metabolism↗
Mycorrhizal symbiosis and response of sorghum plants to combined drought and salinity stresses.
Arbuscular mycorrhizal (AM) symbiosis can confer increased host resistance to drought stress, although the effect is unpredictable. Since AM symbiosis also frequently increases host resistance to salinity stress, and since drought and salinity stress are often linked in drying soils, we speculated that the AM influence on plant drought response may be partially the result of AM influence on salinity stress. We tested the hypothesis that AM-induced effects on drought responses would be more pronounced when plants of comparable size are exposed to drought in salinized soils. In two greenhouse experiments, several water relations characteristics were measured in sorghum plants colonized by Glomus intraradices (Gi), Gigaspora margarita (Gm) or a mixture of AM species, during a sustained drought following exposure to salinity treatments (NaCl stress, osmotic stress via concentrated macronutrients, or soil leaching). The presence of excess salt in soils widened the difference in drought responses between AM and nonAM plants in just two instances. Days required for plants to reach stomatal closure were similar for Gi and nonAM plants exposed to drought alone, but with exposure to combined NaCl and drought stress, stomates of Gi plants remained open 17-22% longer than in nonAM plants. Promotion of stomatal conductance by Gm occurred with exposure to NaCl/drought stress but not with drought alone or with soil leaching before drought. In other instances, however, the addition of salt tended to nullify an AM-induced change in drought response. Our findings confirm that AM fungi can alter host response to drought but do not lend much support to the idea that AM-induced salt resistance might help explain why AM plants can be more resilient to drought stress than their nonAM counterparts.
Biomass↗
Ecophysiological traits associated with drought in Mediterranean tree seedlings: individual responses versus interspecific trends in eleven species.
Species differ regarding their drought tolerance and individuals of a given species can modify their morphology and physiology in response to drought. However, since evolutionary and ecological selective pressures differ, individual and interspecific responses to drought might not match. We determined summer survival and a number of ecophysiological variables in two factorial experiments with seedlings of eleven tree species present in Mediterranean ecosystems, grown under slowly imposed water stress and control conditions. Plants experiencing drought exhibited reduced growth, low specific leaf area, chlorophyll content, and photosynthetic rate when compared to the controls, and species-specific drought tolerance was associated with an analogous set of trait values. However, while species with high leaf area ratio and shoot-root ratio exhibited greater drought tolerance, drought induced the reversed response within species. Contrary to expectations, water use efficiency was lower in drought-tolerant species and decreased in water-stressed individuals compared to the control plants. There was a distinctive phylogenetic signal in the functional grouping of species, with oaks, pines, and other genera being clearly different from each other in their drought tolerance and in their functional responses to drought. However, all relationships between ecophysiological variables and drought tolerance were significant after accounting for phylogenetic effects, with the exception of the relationship between drought tolerance and photochemical efficiency. Our results show that drought tolerance is not achieved by a single combination of trait values, and that even though evolutionary processes and individual responses tend to render similar results in terms of functional traits associated with drought, they do not necessarily match.
Ecosystem↗
Drought tolerance is associated with rooting depth and stomatal control of water use in clones of Coffea canephora.
BACKGROUND AND AIMS: Drought is a major environmental constraint affecting growth and production of Coffea canephora. Selection of C. canephora clones has been largely empirical as little is known about how clones respond physiologically to drought. Using clones previously shown to differ in drought tolerance, this study aimed to identify the extent of variation of water use and the mechanisms responsible, particularly those associated morphological traits. * METHODS: Clones (14 and 120, drought-tolerant; 46 and 109A, drought-sensitive, based on their abilities to yield under drought) were grown in 120-L pots until they were 12-months old, when an irrigation and a drought treatment were applied; plants were droughted until the pressure potential (psi(x)) before dawn (pre-dawn) reached -3.0 MPa. Throughout the drought period, psi(x) and stomatal conductance (g(s)) were measured. At the end of the experiment, carbon isotope ratio and parameters from pressure-volume curves were estimated. Morphological traits were also assessed. * KEY RESULTS AND CONCLUSIONS: With irrigation, plant hydraulic conductance (K(L)), midday psi(x) and total biomass were all greater in clones 109A and 120 than in the other clones. Root mass to leaf area ratio was larger in clone 109A than in the others, whereas rooting depth was greater in drought-tolerant than in drought-sensitive clones. Predawn psi(x) of -3.0 MPa was reached fastest by 109A, followed progressively by clones 46, 120 and 14. Decreases in g(s) with declining psi(x), or increasing evaporative demand, were similar for clones 14, 46, and 120, but lower in 109A. Carbon isotope ratio increased under drought; however, it was lower in 109A than in other clones. For all clones, psi(x), g(s) and K(L) recovered rapidly following re-watering. Differences in root depth, K(L) and stomatal control of water use, but not osmotic or elastic adjustments, largely explained the differences in relative tolerance to drought stress of clones 14 and 120 compared with clones 46 and 109A.
Coffea↗
When defense pathways collide. The response of Arabidopsis to a combination of drought and heat stress.
Within their natural habitat, plants are subjected to a combination of abiotic conditions that include stresses such as drought and heat. Drought and heat stress have been extensively studied; however, little is known about how their combination impacts plants. The response of Arabidopsis plants to a combination of drought and heat stress was found to be distinct from that of plants subjected to drought or heat stress. Transcriptome analysis of Arabidopsis plants subjected to a combination of drought and heat stress revealed a new pattern of defense response in plants that includes a partial combination of two multigene defense pathways (i.e. drought and heat stress), as well as 454 transcripts that are specifically expressed in plants during a combination of drought and heat stress. Metabolic profiling of plants subjected to drought, heat stress, or a combination of drought and heat stress revealed that plants subject to a combination of drought and heat stress accumulated sucrose and other sugars such as maltose and glucose. In contrast, Pro that accumulated in plants subjected to drought did not accumulate in plants during a combination of drought and heat stress. Heat stress was found to ameliorate the toxicity of Pro to cells, suggesting that during a combination of drought and heat stress sucrose replaces Pro in plants as the major osmoprotectant. Our results highlight the plasticity of the plant genome and demonstrate its ability to respond to complex environmental conditions that occur in the field.
Acclimatization↗
Experimental insights in taxon-specific functional responses to droughts in glacier-fed stream biofilms.
BACKGROUND: Glacier-fed streams are predicted to face increasingly frequent and intense droughts. However, the impacts of drought events on benthic biofilm, including bacteria, eukaryotes, and viruses, the dominating life form in glacier-fed streams, remain poorly understood. RESULTS: Using streamside flume mesocosms in the Swiss Alps, we grew glacier-fed stream biofilms over 103 days and exposed them to three droughts. Using a multi-omics approach (metagenomics, metatranscriptomics, and metaproteomics), we assessed the effects of a series of droughts on the taxonomy and metabolic activity of bacterial, eukaryotic, and viral metagenome-assembled genomes (MAGs). We found that the first drought (6 h) caused only minor changes, including mild upregulation of heterotrophic metabolism and signs of stress in diatoms. In contrast, the second drought (24 h) significantly altered both the composition and functionality of the microbiome, shifting phototrophic dominance from diatoms to Cyanobacteriota, while maintaining overall phototropic biomass and further upregulating the heterotrophic metabolism. Interestingly, a third 24 h drought had no detectable transcriptomic effect between pre- and post-drought conditions, suggesting a certain level of adaptive responses to droughts, but with the low diatom abundance being maintained. CONCLUSIONS: These findings indicate that glacier-fed biofilm microorganisms initially resisted short-term drought, but a second longer drought caused important shifts in their community structure, activity, and function. Climate-induced increases in drought frequency or duration may therefore have a lasting impact on microbial ecosystem functioning in glacier-fed streams. Video Abstract.
Biofilms↗
Strigolactones constrain rice drought acclimation by suppressing ROS scavenging through the D53-OsWRKY31-ZFP36 module.
Strigolactones (SLs) are a class of plant hormones essential for tiller development and yield under diverse environmental conditions. Drought is a major limiting factor for rice yields. Although SLs contribute to drought resistance, mechanisms and practical applications of SL pathway in drought acclimation of rice remain poorly understood. Our study shows that short-term dehydration represses SL biosynthesis in rice roots. Genetic assays indicate that disruption of SL biosynthesis or signaling elevates rice drought resistance, whereas SL signaling activation or supplementation with the SL analog GR244DO impairs drought resistance. SLs negatively regulate drought acclimation by promoting degradation of the repressor protein DWARF53 (D53). D53 interacts with the transcription factor OsWRKY31 via its N-terminal domain and suppresses the protein level of OsWRKY31, which binds to and represses transcription of the ZFP36 promoter. ZFP36 encodes a zinc-finger transcription factor that promotes H2O2 scavenging to sustain reactive oxygen species (ROS) homeostasis during drought stress. Notably, the drought-resistant upland rice variety IRAT109 exhibits lower SL levels in root exudates than the lowland rice variety Nipponbare (NP). Genome editing of key components in SL pathway enhances drought resistance in NP, Huazhan (HZ), and IRAT109. The agronomic potential of tuning SL biosynthesis is further supported by the elite D17/HTD1 allele, which weakens SL biosynthesis and improves drought resistance and grain yield in Nekken 2 (NK2) under field conditions. These findings uncover a key mechanism underlying SL-repressed drought acclimation in rice and provide an effective strategy to improve drought resistance in diverse rice varieties amid ongoing climate change.
D53↗
Grafting and biodynamic nanosilica-induced physiological and transcriptomic modulation of chilli (Capsicum annuum L.) under drought stress.
Chilli (Capsicum annuum L.) is an economically important vegetable crop cultivated worldwide. Increasing drought stress associated with climate change has severely reduced chilli productivity. Although grafting and silicon-based nanomaterials have each been investigated independently as drought mitigation strategies in Solanaceae crops, this study represents, to our knowledge, the first investigation of their combined physiological, yield, and genome-wide transcriptomic effects in chilli under experimentally validated drought stress. Biodynamic nanosilica (BNS) is an α-quartz nanoparticle preparation (20-200 nm) derived from the biodynamic agricultural preparation BD501 through a vortex-triturating process, and distinct from chemically synthesised nanosilica in preparation method and surface bioavailability, applied as a foliar spray at 50 mg L-1. Five treatments were established: well-watered (WW), drought (D), grafting + BNS + drought (G+B+D), grafting + drought (G+D), and BNS + drought (B+D), each with three independent biological replicates. Under moderate-to-severe drought conditions (DSI 62-64%; VWC ~12% v/v at 14 days), the combined G+B+D treatment significantly improved plant height (3.05-fold over D), leaf relative water content (83% vs 49% in D), net photosynthetic rate (2.0-fold over D), water-use efficiency (+40%), and antioxidant enzyme activities (SOD: 3.1-fold; CAT: 2.8-fold over D), while reducing lipid peroxidation by 76%. Root architecture was also substantially enhanced, with a 4.1-fold increase in root length and a 3.1-fold increase in root surface area relative to D. Fruit yield increased by 79% relative to drought-stressed non-grafted plants. Transcriptomic analysis using Illumina NovaSeq 6000 identified 1,051 DEGs (431 upregulated, 620 downregulated; FDR < 0.05, |log2FC| > 1). Integrated transcriptomic-phenotypic concordance analysis revealed enrichment of MAPK signalling, ABA-mediated regulation (including ABA binding and (+)-ABA 8'-hydroxylase activity), and phenylpropanoid biosynthesis as the enriched pathways. Protein-protein interaction network analysis further revealed coordinated regulation of redox homeostasis, drought-responsive hormone signalling, and water transport gene modules in the combined treatment. These findings demonstrate that integrating grafting with biodynamic nanosilica is a promising strategy to enhance drought resilience and productivity in chilli, offering a sustainable approach for vegetable production under drought.
Capsicum↗