Crop Drought Research Articles

Precision Agriculture and Water Conservation Strategies for Sustainable Crop Production in Arid Regions

The intensifying challenges posed by global climate change and water scarcity necessitate enhancements in agricultural productivity and sustainability within arid regions. This review synthesizes recent advancements in genetic engineering, molecular breeding, precision agriculture, and innovative water management techniques aimed at improving crop drought resistance, soil health, and overall agricultural efficiency. By examining cutting-edge methodologies, such as CRISPR/Cas9 gene editing, marker-assisted selection (MAS), and omics technologies, we highlight efforts to manipulate drought-responsive genes and consolidate favorable agronomic traits through interdisciplinary innovations. Furthermore, we explore the potential of precision farming technologies, including the Internet of Things (IoT), remote sensing, and smart irrigation systems, to optimize water utilization and facilitate real-time environmental monitoring. The integration of genetic, biotechnological, and agronomic approaches demonstrates a significant potential to enhance crop resilience against abiotic and biotic stressors while improving resource efficiency. Additionally, advanced irrigation systems, along with soil conservation techniques, show promise for maximizing water efficiency and sustaining soil fertility under saline–alkali conditions. This review concludes with recommendations for a further multidisciplinary exploration of genomics, sustainable water management practices, and precision agriculture to ensure long-term food security and sustainable agricultural development in water-limited environments. By providing a comprehensive framework for addressing agricultural challenges in arid regions, we emphasize the urgent need for continued innovation in response to escalating global environmental pressures.

Genome-wide analysis of the Amorphophallus konjac AkCSLA gene family and its functional characterization in drought tolerance of transgenic arabidopsis

BackgroundAmorphophallus konjac (A. konjac), a perennial tuberous plant, is widely cultivated for its high konjac glucomannan (KGM) content, a heteropolysaccharide with diverse applications. The cellulose synthase-like (CSL) gene family is known to be a group of processive glycan synthases involved in the synthesis of cell-wall polysaccharides and plays an important role in the biological process of KGM. However, in A. konjac the classification, structure, and function of the AkCSLA superfamily have been studied very little.ResultsBioinformatics methods were used to identify the 11 AkCSLA genes from the whole genome of Amorphophallus konjac and to systematically analyze their characteristics, phylogenetic evolution, promoter cis-elements, expression patterns, and subcellular locations. Phylogenetic analysis revealed that the AkCSLA gene family can be divided into three subfamilies (Groups I- III), which have close relationships with Arabidopsis. The promoters of most AkCSLA family members contain MBS elements and ABA response elements. Analysis of expression patterns in different tissues showed that most AkCSLAs are highly expressed in the corms. Notably, PEG6000 induced down-regulation of the expression of most AkCSLAs, including AkCSLA11. Subcellular localization results showed that AkCSLA11 was localized to the plasma membrane, Golgi apparatus and endoplasmic reticulum. Transgenic Arabidopsis experiments demonstrated that overexpression of AkCSLA11 reduced the plant’s drought tolerance. This overexpression also inhibited the expression of drought response genes and altered the sugar components of the cell wall. These findings provide new insights into the response mechanisms of A. konjac to drought stress and may offer potential genetic resources for improving crop drought resistance.ConclusionIn conclusion, the study reveals that the AkCSLA11 gene from A. konjac negatively impacts drought tolerance when overexpressed in Arabidopsis. This discovery provides valuable insights into the mechanisms of plant response to drought stress and may guide future research on crop improvement for enhanced resilience.

Effect of exogenous application of salicylic acid on alleviation of drought stress of immature tea (Camellia sinensis L.) plants

Abstract Application of salicylic acid (SA) leads to positive impacts in improving the physiological and growth parameters under drought in other crops. Knowledge on SA regulation on tea is scanty but important especially under drought. Therefore, potential of minimizing the drought effects on tea via exogenous application of SA was studied in a glasshouse at the Tea Research Institute, Talawakelle, Sri Lanka, using one-year-old potted tea cultivars of known drought tolerance (TRI 2025 – tolerant and TRI 2023 – susceptible). Plants were exposed to a drying cycle while they were foliar sprayed with SA in various concentrations (0, 50, 100, 150 and 200 ppm) along with well-watered and no-spray treatments. Data were collected at 18 hours and 3, 7, 14 and 21 days after applying the treatments from randomly selected plants. Physiological parameters were measured along with soil moisture content. Drought stress led to declining of gas exchange parameters (rate of net photosynthesis, transpiration and stomatal conductance), leaf relative water content and increasing accumulation of osmolytes (total soluble sugar and proline) in both tea cultivars compared with well-watered plants. Exogenous application of 150 and 200 ppm SA significantly improved physiological parameters. These results revealed the role of exogenous application of 150 and 200 ppm SA in diminishing the negative effects of drought on tea plants. Exogenous application of SA 150 ppm will therefore be more effective in alleviating the drought impact on immature tea when considering the environmental impact and cost effectiveness.

Potato E3 Ubiquitin Ligase StXERICO1 Positively Regulates Drought Resistance by Enhancing ABA Accumulation in Potato and Tobacco and Interacts with the miRNA Novel-miR1730-3p and Proteins StUBC and StTLP

Potato (Solanum tuberosum L.) is sensitive to drought, which severely impacts tuber yield and quality. In this study, we characterized a XERICO gene, encoding a RING-H2 type E3 ubiquitin ligase, StXERICO1, from a diploid potato, investigated its role in enhancing drought resistance and ABA accumulation, and identified its interaction with the miRNA novel-miR1730-3p, as well as its protein interactions with StUBC and StTLP. StXERICO1, with a complete Open Reading Frame (ORF) of 459 bp encoding 152 amino acids, was highly responsive to drought, ABA treatment, and abiotic stresses in potato plants. Overexpression of the StXERICO1 significantly enhanced drought resistance and ABA accumulation in transgenic potato and tobacco plants and exhibited greater sensitivity to ABA treatment, which was associated with the upregulation of expression of ABA biosynthetic genes NCED and CYP707A. Furthermore, our results revealed that StXERICO1 and its encoding protein interacted with miRNAs and other proteins. 5′ RLM-RACE (cDNA terminal rapid amplification) experiment showed that the miRNA novel-miR1730-3p targets 5′ UTR region of the StXERICO1 gene. Dual luciferase assay and virus-based miRNA silencing experiment showed that the novel-miR1730-3p negatively regulates StXERICO1 expression. Moreover, yeast two-hybrid assay indicated that StXERICO1 interacts with StUBC (an E2 ubiquitin ligase) and StTLP (a Tubby-like protein), suggesting that StXERICO1 might function on ABA homeostasis at the post-translational level. These findings elucidate the molecular mechanisms by which StXERICO1, a RING-H2 type E3 ubiquitin ligase, enhances drought resistance through increased ABA accumulation, how its expression is regulated by miRNA, and how it exerts its function through interactions with other proteins. The results also provide a potential candidate gene for subsequent precision molecular breeding aimed at improving crop drought resistance.

Drought and rewatering practices improve adaptability of seedling maize to drought stress by a super-compensate effect

Periodic drought adversely affects the growth and yield of summer crops in the Huang-Huai-Hai Plain. Drought-rewatering practice as one of the important agronomic measures to improve crop drought resistance. A field experiment was conducted to investigate practice physiological, biochemical, and molecular responses of maize seedling after two rounds of repeated drought and rewatering treatments. The results demonstrated that rewatering following repeated drought events had a compensatory effect on the photosynthetic rate (Pn) and on osmotic and antioxidant regulation. Specifically, the Pn and stomatal conductance (Gs) increased by 10.12% and 5.61%, respectively, compared to the control (CK) during the second round of treatment. Additionally, soluble protein (sPro) and proline (Pro) content rose significantly, with increases of 26.12% and 343.49% observed on day 5 of the second round, leading to a gradual reduction in leaf water content and osmosis. Following drought exposure, the activities of superoxide dismutase (SOD) and peroxidase (POD) contributed to the decreased levels of malondialdehyde (MDA), with both enzymes recovering during rewatering. In contrast, plant height, leaf area, and biomass were significantly reduced in the CK group. Notably, root length increased by 21.05% after the drought-rewatering practice, enhancing the maize seedlings' ability to adapt to drought stress. Overall, maize seedlings exhibited enhanced adaptability to drought conditions following two cycles of drought-rewatering treatments.

Determination of Critical Crop Water Stress Index of Tea under Drought Stress Based on the Intercellular CO2 Concentration

Climatic changes have caused seasonal drought to occur frequently in tea fields of low-mountain and hill regions over the past decades. This leads to huge losses in the quality and yields of famous tea, which restricts the economic development of the tea industry. It is crucial to implement suitable irrigation scheduling. The crop water stress index (CWSI) is the main index to assess the water status of the crop. When the crop suffers irreversible drought stress, its critical water status cannot be easily evaluated using the CWSI. The change from stomatal limitations (SLs) to non-stomatal limitations (NSLs) of photosynthesis is vital for accurately recognizing crop drought stress. Thus, the objective of this research is to determine the critical crop water stress index of tea based on intercellular CO2 concentration (Ci) dynamic responses to drought stress. During two sensitive periods of water stress (famous tea harvest season and summer drought season, which are from March to April and July to August, respectively), the dynamic changes in the CWSI in tea were calculated and analyzed based on the CWSI theoretical model. The upper and lower baselines were determined on a daily basis and during a certain period. A critical value of the CWSI represents irreversible drought damage. This was determined by the characteristic response of the Ci of tea leaves during extreme drought stress. The results showed the following: (1) during the famous tea harvest season and summer drought season, the daily variation in CWSI was similar. During a certain period, the former maintained a stable fluctuation, while the latter increased in fluctuation. (2) The Ci showed a trend of fluctuating downward to a low point and then upward during extreme drought stress. After reaching the low point, it quickly increased in the former and stabilized for a day in the latter. When the Ci reached the low point, the upper benchmark of this critical point was 13.9 μmol·mol−1, the lower benchmark was 3.4, and the CWSI was 0.27. This critical CWSI could be used as an irrigation threshold point to ensure normal production for tea fields.

The novel triangular spectral indices for characterizing winter wheat drought

Agricultural drought threatens food security and agricultural sustainable development. There have been numerous spectral indices from remote sensing images developed for monitoring crop drought. However, most present spectral indices are focusing on crop growth and Land Surface Temperature (LST), and the crop canopy water content are in less consideration simultaneously. Additionally, the Normalized Difference Vegetation Index (NDVI) is used for characterizing crop growth in almost all spectral drought indices, with the spectral saturation problem of NDVI for closed crop canopy. When vegetation cover is high, NDVI values tend to saturate, which makes them insensitive to further changes in crop health. Therefore, the NDVI saturation phenomenon may lead to an underestimation of the extent of crop drought, as it is not effective in identifying subtle changes in crops under high-density vegetation conditions. Hence, we propose three novel triangular spectral indices for characterizing winter wheat drought using three features including LAI, Land Surface Water Index (LSWI) and LST. For validating the proposed spectral indices, we compared the agreement between these indices with measured Relative Soil Moisture (RSM) and Volumetric Water Content (VWC) of soil in agricultural meteorological station and present popular indices including Crop Water Stress Index (CWSI), Temperature-Vegetation Drought Index (TVDI), and Vegetation Health Index (VHI). The results revealed that our proposed indices including Euclidean distance Crop Health Index (ECHI), Difference Crop Health Index (DCHI) and Perpendicular Water Stress Index (PWSI) outperformed the popular CWSI, TVDI and VHI, with stronger correlations with measured RSM and VWC in agricultural meteorological station. Secondly, there are spatial consistencies for characterizing winter wheat drought between proposed ECHI, DCHI and PWSI with popular CWSI, TVDI and VHI. In addition, our proposed ECHI, DCHI and PWSI have achieved good performance of drought monitoring both in irrigated and rainfed croplands. All these results suggest that our proposed indices have great potential in crop drought monitoring.

Loss of OsMATE6 Function Enhances Drought Resistance Without Yield Penalty by Regulating Stomatal Closure in Rice.

Drought is one of the most severe environmental factors limiting plant growth and crop yield, necessitating the identification of genes that enhance drought resistance for crop improvement. Through screening an ethyl methyl sulfonate-mutagenized rice mutant library, we isolated the PEG tolerance mutant 97-1 (ptm97-1), which displays enhanced resistance to osmotic and drought stress, and increased yield under drought conditions. A point mutation in OsMATE6 was identified as being associated with the drought-resistant phenotype of ptm97-1. The role of OsMATE6 in conferring drought resistance was confirmed by additional OsMATE6 knockout mutants. OsMATE6 is expressed in guard cells, shoots and roots and the OsMATE6-GFP fusion protein predominantly localizes to the plasma membrane. Our ABA efflux assays suggest that OsMATE6 functions as an ABA efflux transporter; mutant protoplasts exhibited a slower ABA release rate compared to the wild type. We hypothesize that OsMATE6 regulates ABA levels in guard cells, influencing stomatal closure and enhancing drought resistance. Notably, OsMATE6 knockout mutants demonstrated greater yields under field drought conditions compared to wild-type plants, highlighting OsMATE6 as a promising candidate for improving crop drought resistance.

Hydrogen Sulfide and 5‐Aminolevulinic Acid Synergistically Enhance Drought Tolerance in Tomato (Solanum lycopersicum L.)

ABSTRACTEnhancing crop drought tolerance is crucial for food security amid climate change. This study examines how 5‐aminolevulinic acid (ALA) and hydrogen sulfide (H2S) can improve drought resilience in tomato plants, which are essential for sustainable food production. Drought stress was induced using 12% PEG‐6000. Plants were pre‐treated with 25 mg L−1 ALA and 0.1 mg L−1 hypotaurine (HT), followed by 0.2 mM sodium hydrosulfide (NaHS) treatment to assess the effects on plant physiological effects over 10 days. Drought stress reduced plant dry weight, chlorophylls (a and b), Fv/Fm, leaf water potential, and relative water content, while increasing glycine betaine (GB) and proline levels. Additionally, drought stress elevated NADPH oxidase (NOX) and glycolate oxidase (GOX) activities, inducing oxidative stress and membrane damage. ALA and NaHS enhanced plant growth, photosynthesis, proline, GB, ALA content, ATP synthase, and ATPase activities, while mitigating NOX and GOX activities, thereby reducing and H2O2 radicals. ALA alone boosted L‐DES activity, promoting H2S accumulation. However, ALA + HT reduced H2S levels, compromising ALA's efficacy. NaHS with ALA + HT reinstated positive effects by restoring H2S levels. Biochemical assays confirmed ALA and NaHS promoted H2S accumulation, bolstering antioxidants, mitigating lipid peroxidation, suggesting their drought resilience potential in tomatoes.

Cloning and Functional Study of AmGDSL1 in Agropyron mongolicum.

Agropyron mongolicum Keng is a diploid perennial grass of triticeae in gramineae. It has strong drought resistance and developed roots that can effectively fix the soil and prevent soil erosion. GDSL lipase or esterases/lipase has a variety of functions, mainly focusing on plant abiotic stress response. In this study, a GDSL gene from A. mongolicum, designated as AmGDSL1, was successfully cloned and isolated. The subcellular localization of the AmGDSL1 gene (pCAMBIA1302-AmGDSL1-EGFP) results showed that the AmGDSL1 protein of A. mongolicum was only localized in the cytoplasm. When transferred into tobacco (Nicotiana benthamiana), the heterologous expression of AmGDSL1 led to enhanced drought tolerance. Under drought stress, AmGDSL1 overexpressing plants showed fewer wilting leaves, longer roots, and larger root surface area. These overexpression lines possessed higher superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and proline (PRO) activities. At the same time, the malondialdehyde (MDA) content was lower than that in wild-type (WT) tobacco. These findings shed light on the molecular mechanisms involved in the GDSL gene's role in drought resistance, contributing to the discovery and utilization of drought-resistant genes in A. mongolicum for enhancing crop drought resistance.

Soybean plants enhance growth through metabolic regulation under heterogeneous drought stress

Heterogeneous drought stress (HED) is prevalent in drought-resistant practices such as deficit irrigation, root zone irrigation and strip intercropping. The mechanisms and improvement of crop drought resistance under HED are not fully understood. This study used double-root grafted Nandou 12 (ND12) soybean seedlings to simulate HED treatment under controlled conditions. Seedlings were transplanted into root cups with waterproof partitions to establish different soil moisture treatments: sufficient irrigation (SI) with 80 % soil moisture on both sides, HED with 80 % on one side and 40 % on the other, and homogeneous drought stress (HOD) with 60 % on both sides. The results indicated that soybean plants treated with HED exhibited healthier growth compared to those treated with HOD. Photosynthesis rate (Pn), stomatal conductance (cond.), transpiration rate (Tr), and relative water content (RWC) decreased by 10.24 %, 43.90 %, 152.66 %, and 8.69 % in HED-treated plants, respectively, but dry biomass increased by 3.38 %. Conversely, HOD conditions led to a significant decline in these parameters. Metabolomic and transcriptomic analyses revealed significant changes in the biosynthesis and signaling pathways of key phytohormones and metabolites, including abscisic acid (ABA), gibberellin (GA), jasmonic acid (JA), isoflavones, starch, and sugars. In HED-treated plants, GmNCED downregulation resulted in 54.22 % less ABA than HOD. GA levels increased under HED with upregulation of GmGA3OX1 and GmGA3OX2. JA content in HED-treated roots was 90.90 % higher than in HOD-treated roots. Isoflavones concentration including genistein (73.01 %), genistin (63.63 %), malonylgenistin (20.58 %), malonylgenistin (65 %), diadzin (38.15 %), and malonyldiadzin (47.61 %) levels, were significantly higher in HED-treated plants. Antioxidant enzyme activities indicated a 20 % increase in peroxidase (POD) activity under HED, while malondialdehyde (MDA) content was 27 % higher in HOD-treated plants, indicating greater oxidative stress. Chlorophyll content remained stable, and starch concentration increased by 33.33 % in HED-treated plants compared to HOD-treated plants. HED enhances phytohormonal responses and metabolic adjustments in soybean plants, boosting photosynthetic efficiency, antioxidant capabilities, growth, and drought resilience. This regulatory mechanism balances growth promotion and drought resistance, highlighting HED potential in improving crop resilience.

Controlled drainage with subirrigation systems: Reduce water supply by automatic control

Controlled drainage with subirrigation (CDSI) is a viable measure to supply, retain or discharge groundwater, thereby contributing to freshwater availability in agriculture under changing environmental conditions. Relatively simple CDSI systems can be controlled manually to set a few drainage levels. More advanced systems can be controlled remotely to set any drainage level (between a technical maximum and minimum). CDSI potentially improves hydrological conditions for crop growth, but the required external water supply can be large. Therefore, the objective of this paper is to investigate whether external water supply for subirrigation can be reduced by automatic control of CDSI systems in relation to crop water demand. Field measurements of a CDSI pilot in the Dutch sandy Pleistocene uplands were combined with weather forecasts to simulate the optimal drainage level and day by day water demand and supply using the agro-hydrological Soil, Water, Atmosphere, Plant model (SWAP). Firstly, model simulations showed that the water requirement reduced by 60 mm (dry growing season), 253 mm (average growing season) and 348 mm (wet growing season) using a dynamically managed crest level (CDSI-dyn) compared to using a fixed crest level (CDSI-fix), with minor effects on crop yield. Secondly, model simulations showed that a higher hydraulic resistance to downward seepage, a higher ditch water level or deeper roots reduced the water supply (up to 100 mm). Thirdly, accepting 10 % daily crop drought and oxygen stress for CDSI-dyn reduced the water supply requirement with 235–628 mm (dry vs wet growing season) compared to CDSI-fix. In conclusion, the required water volume for CDSI could be substantially reduced by automated control of the drainage level and water supply rate, while maintaining crop yield or accepting minor reductions, which increases the potential of implementation of CDSI systems.

Biomass-derived carbon dots enhanced maize (Zea mays L.) drought tolerance by regulating phyllosphere microorganisms and ion fluxes

Enhancing crop drought tolerance is beneficial for increasing crop yield and ensuring food security. This study demonstrates that foliar application of biomass-derived carbon dots (Soy-CDs, 10 mg·L−1) can enhance the drought tolerance of maize, leading to an increase in fresh weight of maize shoots and roots (50.5 % and 54.9 %) and dry weight of maize shoots and roots (40.0 % and 37.7 %), respectively. Meanwhile, Soy-CDs altered the abundance of phyllosphere microorganisms (e.g. Proteobacteria, Deinococcus-Thermus, Verrucomicrobia, and Actinobacteria) of maize under drought stress, which enhanced the nitrogen fixation and stress resistance in maize leaves. Besides, Soy-CDs also promote Ca2+ influx and Na+ efflux in maize mesophyll cells under drought stress, facilitating the regulation of ion osmotic balance and contributing to the improvement of maize drought tolerance. Furthermore, Soy-CDs enhanced photosynthesis (55.3 %) of maize under drought stress, and the full life cycle study showed that Soy-CDs can promote the metabolism of maize kernels, ultimately improve the yield (40.5 %) and nutritional quality of maize. Therefore, this work discovers the enormous potential of biomass-derived carbon dots in improving drought resistance and quality of crop, which contributes to ensure food security.

DNA Methylation Dynamics in Response to Drought Stress in Crops.

Drought is one of the most hazardous environmental factors due to its severe damage on plant growth, development and productivity. Plants have evolved complex regulatory networks and resistance strategies for adaptation to drought stress. As a conserved epigenetic regulation, DNA methylation dynamically alters gene expression and chromosome interactions in plants' response to abiotic stresses. The development of omics technologies on genomics, epigenomics and transcriptomics has led to a rapid increase in research on epigenetic variation in non-model crop species. In this review, we summarize the most recent findings on the roles of DNA methylation under drought stress in crops, including methylating and demethylating enzymes, the global methylation dynamics, the dual regulation of DNA methylation on gene expression, the RNA-dependent DNA methylation (RdDM) pathway, alternative splicing (AS) events and long non-coding RNAs (lnc RNAs). We also discuss drought-induced stress memory. These epigenomic findings provide valuable potential for developing strategies to improve crop drought tolerance.

A novel vegetation-water resistant soil moisture index for remotely assessing soil surface moisture content under the low-moderate wheat cover

Soil surface moisture content (SMC) is one of the most critical and fundamental indicators of crop drought because water is vital for vegetation growth. In recent decades, satellite high-spatial-resolution optical multi-spectral remote-sensing sensors have entered a new stage. However, current optical remote sensing SMC indices (SMIs) are sensitive to cropland SMC and vegetation water content (VWC). From dry to saturated, the soil spectra decreased quickly as the SMC increased. For the vegetation spectra, the short-wave infrared (SWIR) bands decreased as the VWC increased. The differences in the responses of near-infrared (NIR) and SWIR bands to water may help distinguish soil moisture from mixed soil-vegetation spectra. This study focuses on (a) analyzing how soil and vegetation reflectance are affected by VWC and SMC, (b) designing a new vegetation-water resistant soil moisture index (VRSMI) based on the differences in the responses of NIR bands and SWIR bands to water, and (c) evaluating the potential of using VRSMI to remotely estimate SMC in low-moderate crop-covered regions. VRSMI uses SWIR1-SWIR2 as the numerator to detect the water absorption features and NIR×(SWIR1)0.5 as the denominator to weaken the vegetation effect. VRSMI and soil-VRSMI (VRSMIs) were tested using laboratory- and field-based spectra datasets. Our study presents the following conclusions: (1) The differences in the responses of NIR and SWIR bands to water help distinguish the effects of soil moisture on mixed soil-vegetation spectra. (2) VRSMIs can provide high-performance SMC estimates under low-moderate vegetation cover (NDVI < 0.55). (3) VRSMIs can be used for cropland SMC evaluation without considering crop VWC (laboratory-based spectra dataset: RMSE = 0.07–0.11, R2 = 0.96–0.98; field-based spectra dataset: RMSE = 0.17–0.18, R2 = 0.63–0.79). Our study indicates that VRSMI and VRSMIs can provide high-performance relative SMC estimates under low-to-moderate vegetation cover.

Phosphorylation of ZmAL14 by ZmSnRK2.2 regulates drought resistance through derepressing ZmROP8 expression.

Drought stress has negative effects on crop growth and production. Characterization of transcription factors that regulate the expression of drought-responsive genes is critical for understanding the transcriptional regulatory networks in response to drought, which facilitates the improvement of crop drought tolerance. Here, we identified an Alfin-like (AL) family gene ZmAL14 that negatively regulates drought resistance. Overexpression of ZmAL14 exhibits susceptibility to drought while mutation of ZmAL14 enhances drought resistance. An abscisic acid (ABA)-activated protein kinase ZmSnRK2.2 interacts and phosphorylates ZmAL14 at T38 residue. Knockout of ZmSnRK2.2 gene decreases drought resistance of maize. A dehydration-induced Rho-like small guanosine triphosphatase gene ZmROP8 is directly targeted and repressed by ZmAL14. Phosphorylation of ZmAL14 by ZmSnRK2.2 prevents its binding to the ZmROP8 promoter, thereby releasing the repression of ZmROP8 transcription. Overexpression of ZmROP8 stimulates peroxidase activity and reduces hydrogen peroxide accumulation after drought treatment. Collectively, our study indicates that ZmAL14 is a negative regulator of drought resistance, which can be phosphorylated by ZmSnRK2.2 through the ABA signaling pathway, thus preventing its suppression on ZmROP8 transcription during drought stress response.

Unexpectedly, triple super phosphate fertilizer induces maize drought resilience

Phosphorus fertilizer is commonly applied to soils in crop production as diammonium phosphate (DAP). To decrease ammonium addition to the environment, triple super phosphate (TSP) is being considered as a DAP replacement. This study was undertaken to compare the response of maize plants to soil fertilization with TSP vs. DAP under well-watered conditions, under soil-drying conditions, and root hydraulic conductance. It was found for well-watered conditions in a controlled environment that there was no difference in plant growth between DAP to TSP treatments. In soil dry-down experiments, however, the initiation of the decrease in transpiration rate was unexpectedly quite different between DAP and TSP treatments. The soil water content threshold for initiation of decrease in transpiration rate with DAP treatment (average fraction transpirable soil water for two experiments = 0.285) was consistent with common observations, but the threshold associated with TSP treatment occurred at an unusually high soil water content (average fraction transpirable soil water for two experiments = 0.545). The higher threshold with TSP resulted in an extended period of soil water use, i.e. soil water conservation. Soil water conservation resulting from the TSP treatment was associated with a 27% greater shoot mass accumulation following a 4-wk re-watering period after the water-deficit treatment than measured with the DAP treatment. The high threshold for decrease in transpiration resulting from TSP was consistent with measured lower root hydraulic conductance as compared to DAP treatment. The unexpected discovery of TSP-induced initiation of transpiration rate decrease at high soil water content is consistent with greater crop drought resilience.

Enhancing crop resilience through thiamine: implications for sustainable agriculture in drought-stressed radish

During 21st century, abiotic stress has adversely affected the agriculture crop production around the globe. Keeping in view the food requirement under water shortage condition, a study was planned to investigate the effect of thiamine application on radish crop under drought stress conditions on plant. For study purpose, two varieties of locally available radish (‘Early-Milo’ and ‘Laal-Pari’) were grown with normal water application as well as thiamine (100 mg L-1) application while maintaining a stress condition (60% field capacity). Increasing water deficit stress linearly reduced plant growth, yield and biomass in both varieties by reducing water use efficiency, while significantly enhanced these attributes with thiamine application. Thiamine application under drought stress exerted significant impacts on physiological attributes in both varieties, including enhanced osmolytic attribute in drought conditions and improvements in superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), H2O2, and malondialdehyde (MDA) activities in plant leaves. Antioxidant and osmoprotectant upregulation positively linked to radish crop's drought tolerance. Moreover, PCA and heatmap analysis revealed a significant interdependence among various traits and interconnected in determining the crop's capacity to sustain growth under conditions of drought stress. In crux, thiamine application conclusively enhances radish growth, yield, biomass, physio-chemical and osmolytic attributes, ionic composition and enzymatic antioxidant potential. Therefore, it is recommended to consider the application of thiamine in commercial agriculture practices to mitigate the negative effects of drought stress on radish crop production.

Evaluation of drought-tolerant varieties based on root system architecture in cotton (Gossypium hirsutum L.)

BackgroundRoot system architecture (RSA) exhibits significant genetic variability and is closely associated with drought tolerance. However, the evaluation of drought-tolerant cotton cultivars based on RSA in the field conditions is still underexplored.ResultsSo, this study conducted a comprehensive analysis of drought tolerance based on physiological and morphological traits (i.e., aboveground and RSA, and yield) within a rain-out shelter, with two water treatments: well-watered (75 ± 5% soil relative water content) and drought stress (50 ± 5% soil relative water content). The results showed that principal component analysis identified six principal components, including highlighting the importance of root traits and canopy parameters in influencing drought tolerance. Moreover, the systematic cluster analysis was used to classify 80 cultivars into 5 categories, including drought-tolerant cultivars, relatively drought-tolerant cultivars, intermediate cultivars, relatively drought-sensitive cultivars, and drought-sensitive cultivars. Further validation of the drought tolerance index showed that the yield drought tolerance index and biomass drought tolerance index of the drought-tolerant cultivars were 8.97 and 5.05 times higher than those of the drought-sensitive cultivars, respectively.ConclusionsThe RSA of drought-tolerant cultivars was characterised by a significant increase in average length-all lateral roots, a significant decrease in average lateral root emergence angle and a moderate root/shoot ratio. In contrast, the drought-sensitive cultivars showed a significant decrease in average length-all lateral roots and a significant increase in both average lateral root emergence angle and root/shoot ratio. It is therefore more comprehensive and accurate to assess field crop drought tolerance by considering root performance.

Precise Drought Threshold Monitoring in Winter Wheat Using the Unmanned Aerial Vehicle Thermal Method

Accurate monitoring of crop drought thresholds at different growth periods is crucial for drought monitoring. In this study, the canopy temperature (Tc) of winter wheat (‘Weilong 169’ variety) during the three main growth periods was extracted from high-resolution thermal and multispectral images taken by a complete unmanned aerial vehicle (UAV) system. Canopy-air temperature difference (ΔT) and statistic Crop Water Stress Index (CWSIsi) indicators were constructed based on Tc. Combined experiment data from the field and drought thresholds for the ΔT and CWSIsi indicators for different drought levels at three main growth periods were monitored. The results showed a strong correlation between the Tc extracted using the NDVI-OTSU method and ground-truth temperature, with an R2 value of 0.94. The CWSIsi was more stable than the ΔT index in monitoring the drought level affecting winter wheat. The threshold ranges of the CWSIsi for different drought levels of winter wheat at three main growth periods were as follows: the jointing–heading period, where the threshold ranges for normal, mild drought, moderate drought, and severe drought are &lt;0.30, 0.30–0.42, 0.42–0.48, and &gt;0.48, respectively; the heading–filling period, where the threshold ranges for normal, and mild, moderate, and severe drought are &lt;0.33, 0.33–0.47, 0.44–0.53, and &gt;0.53, respectively; and the filling–maturation period, where the threshold ranges for normal, mild drought, moderate drought, and severe drought are &lt;0.41, 0.41–0.54, 0.54–0.59, and &gt;0.59, respectively. The UAV thermal threshold method system can improve the accuracy of crop drought monitoring and has considerable potential in crop drought disaster identification.