Synergistic Effect of Salicylic Acid and Proline in Enhancing Drought Tolerance in Mungbean Through Physio-biochemical Adjustments and Enhanced Antioxidant Activity

In pulse crops, synchronized flowering altered the source-sink relationship due to the rapid translocation of nutrients from leaves to the developing pods. Additional nutrition through foliar feeding plays a vital role in pulse production by stimulating root development, nodulation, energy transformation, various metabolic processes and increasing pod setting, thereby increasing the yield. Many researchers are trying to reduce transpiration losses, flower shedding and maximizing productivity, foliar application of nutrient formulations and growth regulators in pulses. Thus, the foliar application of macro and micronutrients and growth regulators is considered an efficient and economical method of supplementing part of the nutrient requirements and moisture stress tolerance at critical stages. The PPFM (Pink pigmented facultative methylobacteria), when used as a foliar spray, it releases osmoprotectants (sugars and alcohols) on the surface of the plants and it increases chlorophyll content, thereby increasing the photosynthetic efficiency and makes drought tolerance ability of plants. This matrix helped to protect the plants from desiccation and high temperatures. Whereas potassium as spray also enhances drought tolerance in plants by mitigating harmful effects by increasing translocation, maintaining water balance and increasing pod filling. Further, Salicylic acid is an endogenous growth regulator of phenolic nature, which regulates physiological processes to mitigate stress, acts as a chelate for phosphorous uptake, increases pod setting, flowering and grain yield. Pulse wonder decreases flower shedding, increases yield by up to 20% and offers moisture stress tolerance.

Synthetic cultivar development in cumin: Enhancing yield and drought tolerance

Magnetized water technology, which involves treating water by passing it through a magnetic field, has gained significant attention for its wide-ranging applications in agriculture, industry, and environmental management. This innovative approach modifies the physical and chemical properties of water, enhancing its utility in various sectors. In agriculture, magnetized water has been shown to improve crop yields, soil quality, and water use efficiency, particularly in arid and semi-arid regions. Studies from countries like India, Brazil, and China demonstrate that magnetized water irrigation increases soil moisture retention, reduces salinity, and enhances drought tolerance in crops such as sugarcane, wheat, and rice. Additionally, it promotes nutrient uptake, seed germination, and overall plant growth by activating enzymes and improving photosynthetic efficiency. In the industrial sector, magnetized water has proven effective in reducing energy consumption, inhibiting scale formation, and improving wastewater treatment processes. For instance, advanced magnetic filtration systems have achieved up to 95% removal of iron oxide contaminants from industrial wastewater. The technology also supports sustainable farming practices by reducing irrigation water requirements and improving the economic efficiency of water and fertilizer use. The scientific mechanisms behind magnetized water involve the alteration of hydrogen bonds, reduction in water cluster size, and changes in viscosity and surface tension, which enhance water absorption and nutrient transport in plants. Cryptochromes, plant photoreceptors, are believed to play a role in mediating the effects of magnetic fields on plant growth and stress responses.

Plants are often subjected to various environmental stresses during their life cycle, among which drought stress is perhaps the most significant abiotic stress limiting plant growth and development. Arbuscular mycorrhizal (AM) fungi, a group of beneficial soil fungi, can enhance the adaptability and tolerance of their host plants to drought stress after infecting plant roots and establishing a symbiotic association with their host plant. Therefore, AM fungi represent an eco-friendly strategy in sustainable agricultural systems. There is still a need, however, to better understand the complex mechanisms underlying AM fungi-mediated enhancement of plant drought tolerance to ensure their effective use. AM fungi establish well-developed, extraradical hyphae on root surfaces, and function in water absorption and the uptake and transfer of nutrients into host cells. Thus, they participate in the physiology of host plants through the function of specific genes encoded in their genome. AM fungi also modulate morphological adaptations and various physiological processes in host plants, that help to mitigate drought-induced injury and enhance drought tolerance. Several AM-specific host genes have been identified and reported to be responsible for conferring enhanced drought tolerance. This review provides an overview of the effect of drought stress on the diversity and activity of AM fungi, the symbiotic relationship that exists between AM fungi and host plants under drought stress conditions, elucidates the morphological, physiological, and molecular mechanisms underlying AM fungi-mediated enhanced drought tolerance in plants, and provides an outlook for future research.

The external application of acetic acid (AA) has been shown to improve drought survival in plants, such as Arabidopsis, rice, maize, wheat, rapeseed and cassava, and the application of AA also increased drought tolerance in perennial woody apple (Malus domestica) plants. An understanding of AA-induced drought tolerance in apple plants at the molecular level will contribute to the development of technology that can be used to enhance drought tolerance. In this study, the morphological, physiological and transcriptomic responses to drought stress were analyzed in apple plants after watering without AA (CK), watering with AA (AA), drought treatment (D) and drought treatment with AA (DA). The results suggested that the AA-treated apple plants had a higher tolerance to drought than water-treated plants. Higher levels of chlorophyll and carotenoids were found under the DA conditions than under D stress. The levels of abscisic acid (ABA), jasmonic acid (JA) and methyl jasmonate were increased in AA-treated apple plants. Transcriptomic profiling indicated the key biological pathways involved in metabolic processes, mitogen-activated protein kinase (MAPK) signaling, plant hormone signal transduction and the biosynthesis of secondary metabolites in response to different drought conditions. The 9-cis-epoxycarotenoid dioxygenase, (9S,13S)-cis-oxophytodienoic acid reductase, allene oxide synthase, allene oxide cyclase and lipoxygenase genes participate in the synthase of ABA and JA under drought and AA treatments. Collectively, the results showed that external application of AA enhanced drought tolerance in apple plants by influencing the ABA- and JA-induced MAPK signaling pathways. These data indicated that the application of AA in plants is beneficial for enhancing drought tolerance and decreasing growth inhibition in agricultural fields.

Water scarcity is a serious agricultural problem causing significant losses to crop yield and product quality. The development of technologies to mitigate the damage caused by drought stress is essential for ensuring a sustainable food supply for the increasing global population. We herein report that the exogenous application of ethanol, an inexpensive and environmentally friendly chemical, significantly enhances drought tolerance in Arabidopsis thaliana, rice and wheat. The transcriptomic analyses of ethanol-treated plants revealed the upregulation of genes related to sucrose and starch metabolism, phenylpropanoids and glucosinolate biosynthesis, while metabolomic analysis showed an increased accumulation of sugars, glucosinolates and drought-tolerance-related amino acids. The phenotyping analysis indicated that drought-induced water loss was delayed in the ethanol-treated plants. Furthermore, ethanol treatment induced stomatal closure, resulting in decreased transpiration rate and increased leaf water contents under drought stress conditions. The ethanol treatment did not enhance drought tolerance in the mutant of ABI1, a negative regulator of abscisic acid (ABA) signaling in Arabidopsis, indicating that ABA signaling contributes to ethanol-mediated drought tolerance. The nuclear magnetic resonance analysis using 13C-labeled ethanol indicated that gluconeogenesis is involved in the accumulation of sugars. The ethanol treatment did not enhance the drought tolerance in the aldehyde dehydrogenase (aldh) triple mutant (aldh2b4/aldh2b7/aldh2c4). These results show that ABA signaling and acetic acid biosynthesis are involved in ethanol-mediated drought tolerance and that chemical priming through ethanol application regulates sugar accumulation and gluconeogenesis, leading to enhanced drought tolerance and sustained plant growth. These findings highlight a new survival strategy for increasing crop production under water-limited conditions.

Ultrasound-assisted formation of chitosan-glucose Maillard reaction products to fabricate nanoparticles with enhanced antioxidant activity

Drought is a major environmental factor that hinders plant growth and development, thereby threatening crop yields. The major latex protein (MLP) plays an important role in modulating plant stress responses and development. However, the roles and molecular mechanism of MLP in drought stress response remain unclear. Here, we identified a wheat MLP member TaSTP, and its overexpression in wheat exhibited enhanced drought tolerance, whereas silencing TaSTP increased drought sensitivity. Additionally, TaSTP-overexpressing lines exhibited higher yields under drought conditions. Transcriptome sequencing analysis revealed that TaSTP significantly upregulates genes involved in the osmotic regulatory and sugar metabolism pathway, thereby increasing antioxidant capacity and sugar content. Moreover, we also found that exogenous application of glucose and sucrose effectively enhanced drought tolerance in wheat. A 172 bp fragment insertion in the TaSTP-2A promoter created two allelic variants, Hap-2A-I and Hap-2A-II, which differ in transcriptional levels and drought tolerance. This insertion allows binding of the zinc finger transcription factor TaZAT5L, strongly repressing TaSTP expression in Hap-2A-I, but not in Hap-2A-II. The superior allele Hap-2A-II has been preferentially selected during wheat breeding in China. Collectively, our results demonstrate that TaSTP enhances drought tolerance by promoting reactive oxygen species (ROS) scavenging and sugar accumulation. These findings provide novel insights into the roles and molecular mechanisms of TaSTP in plants.

BackgroundCCCH-type zinc finger proteins play important roles in plant development and biotic/abiotic stress responses. Wintersweet (Chimonanthus praecox) is a popular ornamental plant with strong resistance to various stresses, which is a good material for exploring gene resource for stress response. In this study, we isolated a CCCH type zinc finger protein gene CpC3H3 (MZ964860) from flower of wintersweet and performed functional analysis with a purpose of identifying gene resource for floral transition and stress tolerance.ResultsCpC3H3 was predicted a CCCH type zinc finger protein gene encoding a protein containing 446 amino acids with five conserved C-X8-C-X5-C-X3-H motifs. CpC3H3 was localized in the cell membrane but with a nuclear export signal at the N-terminal. Transcripts of CpC3H3 were significantly accumulated in flower buds at floral meristem formation stage, and were induced by polyethylene glycol. Overexpression of CpC3H3 promoted flowering, and enhanced drought tolerance in transgenic A. thaliana. CpC3H3 overexpression affects the expression level of genes involved in flower inducement and stress responses. Further comparative studies on physiological indices showed the contents of proline and soluble sugar, activity of peroxidase and the rates of electrolyte leakage were significantly increased and the content of malondialdehyde and osmotic potential was significantly reduced in transgenic A. thaliana under PEG stress.ConclusionOverall, CpC3H3 plays a role in flowering inducement and drought tolerance in transgenic A. thaliana. The CpC3H3 gene has the potential to be used to promote flowering and enhance drought tolerance in plants.

Ectopic expression of HaPEPC1 from the desert shrub Haloxylon ammodendron confers drought stress tolerance in Arabidopsis thaliana

Salicylic acid mediated growth, physiological and proteomic responses in two wheat varieties under drought stress

Drought stress is a crucial environmental factor that limits plant growth, development, and productivity. Autophagy of misfolded proteins can help alleviate the damage caused in plants experiencing drought. However, the mechanism of autophagy-mediated drought tolerance in plants remains largely unknown. Here, we cloned the gene for a maize (Zea mays) selective autophagy receptor, NEXT TO BRCA1 GENE 1 (ZmNBR1), and identified its role in the response to drought stress. We observed that drought stress increased the accumulation of autophagosomes. RNA sequencing and reverse transcription-quantitative polymerase chain reaction showed that ZmNBR1 is markedly induced by drought stress. ZmNBR1 overexpression enhanced drought tolerance, while its knockdown reduced drought tolerance in maize. Our results established that ZmNBR1 mediates the increase in autophagosomes and autophagic activity under drought stress. ZmNBR1 also affects the expression of genes related to autophagy under drought stress. Moreover, we determined that BRASSINOSTEROID INSENSITIVE 1A (ZmBRI1a), a brassinosteroid receptor of the BRI1-like family, interacts with ZmNBR1. Phenotype analysis showed that ZmBRI1a negatively regulates drought tolerance in maize, and genetic analysis indicated that ZmNBR1 acts upstream of ZmBRI1a in regulating drought tolerance. Furthermore, ZmNBR1 facilitates the autophagic degradation of ZmBRI1a under drought stress. Taken together, our results reveal that ZmNBR1 regulates the expression of autophagy-related genes, thereby increasing autophagic activity and promoting the autophagic degradation of ZmBRI1a under drought stress, thus enhancing drought tolerance in maize. These findings provide new insights into the autophagy degradation of brassinosteroid signaling components by the autophagy receptor NBR1 under drought stress.

Drought tolerance is a key trait for increasing and stabilizing barley productivity in dry areas worldwide. Identification of the genes responsible for drought tolerance in barley (Hordeum vulgare L.) will facilitate understanding of the molecular mechanisms of drought tolerance, and also facilitate the genetic improvement of barley through marker-assisted selection or gene transformation. To monitor the changes in gene expression at the transcriptional level in barley leaves during the reproductive stage under drought conditions, the 22K Affymetrix Barley 1 microarray was used to screen two drought-tolerant barley genotypes, Martin and Hordeum spontaneum 41-1 (HS41-1), and one drought-sensitive genotype Moroc9-75. Seventeen genes were expressed exclusively in the two drought-tolerant genotypes under drought stress, and their encoded proteins may play significant roles in enhancing drought tolerance through controlling stomatal closure via carbon metabolism (NADP malic enzyme, NADP-ME, and pyruvate dehydrogenase, PDH), synthesizing the osmoprotectant glycine-betaine (C-4 sterol methyl oxidase, CSMO), generating protectants against reactive-oxygen-species scavenging (aldehyde dehydrogenase,ALDH, ascorbate-dependent oxidoreductase, ADOR), and stabilizing membranes and proteins (heat-shock protein 17.8, HSP17.8, and dehydrin 3, DHN3). Moreover, 17 genes were abundantly expressed in Martin and HS41-1 compared with Moroc9-75 under both drought and control conditions. These genes were possibly constitutively expressed in drought-tolerant genotypes. Among them, seven known annotated genes might enhance drought tolerance through signalling [such as calcium-dependent protein kinase (CDPK) and membrane steroid binding protein (MSBP)], anti-senescence (G2 pea dark accumulated protein, GDA2), and detoxification (glutathione S-transferase, GST) pathways. In addition, 18 genes, including those encoding Δl-pyrroline-5-carboxylate synthetase (P5CS), protein phosphatase 2C-like protein (PP2C), and several chaperones, were differentially expressed in all genotypes under drought; thus they were more likely to be general drought-responsive genes in barley. These results could provide new insights into further understanding of drought-tolerance mechanisms in barley.

Salicylic acid (SA) has been known to induce drought tolerance in many plant species. In this study, we investigated the potential of exogenous application of SA to enhance drought tolerance in immature tea plants under glasshouse conditions at the Tea Research Institute in Talawakelle, Sri Lanka. One-year-old potted tea cultivars known for drought tolerance were used in the study. The plants were subjected to a drying cycle while being foliar sprayed with different concentrations of SA along with well-watered (WW), water-spray (WS) and no-spray (NS) treatments. Data were collected at 18 hours, 14 days after spraying (DAS), 21 DAS, and during the recovery after re-watering at 21 DAS. Based on the results obtained from the glasshouse study, the effective concentration of 150 mg L-1 SA was selected for further testing under field conditions in Talawakelle using three-year-old tea plants. The field experiment followed a randomized complete block design (RCBD) with three blocks. When the plants reached a moderate moisture stress level, they were foliar-sprayed with 150 mg L-1 SA, WS and NS treatments were included as controls. Data were collected at 7 DAS, 14 DAS, 21 DAS, and during the recovery phase after rain. The results showed that drought stress led to a decline in gas exchange parameters, relative water content, and an increase in the accumulation of osmolytes. However, the exogenous application of 150 mg L-1 SA significantly improved physiological processes such as gas exchange, osmolyte accumulation, and antioxidant activity, thus effectively enhancing drought tolerance in immature tea plants.

Drought stress causes substantial yield losses in maize, posing a serious threat to food security. Leaf adaxial-abaxial polarity development is closely associated with drought tolerance. KANADI (KAN) genes play a pivotal role in leaf polarity establishment and are likely involved in regulating drought tolerance in maize. In this study, we identified 11 ZmKAN genes through sequence similarity analysis and functionally characterized one of them, ZmKAN1, in the context of drought response. The kan1-1 mutant exhibited enhanced drought tolerance compared to the wild-type B73. Transcriptome analysis revealed that differentially expressed genes in the mutant before and after drought stress were significantly enriched in pathways associated with drought tolerance, including "response to heat", "secondary metabolite biosynthetic process", and "plant hormone signal transduction", suggesting that ZmKAN1 may modulate maize drought tolerance by regulating key processes such as heat response and plant hormone signaling. Furthermore, the differentially expressed genes in the wild type before and after drought stress were enriched in pathways such as "structural constituent of ribosome", "mitochondrial respiratory chain complex I", and "ribosome", suggesting that drought stress may impair ribosomal and mitochondrial functions more severely in the wild type, along with other cellular organelles. In contrast, mutants exhibited relatively stable ribosomal and mitochondrial activities, enabling them to maintain higher survival rates and enhanced drought tolerance under drought conditions. Our findings provide important insights into the molecular mechanisms underlying drought tolerance in maize and offer valuable genetic resources for breeding drought-resistant maize cultivars.