Exogenous γ-Aminobutyric Acid (GABA) Application Mitigates Salinity Stress in Maize Plants

The effect of γ-Aminobutyrate (GABA) on maize seedlings under saline stress conditions has not been well tested in previous literature. Maize seedlings were subjected to two saline water concentrations (50 and 100 mM NaCl), with distilled water as the control. Maize seedlings under saline and control conditions were sprayed with GABA at two concentrations (0.5 and 1 mM). Our results indicated that GABA application (1 mM) significantly enhanced plant growth parameters (fresh shoots and fresh roots by 80.43% and 47.13%, respectively) and leaf pigments (chlorophyll a, b, and total chlorophyll by 22.88%, 56.80%, and 36.21%, respectively) compared to untreated seedlings under the highest saline level. Additionally, under 100 mM NaCl, methylglyoxal (MG), malondialdehyde (MDA), and hydrogen peroxidase (H₂O₂) were reduced by 1 mM GABA application by 43.66%, 33.40%, and 35.98%, respectively. Moreover, maize seedlings that were treated with 1 mM GABA contained a lower Na content (22.04%) and a higher K content (60.06%), compared to the control under 100 mM NaCl. Peroxidase, catalase, ascorbate peroxidase, and superoxide dismutase activities were improved (24.62%, 15.98%, 62.13%, and 70.07%, respectively) by the highest GABA rate, under the highest stress level. Seedlings treated with GABA under saline conditions showed higher levels of expression of the potassium transporter protein (ZmHKT1) gene, and lower expression of the ZmSOS1 and ZmNHX1 genes, compared to untreated seedlings. In conclusion, GABA application as a foliar treatment could be a promising strategy to mitigate salinity stress in maize plants.

Folic Acid Reinforces Maize Tolerance to Sodic-Alkaline Stress through Modulation of Growth, Biochemical and Molecular Mechanisms

The mechanism by which folic acid (FA) or its derivatives (folates) mediates plant tolerance to sodic-alkaline stress has not been clarified in previous literature. To apply sodic-alkaline stress, maize seedlings were irrigated with 50 mM of a combined solution (1:1) of sodic-alkaline salts (NaHCO₃ and Na₂CO₃; pH 9.7). Maize seedlings under stressed and non-stressed conditions were sprayed with folic acid (FA) at 0 (distilled water as control), 0.05, 0.1, and 0.2 mM. Under sodic-alkaline stress, FA applied at 0.2 mM significantly improved shoot fresh weight (95%), chlorophyll (Chl a (41%), Chl b (57%), and total Chl (42%)), and carotenoids (27%) compared to the untreated plants, while root fresh weight was not affected compared to the untreated plants. This improvement was associated with a significant enhancement in the cell-membrane stability index (CMSI), relative water content (RWC), free amino acids (FAA), proline, soluble sugars, K, and Ca. In contrast, Na, Na/K ratio, H₂O₂, malondialdehyde (MDA), and methylglycoxal (MG) were significantly decreased. Moreover, seedlings treated with FA demonstrated significantly higher activities of antioxidant enzymes including superoxide dismutase (SOD), peroxidase (POX), catalase (CAT), and ascorbate peroxidase (APX) compared to the untreated plants. The molecular studies using RT-qPCR demonstrated that FA treatments, specifically at 0.2 mM, enhanced the K⁺/Na⁺ selectivity and the performance of photosynthesis under alkaline-stress conditions. These responses were observed through up-regulation of the expression of the high-affinity potassium-transporter protein (ZmHKT1), the major core protein of photosystem II (D2-Protein), and the activity of the first enzyme of carbon fixation cycle in C4 plants (PEP-case) by 74, 248, and 225% over the untreated plants, respectively. Conversely, there was a significant down-regulation in the expression ZmSOS1 and ZmNHX1 by 48.2 and 27.8%, respectively, compared to the untreated plants.

Inheritance of resistance against northern leaf blight of maize using conventional breeding methods

Maize (Zea mays L.) is one of the important cereal crops along with wheat and rice worldwide. The purpose of this study was to use classical genetic approaches to assess the resistance of various maize parents and hybrids to the northern corn leaf blight (NCLB) disease in two different locations in Egypt. Eight parents, 28 F1, and 2 check hybrids were evaluated. The analysis of variance showed high significant variations between maize parents and their hybrids for the studied parameters and NCLB disease, besides there are significant variations between both locations. Results of maize parents showed that Sids 63, Giza 602, and Giza 628 cultivars exhibited the highest values and were resistant to NCLB in both locations comparing with Nubaria 39 and Gemmiza 18 that were susceptible to NCLB disease. Concerning the maize hybrids, analysis of variance and mean squares of growth characters in both locations indicated high significant variations between the maize hybrids including the check hybrids. When combined between the two locations for current parameters against NCLB, the data pointed that the Sakha location values for maize hybrids were much closed to the combining data in parents and the hybrids detected high resistance to this disease comparing with Nubaria location. All tested maize lines (38 lines), including parents and hybrids were classified as follows, two lines were rated as 1 (highly resistant), three were rated as 2 (resistant), sixteen were rated as 3 (moderate resistant), eight were rated 4 (moderately susceptible) and nine were rated 5 (susceptible). The data explaining that the crossing between high resistant maize cultivars produced high levels of resistance to NCLB disease. Therefore, our results verified that classical breeding could efficiently increase the resistance levels of maize germplasm against NCLB disease by developing new cultivars with superior performance in terms of grain yield, disease resistance and grain quality.

Using of DNA-Barcoding, SCoT and SDS-PAGE Protein to Assess Soma-Clonal Variation in Micro-Propagated Fig (Ficus carica L.) Plant

<b>Background and Objective:</b> <i>In vitro</i> propagation of fig (<i>Ficus carica</i> L.) is one of the possible approaches that may be used to maximize the diversity of plant species. The current work was carried out to evaluate genetic stability of micropropagated fig plantlets and to determine the effect of <i>in vitro </i>propagation on genomic content of Saudi fig. <b>Materials and Methods:</b> The start codon-targeted (SCoT), DNA-barcoding chloroplast gene RNA polymerase1 (<i>rpoC1</i> sequencing) and total protein profiling assays (SDS-PAGE) techniques were used to detect genetic stability in micropropagated fig plantlets. <b>Results:</b> The Scorable PCR bands were produced with 10 SCoT primers used, where the total number of bands was 135 bands. Twenty polymorphic bands were generated with 18.4% of a polymorphism percentage. According to the result, no visual unique bands were generated which confirmed the genetic homogeneity of micropropagated plantlets samples compared to the control sample (mother plant). Sequence analysis and phylogenetic tree generated using fig <i>rpoC1</i> sequence showed high similarity between control and plantlets samples of fig plant. The protein profiling results revealed no remarkable changes between micropropagated plantlets and the mother plant. <b>Conclusion:</b> The results indicate that using SCoT, DNA barcoding and protein profiling have demonstrated their utility to detect genetic homogeneity in micropropagated fig plantlets, which suggests using of micropropagation protocol of plants applied on the plantlets in the current study as a reliable protocol for <i>in vitro</i> culture and conservation of fig plant.

Sustainable phosphorous management in two different soil series of Pakistan by evaluating dynamics of phosphatic fertilizer source

Phosphorous (P) plays the prominent role to promote the plants storage functions and structural roles, as it is recognized as a vital component of ADP, ATP, Cell wall as well as a part of DNA. Soils acts as the sink to supply P to plants because soil pH and its physical condition are the main factor which regulate the solubility and availability P element. Phosphorus is not deficient in Pakistani soils but its availability to plants is the serious matter of concern. A pot experiment was conducted to evaluate P dynamics in two different soil series of Pakistan (Bahawalpur and Lyallpur) using Maize as test crop. The treatments applied were T0: Control (without any fertilizer), T1: Recommended DAP @648 mg pot⁻¹, T2: Half dose DAP @324 mg pot⁻¹, T3: Recommended rate of TSP @900 mg pot⁻¹, T4: Half dose TSP @450 mg pot⁻¹. Soil analysis showed that Bahawalpur soil has sandy clay loam texture with 33% clay and Lyallpur series has sandy loam texture with 15.5% clay; furthermore, these soil contain 4.6 and 2.12% CaCO₃ respectively. Results showed an increase in P concentration in roots (23 mg kg⁻¹) with the application of half dose of TSP in Lyallpur series and lowest in Bahawalpur series (14.6 mg kg⁻¹) at recommended dose of DAP. Concentration of P in shoots responded the same; increase at half dose of TSP (16.7 mg kg⁻¹) and lowest at full dose of DAP in Bahawalpur series as (15.58 mg kg⁻¹). Adsorbed P (17 mg kg⁻¹) was recorded highest in Bahawalpur soil with more clay amount in pot with DAP application but lower in Lyallpur soil series (14 mg kg⁻¹) with the application of applied TSP. The PUE was recorded highest in Lyallpur series with the application of half dose of TSP and it was 61% more than control and was Highest in Bahawalpur series was with the application of recommended dose of DAP is 72% more than control treatment. On estimation; results showed that applied sources made an increase in P availability than control, but TSP gave better P uptake than DAP unless of rates applied. Soil of Lyallpur series showed better uptake of P and response to applied fertilizers than Bahawalpur series which showed more adsorption of P by high clay and CaCO₃ amount. Conclusively, the study suggested that soil series play a crucial role in choosing fertilizer source for field application.

Production of Virus-Free Rose Plants using Meristem-Tip Culture and in vitro Thermotherapy

<b>Background and Objective:</b> Tissue culture and thermotherapy were proved to be suitable in eliminating viruses of many plants. This study was designed in an attempt to produce virus-free Al-Taif rose plants (<i>Rosa damascena</i> Trigintipetala Dieck) through the practical application of the tissue culture approach and thermotherapy. <b>Materials and Methods:</b> Double Antibody Sandwich-Enzyme-Linked Immunosorbent Assay ( DAS-ELISA) and Reverse Transcription-Polymerase Chain Reaction (RT-PCR) techniques were used to detect the presence of <i>Apple mosaic virus</i> (ApMV) and <i>Strawberry latent ringspot virus</i> (SLRV) in rose plant materials collected from Taif, KSA. RT-PCR was more sensitive than DAS-ELISA in detecting the 2 viruses. <b>Results:</b> Three different meristem-tip sterilization methods were compared and results revealed that treatment 3 (T<sub>3</sub>: 70% Ethanol for 1.0 min and 15% Clorox (Sodium hypochlorite 5.25%) for 10 min) was the most suitable as 97.78% of cleaned meristem tips survived. Meristem tips with different lengths were thermotherapy-treated for different durations. It was indicated that meristem tips of 0.5 or 1.0 cm and heat-treated at 37<sup>o</sup>C for four weeks gave the highest percentage of meristems that were able to differentiate into micro-shoots. <b>Conclusion:</b> RT-PCR detection of ApMV and SLRV revealed that using thermotherapy-treatment, for 4 weeks, of 0.5 cm long meristem tips was successfully applied to eliminate the 2 viruses in 92 and 96% of regenerated plantlets, respectively.

Consecutive seasonal effect on yield and water productivity of drip deficit irrigated sorghum in saline soils

Drought stress destructively affects the growth and productivity of sorghum crop, especially under saline soils. Therefore, Field trials were performed to determine the influence of water stress on water productivity (water productivity for grain, (G-WP) and water productivity for forage, (F-WP), yield of sorghum and soil properties in salt-affected soil (8.20 dS m⁻¹) under different sowing dates and irrigation regimes. The summer sowing (SS) was performed on 1 April while fall sowing (FS) was established on 2 August. The irrigation regimes were; 100, 90, 80, and 70% of crop evapotranspiration (ETc). The findings displayed that the fodder and grain yields were increased by 23% and 26% under SS compared to FS over the two seasons 2017 and 2018, respectively. Among irrigation levels, the maximum values of grain and fodder yield were given by 100% of ETc, while a non-significant difference was observed between 100% and 90% of ETc. Moreover, the maximum values of G-WP (1.31%) and F-WP (9.00%) were recorded for 90% of ETc. Interestingly, the soil salinity was decreased in 0–0.6 m depth, and more decline was noted in 0–0.2 m depth using 90% of ETc. The highest salt accumulation withinside the soil profile was recorded under 70% of ETc in comparison to 100% of ETc. Thereupon, under water scarcity, application of 90% of ETc is recommended with SS to save 10% of the applied irrigation water without a significant decrease in grain yield (GY).

Quantitative response of wheat to sowing dates and irrigation regimes using CERES-Wheat model

An experiment was conducted at Punjab Agricultural University, Ludhiana during 2014-15 and 2015-16, keeping four sowing dates {25th Oct (D₁), 10th Nov (D₂), 25th Nov (D₃) and 10th Dec (D₄)} in main plots and five irrigation schedules {irrigation at 15 (FC₁₅), 25 (FC₂₅), 35 (FC₃₅) and 45 (FC₄₅) % depletion of soil moisture from field capacity (FC) and a conventional practice} in sub plots. The objective of the study was to evaluate the performance of CERES-Wheat model for simulating yield and water use under varying planting and soil moisture regimes. The simulated and observed grain yield was higher in D₁, with irrigation applied at FC₁₅ as compared to all other sowing date and irrigation regime combinations. Simulated grain yield decreased by 19% with delay in sowing from 25th October to 10th December because of 8% reduction in simulated crop evapotranspiration. Simulated evapotranspiration decreased by 16%, wheat grain yield by 23% and water productivity by 15% in drip irrigation at 45% depletion from field capacity as compared to drip irrigation at 15% of field capacity. It was further revealed that the model performed well in simulating the phenology, water use and yield of wheat.

Fluctuation in amino acids content in Triticum aestivum L. cultivars as an indicator on the impact of post-emergence herbicides in controlling weeds

This study was carried out in a demonstrated field in El-Sharkia Governorate, Egypt, during the winter of season 2020 to evaluate the leverage of four post-emergence herbicides i.e., tribenuron-methyl, clodinafop- propargyl, pyroxsulam and pinoxaden compared to control on total protein and amino acid contents in three wheat cultivars (Shandwel 1, Giza 171, and Sakha 95). Generally, the use of foliar herbicides led to a significant decrease in essential, non-essential amino acids and protein contents. However, tribenuran-methyl herbicide signifcantly increased the levels of proline, glycine, arginine, and histidine, but cystine and threonine not affected as compared to control. On the other hand, foliar herbicide application was significantly increased physiological , biochemical parameters and yield of Shandweel cultivar as compared to the other varieties. The physiological and biochemical models of dual-herbicide-tolerant wheat cultivars add to our understanding of the crop. In recent agricultural systems, herbicide tolerant plants are important for long-term weed management. Therefore, the study recommended the safely usage of Tribenuran-methyl as foliar herbicide in weed managment.

CaWRKY30 Positively Regulates Pepper Immunity by Targeting CaWRKY40 against Ralstonia solanacearum Inoculation through Modulating Defense-Related Genes

The WRKY transcription factors (TFs) network is composed of WRKY TFs’ subset, which performs a critical role in immunity regulation of plants. However, functions of WRKY TFs’ network remain unclear, particularly in non-model plants such as pepper (Capsicum annuum L.). This study functionally characterized CaWRKY30—a member of group III Pepper WRKY protein—for immunity of pepper against Ralstonia solanacearum infection. The CaWRKY30 was detected in nucleus, and its transcriptional expression levels were significantly upregulated by R. solanacearum inoculation (RSI), and foliar application ethylene (ET), abscisic acid (ABA), and salicylic acid (SA). Virus induced gene silencing (VIGS) of CaWRKY30 amplified pepper’s vulnerability to RSI. Additionally, the silencing of CaWRKY30 by VIGS compromised HR-like cell death triggered by RSI and downregulated defense-associated marker genes, like CaPR1, CaNPR1, CaDEF1, CaABR1, CaHIR1, and CaWRKY40. Conversely, transient over-expression of CaWRKY30 in pepper leaves instigated HR-like cell death and upregulated defense-related maker genes. Furthermore, transient over-expression of CaWRKY30 upregulated transcriptional levels of CaWRKY6, CaWRKY22, CaWRKY27, and CaWRKY40. On the other hand, transient over-expression of CaWRKY6, CaWRKY22, CaWRKY27, and CaWRKY40 upregulated transcriptional expression levels of CaWRKY30. The results recommend that newly characterized CaWRKY30 positively regulates pepper’s immunity against Ralstonia attack, which is governed by synergistically mediated signaling by phytohormones like ET, ABA, and SA, and transcriptionally assimilating into WRKY TFs networks, consisting of CaWRKY6, CaWRKY22, CaWRKY27, and CaWRKY40. Collectively, our data will facilitate to explicate the underlying mechanism of crosstalk between pepper’s immunity and response to RSI.

Morpho-physiological and biochemical attributes of Chili (Capsicum annum L.) genotypes grown under varying salinity levels

Climate change is causing soil salinization, resulting in huge crop losses throughout the world. Multiple physiological and biochemical pathways determine the ability of plants to tolerate salt stress. Chili (Capsicum annum L.) is a salt-susceptible crop; therefore, its growth and yield is negatively impacted by salinity. Irreversible damage at cell level and photo inhibition due to high production of reactive oxygen species (ROS) and less CO2 availability caused by water stress is directly linked with salinity. A pot experiment was conducted to determine the impact of five NaCl salinity levels, i.e., 0,1.5, 3.0, 5.0 and 7.0 dS m-1 on growth, biochemical attributes and yield of two chili genotypes ('Plahi' and 'A-120'). Salinity stress significantly reduced fresh and dry weight, relative water contents, water use efficiency, leaf osmotic potential, glycine betaine (GB) contents, photosynthetic rate (A), transpiration rate (E), stomatal conductance (Ci), and chlorophyll contents of tested genotypes. Salinity stress significantly enhanced malondialdehyde (MDA) contents and activities of the enzymatic antioxidants such as superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD). In addition, increasing salinity levels significantly reduced the tissue phosphorus and potassium concentrations, while enhanced the tissue sodium and chloride concentrations. Genotype 'Plahi' had better growth and biochemical attributes compared to 'A-120'. Therefore, 'Plahi' is recommended for saline areas to improve chili production.

Molecular Assessment of Genetic Stability Using CDDP and DNA-barcoding Assays in Long-term Micropropagated Rose Plant

BACKGROUND AND OBJECTIVE

Roses are the world's best-known garden plants, established as ornamental plants cultivated for their blooms. Taif rose (Rosa damascena trigintipetala) refers to the Damascus Rose species and is regarded one of Taif Governorate's most significant financial goods, which produces an extremely fragrant commercially precious essential oil. The objective of current study was to assess the genetic stability of micropropagated Taif rose and to assess the usefulness of Conserved DNA Derived Polymorphism (CDDP) and DNA-barcoding genes such as; rpoC1 (chloroplast gene RNA polymerase1) in the detection of somaclonal variation.

MATERIALS AND METHODS

Ten combinations of CDDP PCR primers were employed and the rpoC1 gene region was sequenced for mother plant (control) and micropropagated plantlets of Taif rose plant.

RESULTS

Based on CDDP data, phylogenetic divergence indicated that the distinct specimens of Taif rose micro-propagated plantlets and control were genetically differentiated by a difference of 1% of genetic dissimilarity. Phylogenetic tree which developed using rpoC1 DNA showed that rpoC1 DNA sequencing discovered a genetic difference between the control and micro-propagated plantlets of Taif rose.

CONCLUSION

Furthermore, CDDP and DNA barcoding using rpoC1 gene have demonstrated their usefulness in investigating the genetic history of Rosa species and their ability to explore genetic mutation.

Moringa leaf extract improves biochemical attributes, yield and grain quality of rice (Oryza sativa L.) under drought stress

Changing climate, food shortage, water scarcity and rapidly increasing population are some of the emerging challenges globally. Drought stress is the most devastating threat for agricultural productivity. Natural plant growth substances are intensively used to improve the productivity of crop plants grown under stressed and benign environments. The current study evaluated whether leaf extract of different moringa (Moringa oleifera L.) could play a role in improving drought-tolerance of rice (Oryza sativa L.). Rice plants were grown under three drought conditions, i.e., no, moderate and severe drought (100, 75 and 50% field capacity, respectively). Moringa leaf extract (MLE) obtained from four landraces (Multan, Faisalabad, D. G. Khan and exotic landrace from India) was applied during critical crop growth stages, i.e., tillering, panicle initiation and grain filling. Drought stress adversely affected the gas exchange attributes, photosynthetic pigments, antioxidant enzymes' activities, yield and quality parameters of rice. Application of MLE from all landraces significantly improved physiological, biochemical and yield parameters under stressed and normal environmental conditions. The highest improvement in gas exchange traits (photosynthetic rate, stomatal conductance and respiration rate), photosynthetic pigments (chlorophyll a, b and carotenoids) and enzymatic activities (superoxide dismutase, catalase) and oxidative marker (H2O2) was recorded with MLE obtained from Faisalabad landrace. The application of MLE of Faisalabad landrace also improved yield and grain quality of rice grown under drought stress as well as drought-free environment. Thus, MLE of Faisalabad can be successfully used to improve growth, productivity and grain quality of rice under drought stress.

Transcriptome Analysis of Jojoba (Simmondsia chinensis) during Seed Development and Liquid Wax Ester Biosynthesis

Jojoba is one of the main two known plant source of natural liquid wax ester for use in various applications, including cosmetics, pharmaceuticals, and biofuel. Due to the lack of transcriptomic and genomic data on lipid biosynthesis and accumulation, molecular marker breeding has been used to improve jojoba oil production and quality. In the current study, the transcriptome of developing jojoba seeds was investigated using the Illunina NovaSeq 6000 system, 100 × 10⁶ paired end reads, an average length of 100 bp, and a sequence depth of 12 Gb per sample. A total of 176,106 unigenes were detected with an average contig length of 201 bp. Gene Ontology (GO) showed that the detected unigenes were distributed in the three GO groups biological processes (BP, 5.53%), cellular component (CC, 6.06%), and molecular functions (MF, 5.88%) and distributed in 67 functional groups. The lipid biosynthesis pathway was established based on the expression of lipid biosynthesis genes, fatty acid (FA) biosynthesis, FA desaturation, FA elongation, fatty alcohol biosynthesis, triacylglycerol (TAG) biosynthesis, phospholipid metabolism, wax ester biosynthesis, and lipid transfer and storage genes. The detection of these categories of genes confirms the presence of an efficient lipid biosynthesis and accumulation system in developing jojoba seeds. The results of this study will significantly enhance the current understanding of wax ester biology in jojoba seeds and open new routes for the improvement of jojoba oil production and quality through biotechnology applications.