Total Soluble Sugar Content Research Articles

Green synthesis of silver nanoparticles from endophytic fungus Colletotrichum sp. with special emphasis on antibacterial, antioxidant and plant growth promoting potential

The creation of "microbial nanotechnology" for quick and large-scale manufacturing of nanoparticles would be possible with an effective biosynthesis method. Plumbago zeylanica L. is a medicinal plant from which the endophytic fungus Colletotrichum sp. was isolated and identified by 18S rDNA sequencing and microscopic studies. Cell filtrate of Colletotrichum sp. was employed to produce biological silver nanoparticles which acted as a reducing and stabilising agent during this process. The brown colour proved that silver nanoparticles (AgNPs) are being produced. In characterization of AgNPs, ultraviolet-visible spectroscopy revealed maximum absorption at 425 nm. From transmission electron microscopy and field emission scanning electron microscopic study the shape of the silver nanoparticle was found spherical with 10–30 nm diameters. The existence of elemental silver (peak) was verified by the silver signal in the energy-dispersive X?ray spectroscopy. Fourier-transform infrared analysis showed some major and minor shifts in the peaks of some chemical bonding. Synthesised AgNP had strong antibacterial action against pathogenic bacterial strains in 200 g/mL concentration and against Pseudomonas aeruginosa MTCC 741, it showed the highest inhibition. The AgNP concentration of 150 g/mL demonstrated the highest competency for antioxidant capabilities while ascorbic acid was used as the reference. Also, AgNP exhibited plant growth-promoting ability as in 40 mg/L concentration; it significantly enhanced the shoot and root growth, total soluble protein, sugar, and indole acetic acid content of P. zeylanica L. This AgNP can be useful in pharmaceutical industries and agriculture as nano fertilizers for all these purposes.

Mechanism of induced soluble sugar accumulation and organic acid reduction in plum fruits by application of melatonin

Melatonin (MT) can improve plant resistance and fruit quality. The mechanism by which MT affects soluble sugar and organic acids accumulation in drupe fruits is not clear. In this study, 100 µmol/L MT was sprayed on the leaves of plum trees at the second stage of rapid fruit expansion (90 and 97 d after flowering), and the effects of MT on plum fruit quality and its effects on the soluble sugar-organic acid metabolism were investigated. At 28 d after MT treatment (at maturity), the longitudinal diameter, fruit weight, and vitamin C content of plum fruits were increased by 5.05%, 12.93%, and 56.09%, respectively, compared to the control. MT caused significant increase in the total soluble solids content and decreased the titratable acid content. MT increased the contents of total soluble sugar, sucrose, sorbitol, and citric acid after 21 and 28 days of treatment, while decreasing the contents of fructose, malic acid, quinic acid, and tartaric acid after 28 days of treatment. Additionally, MT increased the activities of sucrose synthase (catabolism direction), sucrose phosphate synthase, glucokinase, fructokinase, sorbitol oxidase, and NADP+-malic enzyme, and decreased the activities of soluble acid converting enzyme, cell wall insoluble converting enzyme, NAD+-sorbitol dehydrogenase, and NAD+-malic dehydrogenase after 21 or 28 days of treatment. Moreover, the differentially expressed genes (DEGs) after 21 and 28 days of treatment were accelerated starch and sucrose metabolism, galactose metabolism, fructose and mannose metabolism, as well as glycolysis, gluconeogenesis, and pentose phosphate metabolism pathways. In conclusion, exogenous MT increases soluble sugar content and decreases organic acid content in plum fruits by regulating various soluble sugar-organic acid metabolic pathways, thereby improving the fruit quality.

Effect of Seed Hydropriming on the Elongation of Plumule and Radicle During the Germination Process and Changes in Enzyme Activity Under Water-Deficient Conditions.

Hydropriming rice seeds effectively improve the germination percentage, shortens the germination period, and promotes seedling growth. The impact of seed hydropriming is to speed up growth under dry soil conditions, thereby avoiding drought damage. This study analyzes the effect of hydropriming on morpho-physiological changes in the water uptake of rice seeds using "Kasalath" and "Nipponbare" under water-deficit conditions. Upon exposure to osmotic stress, both varieties showed delays in the time to reach germination. In addition, all germination phases exhibited reductions in the activity of alpha-amylase and total soluble sugar by osmotic stress; however, in all germination phases of the hydroprimed seeds, the activity and contents of those were significantly increased, resulting in increased size of the coleoptile, plumule, and radicle. In hydroprimed seeds, "Kasalath" was superior to "Nipponbare" in the ratio of the water-deficit-to-well-watered conditions for all traits related to germination, which may have been attributable to hydropriming having a greater effect on "Kasalath". Interestingly, Primed "Kasalath" had a lower level of α-amylase, despite the having a higher content of total soluble sugars than primed "Nipponbare".

Impact of Kombucha Fermentation on the Flavor and Physicochemical Properties of Tea (Camellia sinensis) Flower Infusions

ABSTRACTTea (Camellia sinensis) flower is a nutritious and affordable raw material for beverages. However, the taste of infusions brewed directly from tea flowers with hot water is not very appealing. In the work, the effects of kombucha fermentation on the sensory quality and chemical profiles of tea flower infusions were investigated. During the 5‐day fermentation experiment, the samples fermented for 1 day exhibited the best overall flavor characteristics. The flavor of this sample was significantly improved, with a marked increase in sweet aromas and a noticeable enhancement of fruity, sweet, and sour tastes. PacBio sequencing revealed that four Komagataeibacter spp. (88.64%), Novacetimonas hansenii (7.09%), and Zygosaccharomyces bisporus (97.55%) were the dominant bacterial and fungal species in the used Kombucha. A total of 80 volatiles were detected in all samples, and relative odor activity value (ROAV) analysis showed that alpha‐ionone, linalool, beta‐ionone, decanal, and 1‐octen‐3‐ol were the major contributors to the aroma perception. The pH value and the contents of caffeine, total catechins, amino acids, and proteins decreased, while the contents of total soluble sugars and 21 compounds including sugar derivatives, organic acids, and cyclic adenosine monophosphate (c‐AMP) significantly increased. These results provided new insights into the development of tea flower‐based kombucha beverage.

Impact of Different Plant Growth Regulators on Growth, Yield and Quality of Fennel (Foeniculum vulgare Mill.) in Alluvial Regions of West Bengal

An experiment was conducted during the rabi seasons (November, 2018 –April, 2020) at the Horticultural Research Station, Mondouri, Bidhan Chandra Krishi Viswavidyalaya, Mohanpur, Nadia, West Bengal (741 252), India to assess the impact of different plant growth regulators on the growth, yield, and quality of fennel (Foeniculum vulgare Mill.). The experiment was designed in Randomized Block Design with a total of 9 treatment combinations that were replicated three times. Fennel seeds were sown during the first week of November in 2.5×1.5 m2 plots with a spacing of 50×30 cm2. Growth regulators were applied at 30, 45, and 60 days after sowing. The results revealed that the application of naphthalene acetic acid @ 100 ppm significantly optimized fennel yield and quality in the alluvial regions of West Bengal. This was evident through various yield and its attributing parameters, including number of umbel plant-1, number of umbellate umbel-1, number of seeds umbellate-1, test weight (g), and seed yield (22.95 q ha-1) as well as quality parameters including total soluble sugar content (2.91 mg 100 mg-1) and volatile oil content (1.448%). Additionally, Kinetin @ 10 parts per million significantly enhanced the total chlorophyll content (0.344 mg g-1), while gibberellic acid positively influenced growth parameters like plant height, number of primary and secondary branches, days to 50% flowering, flower stalk length, and umbel diameter.

Chickpea Proteome Analysis Reveals Genotype-Dependent Variations Associated with Seed Traits.

Chickpea (Cicer arietinum L.) is the second most widely grown legume crop after soybean. Here, we measured the macronutrients and performed proteome profiling of eight chickpea cultivars using two complementary protein extraction solvents. The total protein, starch, and soluble sugar contents significantly differ between cultivars, and we quantified 2434 and 1809 proteins, respectively, from urea- and water-based extraction solvents using a data-independent acquisition approach. The proteome-level differences can vary from 9-25% for the urea-extracted proteins, and the storage protein abundances significantly differed between the cultivars, where legumin content was detected as the highest, followed by vicilin and albumin. Fifty common allergens were detected from two extraction solvents, primarily overrepresented in chromosomes 3, 4, and 5. Integrated analysis revealed distinct subclusters of proteins and their associated pathways for total protein, lipids, and starch content. Overall, we established chickpea pan-proteome resources and provided insights into the key pathways that define the genotypes.

Gene expression and soluble sugar accumulation in perennial fruits

Abstract Soluble sugars primarily contribute to fruit flavouring and are crucial for fruit quality. Carbohydrate accumulation in fruits is a multifaceted process that can be influenced by their biosynthesis capacity, sink strength, homeostasis, and vacuolar storage ability. Moreover, total soluble sugar contents in fruits also vary among different varieties/species and environmental conditions. Numerous studies have elucidated the carbohydrate regulatory mechanism in fruits; however, there is a knowledge gap regarding the most important contributor to soluble sugar accumulation in perennial fruits. Here, we briefly discussed the recent advances, including carbohydrate long-distance transportation, metabolism and vacuolar storage, and transcript factors for soluble sugar accumulation in fruits. Most importantly, we elucidated that the sink strength in fruit is the most crucial factor that can trap more soluble sugars by maintaining continuous unloading to fruit by genes of cell wall invertase; moreover, genes of sucrose transporters/pyrophosphatase play key roles in vacuolar storage of soluble sugars in perennial fruits. This review delivers a comprehensive summary of recent findings for soluble sugar regulation and fruit quality improvement, which may facilitate sugar optimisation in fruit crops for enhanced fruit quality.

ABA Affects Distinctive Rice Caryopses Physicochemical Properties on Different Branches

Abscisic acid (ABA) plays an important regulatory role in the grain filling process, which in turn will affect the final yield and quality of rice. The ABA biosynthesis genes of OsNCED3 and degradation gene OsABA8ox3 affect the ABA content, and then further regulate the ABA signaling. During the development of rice panicle, compared with primary grains (superior grains) growing on primary branches, secondary grains (inferior grains) growing on secondary branches exhibit characteristics. However, little is reported on the physicochemical characteristics of starch between superior and inferior grains in ABA related transgenic lines. In this study, OsNCED3 and OsABA8ox3 transgenic plants were used as materials. The results showed that compared with the WT, the OsNCED3-RNAi lines on grain weight was consistent with the trend of superior and inferior grains, while the OsABA8ox3-RNAi lines affected superior or inferior grains. The total starch and soluble sugar content of grains decreased in both OsNCED3-RNAi and OsABA8ox3-RNAi lines, and the total starch content of superior and inferior grains in OsABA8ox3-RNAi lines decreased. The starch granule size distribution of all samples showed a bimodal and increased proportion of starch grains with large granule size, in which the influence on inferior grains was greater than that of superior grains, which eventually led to a significant increase in their average granule size. The apparent amylose content of inferior grains increased significantly in most lines. The swelling power of the superior grains decreased significantly, while that of the inferior grains increased significantly. Fourier analysis showed that the order degree of starch granule surface decreased in the superior grains of the RNAi line, while it increased in the inferior grains of the OsABA8ox3-RNAi line but decreased in the OsNCED3-RNAi lines. In the superior grains, the relative crystallinity of starch decreased in the OsNCED3-RNAi lines, but remained unchanged or increased in the OsABA8ox3-RNAi line. In inferior grains, the relative crystallinity of starch decreased in the ABA synthesis RNAi line, but increased in the OsABA8ox3-RNAi line. In summary, the influence of ABA on the physicochemical properties of inferior grains is greater than that of superior grains.

Enhancement of Tomato Fruit Quality Through Moderate Water Deficit.

In arid areas, water shortage has become a major bottleneck limiting the sustainable development of agriculture, necessitating improved water use efficiency and the full development of innovative water-saving irrigation management technologies to improve quality. In the present study, tomato (Solanum lycopersicum cv. Micro Tom) fruits were used as materials, and different irrigation frequencies were set during the fruit expansion stage. The normal treatment (CK) was irrigated every three days, while the water deficit treatments were irrigated at varying frequencies: once every 4 days (T1), 5 days (T2), 6 days (T3), 7 days (T4), and 8 days (T5). These corresponded to 80%, 70%, 60%, 50%, and 40% of the maximum field moisture capacity (FMC), respectively, with CK maintaining full irrigation at 90% of the maximum FMC. The water deficit treatment T3, with less stress damage to plants and the most significant effect on fruit quality improvement, was selected based on plant growth indices, photosynthetic characteristics, chlorophyll fluorescence parameters, and fruit quality indices, and its effects on carotenoids, glycolic acid fractions, and volatile compounds during tomato fruit ripening were further investigated. The outcome indicated that moderate water deficit significantly increased the carotenoid components of the tomato fruits, and their lycopene, lutein, α-carotene, and β-carotene contents increased by 11.85%, 12.28%, 20.87%, and 63.89%, respectively, compared with the control fruits at the ripening stage. The contents of glucose and fructose increased with the development and ripening of the tomato fruits, and reached their maximum at the ripening stage. Compared to the control treatment, the moderate water deficit treatment significantly increased the glucose and fructose levels during ripening by 86.70% and 19.83%, respectively. Compared to the control conditions, water deficit conditions reduced the sucrose content in the tomato fruits by 27.14%, 18.03%, and 18.42% at the mature green, turning, and ripening stages, respectively. The moderate water deficit treatment significantly increased the contents of tartaric acid, malic acid, shikimic acid, alpha ketoglutaric acid, succinic acid, and ascorbic acid, and decreased the contents of oxalic acid and citric acid compared to the control. The contents of total soluble sugar and total organic acid and the sugar-acid ratio were significantly increased by 48.69%, 3.71%, and 43.09%, respectively, compared with the control at the ripening stage. The moderate water deficit treatment increased the fruit response values to each sensor of the electronic nose, especially W5S, which was increased by 28.40% compared to the control at the ripening stage. In conclusion, during the ripening process of tomato fruit, its nutritional quality and flavor quality contents can be significantly improved under moderate (MD) deficit irrigation treatment. The results of this experiment can lay the foundation for the research on the mechanism of water deficit aiming to promote the quality of tomato fruit, and, at the same time, provide a theoretical basis and reference for tomato water conservation and high-quality cultivation.

Dynamic changes of endogenous phytohormones and carbohydrates during spontaneous morphogenesis of Centaurium erythraea Rafn.

Common centaury (Centaurium eryhtraea Rafn) is a medicinal plant species with vigorous morphogenic potential in vitro. The process of spontaneous shoot regeneration in a solid root culture is characteristic for this plant species. In this context, the aim of this work was to investigate the dynamic changes of endogenous phytohormones and carbohydrates content in root explants at different time points (0, 2, 4, 7, 14, 21, 28, and 60 days) during spontaneous centaury morphogenesis in vitro. Detailed analysis of cytokinins (CKs) showed that trans-zeatin (tZ) was the major bioactive CK at all time points. The corresponding riboside, tZ9R, was also determined in the majority of the identified transport forms, at all time-points. Further analysis of endogenous auxin revealed a significant increase in endogenous indole-3-acetic acid (IAA) after 21 days, when a huge jump in the ratio of IAA/bioactive CKs was also observed. The maximum total soluble sugar content was measured after 14 days, while a significant decrease was determined after 21 days, when the first regenerated adventitious shoots appeared. This undoubtedly indicates an increased energy requirement prior to the actual regeneration of the shoots. The obtained results indicate that the period from day 14 to day 21 involves the most dramatic disturbances in endogenous bioactive CKs, IAA and carbohydrate balance, which are very important and valuable factors for the onset of shoot regeneration.

Partially Substituting Photosynthetic Photon Flux Density with Far-red Photons Differentially Alters Biomass Accumulation and Photochemical Efficiency of Greenhouse Lettuce

Adding far-red (FR) photons to a constant photosynthetic photon flux density (PPFD) alters photosynthesis, leaf morphology, and biomass accumulation of horticultural plants. However, the influences of partially substituting PPFD with FR photons under the same extended PPFD (ePPFD) on the growth of greenhouse lettuce (Lactuca sativa L.) is still unknown. In this study, loose-leaf lettuce (‘Dasusheng’) grown in a greenhouse in the fall was implemented using six supplementary light treatments including white plus red (WR) LEDs with substitutive FR photon flux density at 0, 10, 30, 50, 70, and 90 µmol·m−2·s−1 under the same ePPFD (WR139, WR129+FR10, WR109+FR30, WR89+FR50, WR69+FR70, and WR49+FR90, respectively). Lettuce grown with natural light only was designated as NL. The results indicated that supplementary light led to lower plant height, thicker leaves, higher biomass accumulation, higher vitamin C content, higher starch content, and higher total soluble sugar content in lettuce compared with those of lettuce grown under NL. Lettuce grown under WR139 resulted in a 40.0% decrease in plant height, 66.8% increase in leaf thickness, and 34.1% increase in shoot fresh weight compared with those of lettuce grown under NL. No significant differences were observed in leaf width, specific leaf area, shoot fresh weight, root fresh weight, shoot dry weight, root dry weight, soil plant analysis development value, apparent quantum yield, soluble protein content, and light use efficiency of lettuce among the WR139, WR129+FR10, and WR109+FR30 treatments. Furthermore, decreased trends were observed in the biomass accumulation and maximum net photosynthetic rate of lettuce with the increased substituted FR photon flux density. However, an opposite trend was found in the maximum photochemical quantum yield. In conclusion, partially substituting PPFD with FR photons at 10 to 30 μmol·m−2·s−1 had similar effects on the biomass accumulation and nutritional quality of greenhouse lettuce. The FR photons should be applied with the consideration of photon flux density because the results also demonstrated negative effects of excess substituted FR photons for PPFD.

A comprehensive study of the physiology and chemistry of tea withering based on untargeted metabolomic, transcriptomic, and biochemical analyses

Withering is an important process for achieving high-quality flavor in tea. In this study, histological, metabolomics, transcriptomics, and biochemical analyses were combined to comprehensively explore the accumulation and molecular regulatory profiles of quality metabolites during tea withering. The results of tissue staining indicated that as the water content decreased, the vitality of the nucleus weakened, cytoplasmic content increased, flavone content decreased, and proteins degraded. Omics analysis showed that the total content of soluble sugars, free amino acids, and terpenoids increased, whereas that of catechins decreased significantly, although the caffeine content barely changed. Biochemical analysis revealed that the translated products of genes CSA010827 and CSA001819 catalyzed the biosynthesis of galactose and flavanol 3-O-glycosides, respectively, thereby increasing the content of soluble sugars and contributing to the astringent taste. Overall, by combining omics with histological and biochemical analyses, we revealed the metabolic profile and possible molecular mechanisms during the withering process of tea.

Establishment, Multiplication, and Biochemical Analysis of Embryogenic Lines of the Amazonian Palm Euterpe precatoria Mart. under Suspension Culture

The palm Euterpe precatoria holds great social, cultural, and environmental importance. The heart of palm and the fruit are the main products used for industrialization due to their energetic properties. Thus, the aim of this study was to establish a suspension cultivation protocol for the species using different explant sources. For this, eight lineages of E. precatoria embryogenic calluses were tested, with five in liquid medium Murashige and Skoog (MS) with 5 μM Picloram and three for comparison in semisolid medium MS with 20 μM Picloram and 5 μM 2iP. The growth curve was obtained by weighing the calli from 60 to 180 days of cultivation. The Gompertz model was applied, and growth kinetics were evaluated. At 100 days, the contents of total soluble sugars (TSSs) and total soluble proteins (TSPs) were determined. Principal components (PCA) were measured. According to the analysis of the data, the cultivation of E. precatoria lineages in liquid medium was successfully carried out, and the establishment was achieved. The model can be considered adequate since the R2 values found describe more than 90% of the growth kinetics of the lineages. In the liquid system, lineages L1 (from leaf explants and multiplied in semisolid medium—SM), L2 (from leaf explants and multiplied in SM), and L6 (from zygotic embryo explants and multiplied in liquid medium—LM) showed the shortest time to double the biomass accumulation. Multivariate analysis reveals a significant increase in masses in liquid cultures, represented by lineages L6 and L2. There was statistical difference in the amount of TSSs extracted; the highest TSS levels were observed in lineages cultivated in LM. The protein content found was very low, showing statistical differences among the lineages. In this work, the establishment and multiplication of embryogenic calli of E. precatoria are described for the first time, and they emerge as viable alternatives for the vegetative propagation of the species.

Protective effects of the exogenous application of salicylic acid and chitosan on chromium-induced photosynthetic capacity and osmotic adjustment in Aconitum napellus.

Chitosan (CTS) is recognized for enhancing a plant's resilience to various environmental stresses, such as salinity and drought. Moreover, salicylic acid (SA) is acknowledged as a growth regulator involved in addressing metal toxicity. However, the effectiveness of both compounds in mitigating Cr-induced stress has remained relatively unexplored, especially in the case of Aconitum napellus, a medicinally and floricultural important plant. Therefore, the primary objective of this study was to investigate the potential of CTS and SA in alleviating chromium (Cr)-induced stress in A. napellus. To address these research questions, we conducted a controlled experiment using potted plants to evaluate the individual and combined impacts of CTS and SA on plants exposed to Cr stress. Foliar application of CTS (0.4g/L) or SA (0.25 mmol/L) led to significant improvements in the growth, chlorophyll content, fluorescence, and photosynthetic traits of A. napellus plants under Cr stress. The most notable effects were observed with the combined application of CTS and SA, resulting in increases in various morphological parameters, such as shoot length (2.89% and 7.02%) and root length (27.75% and 3.36%) under the Cr 1 and Cr 2 treatments, respectively. Additionally, several physiological parameters, such as chlorophyll a (762.5% and 145.56%), chlorophyll b (762.5% and 145.56%), carotenoid (17.03% and 28.57%), and anthocyanin (112.01% and 47.96%) contents, were notably improved under the Cr 1 and Cr 2 treatments, respectively. Moreover, the combined treatment of CTS and SA improved the fluorescence parameters while decreasing the levels of enzymatic antioxidants such as catalase (27.59% and 43.79%, respectively). The application also notably increased osmoprotectant parameters, such as the total protein content (54.11% and 20.07%) and the total soluble sugar content (78.17% and 49.82%) in the leaves of A. napellus in the Cr 1 and 2 treatments, respectively. In summary, these results strongly suggest that the simultaneous use of exogenous CTS and SA is an effective strategy for alleviating the detrimental effects of Cr stress on A. napellus. This integrated approach opens promising avenues for further exploration and potential implementation within agricultural production systems.

Changes in the nutritional, flavor, and phytochemical properties of Citrus reticulata Blanco cv. ‘Dahongpao’ whole fruits during enzymatic hydrolysis and fermentation

IntroductionCurrently, the large-scale consumption of fresh citrus fruits in the form of juices, jams, and purees results in significant quantities of waste consisting of citrus peels, pulp, and seeds.MethodsTo improve the utilization rate of whole citrus fruits and reduce the generation of processing waste, the best pre-optimized enzymatic fermentation conditions were used to treat whole citrus fruits and to analyse the changes in nutritional and active components (Enzymatic: pectinase, cellulase, hemicellulase added at a ratio of 1:1:1 for 63.326 min at a temperature of 60°C, with 0.506% of each enzyme added; Fermentation: Lacticaseibacillus rhamnosus TR08, Lactiplantibacillus plantarum subsp. Plantarum CICC 6257, and Limosilactobacillus fermentum CCFM1139 were added at a ratio of 1:1:1 for 30 h, with the concentration was 108 CFU/mL, and the total amount added was 6%).ResultsResults showed that after enzymatic hydrolysis, the mineral elements (Nitrogen, phosphorus), total amino acid, vitamin C, and organic acid content increased. For soluble sugars, the contents of fructose and glucose increased, whereas the sucrose content decreased. Fermentation had a minimal effect on the mineral content; however, the total amino acid, vitamin C, and soluble sugar contents decreased. Additionally, when comparing the samples after enzymatic fermentation to those after enzymatic hydrolysis alone, the total phenols, total flavonoids, carotenoids and antioxidant activities were significantly increased by 1.39, 1.49, 1.21 and 3.79 folds, respectively.DiscussionThis study addresses the challenges of utilizing fruit residue in the current market, including high treatment costs and environmental pollution, by providing a novel perspective on the enzymatic hydrolysis and fermentation of whole red oranges. Furthermore, it aims to improve the nutritional, functional, and health benefits of citrus fruit products.

Proline Priming Enhances Seed Vigour and Biochemical Attributes of Rice (Oryza sativa L.) during Germination.

Seed vigour is a desirable trait especially for direct seeded rice (DSR) cultivation. Seeds with high vigour could improve seed germination, support seedlings in competing with weeds for water and nutrients, and improving seedling establishment throughout the early stages of crop growth. The success of DSR system which account for more 25% of world cultivation areas is highly dependent on the seed vigour and seedling establishment. Seed priming is a promising technique to improve seed vigour. Proline is an amino acid that has been well studied for its roles in plants under different environmental stress conditions. Nevertheless, the effect of proline as a seed priming agent in improving seed vigour in rice remain elusive. In this research, the effect of 24 h of proline priming at various concentrations (0 mM, 1 mM, 2 mM, 10 mM and 20 mM) on rice seed vigour, amylase activity, and total soluble sugar (TSS) content of a Malaysia indica rice variety, MR269 was investigated. Results showed that seeds primed with lower concentration of proline (0 mM, 1 mM and 2 mM) had better germination responses while priming at high concentrations (10 mM and 20 mM) reduced seed germination. Among the concentration tested, priming with 1 mM proline enhanced seed vigour with significantly higher germination percentage (GP), germination rate index (GRI) and seedling vigour index (SVI). In addition, proline primed seeds also exhibited increased amylase activity and TSS content as compared to unprimed seeds. However, priming seed with 20 mM proline was detrimental to the seed vigour and seedling growth whereby lower GP, GRI and SVI and higher mean germination time (MGT) were observed. In short, this study shows that proline could be a potential seed priming agent to improve seed vigour in rice.

Plant Beneficial Desert Actinomycete, Modestobacter caceresii KNN 45-2bT, Promote Growth of Tomato (Lycopersicum esculentum Mill.) under Drought Condition

Drought stress is currently the most serious challenge to global food security and agricultural productivity. Desert actinobacteria have gained attention as potential candidates for enhancing plant growth in water stress environments. In this regard, a desert actinomycete, namely Modestobacter caceresii strain KNN 45-2bT, was selected to investigate its plant growth promoting abilities and drought tolerance. Next, this desert strain was inoculated to tomato (Lycopersicum esculentum Mill.) under drought, and the results included increases in root length, shoot and root fresh weight, shoot and root dry weight, total fresh weight and dry weight, fruit weight, proline accumulation, total soluble sugar content and trolox content. Stress treatments on the bacterized tomato plants also resulted in the reduction of hydrogen peroxide accumulation. Putative proteins coding sequences conferring plant growth promoting (PGP) traits (IAA production, phosphate solubilization, siderophore production, nitrogen fixation) and drought response (biosynthesis of proline metabolism, oxidative and osmotic stress response) were also detected from their genomic analyses. In conclusion, these results provide credence to the idea that the inoculation of tomato plants with plant beneficial desert actinomycete is an effective method of combating the negative effects of drought stress.

Transcriptome Analysis Revealed the Response Mechanism of Pomegranate to Salt Stress

Pomegranate (Punica granatum) is a well-known fruit tree species and a significant pioneer ecological species on saline–alkali land with moderate resistance to salt stress. To explore its response mechanism to salt stress could provide valuable insights into the molecular and physiological strategies plants employ to adapt and survive in high-salt environments. In this study, changes in physiological parameters and gene expressions were examined following salt treatment. After 72 h of salt treatment, change patterns of SOD and POD differed between high and low salt concentrations. Similar changes were found in the contents of proline and total soluble sugar. RNA-Seq analysis of fifteen samples detected 32,630 genes from the pomegranate genome data. A total of 6571 DEGs, including 374 TFs, were identified across different treatments. Six special modules and 180 hub genes were obtained by WGCNA analysis. Functional annotation highlighted signaling pathways and the accumulation of primary and secondary metabolites as significant pathways. These findings could reveal the salt tolerance mechanism in pomegranate leaves, offering a theoretical foundation for enhancing plant salt tolerance through genetic engineering.

Investigation of Drought Stress on Chickpea (Cicer arietinum L.) Genotypes Employing Various Physiological Enzymatic and Non-Enzymatic Biochemical Parameters.

Drought stress is a universal crisis in sustaining the growth and production of major legumes, including the chickpea. Drought severely reduces the biomass of chickpea plants, with the effect on leaves appearing the most apparent. The aim of this study was to investigate, using various physiological and biochemical markers throughout the pod filling stage, how 78 desi chickpea genotypes tolerated drought stress. Most of the evaluated characteristics showed significant variations between control and drought treatments. The mean performance of most of the investigated parameters significantly decreased under moisture-stressed conditions. RWC, SWD, MSI, and CTD were investigated under terminal drought-stressed conditions. Except for saturated water deficit (SWD), all remaining characteristics declined with increasing stress. Genotypes SAGL152210, SAGL152252, SAGL152347, SAGL22-115, and JG11 were recognized as drought-tolerant based on physiological characteristics. Biochemical markers viz., protein content, total soluble sugar, lipid peroxidation, and proline content, had an impact on osmotic adjustment. Based on non-enzymatic biochemical traits, genotypes SAGL22-115, ICC4958, ICCV201108, ICCV201107, SAGL152252, and JG11 were identified for their capability to survive under drought-stressed conditions. H2O2 content, CAT, SOD, POD, APX, and DPPH were considered antioxidant agents. Genotypes SAGL152208, SAGL22-105, SAGL22-112, ICC201108, SAGL152278, SAGL152252, SAGL162371, SAGL162390, ICC 4958, and JG315 may be considered drought-tolerant based on antioxidant activities. These genotypes are believed to be better equipped with physio-biochemical mechanisms and antioxidant defense systems at the cellular level and can be used in breeding programs to breed drought-tolerant cultivar(s). They can also be screened in the future, allowing the line(s) that have remained consistent over time to be recognized and registered as drought-tolerant donors.

IN VITRO CHARACTERIZATION AND ANALYSIS OF RICE VARIETIES AGAINST VARIOUS LEVELS OF SALT STRESS

Salinity is a significant environmental factor that greatly impacts plant yield, particularly in arid and semi-arid regions. The study examined the response of two rice varieties (Swat-1 and Pakhal) to salinity stress on the callus. Various salt concentrations were utilized. Among the two varieties, Swat-1 displayed the highest rate of callogenesis in the initial results. The Calli were exposed to varying concentrations of salt (50mM, 100mM, and 150mM), with each concentration tested in three replicates. Under the influence of stress, Swat-1 experienced a decrease in its Relative growth rate (RGR), whereas Pakhal remained steady at 50mM and 100mM. It was only at 150mM that Pakhal also exhibited a decline in RGR. Regarding water content, the stress caused a decrease in the content. At the highest stress level (150mM), the lowest water content was observed. The impact on soluble sugars was also noteworthy. As stress levels rose, concentrations of total sugars also increased. Similar findings were noted for proline, with stress leading to an increase in its concentration. Out of the two varieties, Pakhal appeared to have the highest proline accumulation. Similarly, there was a noticeable upward trend observed in catalase activity. There was a significant increase in catalase activity in both varieties after being exposed to stress for 30 and 60 days. The findings indicate that both varieties effectively developed strategies to combat salinity stress. They exhibited high concentrations of total soluble sugars and proline, as well as demonstrated significant catalase activity.