Exploring the perspectives of irradiated sodium alginate on molecular and physiological parameters of heavy metal stressed Vigna radiata L. plants.

Heavy metal (HM) contamination causes severe detrimental effects on plant growth. Irradiated sodium alginate (ISA) has been proposed for enhancing the efficacy and selectivity of metal ion biosorption from plants under HM-toxicity. The present study has been planned to investigate the morphological, molecular, physiological, and regulation of transcript levels of defence mechanisms for alleviation of HM toxicity in Vigna radiata plants by irradiated sodium alginate (ISA). V. radiata L. plants were treated with T0-water (control); TCd-CdCl2 (100 µM); TPb-Pb(NO3)2 (500 µM); TFe-FeSO4 (300 µM), and ISA solution at 75 mg/l as a foliar spray onto leaves. Our results suggested the positive impact of ISA for HM stress mitigation by V. radiata L. plants, through modulatory effects on molecular and physiological attributes. In our study, we evaluated the growth characteristics (plant height, leaf area, total fresh weight and grain weight), pigment contents, photosynthetic efficiency (14CO2-fixation), enzyme activities (nitrate reductase, ribulose-1,5-bisphosphate-carboxylase/oxygenase, and carbonic anhydrases), and macronutrient contents (P, N, and K) in metal-stressed plants. All these attributes were found to be stimulated after ISA application. Also, ISA reduced the total malondialdehyde, free proline, and total phenol content in heavy metal-exposed plants. The transcriptional expression profiling was conducted by examining the expression levels of AtPDR12, AtATM3, AtPCR1, MPK4, MPK6, and AtPDR8 genes that inferred the ISA-mediated detoxification of HMs in V. radiata plants. The data in the present research clearly indicated that treatment with foliar sprays of ISA (75 mg/l) resulted in enhanced tolerance of V. radiata plants against different HM stresses.

Ultrastructural analysis of zinc oxide nanospheres enhances anti-tumor efficacy against Hepatoma.

Zinc oxide nanomaterial is a potential material in the field of cancer therapy. In this study, zinc oxide nanospheres (ZnO-NS) were synthesized by Sol-gel method using yeast extract as a non-toxic bio-template and investigated their physicochemical properties through various techniques such as FTIR, XR, DLS, and TEM. Furthermore, free zinc ions released from the zinc oxide nanosphere suspended medium were evaluated by using the ICP-AS technique. Therefore, the cytotoxicity of ZnO nanospheres and released Zn ions on both HuH7 and Vero cells was studied using the MTT assay. The data demonstrated that the effectiveness of ZnO nanospheres on HuH7 was better than free Zn ions. Similarly, ZnO-Ns were significantly more toxic to HuH7 cell lines than Vero cells in a concentration-dependent manner. The cell cycle of ZnO-Ns against Huh7 and Vero cell lines was arrested at G2/M. Also, the apoptosis assay using Annexin-V/PI showed that apoptosis of HuH7 and Vero cell lines by ZnO nanospheres was concentration and time-dependent. Caspase 3 assay results showed that the apoptosis mechanism may be intrinsic and extrinsic pathways. The mechanism of apoptosis was determined by applying the RT-PCR technique. The results revealed significantly up-regulated Bax, P53, and Cytochrome C, while the Bcl2 results displayed significant down-regulation and the western blot data confirmed the RT-PCR data. There is oxidative stress of the ZnO nanospheres and free Zn+2 ions. Results indicated that the ZnO nanospheres and free Zn+2 ions induced oxidative stress through increasing reactive oxygen species (ROS) and lipid peroxidation. The morphology of the HuH7 cell line after exposure to ZnO nanospheres at different time intervals revealed the presence of the chromatin condensation of the nuclear periphery fragmentation. Interestingly, the appearance of canonical ultrastructure features of apoptotic morphology of Huh7, Furthermore, many vacuoles existed in the cytoplasm, the majority of which were lipid droplets, which were like foamy cells. Also, there are vesicles intact with membranes that are recognized as swollen mitochondria.

Post-transcriptional regulation of 2-acetyl-1-pyrroline (2-AP) biosynthesis pathway, silicon, and heavy metal transporters in response to Zn in fragrant rice.

Fragrant rice (Oryza sativa L.) has a high economic and nutritional value, and the application of micronutrients regulates 2-acetyl-1-pyrroline (2-AP) production, which is responsible for aroma in fragrant rice. Alternative splicing (AS) is an important post-transcriptional regulatory mechanism to generate transcript variability and proteome diversity in plants. However, no systematic investigation of AS events in response to micronutrients (Zn) has been performed in fragrant rice. Furthermore, the post-transcriptional regulation of genes involved in 2-AP biosynthesis is also not known. In this study, a comprehensive analysis of AS events under two gradients of Zn treatment in two different fragrant rice cultivars (Meixiangzhan-2 and Xiangyaxiangzhan) was performed based on RNA-seq analysis. A total of 386 and 598 significant AS events were found in Meixiangzhan-2 treated with low and high doses of Zn, respectively. In Xiangyaxiangzhan, a total of 449 and 598 significant AS events were found in low and high doses of Zn, respectively. Go analysis indicated that these genes were highly enriched in physiological processes, metabolism, and cellular processes in both cultivars. However, genotype and dose-dependent AS events were also detected in both cultivars. By comparing differential AS (DAS) events with differentially expressed genes (DEGs), we found a weak overlap among DAS and DEGs in both fragrant rice cultivars indicating that only a few genes are post-transcriptionally regulated in response to Zn treatment. We further report that Zn differentially regulates the expression of 2-AP biosynthesis-related genes in both cultivars and Zn treatment altered the editing frequency of single nucleotide polymorphism (SNPs) in the genes involved in 2-AP biosynthesis. Finally, we showed that epigenetic modifications associated with active gene transcription are generally enriched over 2-AP biosynthesis-related genes. Similar to the 2-AP pathway, we found that heavy metal transporters (genes related to silicon, iron, Zn and other metal transport) are also regulated at transcriptional and post-transcriptional levels in response to Zn in fragrant rice. Taken together, our results provide evidence of the post-transcriptional gene regulation in fragrant rice in response to Zn treatment and highlight that the 2-AP biosynthesis pathway and heavy metal transporters may also be regulated through epigenetic modifications. These findings will serve as a cornerstone for further investigation to understand the molecular mechanisms of 2-AP biosynthesis and regulation of heavy metal transporters in fragrant rice.

Genetic Diversity, Analysis of Some Agro-Morphological and Quality Traits and Utilization of Plant Resources of Alfalfa.

Alfalfa (Medicago sativa L.) is one of the most important perennial forage crops to build effective diets for livestock producers. Forage crop improvement depends largely on the availability of diverse germplasms and their efficient utilization. The present investigation was conducted at Ismailia Agricultural Research Station to assess twenty-one alfalfa genotypes for yield components, forage yield and quality traits during 2019/2020 and 2020/2021. The genotypes were evaluated in field experiments with three replicates and a randomized complete block design, using analysis of variance, estimate of genetic variability, estimate of broad sense heritability (hb2) and cluster analysis to identify the inter relationships among the studied genotypes as well as principal component analysis (PCA) to explain the majority of the total variation. Significant differences were found among genotypes for all studied traits. The general mean of the studied traits was higher in the second year than the first year. Moreover, the combined analysis showed highly significant differences between the two years, genotypes and the year × gen. interaction for the traits studied. The genotype F18 recorded the highest values for plant height, number of tiller/m2, total fresh yield and total dry yield, while, the genotype F49 ranked first for leaf/stem ratio. The results showed highly significant variation among the studied genotypes for crude protein %, crude fiber % and ash %. Data revealed that the genotypes P13 and P5 showed the highest values for crude protein %, whereas, the genotype F18 recorded the highest values for crude fiber % and ash content. The results revealed high estimates of genotypic coefficient and phenotypic coefficient of variation (GCV% and PCV%) with high hb2, indicating the presence of genetic variability and effective potential selection for these traits. The cluster analysis exhibited considerable genetic diversity among the genotypes, which classified the twenty one genotypes of alfalfa into five sub-clusters. The genotypes F18, F49, K75, S35, P20, P5 and P13 recorded the highest values for all studied traits compared with other clusters. Furthermore, the PC analysis grouped the studied genotypes into groups and remained scattered in all four quadrants based on all studied traits. Ultimately, superior genotypes were identified can be utilized for crop improvement in future breeding schemes.

Antioxidants Application Enhances Regeneration and Conversion of Date Palm (Phoenix dactylifera L.) Somatic Embryos.

Many embryogenic systems have been designed to generate somatic embryos (SEs) with the morphology, biochemistry, and vigor uniformity of zygotic embryos (ZEs). During the current investigation, several antioxidants were added to the maturation media of the developing somatic embryos of date palm. Explant material was a friable embryogenic callus that was placed in maturation media containing ABA at 0.5 mg L-1, 5 g L-1 polyethylene glycol, and 10 g L-1 phytagel. Furthermore, α-tocopherol or reduced glutathione (GSH) were used separately at (25 and 50 mg L-1). These treatments were compared to a widely used date palm combination of reduced ascorbic acid (ASC) and citric acid at 150 and 100 mg L-1, respectively, and to the medium free from any antioxidants. The relative growth percentage of embryogenic callus (EC), globularization degree, differentiation%, and SEs number were significantly increased with GSH (50 mg L-1). Additionally, the latter treatment significantly enhanced the conversion% of SEs and the number of secondary somatic embryos (SSEs). ASC and citric acid treatment increased leaf length, while α-tochopherol (50 mg L-1) elevated the number of leaves plantlet-1. GSH at 50 mg L-1 catalyzed the activities of polyphenol oxidase (PPO) and peroxidase (POD) in EC and enhanced the accumulation of proteins in SEs.

Nanobiotechnological Approaches to Enhance Drought Tolerance in Catharanthus roseus Plants Using Salicylic Acid in Bulk and Nanoform.

Drought has a detrimental effect on crop production, affecting economically important plants' growth rates and development. Catharanthus roseus is an important medicinal plant that produces many pharmacologically active compounds, some of which have significant antitumor activity. The effect of bulk salicylic acid (SA) and salicylic acid nanoparticles (SA-NPs) were evaluated on water-stressed Catharanthus roseus plants. The results showed that SA and SA-NPs alleviated the negative effects of drought in the treated plants by increasing their shoot and root weights, relative water content, leaf area index, chlorophyll content, and total alkaloids percentage. From the results, a low concentration (0.05 mM) of SA-NPs exerted positive effects on the treated plants, while the best results of the bulk SA were recorded after using the highest concentration (0.1 mM). Both treatments increased the expression level of WRKY1, WRKY2, WRKY40, LEA, and MYC2 genes, while the mRNA level of MPKK1 and MPK6 did not show a significant change. This study discussed the importance of SA-NPs in the induction of drought stress tolerance even when used in low concentrations, in contrast to bulk SA, which exerts significant results only at higher concentrations.

Synergistic Effect of Zinc Oxide Nanoparticles and Moringa oleifera Leaf Extract Alleviates Cadmium Toxicity in Linum usitatissimum: Antioxidants and Physiochemical Studies.

Among heavy metals, cadmium (Cd) is one of the toxic metals, which significantly reduce the growth of plants even at a low concentration. Cd interacts with various plant mechanisms at the physiological and antioxidant levels, resulting in decreased plant growth. This research was conducted to exploit the potential of synergistic application of zinc oxide nanoparticles (ZnO NPs) and Moringa oleifera leaf extract in mitigation of Cd stress in linseed (Linum usitatissimum L.) plants. The main aim of this study was to exploit the role of M. oleifera leaf extract and ZnO NPs on Cd-exposed linseed plants. Cd concentrations in the root and shoot of linseed plants decreased after administration of MZnO NPs. Growth parameters of plants, antioxidant system, and physiochemical parameters decreased as the external Cd level increased. The administration of MZnO NPs to the Cd-stressed linseed plant resulted in a significant increase in growth and antioxidant enzymes. Furthermore, the antioxidative enzymes superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX) exhibited a considerable increase in the activity when MZnO NPs were applied to Cd-stressed seedlings. The introduction of MZnO NPs lowered the levels of malondialdehyde (MDA) and hydrogen peroxide (H2O2) in the linseed plant grown in Cd-toxic conditions. The NPs decreased electrolyte leakage (EL) in Cd-stressed linseed leaves and roots. It was concluded that synergistic application of ZnO NPs and M. oleifera leaf extract alleviated Cd stress in linseed plants through enhanced activity of antioxidant enzymes. It is proposed that role of MZnO NPs may be evaluated for mitigation of numerous abiotic stresses.

Exogenous Paclobutrazol Reinforces the Antioxidant and Antimicrobial Properties of Lavender (Lavandula officinalis L.) Oil through Modulating Its Composition of Oxygenated Terpenes.

Plant growth regulators can affect the primary and secondary metabolites of various plant species. However, the effect of paclobutrazol (PBZ) on the composition of lavender oil, especially related to the terpenoid pathway, is still unclear in literatures. In this study, the effect of PBZ as a foliar spray (0.200, 400 and 600 ppm) on the vegetative growth, phytochemical content, and both antioxidant and antimicrobial properties of lavender oil were investigated. The results indicated that all examined PBZ treatments led to a significant (p ≤ 0.05) decrease in growth parameters compared to the untreated plants. Meanwhile, the yield of essential oil was significantly decreased by the treatment of PBZ at 200 ppm compared to the control. In contrast, applied-PBZ significantly enhanced the chlorophyll content and displayed a marked change in the composition of the essential oil. This change included an obvious and significant increase in 3-carene, eucalyptol, γ-terpinene, α-pinocarvone, caryophyllene, ß-vetivenene, ß-santalol, ledol, geranyl isovalerate, farnesol, caryophyllene oxide, and phytol percentage. Generally, the highest significant values were achieved by the treatment of 400 ppm compared to the other treatments. Furthermore, this treatment showed the highest free radical scavenging activity against DPPH (1,1-diphenyl-2-picrylhydrazyl) by 13% over the control. Additionally, to determine the antimicrobial activities of the extracted oil, each treatment was examined against two strains of Gram positive bacteria (S. aureus and B. cereus), two strains of Gram negative bacteria (S. enteritidis and E. coli), and two fungal species (C. albicans and A. niger) represent the yeast modal and filamentous fungus, respectively. The findings demonstrated that all examined species were more sensitive to the oil that was extracted from lavender plants, treated with 400 ppm PBZ, compared to the other concentrations.

Cytokinin Production by Azospirillum brasilense Contributes to Increase in Growth, Yield, Antioxidant, and Physiological Systems of Wheat (Triticum aestivum L.).

Plant growth-promoting rhizobacteria are known to associate with several cereal crops. The rhizobacterium exerts its function by synthesizing diverse arrays of phytohormones, such as cytokinin (Ck). However, it is difficult to determine the plant growth promotion when a bacterium produces many different kinds of phytohormones. Therefore, to assess the involvement of Ck in growth promotion and activation of antioxidant and physiological systems, we set up this experiment. Wheat seeds (Triticum aestivum L.) were inoculated with Azospirillum brasilense RA-17 (which produces zeatin type Ck) and RA-18 (which failed to produce Ck). Results showed that seed inoculation with RA-17 significantly improved growth and yield-related parameters compared with RA-18. The activity of enzymes, proline contents, and endogenous hormonal levels in wheat kernels were improved considerably with RA-17 than with RA-18. Strain RA-17 enhanced grain assimilation more than strain RA-18 resulting in a higher crop yield. These results suggest that microbial Ck production may be necessary for stimulating plant growth promotion and activating antioxidant and physiological systems in wheat.

Melatonin Mitigates Drought Induced Oxidative Stress in Potato Plants through Modulation of Osmolytes, Sugar Metabolism, ABA Homeostasis and Antioxidant Enzymes.

The effect of melatonin (MT) on potato plants under drought stress is still unclear in the available literature. Here, we studied the effect of MT as a foliar application at 0, 0.05, 0.1, and 0.2 mM on potato plants grown under well-watered and drought stressed conditions during the most critical period of early tuberization stage. The results indicated that under drought stress conditions, exogenous MT significantly (p ≤ 0.05) improved shoot fresh weight, shoot dry weight, chlorophyll (Chl; a, b and a + b), leaf relative water content (RWC), free amino acids (FAA), non-reducing sugars, total soluble sugars, cell membrane stability index, superoxide dismutase (SOD), catalase (CAT), guaiacol peroxidase (G-POX), and ascorbate peroxidase (APX) compared to the untreated plants. Meanwhile, carotenoids, proline, methylglyoxal (MG), H2O2, lipid peroxidation (malondialdehyde; MDA) and abscisic acid (ABA) were significantly decreased compared to the untreated plants. These responses may reveal the protective role of MT against drought induced carbonyl/oxidative stress and enhancing the antioxidative defense systems. Furthermore, tuber yield was differentially responded to MT treatments under well-watered and drought stressed conditions. Since, applied-MT led to an obvious decrease in tuber yield under well-watered conditions. In contrast, under drought conditions, tuber yield was substantially increased by MT-treatments up to 0.1 mM. These results may imply that under water deficiency, MT can regulate the tuberization process in potato plants by hindering ABA transport from the root to shoot system, on the one hand, and by increasing the non-reducing sugars on the other hand.

Development of New Iso-Cytoplasmic Rice-Restorer Lines and New Rice Hybrids with Superior Grain Yield and Grain Quality Characteristics by Utilizing Restorers' Fertility Genes.

This research was carried out at the Experimental Farm of Sakha Agricultural Research Station, Sakha, Kafr El-Sheikh, Egypt, during the 2018-2020 rice-growing seasons to develop and evaluate four iso-cytoplasmic rice-restorer lines: NRL79, NRL80, NRL81, and NRL82, as well as Giza 178, with ten new hybrids in order to estimate genotypic coefficient, phenotypic coefficient, heritability in a broad sense, and advantage over Giza 178 as a check variety (control) of new restorer lines. This study also estimated combining ability, gene action, better-parent heterosis (BP), mid-parents heterosis (MP), and standard heterosis (SH) over Egyptian Hybrid one (IR69A × Giza 178) as a check hybrid (control) for grain yield, agronomic traits, and some grain quality characters in restorer lines and hybrids. The percentage of advantage over commercial-variety Giza 178 (check) was significant, and highly significant among the newly developed restorer fertility lines for all the studied traits. This indicates that the selection is a highly effective factor in improving these traits. New restorer fertility lines showed highly significant positive values over commercial restorer for grain yield; the values ranged from 51% for NRL80 to 100.4% for NRL82, respectively. Meanwhile, in regard to the grain shape of paddy rice, three lines of the promising lines showed highly significant negative desirable values compared with Giza 178; the values ranged from -7.7% for the NRL80 to -15.2% for NRL79, respectively. Based on the superiority of the new lines, the new lines can be used as new restorer fertility lines to breed promising new hybrids and new inbred rice lines or varieties. From the results of the testcross experiment, the four promising lines were identified as effective restorer fertility lines for two cytoplasmic male sterile (CMS) lines. Moreover, the six rice hybrids showed values for SH heterosis of grain yield/plant of more than 15% over the check hybrid variety, with high values of 1000-grain weight and desirable grain shape; these hybrids were G46A × NRL81 (125.1%), G46A × NRL80 (66.9%), IR69A × NRL79 (47.2%), G46A × NRL79 (24.6%), IR69A × NRL81 (23.4%), and IR69A × NRL82 (16.2%).

Combining Ability and Gene Action Controlling Agronomic Traits for Cytoplasmic Male Sterile Line, Restorer Lines, and New Hybrids for Developing of New Drought-Tolerant Rice Hybrids.

This study aimed to identify new rice lines and hybrids that are tolerant to water deficit and produce high yields under water stress conditions. A line × tester mating design was used to study the lines and testers' general combining ability (GCA) effects. The specific combining ability (SCA) of the hybrid rice combinations was measured under three different irrigation regimes; 6, 9, and 12 days. The study was carried out at the experimental farm of Sakha Agricultural Research Station, Sakha, Kafr El-Sheikh, Egypt, during the 2018 and 2019 rice growing seasons. Due to the genotypes and their partitions to the parents and the crosses, the mean squares were highly significant for all studied traits under the three irrigation regimes. The additive gene effects play an important role in expressing most of the studied traits. Therefore, the selection procedures based on the accumulation of the additive effect would be successful at improving these traits and the grain yield. The cytoplasmic male sterile (CMS) line G46A (L1) was the best combiner for most yield component traits in the three irrigation regimes. The newly devolved restorer lines T11, T1, T2, T5, T4, and T3, as well as the new hybrids L2 × T10, L2 × T6, L1 × T7, L1 × T5, L1 × T3, L2 × T7, L2 × T9, L2 × T8, L2 × T4, L1 × T4, L2 × T2, L1 × T8, L1 × T9, and L2 × NRL 10, showed good, desirable values of the studied traits such as earliness of flowering, short plant height, number of panicles/plant, panicle length, number of spikelets/panicle, number of filled grains/panicle, panicle weight, 1000-grain weight, hulling percentage, milling percentage, head rice percentage, and grain yield under the irrigation regimes of 6, 9, and 12 days. The hybrids L2 × T10, L2 × T6, L1 × T7, and L1 × T5, showed significant positive SCA effects for grain yield, under all three irrigation regimes.

Exogenous Putrescine Increases Heat Tolerance in Tomato Seedlings by Regulating Chlorophyll Metabolism and Enhancing Antioxidant Defense Efficiency.

Crops around the world are facing a diversity of environmental problems, of which high temperatures are proving to be the most serious threat to crops. Polyamine putrescine (Put) acts as a master growth regulator that contributes to optimal plant growth and development and increased stress tolerance. Here, the current study aimed to elucidate how Put functions in regulating chlorophyll (Chl) metabolism, oxidative stress, and antioxidant defense, as well as to characterize the expression of genes related to heat stress in tomato seedlings under such stress. The results revealed that Put treatment significantly attenuates heat-induced damage by promoting biomass production, increasing photosynthetic efficiency, and inhibiting excessive production of oxidative stress markers. Heat stress markedly decreased the Chl content in the tomato leaf and accelerated the leaf yellowing process. However, Put-treated tomato seedlings showed a higher Chl content, which could be associated with the functions of Put in elevating PBGD activity (Chl biosynthesis enzyme) and suppressing the activity of the Chl catabolic enzyme (Chlase and MDCase). Under high-temperature stress, the expression levels of the gene encoding factors involved in Chl biosynthesis and Chl catabolism were significantly down- and upregulated, respectively, and this trend was reversed in Put-treated heat-stressed seedlings. In addition, exogenous application of Put boosted the activity of antioxidant enzymes, along with the levels of expression of their encoding genes, only in plants that were heat stressed. Furthermore, the expression levels of heat-shock-related genes (HSP90, HSP70, and HsfA1) were elevated in Put-treated, high-temperature-stressed tomato seedlings. Taken together, our results indicate that Put treatment significantly increases the heat tolerance of tomato seedlings, by elevating Chl concentrations and suppressing Chl catabolic enzyme activity, modulating endogenous free PA content, increasing antioxidant defense efficiency, and upregulating the expression of heat-shock-related genes.

Effects of Nitrogen Application Rate Under Straw Incorporation on Photosynthesis, Productivity and Nitrogen Use Efficiency in Winter Wheat.

Developing a nitrogen fertilizer (N) reduction method under straw incorporation is essentially important for increasing wheat productivity in terms of improved fertilizer use efficiency and high yield in semiarid areas. A two-year field experiment, with five different nitrogen application rates: control (without N application, N0), low N (75 kg ha-1, N75), medium N (150 kg ha-1, N150), high N (225 kg ha-1, N225) and excessive N (300 kg ha-1, N300), was conducted in 2018 and 2019 to quantify their impacts on the photosynthetic characteristics, nitrogen utilization (in terms of N accumulation, distribution and transportation, and residual soil NO3 --N) and productivity of winter wheat. There was a significant impact of N rates on photosynthetic traits, and N accumulation in different organs. As compared with the N300, N150, and N225 improved the photosynthetic characteristics, increased N accumulation in grains by 5.55 and 10.97%, the N contribution proportion of that accumulated after anthesis by 67.90 and 115.56%, and reduced residual N by 62.50 and 46.48%, respectively, thereby effectively improved N absorption efficiency and N contribution rates. Grain yield remained slightly or unchanged among N treatments. Although N0 and N75 treatments reduced the nitrate-N leaching but caused a significant reduction of 18.13 and 28.37%, respectively, in grain yield. From these results, we conclude that N application at 150 and 225 kg⋅ha-1 under straw incorporation was the most effective fertilization method in achieving the higher photosynthetic characteristics, improving NUE and grain yield. This study provides theoretical and practical guidance for wheat production techniques.

Transcriptome Analysis Reveals a Gene Expression Pattern That Contributes to Sugarcane Bud Propagation Induced by Indole-3-Butyric Acid.

Sugarcane is a cash crop that plays an integral part in the sugar industry. The Sustainable Sugarcane Initiative (SSI) has been adopted globally, ensuring enough and aiming for more yield, helping increase disease-free sugarcane cultivation. Single-bud seeds could be the best approach for sugarcane cultivation. Indole-3-butyric acid (IBA) is a rooting agent utilized significantly in seedling propagation. Greenhouse experiment results discovered the significant growth promotion in sugarcane seedlings and accumulation of plant hormones at 100 ppm IBA. Next, we performed transcriptomic analysis of sugarcane buds using RNA sequencing and compared their gene expression during root development due to affect of IBA (100 ppm). A total of 113,475 unigenes were annotated with an average length of 836 bp (N50 = 1,536). The comparative RNA-seq study between the control (CK) and IBA-treated (T) buds showed significant differentially expressed unigenes (494 upregulated and 2086 downregulated). The IBA influenced major biological processes including metabolic process, the cellular process, and single-organism process. For cellular component category, cell, cell part, organelle, membrane, and organelle part were mainly affected. In addition, catalytic activity and binding were primarily affected in the molecular function categories. Furthermore, the expression of genes related to plant hormones and signaling pathways was analyzed by qRT-PCR, which was consistent with the RNA-seq expression profile. This study provides new insights into the IBA response to the bud sprouting in sugarcane based on RNA sequencing, and generated information could help further research on breeding improvement of sugarcane.

Single nucleotide polymorphism based assessment of genetic diversity in local and exotic onion genotypes.

BACKGROUND: Onion is an economically important vegetable cultivated worldwide on a large scale. Liberal exchange of germplasm and frequent selection caused narrow genetic diversity in most crops, including onion. Thus, it is essential to estimate and understand genetic diversity before launching of any breeding program. The current study was conducted to explore genetic diversity among 39 short-day onion genotypes (indigenous and exotic). METHODS AND RESULTS: All the genotypes were evaluated for various phenotypic traits by using single nucleotide polymorphism (SNP) genotyping based on KASPar assays. Principal component analysis (PCA) was performed to determine the variability among genotypes. The four principal components with eigenvalue greater than 1 accounted for 67.5656% variability for quantitative traits, whereas first five principal components with eigenvalue greater than 0.7 accounted for 86.24% variation among the genotypes for qualitative traits. The principal component analysis identified diverse traits including bulb weight, bulb diameter, plant height, number of survived plants and vitamin C. These traits were further analyzed through ANOVA (Analysis of Variance) following augmented block design to describe genotypic variability for selected traits. Onion genotypes showed significant variation for bulb weight, bulb diameter and Vitamin C. Genotypic clustering based on PCA showed that 15 indigenous genotypes were clustered with exotic genotypes (14) while remaining indigenous genotypes (10) were distant. A total of 30 SNPs were used for assessment of genetic diversity out of these, 24 SNPs were detected with polymorphic loci (0.8%, heterozygosity), while only six markers were with monomorphic sites (0.2% heterozygosity). Subsequently, population structure analysis revealed three different populations indicating significant variability. CONCLUSION: Conclusively, a significant similarity between exotic and a group of indigenous genotypes indicates direct adoption of exotic genotypes or their sister lines. A further broadening of the genetic base is required and could be done by crossing distant genotypes.

High-Throughput Sequencing-Based Analysis of Rhizosphere and Diazotrophic Bacterial Diversity Among Wild Progenitor and Closely Related Species of Sugarcane (Saccharum spp. Inter-Specific Hybrids).

Considering the significant role of genetic background in plant-microbe interactions and that most crop rhizospheric microbial research was focused on cultivars, understanding the diversity of root-associated microbiomes in wild progenitors and closely related crossable species may help to breed better cultivars. This study is aimed to fill a critical knowledge gap on rhizosphere and diazotroph bacterial diversity in the wild progenitors of sugarcane, the essential sugar and the second largest bioenergy crop globally. Using a high-throughput sequencing (HTS) platform, we studied the rhizosphere and diazotroph bacterial community of Saccharum officinarum L. cv. Badila (BRS), Saccharum barberi (S. barberi) Jesw. cv Pansahi (PRS), Saccharum robustum [S. robustum; (RRS), Saccharum spontaneum (S. spontaneum); SRS], and Saccharum sinense (S. sinense) Roxb. cv Uba (URS) by sequencing their 16S rRNA and nifH genes. HTS results revealed that a total of 6,202 bacteria-specific operational taxonomic units (OTUs) were identified, that were distributed as 107 bacterial groups. Out of that, 31 rhizobacterial families are commonly spread in all five species. With respect to nifH gene, S. barberi and S. spontaneum recorded the highest and lowest number of OTUs, respectively. These results were validated by quantitative PCR analysis of both genes. A total of 1,099 OTUs were identified for diazotrophs with a core microbiome of 9 families distributed among all the sugarcane species. The core microbiomes were spread across 20 genera. The increased microbial diversity in the rhizosphere was mainly due to soil physiochemical properties. Most of the genera of rhizobacteria and diazotrophs showed a positive correlation, and few genera negatively correlated with the soil properties. The results showed that sizeable rhizospheric diversity exists across progenitors and close relatives. Still, incidentally, the rhizosphere microbial abundance of progenitors of modern sugarcane was at the lower end of the spectrum, indicating the prospect of Saccharum species introgression breeding may further improve nutrient use and disease and stress tolerance of commercial sugarcane. The considerable variation for rhizosphere microbiome seen in Saccharum species also provides a knowledge base and an experimental system for studying the evolution of rhizobacteria-host plant association during crop domestication.

Kernel Water Relations and Kernel Filling Traits in Maize (Zea mays L.) Are Influenced by Water-Deficit Condition in a Tropical Environment.

Water deficit is a major limiting condition for adaptation of maize in tropical environments. The aims of the current observations were to evaluate the kernel water relations for determining kernel developmental progress, rate, and duration of kernel filling, stem reserve mobilization in maize. In addition, canopy temperature, cell membrane stability, and anatomical adaptation under prolonged periods of pre- and post-anthesis water deficit in different hybrids was quantified to support observations related to kernel filling dynamics. In this context, two field experiments in two consecutive years were conducted with five levels of water regimes: control (D1), and four water deficit treatments [V10 to V13 (D2); V13 to V17 (D3); V17 to blister stage (D4); blisters to physiological maturity (D5)], on three maize hybrids (Pioneer 30B80, NK 40, and Suwan 4452) in Expt. 1. Expt. 2 had four water regimes: control (D1), three water deficit treatments [V10 to anthesis (D2); anthesis to milk stage (D3); milk to physiological maturity (D4)], and two maize hybrids (NK 40 and Suwan 4452). Water deficit imposed at different stages significantly reduced maximum kernel water content (MKWC), kernel filling duration (KFD), final kernel weight (FKW), and kernel weight ear-1 while it increased kernel water loss rate (KWLR), kernel filling rate (KFR), and stem weight depletion (SWD) across maize hybrids in both experiments. The lowest MKWC under water deficit was at D3 in both experiments, indicating that lower KFR results in lowest FKW in maize. Findings indicate that the MKWC (R 2 = 0.85 and 0.41) and KFR (R 2 = 0.62 and 0.37) were positively related to FKW in Expt. 1 and 2, respectively. The KFD was reduced by 5, 7, 7, and 11 days under water deficit at D3, D4 in Expt. 2 and D4, D5 in Expt. 1 as compared to control, respectively. Water deficit at D5 in Expt. 1 and D4 in Expt. 2 increased KWLR, KFR, and SWD. In Expt. 2, lower canopy temperature and electrical conductivity indicated cell membrane stability across water regimes in NK 40. Hybrid NK 40 under water deficit had significantly higher cellular adaptation by increasing the number of xylem vessel while reducing vessel diameter in leaf mid-rib and attached leaf blade. These physiological adjustments improved efficient transport of water from root to the shoot, which in addition to higher kernel water content, MKWC, KFD, KFR, and stem reserve mobilization capacity, rendered NK 40 to be better adapted to water-deficit conditions under tropical environments.

Antimicrobial, antioxidant and cytotoxic properties of Chenopodium glaucum L.

We evaluated phytochemical composition, antibacterial, antifungal, anti-oxidant and cytotoxic properties of aqueous (water) and organic extracts (methanol, ethyl acetate and n-hexane) of Chenopodium glaucum. Highest phenolic content 45 mg gallic acid equivalents (GAE)/g d.w was found in aqueous extract followed by ethyl acetate (41mg GAE/g d.w) and methanol extract (34.46 mg GAE/g d.w). Antibacterial potential of aqueous and organic extracts of C. glaucum was examined against Acinetobacter baumannii, Klebsiella pneumoniae, Escherichia coli and Staphylococcus epidermidis. The aqueous, methanolic, ethyl acetate, and n-hexane extract showed antibacterial activity against A. baumannii, K. pneumoniae, E. coli and S. epidermidis. However, against A. baumannii significantly higher inhibition zone (19 mm and 18.96 mm respectively) was shown by ethyl acetate and methanol extracts. Aqueous extract possessed highest growth inhibition (11 mm) against E. coli. Aqueous, ethyl acetate and methanol extracts showed 9 mm, 10 mm, and 10.33 mm zone of inhibition against the K. pneumoniae. For antifungal activity, the extracts were less effective against Aspergillus niger but showed strong antifungal activity against Aspergillus flavus (A. flavus). The antioxidant activity was measured as DPPH (2, 2-diphenyl-1-picrylhydrazyl), H2O2 and ABTS (2, 2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) scavenging activity of free radicals. All the organic extracts of C. glaucum possessed ABTS, DPPH and H2O2 scavenging properties. The highest cytotoxic activity measured as half maximal inhibitory concentration (IC50) against human lungs carcinoma cells was recorded for methanolic (IC50 = 16 µg/mL) and n-hexane (IC50 = 25 µg/mL) extracts, respectively. The Gas chromatography-mass spectrometry (GC-MS) analysis showed 4 major and 26 minor compounds in n-hexane extract and 4 major and 7 minor compounds in methanol extract of the C. glaucum. It is concluded that aqueous and organic extracts of C. glaucum would be potential therapeutic agents and could be exploited on a pilot scale to treat human pathogenic diseases.

The Response of Lentil (Lens culinaris Medik.) to Soil Moisture and Heat Stress Under Different Dates of Sowing and Foliar Application of Micronutrients.

Soil moisture and air temperature stress are the two major abiotic factors limiting lentil (Lens culinaris Medik.) growth and productivity in the humid tropics. Field experiments were conducted during winter seasons (November to March) of 2018-2019 and 2019-2020 on clay loam soil (AericHaplaquept) of Eastern India to cultivate rainfed lentil, with residual moisture. The objective was to study the effect of different time of sowing and foliar spray of micronutrients in ameliorating the effect of heat and moisture stress lentil crop experience in its reproductive stage. The study was conducted with two different dates of sowing, November and December, as main plot treatment and micronutrients foliar spray of boron, iron, and zinc either alone or in combination as subplot treatment. No foliar spray treatment was considered as a control. The soil moisture content is depleted from 38 to 18% (sowing to harvest) during November sowing; however, in December sowing, the depletion is from 30 to 15%. The foliar spray of micronutrients helped to have a better canopy cover and thus reduced soil evaporation during the later stages of crop growth when the temperature was beyond the threshold temperature of the crop. Crop growth rate (CGR) and biomass were significantly higher (p ≤ 0.05) for November sown crop and with foliar spray of boron and iron (FSB + FE) micronutrients. In the later stages of the crop when the soil moisture started depleting with no precipitation, the canopy temperature increased compared with air temperature, leading to positive values of Stress Degree Days (SDD) index. Delay in sowing reduced the duration by 11.4 days (113.5 vs. 102.1 days), resulting in varied accumulated Growing Degree Days (GDD). FSB + FE resulted in the highest yield in both years (1,436 and 1,439 kg ha-1). The results of the study concluded that the optimum time of sowing and foliar spray of micronutrients may be helpful to alleviate the soil moisture and heat stress for the sustainability of lentil production in the subtropical region.