iTRAQ-based comparative proteomic analysis reveals high temperature accelerated leaf senescence of tobacco (Nicotiana tabacum L.) during flue-curing

Preharvest Application of Exogenous 2,4-Epibrassinolide and Melatonin Enhances the Maturity and Flue-Cured Quality of Tobacco Leaves

Tobacco (Nicotiana tabacum) is a globally cultivated crop, with its quality closely associated with the color and chemical composition of cured tobacco leaves. In this experiment, the effects of spraying exogenous 2, 4-epibrassinolide (EBR) and melatonin (MT) on the development of tobacco leaves at maturity stage and the quality after curing were investigated. Both EBR and MT treatments significantly enhanced the appearance quality of tobacco leaves at the stem-drying stage. Following preharvest applications, the sugar-to-alkali ratio and potassium content increased, while the contents of starch, total alkaloids, and proteins decreased. The levels of conventional chemical components were improved, enhancing the overall coordination of the tobacco. Transcriptome analysis revealed that EBR treatment down-regulated the chlorophyll biosynthetic genes hemA, MgPEC, and ChlD, while up-regulating the chlorophyll degradation genes CHL2, SGR, and PAOs. Similarly, MT treatment down-regulated the chlorophyll biosynthetic genes FC2 and MgPEC and up-regulated the degradation genes CHL2 and SGR, thus promoting chlorophyll degradation. Furthermore, in the downstream carotenoid biosynthetic pathway, both EBR and MT treatments regulated abscisic acid-related genes, with NCEDs being up-regulated and CYP707A1s down-regulated, thereby promoting the leaf ripening. Metabolomics analysis indicated that EBR treatment primarily regulated alkaloids, terpenoids, and flavonoids, while MT treatment mainly affected flavonoids. Both treatments also reduced the accumulation of the harmful substance aristolochic acid B. Comprehensive evaluations of appearance quality, physiological parameters, transcriptome, and metabolomics analyses demonstrated that exogenous spraying of EBR and MT treatments improved the maturity and quality of cured tobacco leaves, with EBR treatment exhibiting a greater effect than MT treatment.

Comparative proteomic analysis reveals novel insights into the continuous cropping induced response in Scrophularia ningpoensis

BACKGROUND

Scrophularia ningpoensis is a well-known medicinal crop. Continuous cropping seriously affects the yield and quality, but little is known about the influence of continuous cropping on metabolic pathways. In this study, the difference in protein abundance between continuous cropping and non-continuous cropping of S. ningpoensis roots was studied by proteomics, and the molecular mechanism that protects S. ningpoensis against continuous cropping was explored.

RESULTS

The results suggested that continuous cropping in S, ningpoensis altered the expression of proteins related to starch and sucrose metabolism, glycolysis/gluconeogenesis, pentose phosphate pathway, citric acid cycle, phenylalanine, tyrosine and tryptophan biosynthesis, phenylpropanoid biosynthesis, terpenoid backbone biosynthesis, monoterpenoid biosynthesis, sesquiterpenoid and triterpenoid biosynthesis, and steroid biosynthesis. Among these processes, the most affected were phenylpropanoid biosynthesis and starch and sucrose metabolism, which may be important for continuous cropping resistance.

CONCLUSION

The effect of continuous cropping on S. ningpoensis was demonstrated at the proteome level in this work, and identified candidate proteins that may cause continuous cropping reactions. The paper provides the theoretical foundation and scientific reference for enhancing the continuous cropping resistance of S. ningpoensis. © 2022 Society of Chemical Industry.

Effect of different drying techniques on rose (Rosa rugosa cv. Plena) proteome based on label-free quantitative proteomics

To explore the molecular mechanisms of different processing technologies on rose tea (Rosa rugosa cv. Plena), we investigated the rose tea proteome (fresh rose tea [CS], vacuum freeze-drying rose tea [FD], and vacuum microwave rose tea [VD]) using label-free quantification proteomics (LFQ). A total of 2187 proteins were identified, with 1864, 1905, and 1660 proteins identified in CS, FD, and VD, respectively. Of those, 1500 proteins were quantified. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) annotation and enrichment analysis of differential expression proteins (DEPs) in VD vs. CS, FD vs. CS, and FD vs. VD showed that these pathways were associated with energy metabolism, the metabolic breakdown of energy substances and protein biosynthesis, such as oxidative phosphorylation, citrate cycle, carbon metabolism pathways, and ribosome and protein processing in endoplasmic reticulum. FD could ensure the synthesis of protein translation and energy metabolism, thereby maintaining the high quality of rose tea.

Metabolomics and proteomics revealed the synthesis difference of aroma precursors in tobacco leaves at various growth stages

Tobacco has a high economic value as the largest cash crop worldwide. The quality of flue-cured tobacco is closely related to the overall status of compounds in fresh tobacco leaves, and the aroma precursor plays a key role in the aroma quality of flue-cured tobacco. The untargeted metabolomics and label-free quantitative proteomics analysis of tobacco leaves in three growth stages (root stretching, prosperous growth, and maturation) retrieved 243 metabolites and 4313 proteins (944 differentially expressed proteins), which showed that carbohydrate, amino acid, and fatty acid metabolism varies among the three growth stages. Also, the most of amino acids, organic acids, fatty acids, and polyphenols reduced in the vegetative growth stage, while increased in the reproductive growth stage. On the other hand, alkaloids such as nicotine, nornicotine, and anatabine increased continuously in tobacco leaves during the three growth stages. This study helps us understand the growth and development characteristics of Yun87 flue-cured tobacco in the field before harvest, and it provides a certain omics basis for the industrial crop flue-cured tobacco.

Assessing environmental thresholds in relation to plant structure and nutritional value for improved maize calendar ensuring food security

The environment has been continuously changed, and it's a bitter truth that we can't minimize anthropogenic activities to mitigate harmful impacts on the environment. The changing environment is a great threat to food security by affecting crop yields. However, there is no comprehensive study to assess the environmental impact on the nutritional quality of the crops. In this study, we have investigated the nutritional profile and yield of maize crops around the globe and synchronized the findings with physiological reasoning. The study enlightens the time-scale activities of maize plant enzymes and describes their response to changing environments. The study also explained time-scale-based changes in the physiological conditions of maize crops against environmental dynamics around the globe. It also detected the impact of climate change on the deterioration of the nutritional quality of maize. The current study reports the activities of three different enzyme classes. It was noted that the photosynthesis-related enzyme activities were boosted after a sudden increase in carbon dioxide concentration. However, the drought years (2005-2010) decreased photosynthesis and increased oxidative enzyme activities. Overall, the glycemic index of the maize crop has been increased during the last four decades. However, the crop production threshold levels have been raised more quickly. The nutritional index values are alarming and have frequently been recorded under the threshold levels in recent years. The study paves a path for maize toward nutritional contents richness, ensuring food security and nutritional security in the future.

Unraveling the expression of differentially expressed proteins and enzymatic activity in response to Phytophthora nicotianae across different flue-cured tobacco cultivars

BACKGROUND

Black shank disease caused by Phytophthora nicotianae is a serious threat to flue-cured tobacco production. Whole-plant resistance is characterized by the expression of a number of pathogenesis-related proteins, genes, and the activity of different defense-related enzymes. In this study, we investigated the activity of defense-related enzymes and expression of differentially expressed proteins through the iTRAQ technique across two flue-cured tobacco cultivars, i.e., K326 and Hongda, in response to the black shank pathogen.

RESULTS

Results showed that the highest disease incidence was recorded in flue-cured tobacco cultivar Hongda compared with K326, which shows that Hongda is more susceptible to P. nicotianae than K326. A total of 4274 differentially expressed proteins were detected at 0 h and after 24 h, 72 h of post-inoculation with P. nicotianae. We found that 17 proteins induced after inoculation with P. nicotianae, including pathogenesis (5), photosynthesis (3), oxidative phosphorylation (6), tricarboxylic acid cycle (1), heat shock (1), and 14-3-3 (1) and were involved in the resistance of flue-cured tobacco against black shank disease. The expression of 5 pathogenesis-related proteins and the activities of defense-related enzymes (PPO, POD, SOD, and MDA) were significantly higher in the leaves of K326 than Hongda after inoculation with P. nicotianae.

CONCLUSION

These results provide new molecular insights into flue-cured tobacco responses to P. nicotianae. It is concluded that differences in protein expressions and defense-related enzymes play an important role in developing resistance in flue-cured tobacco cultivars against black shank disease.

Impacts, Tolerance, Adaptation, and Mitigation of Heat Stress on Wheat under Changing Climates

Heat stress (HS) is one of the major abiotic stresses affecting the production and quality of wheat. Rising temperatures are particularly threatening to wheat production. A detailed overview of morpho-physio-biochemical responses of wheat to HS is critical to identify various tolerance mechanisms and their use in identifying strategies to safeguard wheat production under changing climates. The development of thermotolerant wheat cultivars using conventional or molecular breeding and transgenic approaches is promising. Over the last decade, different omics approaches have revolutionized the way plant breeders and biotechnologists investigate underlying stress tolerance mechanisms and cellular homeostasis. Therefore, developing genomics, transcriptomics, proteomics, and metabolomics data sets and a deeper understanding of HS tolerance mechanisms of different wheat cultivars are needed. The most reliable method to improve plant resilience to HS must include agronomic management strategies, such as the adoption of climate-smart cultivation practices and use of osmoprotectants and cultured soil microbes. However, looking at the complex nature of HS, the adoption of a holistic approach integrating outcomes of breeding, physiological, agronomical, and biotechnological options is required. Our review aims to provide insights concerning morpho-physiological and molecular impacts, tolerance mechanisms, and adaptation strategies of HS in wheat. This review will help scientific communities in the identification, development, and promotion of thermotolerant wheat cultivars and management strategies to minimize negative impacts of HS.

Physio-ultrastructural footprints and iTRAQ-based proteomic approach unravel the role of Piriformospora indica-colonization in counteracting cadmium toxicity in rice

Due to its immense capability to concentrate in rice grain and ultimately in food chain, cadmium (Cd) has become the cause of an elevated concern among agriculturists, scientists and the environmental activists. Symbiotic association of Piriformospora indica (P. indica) has been characterized as a potential aid in combating heavy metal stress in plants for sustainable crop production but our scant knowledge regarding ameliorative tendency of P. indica against Cd, specifically in rice, necessitates an in-depth investigation. This study aimed at elaborating the underlying mechanisms involved in P. indica-mediated tolerance against Cd stress in two rice genotypes, IR8 and ZX1H, varying in Cd accumulation pattern. Either colonized or un-inoculated with P. indica, seedlings of both genotypes were subjected to Cd stress. The results showed that P. indica colonization significantly supported plant biomass, photosynthetic attributes and chlorophyll contents in Cd stressed plants. P. indica colonization sustained chloroplast integrity and reduced Cd translocation (46% and 64%), significantly lowering malondialdehyde (MDA) content (11.3% and 50.4%) compared to uninoculated roots under Cd stress in IR8 and ZX1H, respectively. A genotypic difference was evident when a 2-fold enhancement in root peroxidase (POD) activity was recorded in P. indica colonized IR8 plants as compared to ZX1H. The root proteomic analysis was performed using isobaric tags for relative and absolute quantification (iTRAQ) and the results showed that P. indica alleviates Cd stress in rice via down-regulation of key glycolysis cycle enzymes in a bid to reduce energy consumption by the plants and possibly re-directing it to Cd defense response pathways; and up-regulation of glutamine synthetase, a key enzyme in the L-Arg-dependent pathway for nitric oxide (NO) production, which acts as a stress signaling molecule, thus conferring tolerance by reduction of NO-mediated modification of essential proteins in response to Cd stress. Conclusively, both the tested genotypes benefited from P. indica symbiosis at varying levels by an enhanced detoxification capacity and signaling efficiency in response to stress. Hence, a step forward towards the employment of an environmentally sound and self-renewing approach holding the hope for a healthy future.

Silicon assisted ameliorative effects of iron nanoparticles against cadmium stress: Attaining new equilibrium among physiochemical parameters, antioxidative machinery, and osmoregulators of Phaseolus lunatus

Currently, producing safe agricultural commodities from the crop plants cultivated in the soil with increasing heavy metal toxicity is a gigantic challenge in front of researchers. Heavy metals are absorbed and translocated in the crop plants and then transferred to every downstream consumer of the food chain, including humans, causing serious disorders and ailments. The current research presents a combined schematic application of iron nanoparticles (Fe-NPs) and/or silicon (Si), to mitigate cadmium (Cd) stress in Lima bean (Phaseolus lunatus). It was noted that Cd-induced toxicity curtailed growth, antioxidative machinery, glyoxalase system and nutrient uptake of the plants. Furthermore, the physiochemical features of Cd stressed plants, including carotenoids, chlorophyll, photochemical quenching, photosynthetic efficiency, and leaf relative water contents, were improved by the combined application of Si and Fe-NPs. Moreover, higher levels of malondialdehyde (MDA), methylglyoxal (MG), hydrogen peroxide (H₂O₂), and electrolyte leakage (EL) were observed in Cd stressed plants. Nevertheless, the independent treatment or combined application of Si and/or Fe-NPs attenuated the adversative effects of Cd on the aforementioned growth attributes. Furthermore, Si and Fe-NPs defended plants from the injurious effects of MG by improving the activities of the glyoxalase enzyme. The Si and Fe-NPs reduced Cd contents but at the same time improved uptake and accumulation of nutrients in treated plants exposed to the Cd regime. This study highlights that Si and Fe-NPs have enormous potential to mitigate Cd-induced phytotoxicity by declining Cd uptake and improving the growth attributes of plants if applied in combination.

Label-Free Proteomic Analysis of Smoke-Drying and Shade-Drying Processes of Postharvest Rhubarb: A Comparative Study

Postharvest processing plays a very important role in improving the quality of traditional Chinese medicine. According to previous studies, smoke-drying could significantly promote the accumulation of the bioactive components and pharmacological activities of rhubarb, but so far, the molecular mechanism has not been studied yet. In this research, to study the molecular mechanisms of postharvest processing for rhubarb during shade-drying and smoke-drying, label-free proteomic analyses were conducted. In total, 1,927 differentially abundant proteins (DAPs) were identified from rhubarb samples treated by different drying methods. These DAPs were mainly involved in response and defense, signal transduction, starch, carbohydrate and energy metabolism, and anthraquinone and phenolic acid biosynthesis. Smoke-drying significantly enhanced the expression of proteins involved in these metabolic pathways. Accordingly, the molecular mechanism of the accumulation of effective ingredients of rhubarb was clarified, which provided a novel insight into the biosynthesis of active ingredients that occur during the rhubarb dry process.

Physiological and proteomic analysis reveals the impact of boron deficiency and surplus on alfalfa (Medicago sativa L.) reproductive organs

Boron (B), an essential element for increasing seed yield and germinability in alfalfa (Medicago sativa L.), plays a vital role in its reproductive processes. However, effects of B stress on physiological and proteomic changes in reproductive organs related to alfalfa seed yield and germinability are poorly understood. In order to gain a better insight into B response or tolerance mechanisms, field trials were designed for B deficiency (0 mg B L^-1), B sufficiency (800 mg B L^-1), and B surplus (1600 mg B L^-1) application during alfalfa flowering to analyze the proteomics and physiological responses of alfalfa 'Aohan' reproductive organs. Results showed that B deficiency weakened the stress-responsive ability in these organs, while B surplus reduced the sugar utilization of 'Aohan' flowers and caused lipid membrane peroxidation in 'Aohan' seeds. In addition, four upregulated stress responsive proteins (ADF-like protein, IMFP, NAD(P)-binding Rossmann-fold protein and NAD-dependent ALDHs) might play pivotal roles in the response of 'Aohan' reproductive organs to conditions of B deficiency and B surplus. All of the above results would be helpful to understand the tolerance mechanisms of alfalfa reproductive organs to both B deficiency and B surplus conditions, and also to give insight into the regulatory role of B in improving seed yield and germinability in alfalfa seed production. In summary, B likely plays a structural and regulatory role in relation to lipid metabolism, carbohydrate metabolism, amino acid metabolism, and signal transduction, thus regulates alfalfa reproductive processes eventually affecting the seed yield and germinability of alfalfa seeds.

Can omics deliver temperature resilient ready-to-grow crops?

Plants are extensively well-thought-out as the main source for nourishing natural life on earth. In the natural environment, plants have to face several stresses, mainly heat stress (HS), chilling stress (CS) and freezing stress (FS) due to adverse climate fluctuations. These stresses are considered as a major threat for sustainable agriculture by hindering plant growth and development, causing damage, ultimately leading to yield losses worldwide and counteracting to achieve the goal of "zero hunger" proposed by the Food and Agricultural Organization (FAO) of the United Nations. Notably, this is primarily because of the numerous inequities happening at the cellular, molecular and/or physiological levels, especially during plant developmental stages under temperature stress. Plants counter to temperature stress via a complex phenomenon including variations at different developmental stages that comprise modifications in physiological and biochemical processes, gene expression and differences in the levels of metabolites and proteins. During the last decade, omics approaches have revolutionized how plant biologists explore stress-responsive mechanisms and pathways, driven by current scientific developments. However, investigations are still required to explore numerous features of temperature stress responses in plants to create a complete idea in the arena of stress signaling. Therefore, this review highlights the recent advances in the utilization of omics approaches to understand stress adaptation and tolerance mechanisms. Additionally, how to overcome persisting knowledge gaps. Shortly, the combination of integrated omics, genome editing, and speed breeding can revolutionize modern agricultural production to feed millions worldwide in order to accomplish the goal of "zero hunger."