Physiological responses and genome-wide characterization of TaNRAMP1 gene in Mn-deficient wheat

Evaluation of efficacy of non-coding RNA in abiotic stress management of field crops: Current status and future prospective

Abiotic stresses are responsible for the major losses in crop yield all over the world. Stresses generate harmful ROS which can impair cellular processes in plants. Therefore, plants have evolved antioxidant systems in defence against the stress-induced damages. The frequency of occurrence of abiotic stressors has increased several-fold due to the climate change experienced in recent times and projected for the future. This had particularly aggravated the risk of yield losses and threatened global food security. Non-coding RNAs are the part of eukaryotic genome that does not code for any proteins. However, they have been recently found to have a crucial role in the responses of plants to both abiotic and biotic stresses. There are different types of ncRNAs, for example, miRNAs and lncRNAs, which have the potential to regulate the expression of stress-related genes at the levels of transcription, post-transcription, and translation of proteins. The lncRNAs are also able to impart their epigenetic effects on the target genes through the alteration of the status of histone modification and organization of the chromatins. The current review attempts to deliver a comprehensive account of the role of ncRNAs in the regulation of plants' abiotic stress responses through ROS homeostasis. The potential applications ncRNAs in amelioration of abiotic stresses in field crops also have been evaluated.

Effect of Mn Deficiency on Carbon and Nitrogen Metabolism of Different Genotypes Seedlings in Maize (Zea mays L.)

Manganese deficiency critically impairs the function and stability of photosystem II (PSII) and negatively impacts crop growth and yield. However, the response mechanisms of carbon and nitrogen metabolism to Mn deficiency in different genotypes of maize and the differences in Mn deficiency tolerance are unclear. Herein, three different genotypes of maize seedlings (sensitive genotype: Mo17, tolerant genotype: B73, and B73 × Mo17) were exposed to Mn deficiency treatment for 16 days using liquid culture with different concentrations of MnSO₄ [0.00, 2.23, 11.65, and 22.30 mg/L (control)]. We found that complete Mn deficiency significantly reduced maize seedling biomass; negatively affected the photosynthetic and chlorophyll fluorescence parameters; and depressed nitrate reductase, glutamine synthetase, and glutamate synthase activity. This resulted in reduced leaf and root nitrogen uptake, with Mo17 being most severely inhibited. B73 and B73 × Mo17 maintained higher sucrose phosphate synthase and sucrose synthase activities and lower neutral convertase activity compared to Mo17, which resulted in higher accumulation of soluble sugars and sucrose and maintenance of the osmoregulation capacity of leaves, which helped mitigate damage caused by Mn deficiency. The findings revealed the physiological regulation mechanism of carbon and nitrogen metabolism in different genotypes of maize seedlings that resist Mn deficiency stress, providing a theoretical basis for developing high yield and quality.

Multi-Omics Uncover the Mechanism of Wheat under Heavy Metal Stress

Environmental pollution of heavy metals has received growing attention in recent years. Heavy metals such as cadmium, lead and mercury can cause physiological and morphological disturbances which adversely affect the growth and quality of crops. Wheat (Triticum aestivum L.) can accumulate high contents of heavy metals in its edible parts. Understanding wheat response to heavy metal stress and its management in decreasing heavy metal uptake and accumulation may help to improve its growth and grain quality. Very recently, emerging advances in heavy metal toxicity and phytoremediation methods to reduce heavy metal pollution have been made in wheat. Especially, the molecular mechanisms of wheat under heavy metal stress are increasingly being recognized. In this review, we focus on the recently described epigenomics, transcriptomics, proteomics, metabolomics, ionomics and multi-omics combination, as well as functional genes uncovering heavy metal stress in wheat. The findings in this review provide some insights into challenges and future recommendations for wheat under heavy metal stress.

Interaction of silicon and manganese in nutritional and physiological aspects of energy cane with high fiber content

BACKGROUND

Silicon (Si) is a multiple stress attenuator element in plants, however more research is needed to elucidate the actions in the plants defense system with low nutrition of manganese (Mn) for a prolonged period, and the attenuation mechanisms involved in the effects of Mn deficiency on energy cane with high fiber content. Thus, the objective of this study was to evaluate whether Si reduces the oxidative stress of the energy cane grown in low Mn in nutrient solution, to mitigate the effects of Mn deficiency, improving enzymatic and non-enzymatic defense, uptake of Mn the plant growth.

METHODS

An experiment was carried out with pre-sprouted seedlings of Saccharum spontaneum L. in a 2 × 2 factorial scheme in five replications in which the plants were grown under sufficiency (20.5 μmol L^-1) and deficiency (0.1 μmol L^-1) of Mn combined with the absence and presence of Si (2.0 mmol L^-1) for 160 days from the application of the treatments. The following parameters were evaluated: accumulation of Mn and Si, H₂O_2, MDA, activity of SOD and GPOX, total phenol content, pigments, and quantum efficiency of PSII.

RESULTS

Mn deficiency induced the oxidative stress for increase the H₂O₂ and MDA content in leaves of plants and reduce the activity of antioxidant enzymes and total phenols causing damage to quantum efficiency of photosystem II and pigment content. Si attenuated the effects of Mn deficiency even for a longer period of stress by reducing H₂O₂ (18%) and MDA (32%) content, and increased the Mn uptake efficiency (53%), SOD activity (23%), GPOX (76%), phenol contents, thus improving growth.

CONCLUSIONS

The supply of Si promoted great nutritional and physiological improvements in energy cane with high fiber content in Mn deficiency. The results of this study propose the supply of Si via fertirrigation as a new sustainable strategy for energy cane cultivation in low Mn environments.