Salt Priming as a Smart Approach to Mitigate Salt Stress in Faba Bean (Vicia faba L.)

Revisiting plant stress memory: mechanisms and contribution to stress adaptation

Highly repetitive adverse environmental conditions are encountered by plants multiple times during their lifecycle. These repetitive encounters with stresses provide plants an opportunity to remember and recall the experiences of past stress-associated responses, resulting in better adaptation towards those stresses. In general, this phenomenon is known as plant stress memory. According to our current understanding, epigenetic mechanisms play a major role in plants stress memory through DNA methylation, histone, and chromatin remodeling, and modulating non-coding RNAs. In addition, transcriptional, hormonal, and metabolic-based regulations of stress memory establishment also exist for various biotic and abiotic stresses. Plant memory can also be generated by priming the plants using various stressors that improve plants' tolerance towards unfavorable conditions. Additionally, the application of priming agents has been demonstrated to successfully establish stress memory. However, the interconnection of all aspects of the underlying mechanisms of plant stress memory is not yet fully understood, which limits their proper utilization to improve the stress adaptations in plants. This review summarizes the recent understanding of plant stress memory and its potential applications in improving plant tolerance towards biotic and abiotic stresses.

Nutrition security, constraints, and agro-diversification strategies of neglected and underutilized crops to fight global hidden hunger

Introduction

Neglected and underutilized crop species (NUCS) or forbidden crops offer tremendous potential to combat malnutrition, poverty, and global hidden hunger. Since overdependence on a few dominant cereal crops, viz., rice, maize, and wheat, is insufficient to meet the global food energy intake, the identification, genetic improvement, and implementation of various policies for wenumerates comprehensive comparative analyses of the nutrient profile of staple crops vs. potent underutilized crops with reference to cultivation constraints and climate resilience with different agro-diversification strategies.

Methodology

The research databases Scopus, JSTOR, Web of Science, EBSCO, Google Scholar, ScienceDirect, PubMed, and Academic Search were searched using relevant research queries.

Result

Out of 2,345 hits, 99 articles pertinent to the subject domain showed that underutilized crops are nutritionally superior, contain health-promoting bioactive components, and are more climate resilient than cereal crops. However, several constraints hinder the efficient utilization of these crops.

Discussion

Despite underutilized crops' many health benefits, improved cultivation techniques for the large-scale production of these crops are still in their infancy. Most of the time, however, the scientific knowledge gleaned from various study domains stays within the scientific community. The most crucial need of the hour, therefore, is an efficient network structure connecting governments, farmers, researchers, and people in business. Moreover, care must be taken to ensure that the policies of governments and INGOs/NGOs are properly implemented within a NUCS framework.

Physio-biochemical and transcriptomic analysis reveals that the mechanism of Bacillus cereus G2 alleviated oxidative stress of salt-stressed Glycyrrhiza uralensis Fisch. seedlings

Salt stress severely affects the growth and productivity of Glycyrrhiza uralensis. Our previous research found that the endophyte Bacillus cereus G2 alleviated the osmotic and oxidative stress in G. uralensis exposed to salinity. However, the mechanism is still unclear. Here, a pot experiment was conducted to analyse the change in parameters related to osmotic adjustment and antioxidant metabolism by G2 in salt-stressed G. uralensis at the physio-biochemistry and transcriptome levels. The results showed that G2 significantly increased proline content by 48 %, glycine betaine content by 75 % due to activated expression of BADH1, and soluble sugar content by 77 % due to upregulated expression of α-glucosidase and SS, which might help to decrease the cell osmotic potential, enable the cell to absorb water, and stabilize the cell's protein and membrane structure, thereby alleviating osmotic stress. Regarding antioxidant metabolism, G2 significantly decreased malondialdehyde (MDA) content by 27 %, which might be ascribed to the increase in superoxide dismutase (SOD) activity that facilitated the decrease in the superoxide radical (O₂^‾) production rate; it also increased the activities of catalase (CAT), ascorbate peroxidase (APX) and glutathione peroxidase (GPX), which helped stabilize the normal level of hydrogen peroxide (H₂O₂). G2 also increased glutathione (GSH) content by 65 % due to increased glutathione reductase (GR) activity and GSH/GSSG ratio, but G2 decreased oxidized glutathione (GSSG) content by 13 % due to decreased activity of dehydroascorbate reductase (DHAR), which could provide sufficient substrates for the ascorbate-glutathione (AsA-GSH) cycle to eliminate excess H₂O₂ that was not cleared in a timely manner by the antioxidant enzyme system. Taken together, G2 alleviated osmotic stress by increasing proline, soluble sugar, and glycine betaine contents and alleviated oxidative stress by the synergistic effect of antioxidant enzymes and the AsA-GSH cycle. Therefore, the results may be useful for explaining the mechanism by which endophyte inoculation regulates the salt tolerance of crops.