Crop plants often have challenges of biotic and abiotic stresses, and they adapt sophisticated ways to acclimate and cope with these through the expression of specific genes. Changes in chromatin, histone, and DNA mostly serve the purpose of combating challenges and ensuring the survival of plants in stressful environments. Epigenetic changes, due to environmental stress, enable plants to remember a past stress event in order to deal with such challenges in the future. This heritable memory, called “plant stress memory”, enables plants to respond against stresses in a better and efficient way, not only for the current plant in prevailing situations but also for future generations. Development of stress resistance in plants for increasing the yield potential and stability has always been a traditional objective of breeders for crop improvement through integrated breeding approaches. The application of epigenetics for improvements in complex traits in tetraploid and some other field crops has been unclear. An improved understanding of epigenetics and stress memory applications will contribute to the development of strategies to incorporate them into breeding for complex agronomic traits. The insight in the application of novel plant breeding techniques (NPBTs) has opened a new plethora of options among plant scientists to develop germplasms for stress tolerance. This review summarizes and discusses plant stress memory at the intergenerational and transgenerational levels, mechanisms involved in stress memory, exploitation of induced and natural epigenetic changes, and genome editing technologies with their future possible applications, in the breeding of crops for abiotic stress tolerance to increase the yield for zero hunger goals achievement on a sustainable basis in the changing climatic era.

As global arid conditions worsen and groundwater resources diminish, drought stress has emerged as a critical impediment to plant growth and development globally, notably causing declines in crop yields and even the extinction of certain cultivated species. Numerous studies on drought resistance have demonstrated that DNA methylation dynamically interacts with plant responses to drought stress by modulating gene expression and developmental processes. However, the precise mechanisms underlying these interactions remain elusive. This article consolidates the latest research on the role of DNA methylation in plant responses to drought stress across various species, focusing on methods of methylation detection, mechanisms of methylation pattern alteration (including DNA de novo methylation, DNA maintenance methylation, and DNA demethylation), and overall responses to drought conditions. While many studies have observed significant shifts in genome-wide or gene promoter methylation levels in drought-stressed plants, the identification of specific genes and pathways involved remains limited. This review aims to furnish a reference for detailed research into plant responses to drought stress through epigenetic approaches, striving to identify drought resistance genes regulated by DNA methylation, specific signaling pathways, and their molecular mechanisms of action.

Soilless cultivation of potatoes often utilizes organic coconut peat and inorganic vermiculite as growing substrates. The unique microbial communities and physicochemical characteristics inherent to each substrate significantly influence the microecological environment crucial for potato growth and breeding. This study analyzed environmental factors within each substrate and employed Illumina sequencing alongside bioinformatics tools to examine microbial community structures, their correlation with environmental factors, core microbial functions, and the dynamics of microbial networks across various samples. These included pure coconut peat (CP1) and pure vermiculite (V1), substrates mixed with organic fertilizer for three days (CP2 and V2), and three combinations cultivated with potatoes for 50 days (CP3, V3, and CV3—a 1:1 mix of coconut peat and vermiculite with organic fertilizer). Vermiculite naturally hosts a more diverse microbial community. After mixing with fertilizer and composting for 3 days, and 50 days of potato cultivation, fungal diversity decreased in both substrates. Coconut peat maintains higher bacterial diversity and richness compared to vermiculite, harboring more beneficial bacteria and fungi, resulting in a more complex microbial network. However, vermiculite shows lower bacterial diversity and richness, with an accumulation of pathogenic microorganisms. Among the 11 environmental factors tested, water-soluble nitrogen (WSN), total nitrogen (TN), available potassium (AK), total organic carbon (TOC) and air-filled porosity (AFP) were significantly associated with microbial succession in the substrate.The nutritional type composition and interaction patterns of indigenous microorganisms differ between vermiculite and coconut peat. Adding abundant nutrients significantly affects the stability and interaction of the entire microbial community, even post-potato cultivation. When using vermiculite for soilless cultivation, precise control and adjustment of nutrient addition quantity and frequency are essential.

Eupatorium fortunei Turcz, a perennial herb of the Asteraceae family, is one of the horticultural and medicinal plants used for curing various diseases and is widely distributed in China and other Asian countries. It possesses antibacterial, antimetastatic, antiangiogenic, and antioxidant properties along with anticancer potential. However, the intrageneric classification and phylogenetic relationships within Eupatorium have long been controversial due to the lack of high-resolution molecular markers, and the complete chloroplast (cp) genome sequencing has not been reported with new evolutionary insights. In the present study, E. fortunei was used as an experimental material, and its genome was sequenced using high-throughput sequencing technology. We assembled the complete cp genome, and a systematic analysis was conducted for E. fortunei, acquiring the correspondence of its NCBI accession number (OK545755). The results showed that the cp genome of E. fortunei is a typical tetrad structure with a total length of 152,401 bp, and the genome encodes 133 genes. Analysis of the complete cp genomes of 20 Eupatorieae shows that the number of simple sequence repeats (SSRs) ranged from 19 to 36 while the number of long sequence repeats was 50 in all cases. Eleven highly divergent regions were identified and are potentially useful for the DNA barcoding of Eupatorieae. Phylogenetic analysis among 22 species based on protein-coding genes strongly supported that E. fortunei is more closely related to Praxelis clematidea and belongs to the same branch. The genome assembly and analysis of the cp genome of E. fortunei will facilitate the identification, taxonomy, and utilization of E. fortunei as well as provide more accurate evidence for the taxonomic identification and localization of Asteraceae plants.

The Hypericaceae family, comprising nine genera and over seven hundred species, includes Hypericum plants traditionally used for medicinal purposes. In this study, we performed high-throughput sequencing on three Hypericum species: Hypericum acmosepalum, Hypericum addingtonii, and Hypericum beanii, and conducted comparative genomic analyses with related species. The chloroplast genome sizes were 152,654 bp, 122,570 bp, and 137,652 bp, respectively, with an average GC content of 37.9%. All genomes showed a quadripartite structure, with significant variations in IR regions (3231–26,846 bp). The total number of genes ranged from 91 to 129. SSRs were predominantly located in the LSC region, with mononucleotide repeats being dominant. Comparative analysis identified several hotspot regions, including accD, rpoC2, rpoB, and rpl22 in the LSC region and matK, rpl32, rpl33, and rps4 in the SSC region. Nucleotide polymorphism analysis revealed eight highly variable regions and eleven gene loci, providing potential molecular markers for species identification. Phylogenetic analysis indicated that Triadenum and Cratoxylum are closely related to Hypericum, with H. acmosepalum and H. beanii being closest relatives and Hypericum hookerianum as their sister species. These findings provide molecular tools for species identification and insights for conservation strategies of medicinal Hypericum species.

As the global arid climate intensifies and the groundwater becomes increasingly scarce, drought stress has become a major challenge to plant growth and development worldwide, especially causing yield reduction and extinction of cultivated crops. In a large number of drought resistance studies, DNA methylation has been found dynamically associated with response to drought stress in plants by regulating gene expression and developments in plants, but the specific mechanisms are not yet clear. In this article, the current advances of research have been summarized on DNA methylation response to drought stress in various plant species, in terms of methylation detection methods, mechanisms of pattern changes (DNA de novo methylation, DNA maintenance methylation, and DNA demethylation), and its response to drought stress. With Most of the studies showed significant changes in genome or gene promoter methylation levels in plants subjected to drought stress, but the identification of the genes and pathways involved is still in the minority. The aim is to provide references for in-depth research on the response of plants to drought stress through epigenetics, and to uncover drought resistance genes regulated by DNA methylation, specific signaling pathways, and molecular mechanisms of action.