Unfolding molecular switches for salt stress resilience in soybean: recent advances and prospects for salt-tolerant smart plant production

Genetic transformation of GmFBX322 gene and salt tolerance physiology in soybean

Soybean is one of the most important food crops, breeding salt-tolerant soybean varieties is of great significance to alleviate soybean shortage. In this study, the F-box protein family homologous gene GmFBX322 was cloned from the soybean variety Williams 82 and overexpressed in the Shennong 9 soybean variety to further study and explore the physiological mechanism of soybean salt tolerance. GmFBX322 was constructed on the vector pTF101:35S, and integrated into the genome of Shennong 9 soybean variety by Agrobacterium EHA101-mediated cotyledonary node transformation technology, and 4 overexpressed transgenic lines were obtained, molecular assays were performed on the transformed plants. The expression of GmFBX322 was detected by qRT-PCR and it was found that the leaves of the 4 transgenic lines increased by 2.49, 2.46, 2.77, 2.95 times compared with the wild type; after salt treatment for 12 hours, it was found that the expression of wild type Shennong 9 Inducible expression of GmFBX322. After 72 hours of salt treatment, the leaves of wild-type Shennong 9 soybean plants showed obvious wilting and chlorosis, while the leaves of GmFBX322 plants overexpressing GmFBX322 showed no obvious changes. The leaves were taken at 0, 6, 12, 24, and 48 hours of salt stress to determine the antioxidant activity. Ability and osmotic adjustment level, etc. The results showed that the catalase activity in the leaves of the transgenic lines 2265, 2267, 2269, and 2271 was 2.47, 2.53, 3.59, 2.96 times that of the wild-type plant after 48 hours of salt treatment; the soluble sugar content was 1.22, 1.14, and 1.22 of the wild-type plant. 1.14, 1.57 times; the proline content is 2.20, 1.83, 1.65, 1.84 times of the wild type. After comparing the physiological indicators determined by the experiment, the transgenic lines performed better than the control group, indicating that overexpression of GmFBX322 can enhance the salt tolerance of soybean plants. To verify the function of GmFBX322 gene related to stress resistance, add it to the candidate gene of stress resistance, and provide scientific basis for the selection and breeding of salt-tolerant varieties.

Genome-Wide Identification of the Whirly Gene Family and Its Potential Function in Low Phosphate Stress in Soybean (Glycine max)

The Whirly (WHY) gene family, functioning as transcription factors, plays an essential role in the regulation of plant metabolic responses, which has been demonstrated across multiple species. However, the WHY gene family and its functions in soybean remains unclear. In this paper, we conducted genome-wide screening and identification to characterize the WHY gene family. Seven WHY members were identified and randomly distributed across six chromosomes. The phylogenetic evolutionary tree of WHY genes in soybean and other species was divided into five clades. An in-depth analysis revealed that segmental duplications significantly contributed to the expansion of GmWHYs, and the GmWHY gene members may have experienced evolutionary pressure for purifying selection in soybeans. The analysis of promoter Cis-elements in GmWHYs suggested their potential significance in addressing diverse stress conditions. The expression patterns of GmWHYs exhibited tissue-specific variations throughout the different stages of soybean development. Additionally, six GmWHY genes exhibited different responses to low phosphate stress. These findings will provide a theoretical basis and valuable reference for the future exploration of WHY gene function.

Designing salt stress-resilient crops: Current progress and future challenges

Excess soil salinity affects large regions of land and is a major hindrance to crop production worldwide. Therefore, understanding the molecular mechanisms of plant salt tolerance has scientific importance and practical significance. In recent decades, studies have characterized hundreds of genes associated with plant responses to salt stress in different plant species. These studies have substantially advanced our molecular and genetic understanding of salt tolerance in plants and have introduced an era of molecular design breeding of salt-tolerant crops. This review summarizes our current knowledge of plant salt tolerance, emphasizing advances in elucidating the molecular mechanisms of osmotic stress tolerance, salt-ion transport and compartmentalization, oxidative stress tolerance, alkaline stress tolerance, and the trade-off between growth and salt tolerance. We also examine recent advances in understanding natural variation in the salt tolerance of crops and discuss possible strategies and challenges for designing salt stress-resilient crops. We focus on the model plant Arabidopsis (Arabidopsis thaliana) and the four most-studied crops: rice (Oryza sativa), wheat (Triticum aestivum), maize (Zea mays), and soybean (Glycine max).

Salt Tolerance in Soybeans: Focus on Screening Methods and Genetics

Salinity greatly affects the production of soybeans in arid and semi-arid lands around the world. The responses of soybeans to salt stress at germination, emergence, and other seedling stages have been evaluated in multitudes of studies over the past decades. Considerable salt-tolerant accessions have been identified. The association between salt tolerance responses during early and later growth stages may not be as significant as expected. Genetic analysis has confirmed that salt tolerance is distinctly tied to specific soybean developmental stages. Our understanding of salt tolerance mechanisms in soybeans is increasing due to the identification of key salt tolerance genes. In this review, we focus on the methods of soybean salt tolerance screening, progress in forward genetics, potential mechanisms involved in salt tolerance, and the importance of translating laboratory findings into field experiments via marker-assisted pyramiding or genetic engineering approaches, and ultimately developing salt-tolerant soybean varieties that produce high and stable yields. Progress has been made in the past decades, and new technologies will help mine novel salt tolerance genes and translate the mechanism of salt tolerance into new varieties via effective routes.

Molecular switches in plant stress adaptation

Climate change poses a significant threat to the global ecosystem, prompting plants to use various adaptive mechanisms via molecular switches to combat biotic and abiotic stress factors. These switches activate stress-induced pathways by altering their configuration between stable states. In this review, we investigated the regulation of molecular switches in different plant species in response to stress, including the stress-regulated response of multiple switches in Arabidopsis thaliana. We also discussed techniques for developing stress-resilient crops using molecular switches through advanced biotechnological tools. The literature search, conducted using databases such as PubMed, Google Scholar, Web of Science, and SCOPUS, utilized keywords such as molecular switch, plant adaptation, biotic and abiotic stresses, transcription factors, Arabidopsis thaliana, and crop improvement. Recent studies have shown that a single molecular switch can regulate multiple stress networks, and multiple switches can regulate a single stress condition. This multifactorial understanding provides clarity to the switch regulatory network and highlights the interrelationships of different molecular switches. Advanced breeding techniques, along with genomic and biotechnological tools, have paved the way for further research on molecular switches in crop improvement. The use of synthetic biology in molecular switches will lead to a better understanding of plant stress biology and potentially bring forth a new era of stress-resilient, climate-smart crops worldwide.

Co-Expression Network Analysis of the Transcriptome Identified Hub Genes and Pathways Responding to Saline-Alkaline Stress in Sorghum bicolor L

Soil salinization, an intractable problem, is becoming increasingly serious and threatening fragile natural ecosystems and even the security of human food supplies. Sorghum (Sorghum bicolor L.) is one of the main crops growing in salinized soil. However, the tolerance mechanisms of sorghum to saline-alkaline soil are still ambiguous. In this study, RNA sequencing was carried out to explore the gene expression profiles of sorghum treated with sodium bicarbonate (150 mM, pH = 8.0, treated for 0, 6, 12 and 24 h). The results show that 6045, 5122, 6804, 7978, 8080 and 12,899 differentially expressed genes (DEGs) were detected in shoots and roots after 6, 12 and 24 h treatments, respectively. GO, KEGG and weighted gene co-expression analyses indicate that the DEGs generated by saline-alkaline stress were primarily enriched in plant hormone signal transduction, the MAPK signaling pathway, starch and sucrose metabolism, glutathione metabolism and phenylpropanoid biosynthesis. Key pathway and hub genes (TPP1, WRKY61, YSL1 and NHX7) are mainly related to intracellular ion transport and lignin synthesis. The molecular and physiological regulation processes of saline-alkali-tolerant sorghum are shown by these results, which also provide useful knowledge for improving sorghum yield and quality under saline-alkaline conditions.

"Bet hedging" against climate change in developing and adult animals: roles for stochastic gene expression, phenotypic plasticity, epigenetic inheritance and adaptation

Animals from embryos to adults experiencing stress from climate change have numerous mechanisms available for enhancing their long-term survival. In this review we consider these options, and how viable they are in a world increasingly experiencing extreme weather associated with climate change. A deeply understood mechanism involves natural selection, leading to evolution of new adaptations that help cope with extreme and stochastic weather events associated with climate change. While potentially effective at staving off environmental challenges, such adaptations typically occur very slowly and incrementally over evolutionary time. Consequently, adaptation through natural selection is in most instances regarded as too slow to aid survival in rapidly changing environments, especially when considering the stochastic nature of extreme weather events associated with climate change. Alternative mechanisms operating in a much shorter time frame than adaptation involve the rapid creation of alternate phenotypes within a life cycle or a few generations. Stochastic gene expression creates multiple phenotypes from the same genotype even in the absence of environmental cues. In contrast, other mechanisms for phenotype change that are externally driven by environmental clues include well-understood developmental phenotypic plasticity (variation, flexibility), which can enable rapid, within-generation changes. Increasingly appreciated are epigenetic influences during development leading to rapid phenotypic changes that can also immediately be very widespread throughout a population, rather than confined to a few individuals as in the case of favorable gene mutations. Such epigenetically-induced phenotypic plasticity can arise rapidly in response to stressors within a generation or across a few generations and just as rapidly be "sunsetted" when the stressor dissipates, providing some capability to withstand environmental stressors emerging from climate change. Importantly, survival mechanisms resulting from adaptations and developmental phenotypic plasticity are not necessarily mutually exclusive, allowing for classic "bet hedging". Thus, the appearance of multiple phenotypes within a single population provides for a phenotype potentially optimal for some future environment. This enhances survival during stochastic extreme weather events associated with climate change. Finally, we end with recommendations for future physiological experiments, recommending in particular that experiments investigating phenotypic flexibility adopt more realistic protocols that reflect the stochastic nature of weather.

Advances in CRISPR/Cas9-based research related to soybean [Glycine max (Linn.) Merr] molecular breeding

Soybean [Glycine max (Linn.) Merr] is a source of plant-based proteins and an essential oilseed crop and industrial raw material. The increase in the demand for soybeans due to societal changes has coincided with the increase in the breeding of soybean varieties with enhanced traits. Earlier gene editing technologies involved zinc finger nucleases and transcription activator-like effector nucleases, but the third-generation gene editing technology uses clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9). The rapid development of CRISPR/Cas9 technology has made it one of the most effective, straightforward, affordable, and user-friendly technologies for targeted gene editing. This review summarizes the application of CRISPR/Cas9 technology in soybean molecular breeding. More specifically, it provides an overview of the genes that have been targeted, the type of editing that occurs, the mechanism of action, and the efficiency of gene editing. Furthermore, suggestions for enhancing and accelerating the molecular breeding of novel soybean varieties with ideal traits (e.g., high yield, high quality, and durable disease resistance) are included.

Overexpression of TCP9-like gene enhances salt tolerance in transgenic soybean

TEOSINTE BRANCHED1/CYCLOIDEA/PROLIFERATING CELL FACTOR (TCP) transcription factors are a plant-specific family and play roles in plant growth, development, and responses to biotic and abiotic stresses. However, little is known about the functions of the TCP transcription factors in the soybean cultivars with tolerance to salt stress. In this study, TCP9-like, a TCP transcription factor, was identified in the soybean cultivars exposed to salt stress. The expression of TCP9-like gene in the roots of salt-tolerant soybean cultivars was higher than that in salt-sensitive cultivars treated with NaCl. The overexpression of TCP9-like enhanced the salt tolerance of the salt-sensitive soybean cultivar 'DN50'. In T2 generation, the plants with TCP9-like overexpression had significantly lower Na+ accumulation and higher K+ accumulation than the WT plants exposed to 200 or 250 mmol/L NaCl. The K+/Na+ ratio in the plants overexpressing TCP9-like was significantly higher than that in WT plants treated with 200 mmol/L NaCl. Meanwhile, the overexpression of TCP9-like up-regulated the expression levels of GmNHX1, GmNHX3, GmSOS1, GmSOS2-like, and GmHKT1, which were involved in the K+/Na+ homeostasis pathway. The findings indicated that TCP9-like mediated the regulation of both Na+ and K+ accumulation to improve the tolerance of soybean to salt stress.