Bioscience Method 2025, Vol.16 http://bioscipublisher.com/index.php/bm © 2025 BioSci Publisher, registered at the publishing platform that is operated by Sophia Publishing Group, founded in British Columbia of Canada. All Rights Reserved.
Bioscience Method 2025, Vol.16 http://bioscipublisher.com/index.php/bm © 2025 BioSci Publisher, registered at the publishing platform that is operated by Sophia Publishing Group, founded in British Columbia of Canada. All Rights Reserved. BioSci Publisher is an international Open Access publisher specializing in bioscience methods, including technology, lab tool, statistical software and relative fields registered at the publishing platform that is operated by Sophia Publishing Group (SPG), founded in British Columbia of Canada. Publisher BioSci Publisher Editedby Editorial Team of Bioscience Methods Email: edit@bm.bioscipublisher.com Website: http://bioscipublisher.com/index.php/bm Address: 11388 Stevenston Hwy, PO Box 96016, Richmond, V7A 5J5, British Columbia Canada Bioscience Methods (ISSN 1925-1920) is an open access, peer reviewed journal published online by BioSci Publisher. The journal publishes all the latest and outstanding research articles, letters and reviews in all areas of bioscience, the range of topics including (but are not limited to) technology review, technique know-how, lab tool, statistical software and known technology modification. Case studies on technologies for gene discovery and function validation as well as genetic transformation. All the articles published in Bioscience Methods are Open Access, and are distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. BioSci Publisher uses CrossCheck service to identify academic plagiarism through the world’s leading plagiarism prevention tool, iParadigms, and to protect the original authors’ copyrights.
Bioscience Methods (online), 2025, Vol.16, No.1 ISSN 1925-1920 https://bioscipublisher.com/index.php/bm © 2025 BioSci Publisher, registered at the publishing platform that is operated by Sophia Publishing Group, founded in British Columbia of Canada. All Rights Reserved. Latest Content Latest Progress on the Effects of Drought, Salinity, and Temperature Stress on Sweet Potatoes and Their Resistance Mechanisms Lin Zhao, Xinhao Zhou, Li Qiu, Liping Tao Bioscience Methods, 2025, Vol.16, No.1, 1-10 Insights into Optimizing Cultivation Practices for Enhanced Yield and Quality in Fresh-Eating Maize Meili Chen Bioscience Methods, 2025, Vol.16, No.1, 11-22 Recent Insights into Molecular Breeding for High Yield Sweet Potato Cultivars Liang Zhang, Honghu Ji, Meiqiao Jiang, Ziyu Zhong, Linrun Cheng Bioscience Methods, 2025, Vol.16, No.1, 23-32 Adaptability of Drill Seeding and Broadcast Seeding in Rice-Wheat Rotation Systems Xiaohong Shen, Jie Shen, Huazhong Shen Bioscience Methods, 2025, Vol.16, No.1, 33-40 Meta-Analysis of Sweet Potato Storage Methods and Their Impact on Quality Hangqi Cai, Renxiang Cai, Liang Zhang Bioscience Methods, 2025, Vol.16, No.1, 41-51
Bioscience Methods 2025, Vol.16, No.1, 1-10 http://bioscipublisher.com/index.php/bm 1 Review Article Open Access Latest Progress on the Effects of Drought, Salinity, and Temperature Stress on Sweet Potatoes and Their Resistance Mechanisms LinZhao1 , Xinhao Zhou2, Li Qiu3, Liping Tao4 1 Crop (Ecology) Research Institute of Hangzhou Academy of Agricultural Sciences, Hangzhou, 311300, Zhejiang, China 2 Young Couple Family Farm in Lin'an District, Hangzhou, Hangzhou, 311300, Zhejiang, China 3 Zhejiang Yuhe Yueyue Agricultural Development Co., Ltd, Hangzhou, 311300, Zhejiang, China 4 People’s Government of Tianmushan Town, Lin'an District, Hangzhou, 311300, Zhejiang, China Corresponding email: zhaolin0227@163.com Bioscience Methods, 2025, Vol.16, No.1 doi: 10.5376/bm.2025.16.0001 Received: 23 Jul., 2024 Accepted: 30 Dec., 2024 Published: 15 Jan., 2025 Copyright © 2025 Zhao et al., This is an open access article published under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Preferred citation for this article: Zhao L., Zhou X.H., Qiu L., Tao L.P., 2025, Latest progress on the effects of drought, salinity, and temperature stress on sweet potatoes and their resistance mechanisms, Bioscience Methods, 16(1): 1-10 (doi: 10.5376/bm.2025.16.0001) Abstract Abiotic stresses such as drought, salinity, extreme temperatures, and heavy metal toxicity pose significant challenges to global agriculture, impacting crop yields and food security. Sweet potato (Ipomoea batatas), an essential staple crop, is particularly affected by these stresses, necessitating enhanced tolerance mechanisms to maintain productivity. This study examines the physiological, molecular, and genetic mechanisms that support the abiotic stress tolerance of sweet potatoes, with a focus on key traits such as water use efficiency, osmotic regulation, and antioxidant defense. At the same time, specific genes and transcription factors involved in stress response pathways, including ABA and ROS signaling, as well as the role of epigenetic modifications in adapting to environmental stress, were also analyzed. Additionally, breeding strategies and biotechnological interventions such as CRISPR and marker-assisted selection are discussed, emphasizing their role in developing stress-resilient varieties. Case studies on drought and salinity-resistant sweet potato varieties highlight practical outcomes of current breeding programs. This study summarizes the limitations of existing methods and proposes directions for future research. Enhancing abiotic stress tolerance in sweet potato remains a crucial goal, with promising potential through integrated breeding and biotechnological approaches to support sustainable agriculture. Keywords Sweet potato; Abiotic stress tolerance; Drought resistance; Salinity tolerance; Molecular mechanisms 1 Introduction Abiotic stress, including drought, salinity, extreme temperatures, and oxidative stress, poses significant challenges to agricultural productivity worldwide (Tao and Han, 2024; Zhu and Shen, 2024). These stressors can severely limit crop growth, yield, and quality, leading to substantial economic losses and food insecurity. The increasing frequency and intensity of these stresses due to climate change further exacerbate the problem, necessitating the development of crops with enhanced tolerance to abiotic stresses (Fan et al., 2012; Demirel et al., 2020; Villalobos-López et al., 2022). Sweet potato (Ipomoea batatas) is a vital staple crop globally, known for its high nutritional value and adaptability to diverse environmental conditions. It ranks as the seventh most important food crop, providing essential nutrients and calories to millions of people, particularly in developing countries (Liu et al., 2023). Despite its resilience, sweet potato production is still significantly affected by abiotic stresses such as drought, salinity, and low temperatures, which can lead to reduced yields and compromised food security (Fan et al., 2015; Ren et al., 2020). Enhancing the abiotic stress tolerance of sweet potato is therefore crucial for stabilizing its production and ensuring food availability in stress-prone regions. This study seeks to highlight strategies for sweet potato to cope with various abiotic stresses by examining recent advancements in genetic, physiological, and molecular research, exploring the roles of specific genes and proteins-such as betaine aldehyde dehydrogenase (BADH), peroxidases (PRXs), and sucrose non-fermenting-1 related protein kinase-1 (SnRK1)-in enhancing stress tolerance, and discussing the potential of biotechnological
Bioscience Methods 2025, Vol.16, No.1, 1-10 http://bioscipublisher.com/index.php/bm 2 approaches, including gene overexpression and genetic transformation, for developing stress-resistant sweet potato varieties, aiming to provide insights to guide future research and breeding programs to improve sweet potato’s resilience to abiotic stress. 2 Types of Abiotic Stresses Affecting Sweet Potato Sweet potato (Ipomoea batatas) is a vital crop globally, but its productivity is significantly affected by various abiotic stresses. These stresses include drought, salinity, extreme temperatures, and heavy metal toxicity. Understanding the mechanisms of tolerance to these stresses is crucial for developing resilient sweet potato cultivars. 2.1 Drought stress Drought stress is one of the most critical factors limiting sweet potato yield. Drought conditions lead to reduced photosynthetic activity, oxidative stress, and impaired growth (Sapakhova et al., 2023). Studies have shown that the overexpression of certain genes, such as IbSnRK1, enhances drought tolerance by activating the reactive oxygen species (ROS) scavenging system and controlling stomatal closure via the abscisic acid (ABA) signaling pathway (Ren et al., 2020). Additionally, the IbBBX24-IbTOE3-IbPRX17 module has been identified to improve drought tolerance by scavenging ROS, thereby reducing oxidative damage (Figure 1) (Zhang et al., 2021). Transcriptomic analyses have revealed that drought-tolerant cultivars regulate flavonoid and carbohydrate biosynthesis/metabolism to mitigate drought stress (Liu et al., 2023). Figure 1 Proposed working model of the IbBBX24-IbTOE3-IbPRX17 regulatory module in abiotic stress responses. IbBBX24, IbTOE3 and IbPRX17 expression is induced by NaCl, polyethylene glycol 6000 (PEG6000), and H2O2 treatments. IbBBX24 and IbTOE3 bindseparatelytotheGT-1motifat-213 bpandtheTTTGTTmotifat-141 bpinthe IbPRX17 promoter and activate IbPRX17 transcription. Interaction between IbBBX24 and IbTOE3 enhances the ability of IbBBX24 to activate IbPRX17 transcription bybindingtheGT-1motifat-213 bpofitspromoter.Inaddition,overexpressionofIbBBX24, IbTOE3 and IbPRX17 promotes reactive oxygen species (ROS) scavenging under abiotic stress conditions, leading to abiotic stress tolerance. Brown circle, IbBBX24; blue circle, IbTOE3; green circles, IbPRX17; red triangles, activated transcription (Adopted from Zhang et al., 2021) 2.2 Salinity stress Salinity stress adversely affects sweet potato by causing ionic imbalance and osmotic stress, leading to reduced growth and yield. The overexpression of genes such as IbMIPS1 and IbC3H18 has been shown to enhance salt tolerance by up-regulating stress-responsive genes involved in ROS scavenging, ABA signaling, and ion transport pathways (Zhai et al., 2016; Zhang et al., 2019). Furthermore, the introduction of the AtNHX1 gene, which
Bioscience Methods 2025, Vol.16, No.1, 1-10 http://bioscipublisher.com/index.php/bm 3 encodes a vacuolar Na+/H+ antiporter, into sweet potato has demonstrated improved salt tolerance by enhancing Na+ compartmentalization into vacuoles, thus maintaining ionic homeostasis and reducing cellular damage. 2.3 Temperature stress (heat and cold) Sweet potato is also susceptible to temperature extremes, including both heat and cold stress. Heat stress can lead to protein denaturation and membrane instability, while cold stress can cause cellular damage and metabolic disruptions. The overexpression of the StnsLTP1 gene in transgenic potato plants has shown enhanced tolerance to heat stress by improving cell membrane integrity and activating antioxidative defense mechanisms (Gangadhar et al., 2016). Similarly, the overexpression of the SoBADH gene in sweet potato has been found to improve cold tolerance by increasing glycine betaine (GB) accumulation, which helps in maintaining cell membrane integrity and reducing ROS production (Fan et al., 2012). Additionally, the AtNHX1 gene has been shown to confer cold tolerance by enhancing ROS scavenging and maintaining cellular homeostasis (Fan et al., 2015). 2.4 Heavy metal toxicity Heavy metal toxicity, although less studied in sweet potato, poses a significant threat to plant health by inducing oxidative stress and disrupting cellular functions. The mechanisms of tolerance to heavy metals involve the activation of antioxidative defense systems and the sequestration of heavy metals into vacuoles. While specific studies on heavy metal tolerance in sweet potato are limited, the general principles of ROS scavenging and ion compartmentalization observed in other abiotic stresses are likely applicable. 3 Physiological Mechanisms of Abiotic Stress Tolerance in Sweet Potato 3.1 Water-use efficiency and stomatal regulation Water-use efficiency (WUE) and stomatal regulation are critical for sweet potato’s adaptation to abiotic stresses such as drought and salinity. The IbSnRK1 gene has been shown to play a significant role in controlling stomatal closure via the abscisic acid (ABA) signaling pathway, thereby enhancing drought and salt tolerance. Overexpression of IbSnRK1 in transgenic sweet potato plants resulted in increased ABA content and improved stomatal regulation, which are essential for maintaining water balance under stress conditions (Ren et al., 2020). Additionally, the non-tandem CCCH-type zinc-finger protein IbC3H18 regulates the expression of stress-responsive genes involved in stomatal closure, further contributing to enhanced water-use efficiency (Zhang et al., 2019). 3.2 Osmotic adjustment and ion homeostasis Osmotic adjustment and ion homeostasis are vital for sweet potato's resilience to abiotic stresses. The overexpression of the IbMIPS1 gene in sweet potato has been shown to enhance osmotic adjustment by increasing the levels of inositol, proline, and other osmolytes, which help maintain cell turgor and protect cellular structures under salt and drought stress (Zhai et al., 2016). Furthermore, the IbSnRK1 gene also contributes to ion homeostasis by increasing potassium (K+) content and reducing sodium (Na+) accumulation, thereby mitigating the detrimental effects of salt stress. The accumulation of glycine betaine (GB) through the overexpression of the SoBADH gene also aids in osmotic adjustment and ion homeostasis, enhancing the plant's tolerance to multiple abiotic stresses (Fan et al., 2012). 3.3 Antioxidant defense system The antioxidant defense system is crucial for scavenging reactive oxygen species (ROS) generated under abiotic stress conditions (Golldack et al., 2014). The IbBBX24-IbTOE3-IbPRX17 module has been identified as a key player in enhancing the antioxidant defense system in sweet potato. Overexpression of IbBBX24 and IbPRX17 leads to increased peroxidase activity and reduced H2O2 accumulation, thereby improving tolerance to salt and drought stresses (Zhang et al., 2021). Similarly, the IbSnRK1 gene enhances the activities of ROS-scavenging enzymes, such as superoxide dismutase (SOD) and catalase (CAT), which are essential for mitigating oxidative damage (Figure 2). The overexpression of the IbC3H18 gene also upregulates genes involved in the ROS scavenging system, further bolstering the plant's antioxidant defenses.
Bioscience Methods 2025, Vol.16, No.1, 1-10 http://bioscipublisher.com/index.php/bm 4 Figure 2 Diagram of a proposed model for regulation of IbSnRK1 in abiotic stress tolerance in transgenic sweet potato. ↑ indicates up-regulation of genes coding these enzymes (proteins) (Adopted from Ren et al., 2020) 3.4 Heat shock proteins and molecular chaperones Heat shock proteins (HSPs) and molecular chaperones play a pivotal role in protecting sweet potato from abiotic stresses by maintaining protein stability and preventing aggregation. HSPs are dynamically regulated in response to stress and are involved in the detoxification of ROS, thereby enhancing membrane stability and overall stress tolerance (Haq et al., 2019). The expression of HSPs is often induced by ROS signaling, which acts as a trigger for their production. This regulatory mechanism ensures that HSPs are available to counteract the damaging effects of abiotic stresses, such as heat and drought. The role of HSPs in sweet potato is further supported by the upregulation of stress-related genes, including those encoding HSPs, in transgenic plants overexpressing various stress-responsive genes (Gangadhar et al., 2016). 4 Molecular and Genetic Mechanisms Underpinning Stress Tolerance 4.1 Key genes involved in abiotic stress response Several key genes have been identified in sweet potato that contribute to abiotic stress tolerance. The gene IbC3H18, a non-tandem CCCH-type zinc-finger protein, is one such gene that enhances tolerance to salt, drought, and oxidative stresses by regulating the expression of stress-responsive genes involved in ROS scavenging, ABA signaling, photosynthesis, and ion transport pathways. Another important gene is IbSnRK1, which confers tolerance to salt, drought, and cold by activating the ROS scavenging system and controlling stomatal closure via the ABA signaling pathway (Ren et al., 2020). Additionally, IbMIPS1 enhances salt and drought tolerance by up-regulating genes involved in inositol biosynthesis, PI and ABA signaling pathways, and the ROS-scavenging system (Zhai et al., 2016). 4.2 Role of transcription factors Transcription factors (TFs) play a crucial role in regulating gene expression in response to abiotic stress. The ItfWRKY70 transcription factor from Ipomoea trifida has been shown to increase drought tolerance in sweet potato by up-regulating genes involved in ABA biosynthesis, stress response, and the ROS-scavenging system (Sun et al., 2022). The IbMYB73 transcription factor regulates root growth and stress tolerance by influencing the transcription of genes in the ABA pathway and forming homodimers to activate the transcription of the abscisic
Bioscience Methods 2025, Vol.16, No.1, 1-10 http://bioscipublisher.com/index.php/bm 5 acid-responsive protein IbGER5. Another significant TF is IbBBX24, which activates the expression of the class III peroxidase gene IbPRX17 to enhance salt and drought tolerance by scavenging ROS (Zhang et al., 2021). 4.3 Signaling pathways in stress response Signaling pathways such as ABA and ROS play pivotal roles in the abiotic stress response in sweet potato. The IbSnRK1 gene activates the ROS scavenging system and controls stomatal closure via the ABA signaling pathway, thereby enhancing tolerance to salt, drought, and cold stresses. The IbCAR1 gene, a C2-domain abscisic acid-related protein, improves salt tolerance by relying on the ABA signal transduction pathway and activating the ROS-scavenging system (You et al., 2022). Additionally, the IbNAC3 transcription factor modulates combined salt and drought stresses by promoting the transcription of genes involved in ABA signaling and ROS scavenging (Meng et al., 2022). 4.4 Epigenetic modifications and gene regulation Epigenetic modifications and gene regulation are essential for the adaptation of sweet potato to abiotic stress. The IbC3H18 gene functions as a nuclear transcriptional activator and regulates the expression of a range of abiotic stress-responsive genes (Zhang et al., 2019). The IbMYB73 transcription factor influences the transcription of genes involved in the ABA pathway, demonstrating the importance of transcriptional regulation in stress tolerance (Wang et al., 2023). Furthermore, the IbBBX24-IbTOE3-IbPRX17 module elucidates the mechanism of transcriptional regulation in response to abiotic stress by modulating the expression of genes encoding ROS scavenging enzymes. 5 Breeding and Biotechnological Approaches for Enhancing Stress Tolerance 5.1 Conventional breeding techniques Conventional breeding techniques have been instrumental in developing sweet potato varieties with enhanced tolerance to abiotic stresses. These methods involve selecting and cross-breeding plants that exhibit desirable traits such as drought and salinity tolerance. The genetic diversity within the genus Solanum, for example, has been a valuable resource for breeding programs aimed at improving stress tolerance in related crops like sweet potato (Tiwari et al., 2022). However, the multigenic nature of abiotic stress tolerance poses a significant challenge, often requiring the integration of multiple traits to achieve the desired level of resilience (Esmaeili et al., 2022). 5.2 Genetic engineering and CRISPR technology Genetic engineering has emerged as a powerful tool for enhancing abiotic stress tolerance in sweet potato. Techniques such as the overexpression of stress-related genes have shown promising results. For instance, the introduction of the Spinacia oleracea betaine aldehyde dehydrogenase (SoBADH) gene into sweet potato has significantly improved its tolerance to salt, oxidative stress, and low temperatures by enhancing glycine betaine biosynthesis (Fan et al., 2012). Additionally, CRISPR-Cas9 technology offers precise genome editing capabilities, allowing for the targeted modification of genes involved in stress responses. This approach has the potential to create novel quantitative trait loci for abiotic stress tolerance by targeting regulatory sequences and promoters (Zafar et al., 2020). 5.3 Marker-assisted selection and genomic approaches Marker-assisted selection (MAS) has revolutionized the breeding process by enabling the rapid and accurate selection of stress-tolerant traits. This technique utilizes molecular markers linked to desirable traits, thereby accelerating the breeding cycle and increasing the precision of selection (Wani et al., 2018). Advances in genomics, such as high-throughput genotyping and multi-omics platforms, have further enhanced the effectiveness of MAS. These tools facilitate the identification of key genes and pathways involved in stress tolerance, enabling the development of sweet potato varieties with improved resilience to abiotic stresses (Villalobos-López et al., 2022). 5.4 Integrating biotechnology with breeding programs The integration of biotechnological approaches with conventional breeding programs holds great promise for the
Bioscience Methods 2025, Vol.16, No.1, 1-10 http://bioscipublisher.com/index.php/bm 6 development of sweet potato varieties with enhanced abiotic stress tolerance. By combining the strengths of genetic engineering, CRISPR technology, and marker-assisted selection, it is possible to achieve more robust and resilient crops. For example, the overexpression of transcription factors such as IbBBX24 and IbTOE3 has been shown to enhance ROS scavenging and improve tolerance to salt and drought stresses in sweet potato (Zhang et al., 2021). Similarly, the manipulation of genes involved in inositol biosynthesis and ABA signaling pathways has demonstrated significant improvements in stress tolerance and resistance to biotic stresses (Zhai et al., 2016). These integrated approaches not only stabilize yield production under unfavorable conditions but also provide novel germplasm for sweet potato cultivation on marginal lands (Anwar and Kim, 2020). 6 Case Studies 6.1 Drought-resistant sweet potato varieties Several studies have identified key genetic modifications that enhance drought resistance in sweet potato. For instance, the overexpression of the IbBBX24 and IbPRX17 genes has been shown to significantly improve drought tolerance by enhancing reactive oxygen species (ROS) scavenging capabilities (Zhang et al., 2021). Similarly, the IbMIPS1 gene, which is involved in myo-inositol biosynthesis, has been found to enhance drought tolerance by upregulating stress response pathways and increasing the accumulation of protective metabolites such as proline and trehalose. Another gene, IbC3H18, a non-tandem CCCH-type zinc-finger protein, has also been reported to increase drought tolerance by regulating the expression of stress-responsive genes and enhancing ROS scavenging. Additionally, the IbSnRK1 gene has been shown to confer drought tolerance by activating the ROS scavenging system and controlling stomatal closure via the ABA signaling pathway (Ren et al., 2020). 6.2 Salinity tolerance in sweet potato Salinity stress is another major abiotic factor limiting sweet potato productivity. The overexpression of the IbBBX24 and IbPRX17 genes not only improves drought tolerance but also enhances salinity tolerance by reducing H2O2 accumulation and increasing peroxidase activity (Figure 3). The IbMIPS1 gene has also been shown to confer salinity tolerance by upregulating genes involved in inositol biosynthesis and ABA signaling pathways, leading to increased accumulation of protective metabolites and reduced Na+ content. The IbC3H18 gene enhances salinity tolerance by regulating ion transport pathways and increasing ROS scavenging (Zhang et al., 2019). Furthermore, the overexpression of the AtNHX1 gene, which encodes a vacuolar Na+/H+ antiporter, has been demonstrated to improve salinity tolerance by enhancing Na+ compartmentalization into vacuoles, thereby maintaining high K+/Na+ ratios and reducing cell damage. 6.3 Results and key learnings from case studies The case studies on drought and salinity tolerance in sweet potato reveal several key mechanisms that contribute to enhanced abiotic stress tolerance. One common theme is the importance of ROS scavenging systems. Genes such as IbBBX24, IbPRX17, IbC3H18, and IbSnRK1 all play crucial roles in enhancing the plant's ability to scavenge ROS, thereby reducing oxidative damage under stress conditions. Another critical mechanism is the regulation of ion transport and compartmentalization, as demonstrated by the AtNHX1 gene, which helps maintain ionic balance and reduce toxicity under salinity stress (Fan et al., 2015). Additionally, the accumulation of protective metabolites such as proline, trehalose, and inositol is a recurring strategy for enhancing stress tolerance, as seen with the IbMIPS1 gene (Zhai et al., 2016). These findings highlight the potential of genetic engineering to develop sweet potato varieties with improved tolerance to multiple abiotic stresses (Zhao et al., 2022). By targeting key genes involved in ROS scavenging, ion transport, and metabolite accumulation, it is possible to create crops that can withstand harsh environmental conditions, thereby ensuring stable yield production. 7 Challenges and Future Directions 7.1 Limitations in current breeding programs Current breeding programs for sweet potato face several limitations in developing abiotic stress-tolerant varieties. Traditional breeding methods have primarily focused on traits such as yield and disease resistance, often neglecting abiotic stress tolerance (Kikuchi et al., 2015). The polygenic nature of stress tolerance traits
Bioscience Methods 2025, Vol.16, No.1, 1-10 http://bioscipublisher.com/index.php/bm 7 complicates the breeding process, as it involves multiple genes and complex interactions (Villalobos-López et al., 2022). Additionally, the lack of comprehensive phenotyping tools to assess belowground traits, such as root and tuber development, further hampers the breeding efforts (Harsselaar et al., 2021). The integration of advanced molecular tools and high-throughput phenotyping methods is essential to overcome these limitations and accelerate the development of stress-tolerant cultivars. Figure 3 IbBBX24 overexpression enhances tolerance to salt, drought and oxidative stresses in sweet potato. (a) Responses of IbBBX24-OE, IbBBX24-RNAi and wild-type (WT) sweet potato plants grown for 4 wk on Murashige & Skoog (MS) medium in control conditions (normal) or with 86 mM NaCl or 30% polyethylene glycol 6000 (PEG6000). (b) Responses of IbBBX24-OE, IbBBX24-RNAi and WT sweet potato plants grown hydroponically in half-strength Hoagland solution (normal) or half-strength Hoagland solution containing 86 mM NaCl or 30% PEG6000. (c) Responses of IbBBX24-OE, IbBBX24-RNAi and WT sweet potato plantsgrownintransplantingboxesundercontrolconditions(normal)orsubjectedto200 mMNaCl,droughtor200 μMmethyl viologen (MV). Representative photographs were taken after stress treatment for 4 wk (salt), 8 wk (drought) or 2b wk (MV). Data are shown as means ± SD (n = 3). **, Significant difference from WT at P < 0.01 based on Student’s t-test (Adopted from Zhang et al., 2021)
Bioscience Methods 2025, Vol.16, No.1, 1-10 http://bioscipublisher.com/index.php/bm 8 7.2 Technological and funding challenges The development of abiotic stress-tolerant sweet potato varieties is also constrained by technological and funding challenges. Advanced biotechnological approaches, such as CRISPR-Cas9 and transgenic techniques, hold promise for improving stress tolerance but require significant investment in infrastructure and expertise (Anwar and Kim, 2020). Moreover, the regulatory landscape for genetically modified organisms (GMOs) varies globally, posing additional hurdles for the commercialization of transgenic sweet potato varieties. Funding for research in this area is often limited, with a significant portion allocated to staple crops like rice and wheat, leaving root crops like sweet potato underfunded (Fan et al., 2012). Increased investment in research and development, along with streamlined regulatory processes, is crucial to harness the full potential of these technologies. 7.3 Future prospects in abiotic stress research Future research in abiotic stress tolerance in sweet potato should focus on several key areas. First, the identification and functional characterization of stress-responsive genes, such as IbBBX24, IbTOE3, and IbPRX17, can provide valuable targets for genetic engineering. The overexpression of these genes has shown to enhance tolerance to salt and drought stresses by improving ROS scavenging and maintaining cellular homeostasis (Zhang et al., 2021). The integration of omics technologies, including genomics, transcriptomics, and metabolomics, can offer a holistic understanding of the stress response mechanisms and identify novel candidate genes for breeding programs (Zhai et al., 2016; Demirel et al., 2020). The development of high-throughput phenotyping platforms, such as X-ray CT imaging, can facilitate the non-invasive monitoring of tuber growth and stress responses, thereby accelerating the selection of stress-tolerant genotypes. Lastly, collaborative efforts between public and private sectors, along with increased funding, are essential to translate research findings into practical applications and develop resilient sweet potato varieties capable of withstanding the challenges posed by climate change. 8 Conclusion The review of recent studies on abiotic stress tolerance in sweet potato highlights several key mechanisms that enhance the plant's resilience to adverse environmental conditions. The overexpression of genes such as Spinacia oleracea betaine aldehyde dehydrogenase (SoBADH) has been shown to improve tolerance to salt, oxidative stress, and low temperatures by increasing glycine betaine (GB) accumulation, which helps maintain cell membrane integrity and reduce reactive oxygen species (ROS) production. Similarly, the IbBBX24-IbTOE3-IbPRX17 module enhances stress tolerance by scavenging ROS, thereby improving the plant's resistance to salt and drought. The introduction of the AtNHX1 gene, which encodes a vacuolar Na+/H+ antiporter, has also been effective in improving salt and cold stress tolerance by enhancing Na+ compartmentalization and maintaining high K+/Na+ ratios. Additionally, the IbMYB73-IbGER5 module regulates root growth and stress tolerance through the abscisic acid (ABA) pathway, further contributing to the plant's resilience. The application of effective microorganisms (EMs) and nanomagnesium has also been shown to boost agronomic and physiological traits, enhancing the plant's defense mechanisms against salt stress. Future research should focus on the integrative and multi-gene approaches to enhance abiotic stress tolerance in sweet potato. Studies should explore the combined effects of multiple gene overexpressions, such as combining SoBADHwith IbBBX24 and AtNHX1, to create transgenic lines with broad-spectrum stress tolerance. Additionally, the role of non-tandem CCCH-type zinc-finger proteins like IbC3H18in regulating stress-responsive genes should be further investigated to understand their potential in improving stress resilience. The application of bio- and nanofertilizers, such as EMs and MgO nanoparticles, should be expanded to other stress conditions and crop varieties to validate their efficacy and optimize their use in sustainable agriculture. Moreover, the molecular mechanisms underlying the interaction between different stress pathways, such as the ABA signaling pathway and ROS scavenging systems, should be elucidated to develop more effective stress mitigation strategies. Enhancing abiotic stress tolerance in sweet potato is crucial for ensuring stable yield production under increasingly unpredictable climatic conditions. The integration of genetic engineering, molecular biology, and sustainable agricultural practices offers promising avenues for developing stress-resilient sweet potato varieties. By leveraging the synergistic effects of multiple stress-responsive genes and innovative agronomic practices, it is possible to create robust sweet potato cultivars capable of thriving in marginal lands and under various environmental stresses. Continued research and collaboration among scientists, agronomists, and farmers will be
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Bioscience Methods 2025, Vol.16, No.1, 11-22 http://bioscipublisher.com/index.php/bm 11 Research Insight Open Access Insights into Optimizing Cultivation Practices for Enhanced Yield and Quality in Fresh-Eating Maize Meili Chen Jinhua Wucheng Chenmeili Family Farm, Jinhua, 321075, Zhejiang, China Corresponding email: ameilove23@126.com Bioscience Methods, 2025, Vol.16, No.1 doi: 10.5376/bm.2025.16.0002 Received: 03 Nov., 2024 Accepted: 05 Jan., 2025 Published: 26 Jan., 2025 Copyright © 2025 Chen, This is an open access article published under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Preferred citation for this article: Chen M.L., 2025, Insights into optimizing cultivation practices for enhanced yield and quality in fresh-eating maize, Bioscience Methods, 16(1): 11-22 (doi: 10.5376/bm.2025.16.0002) Abstract The increasing consumer demand for high-yield and high-quality fresh-eating maize necessitates the adoption of scientific cultivation practices to enhance its yield and quality. This study reviews the latest advancements in optimizing cultivation practices for fresh maize, focusing on key strategies such as planting density, water and fertilizer management, integrated pest and disease control, mechanization, and smart technologies. Findings indicate that precise planting density and water-fertilizer management significantly improve yield and quality, while eco-friendly practices like intercropping and crop rotation enhance soil health and reduce pest risks. Moreover, intelligent monitoring and mechanized operations further boost management efficiency and product quality. Despite the immense potential of optimized cultivation practices in fresh maize production, challenges such as climate change, technical dissemination, and limitations of small-scale farming persist. Future efforts should integrate smart technologies with precision management, develop region-specific cultivation models, and promote sustainable agricultural practices. This study provides theoretical support and practical guidance for fresh maize producers, contributing to the development of efficient and sustainable modern agriculture. Keywords Fresh-eating maize; Cultivation optimization; Precision management; Ecological agriculture; Smart technologies 1 Introduction Fresh corn refers to a type of corn that is harvested during the milk ripening period,for fresh-eating ears or processing fresh corn kernels.The cultivation of fresh corn is of significant importance due to its multifaceted value as a food grain, vegetable, and economic crop. Fresh corn is not only a staple in many diets but also a crucial component of agricultural economies, providing substantial income for farmers and contributing to food security (Piao et al., 2016; Li et al., 2022; Zheng et al., 2023). The increasing demand for high yield and quality in the fresh corn market underscores the need for optimized cultivation practices that can meet consumer expectations and market standards (Ren et al., 2020; Capo et al., 2023; El-Syed et al., 2023). Proper cultivation management plays a pivotal role in enhancing the yield and quality of fresh corn. Techniques such as optimized fertilization, strategic planting patterns, and effective nutrient management have been shown to significantly improve crop performance. For instance, zigzag planting combined with deep nitrogen fertilization has been found to increase maize yield by optimizing root and canopy structures (Zheng et al., 2023). Similarly, the use of organic amendments like biochar and compost, alongside inorganic fertilizers, can enhance nitrogen use efficiency and yield, especially under challenging conditions such as water deficits (Zhou et al., 2022; El-Syed et al., 2023). This study aims to summarize the mechanisms by which optimized cultivation practices impact the yield and quality of fresh-eating maize and propose cultivation strategies suitable for different environments and market demands. By providing insights into effective agronomic practices, this study seeks to support sustainable intensification and enhance the economic viability of fresh-eating maize production in diverse agro-ecological zones. 2 Key Factors Affecting Yield and Quality of Fresh Corn 2.1 Variety characteristics Fresh corn is mainly divided into sweet corn, waxy corn, and sweet-waxy corn (Wang et al.,2015).The yield and quality of fresh corn are significantly influenced by the type of corn variety. Sweet corn, supersweet corn, and
Bioscience Methods 2025, Vol.16, No.1, 11-22 http://bioscipublisher.com/index.php/bm 12 waxy corn each have distinct characteristics that affect their performance (Zhou and Hong, 2024). Sweet corn varieties, such as those studied in Turkey, show significant differences in yield and quality traits like flowering time, plant length, and grain yield. Supersweet corn, known for its high sugar retention post-harvest, demonstrates a high potential for yield and quality, as seen in the Hybrix 39 variety, which achieved the highest wet cob yield (Özata, 2019). Waxy corn, primarily consumed as a fresh vegetable, benefits from specific nitrogen management to enhance its nutritional quality, including anthocyanin and carbohydrate content (Feng et al., 2024). The genetic diversity among these corn types allows for targeted breeding to optimize traits like sweetness, texture, and yield (Dermail et al., 2021). 2.2 Environmental conditions Environmental factors such as climate, soil type, and water supply play crucial roles in the growth and development of fresh corn. Temperature and photoperiod are strong determinants of flowering and harvest dates, impacting yield in various climates. In Zhejiang, due to the influence of temperature, fresh corn can generally be sown from March to August. However, corn sown during the one month period from mid June to mid July, due to the fact that the heading and flowering period coincides with the local high temperature or even dry season in August, causes pollen breakage, a significant decrease in seed setting rate, and the appearance of missing rows, few grains, and even bald heads in the ear, affecting yield and quality. Soil fertility and water supply also significantly influence sweet corn growth, with effective fertilization improving performance (Sidahmed et al., 2024). A case study on water stress revealed that deficit irrigation can maintain yield and quality by optimizing leaf area index and SPAD values, which are indicators of plant health and productivity (Nemeskéri et al., 2019). In subtropical environments, weather variability, particularly temperature and rainfall, affects biomass accumulation and yield, with spring conditions generally being more favorable than fall (Paranhos et al., 2023). 2.3 The role of cultivation management Cultivation management practices, including planting density, water and nutrient management, and pest and disease control, have comprehensive effects on the yield and quality of fresh corn. Proper nitrogen application is crucial for enhancing the nutritional quality of waxy corn by regulating nitrogen metabolism and carbohydrate biosynthesis (Feng et al., 2024). Studies have shown that nitrogen fertilization has a significant impact on the accumulation and content of anthocyanins in purple waxy corn kernels. Under high nitrogen levels (N2 and N3), the accumulation and content of anthocyanins were significantly higher compared to low nitrogen levels (N0 and N1) (Figure 1). This indicates that appropriate nitrogen application not only enhances crop yield but also improves the nutritional quality of purple waxy corn by regulating the accumulation of secondary metabolites. Adjusting sowing dates can mitigate adverse meteorological impacts, such as temperature and rainfall, on waxy corn yield (Heping et al., 2020). Additionally, the choice of planting density and the timing of sowing are critical, as deviations from optimal conditions can significantly reduce yield (Sidahmed et al., 2024). Effective pest and disease control are also essential to maintain high-quality yields, particularly in environments prone to stress and disease (Olsen et al., 1990). 3 Optimization of Planting Density 3.1 Relationship between planting density and yield The relationship between planting density and yield in maize cultivation is complex, involving factors such as canopy structure, light utilization efficiency, and kernel number. Increased planting density can enhance the leaf area index (LAI) and intercepted photosynthetically active radiation (IPAR), which are crucial for promoting plant growth and crop productivity. However, excessive density can lead to reduced photosynthetic capacity and yield stability due to decreased stomatal conductance and chlorophyll content (Zhang et al., 2021; Duan et al., 2024). A field study in Southeast China demonstrated that increasing plant density improved the fresh ear yield of certain sweet maize varieties without affecting grain carbohydrate concentration, although it reduced the grain-filling rate and ear length (Ye et al., 2023b). Another study highlighted that higher planting densities increased biomass and radiation use efficiency but also led to a decrease in the light extinction coefficient and harvest index, indicating a trade-off between yield and resource use efficiency (Duan et al., 2024).
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