Molecular Plant Breeding 2024, Vol.15, No.6, 351-361 http://genbreedpublisher.com/index.php/mpb 353 stress responses (Tao et al., 2012). Furthermore, genome-wide analyses have identified a vast number of single nucleotide polymorphisms (SNPs) and expression quantitative trait loci (eQTLs), which are essential for dissecting the genetic regulation of gene expression in sweet potato (Zhang et al., 2020). The availability of these resources facilitates the cloning and identification of genes of interest, thereby accelerating research in sweet potato genomics and breeding (Tao et al., 2012; Zhang et al., 2020). 3.3 The role of bioinformatics in genetic analysis Bioinformatics plays a pivotal role in the analysis and interpretation of the vast amounts of genomic data generated from sequencing technologies. Tools such as Blast2GO have been employed to annotate transcripts, linking them to gene ontology (GO) terms and KEGG pathways, which helps in understanding the functional roles of genes (Tao et al., 2012). Additionally, bioinformatics approaches are crucial for identifying and characterizing alternative splicing events, transcription factors, and non-coding RNAs, as demonstrated in studies utilizing single-molecule real-time sequencing (Ding et al., 2019). The integration of bioinformatics with genomic data allows for the construction of regulatory networks and the identification of master regulators, such as IbMYB1-2, which is involved in anthocyanin biosynthesis in sweet potato storage roots (Zhang et al., 2020). These analyses are essential for uncovering the genetic architecture underlying important agronomic traits and for guiding molecular breeding efforts (Tao et al., 2012; Ding et al., 2019; Zhang et al., 2020). 4 Key Genes and Pathways Involved in Adaptation 4.1 Identification of genes associated with abiotic stress tolerance (e.g., drought, salinity) Recent studies have identified several key genes that enhance abiotic stress tolerance in sweet potato. The IbBBX24-IbTOE3-IbPRX17 module has been shown to improve tolerance to salt and drought stresses by scavenging reactive oxygen species (ROS) (Figure 1). Overexpression of these genes results in higher peroxidase activity and lower H2O2 accumulation, which are critical for stress response (Zhang et al., 2021). Another significant gene, IbMIPS1, enhances salt and drought tolerance by up-regulating genes involved in inositol biosynthesis, phosphatidylinositol (PI) and abscisic acid (ABA) signaling pathways, and the ROS-scavenging system (Zhai et al., 2016). Additionally, the overexpression of the betaine aldehyde dehydrogenase (BADH) gene from spinach in sweet potato has been shown to improve tolerance to multiple abiotic stresses, including salt, oxidative stress, and low temperature, by increasing glycine betaine (GB) accumulation (Fan et al., 2012). The ItfWRKY70 gene from Ipomoea trifida also plays a crucial role in drought tolerance by regulating ABA biosynthesis, stomatal aperture, and activating the ROS scavenging system (Sun et al., 2022). 4.2 Genetic basis of resistance to pests and diseases The genetic transformation of sweet potato has led to the development of varieties with enhanced resistance to pests and diseases. For instance, transgenic sweet potatoes expressing the endotoxin genes cry8Db, cry7A1, and cry3Ca have shown lower infestation rates by the sweet potato weevil compared to non-transformed lines. Additionally, the expression of the oryzacystatin-1 (OC1) gene has conferred resistance to sweet potato stem nematodes and the sweet potato feathery mottle virus (SPFMV) (Imbo et al., 2016). The IbMIPS1 gene not only enhances abiotic stress tolerance but also significantly improves resistance to stem nematodes by modulating inositol and ABA signaling pathways (Zhai et al., 2016). 4.3 Pathways influencing growth, yield, and quality traits Several pathways have been identified that influence the growth, yield, and quality traits of sweet potato. The overexpression of the IbC3H18 gene, a non-tandem CCCH-type zinc-finger protein, enhances tolerance to salt, drought, and oxidative stresses by regulating genes involved in ROS scavenging, ABA signaling, photosynthesis, and ion transport pathways (Zhang et al., 2019). The WRKY transcription factor ItfWRKY70 also contributes to improved growth and yield under drought conditions by increasing ABA and proline content, and enhancing the activity of superoxide dismutase (SOD) and peroxidase (POD) enzymes (Sun et al., 2022). Furthermore, the overexpression of the BADHgene from spinach in sweet potato leads to increased GB accumulation, which helps maintain cell membrane integrity, stronger photosynthetic activity, and reduced ROS production under stress conditions, thereby stabilizing yield production (Fan et al., 2012).
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