Sweetpotato Gene Research Articles

Overexpression of dehydroascorbate reductase gene IbDHAR1 improves the tolerance to abiotic stress in sweet potato.

Dehydroascorbate reductase (DHAR), an indispensable enzyme in the production of ascorbic acid (AsA) in plants, is vital for plant tolerance to various stresses. However, there is limited research on the stress tolerance functions of DHAR genes in sweet potato (Ipomoea batatas [L.] Lam). In this study, the full-length IbDHAR1 gene was cloned from the leaves of sweet potato cultivar Xu 18. The IbDHAR1 protein is speculated to be located in both the cytoplasm and the nucleus. As revealed by qRT-PCR, the relative expression level of IbDHAR1 in the proximal storage roots was much greater than in the other tissues, and could be upregulated by high-temperature, salinity, drought, and abscisic acid (ABA) stress. The results of pot experiments indicated that under high salinity and drought stress conditions, transgenic Arabidopsis and sweet potato plants exhibited decreases in H2O2 and MDA levels. Conversely, the levels of antioxidant enzymes APX, SOD, POD, and ACT, and the content of DHAR increased. Additionally, the ratio of AsA/DHA was greater in transgenic lines than in the wild type. The results showed that overexpression of IbDHAR1 intensified the ascorbic acid-glutathione cycle (AsA-GSH) and promoted the activity of the related antioxidant enzyme systems to improve plant stress tolerance and productivity.

Genome-wide identification and expression analysis of the KNOX family and its diverse roles in response to growth and abiotic tolerance in sweet potato and its two diploid relatives

KNOXs, a type of homeobox genes that encode atypical homeobox proteins, play an essential role in the regulation of growth and development, hormonal response, and abiotic stress in plants. However, the KNOX gene family has not been explored in sweet potato. In this study, through sequence alignment, genomic structure analysis, and phylogenetic characterization, 17, 12 and 11 KNOXs in sweet potato (I. batatas, 2n = 6x = 90) and its two diploid relatives I. trifida (2n = 2x = 30) and I. triloba (2n = 2x = 30) were identified. The protein physicochemical properties, chromosome localization, phylogenetic relationships, gene structure, protein interaction network, cis-elements of promoters, tissue-specific expression and expression patterns under hormone treatment and abiotic stresses of these 40 KNOX genes were systematically studied. IbKNOX4, -5, and − 6 were highly expressed in the leaves of the high-yield varieties Longshu9 and Xushu18. IbKNOX3 and IbKNOX8 in Class I were upregulated in initial storage roots compared to fibrous roots. IbKNOXs in Class M were specifically expressed in the stem tip and hardly expressed in other tissues. Moreover, IbKNOX2 and − 6, and their homologous genes were induced by PEG/mannitol and NaCl treatments. The results showed that KNOXs were involved in regulating growth and development, hormone crosstalk and abiotic stress responses between sweet potato and its two diploid relatives. This study provides a comparison of these KNOX genes in sweet potato and its two diploid relatives and a theoretical basis for functional studies.

Metagenome-enabled models improve genomic predictive ability and identification of herbivory-limiting genes in sweetpotato.

Plant-insect interactions are often influenced by host- or insect-associated metagenomic community members. The relative abundance of insects and the microbes that modulate their interactions were obtained from sweetpotato (Ipomoea batatas) leaf-associated metagenomes using quantitative reduced representation sequencing and strain/species-level profiling with the Qmatey software. Positive correlations were found between whitefly (Bemisia tabaci) and its endosymbionts (Candidatus Hamiltonella defensa, Candidatus Portiera aleyrodidarum, and Rickettsia spp.) and negative correlations with nitrogen-fixing bacteria that implicate nitric oxide in sweetpotato-whitefly interaction. Genome-wide associations using 252 975 dosage-based markers, and metagenomes as a covariate to reduce false positive rates, implicated ethylene and cell wall modification in sweetpotato-whitefly interaction. The predictive abilities (PA) for whitefly and Ocypus olens abundance were high in both populations (68%-69% and 33.3%-35.8%, respectively) and 69.9% for Frankliniella occidentalis. The metagBLUP (gBLUP) prediction model, which fits the background metagenome-based Cao dissimilarity matrix instead of the marker-based relationship matrix (G-matrix), revealed moderate PA (35.3%-49.1%) except for O. olens (3%-10.1%). A significant gain in PA after modeling the metagenome as a covariate (gGBLUP, ≤11%) confirms quantification accuracy and that the metagenome modulates phenotypic expression and might account for the missing heritability problem. Significant gains in PA were also revealed after fitting allele dosage (≤17.4%) and dominance effects (≤4.6%). Pseudo-diploidized genotype data underperformed for dominance models. Including segregation-distorted loci (SDL) increased PA by 6%-17.1%, suggesting that traits associated with fitness cost might benefit from the inclusion of SDL. Our findings confirm the holobiont theory of host-metagenome co-evolution and underscore its potential for breeding within the context of G × G × E interactions.

A highly efficient Agrobacterium-mediated infectious system for Sweet potato leaf curl virus and a deltasatellite-based VIGS vector

Plant virus disease is one of the major threats to the yield and quality of sweetpotato (Ipomoea batatas [L.] Lam.), the seventh most important food crop in the world in terms of production. Sweepoviruses are a group of monopartite geminiviruses (genus Begomovirus, family Geminiviridae) that infect Ipomoea plants and cause significant damage. However, investigations on the mechanisms of sweepovirus infection are scarce due to the low efficiency of the current infectious system. In this work, we used the genomic sequence of Sweet potato leaf curl virus (SPLCV) to construct an effective infectious clone, SPLCV-1.01. We optimized the inoculation procedure in Nicotiana benthamiana by improving the Agrobacterium virulence using an induction medium. Finally, we established a highly efficient agroinoculation protocol for SPLCV on sweetpotato. Furthermore, a simple and reliable “Agro-soaking” method was developed for SPLCV on sweetpotato and Ipomoea aquatica. The “Agro-soaking” method also worked well with Tomato yellow leaf curl China virus (TYLCCNV) and Beet severe curly top virus (BSCTV) on tomato. Based on the “Agro-soaking” method and a deltasatellite, the SBG51 VIGS vector worked with the SPLCV-1.01 infectious clone and silenced two endogenous genes IbCHL (magnesium-chelatase subunit) and IbPDS (phytoene desaturase) in two weeks. Moreover, the VIGS system identified IbADK1 (adenosine kinase 1) as a positive regulator to dampen the SPLCV accumulation in sweetpotato. Our work provides a practical method for studying the interaction between sweetpotato and SPLCV and the functional studies of genes in sweetpotato.

Genome-Wide Identification and Expression Analysis of the DMP and MTL Genes in Sweetpotato (Ipomoea batatas L.).

Sweetpotato (Ipomoea batatas L.) is a strategic crop with both economic and energy value. However, improving sweetpotato varieties through traditional breeding approaches can be a time-consuming and labor-intensive process due to the complex genetic nature of sweetpotato as a hexaploid species (2n = 6x = 90). Double haploid (DH) breeding, based on in vivo haploid induction, provides a new approach for rapid breeding of crops. The success of haploid induction can be achieved by manipulating specific genes. Two of the most critical genes, DMP (DUF679 membrane proteins) and MTL (MATRILINEAL), have been shown to induce haploid production in several species. Here, we identified and characterized DMP and MTL genes in sweetpotato using gene family analysis. In this study, we identified 5 IbDMPs and 25 IbpPLAs. IbDMP5 and IbPLAIIs (IbPLAIIκ, IbPLAIIλ, and IbPLAIIμ) were identified as potential haploid induction (HI) genes in sweetpotato. These results provide valuable information for the identification and potential function of HI genes in sweetpotato and provide ideas for the breeding of DH lines.

Genome-Wide Analysis of the Lateral Organ Boundaries Domain (LBD) Gene Family in Sweet Potato (Ipomoea batatas).

The LBD family is a plant-specific transcription factor family that plays an important role in a variety of biological processes. However, the function of IbLBD genes in sweet potato remains unclear. In this study, we identified a total of 53 IbLBD genes in sweet potato. Genetic structure showed that most of the IbLBD genes contained only two exons. Following the phylogenetic investigation, the IbLBD gene family was separated into Class I (45 members) and Class II (8) members. Both classes of proteins contained relatively conservative Motif1 and Motif2 domains. The chromosomal locations, gene duplications, promoters, PPI network, and GO annotation of the sweet potato LBD genes were also investigated. Furthermore, gene expression profiling and real-time quantitative PCR analysis showed that the expression of 12 IbLBD genes altered in six separate tissues and under various abiotic stresses. The IbLBD genes belonging to Class I were mostly expressed in the primary root, the pencil root, and the leaves of sweet potatoes, while the genes belonging to Class II were primarily expressed in the various sweet potato roots. The IbLBD genes belonging to Class I were mostly expressed in the primary root, the pencil root, and the leaves of sweet potatoes, while the genes belonging to Class II were primarily expressed in the fibrous root, pencil root, and tuber root.

Genome-wide identification and expression analysis of the glutamate receptor gene family in sweet potato and its two diploid relatives.

Plant glutamate receptor (GLR) homologs are crucial calcium channels that play an important role in plant development, signal transduction, and response to biotic and abiotic stresses. However, the GLR gene family has not yet been thoroughly and systematically studied in sweet potato. In this study, a total of 37 GLR genes were identified in the cultivated hexaploid sweet potato (Ipomoea batatas), and 32 GLR genes were discovered in each of the two diploid relatives (Ipomoea trifida and Ipomoea triloba) for the first time. Based on their evolutionary relationships to those of Arabidopsis, these GLRs were split into five subgroups. We then conducted comprehensive analysis to explore their physiological properties, protein interaction networks, promoter cis-elements, chromosomal placement, gene structure, and expression patterns. The results indicate that the homologous GLRs of the cultivated hexaploid sweet potato and its two relatives are different. These variations are reflected in their functions related to plant growth, hormonal crosstalk, development of tuberous roots, resistance to root rot, and responses to abiotic stress factors, all of which are governed by specific individual GLR genes. This study offers a comprehensive analysis of GLR genes in sweet potato and its two diploid relatives. It also provides a theoretical basis for future research into their regulatory mechanisms, significantly influencing the field of molecular breeding in sweet potatoes.

Genome-wide identification of the C2H2 zinc finger gene family and expression analysis under salt stress in sweetpotato.

The higher plant transcription factor C2H2 zinc finger protein (C2H2-ZFP) is essential for plant growth, development, and stress response. There are limited studies on C2H2-ZFP genes in sweetpotato, despite a substantial number of C2H2-ZFP genes having been systematically found in plants. In this work, 178 C2H2-ZFP genes were found in sweetpotato, distributed randomly on 15 chromosomes, and given new names according to where they were located. These members of the zinc finger gene family are separated into six branches, as shown by the phylogenetic tree. 24 tandem repeats of IbZFP genes and 46 fragment repeats were identified, and a homology study revealed that IbZFP genes linked more regions with wild relative species of sweetpotato as well as rhizome plants like potato and cassava. And we analyzed the expression patterns of IbZFP genes during the early development of sweetpotato storage roots (SRs) and salt stress using transcriptome data, and identified 44 IbZFP genes that exhibited differences in expression levels during the early expansion of sweetpotato SRs in different varieties, and 92 IbZFP genes that exhibited differences in expression levels under salt stress in salt tolerant and salt sensitive sweetpotato varieties. Additionally, we cloned six IbZFP genes in sweetpotato and analyzed their expression patterns in different tissues, their expression patterns under abiotic stress and hormone treatment, and subcellular localization. The results showed that the IbZFP genes had tissue specificity in sweetpotato and were induced to varying degrees by drought and salt stress. ABA and GA3 treatments also affected the expression of the IbZFP genes. We selected IbZFP105, which showed significant differences in expression levels under salt stress and ABA treatment, to be heterologously expressed in Arabidopsis thaliana. We found that IbZFP105 OE lines exhibited higher tolerance to salt stress and ABA stress. This indicates that IbZFP105 can enhance the salt tolerance of plants. These results systematically identified the evolution and expression patterns of members of the C2H2-ZFP gene family in sweetpotato, providing a theoretical basis for studying the role of IbZFP genes in the development of sweetpotato SRs and in resistance to stress.

Genome-Wide Identification and Expression Analysis of Malate Dehydrogenase Gene Family in Sweet Potato and Its Two Diploid Relatives

Malate dehydrogenase (MDH; EC 1.1.1.37) plays a vital role in plant growth and development as well as abiotic stress responses, and it is widely present in plants. However, the MDH family genes have not been explored in sweet potato. In this study, nine, ten, and ten MDH genes in sweet potato (Ipomoea batatas) and its two diploid wild relatives, Ipomoea trifida and Ipomoea triloba, respectively, were identified. These MDH genes were unevenly distributed on seven different chromosomes among the three species. The gene duplications and nucleotide substitution analysis (Ka/Ks) revealed that the MDH genes went through segmental duplications during their evolution under purifying selection. A phylogenetic and conserved structure divided these MDH genes into five subgroups. An expression analysis indicated that the MDH genes were omni-presently expressed in distinct tissues and responded to various abiotic stresses. A transcription factor prediction analysis proved that Dof, MADS-box, and MYB were the main transcription factors of sweet potato MDH genes. These findings provide molecular features of the MDH family in sweet potato and its two diploid wild relatives, which further supports functional characterizations.

Research Progress in the Mechanisms of Resistance to Biotic Stress in Sweet Potato.

Sweet potato (Ipomoea batatas (L.) Lam.) is one of the most important food, feed, industrial raw materials, and new energy crops, and is widely cultivated around the world. China is the largest sweet potato producer in the world, and the sweet potato industry plays an important role in China's agriculture. During the growth of sweet potato, it is often affected by biotic stresses, such as fungi, nematodes, insects, viruses, and bacteria. These stressors are widespread worldwide and have severely restricted the production of sweet potato. In recent years, with the rapid development and maturity of biotechnology, an increasing number of stress-related genes have been introduced into sweet potato, which improves its quality and resistance of sweet potato. This paper summarizes the discovery of biological stress-related genes in sweet potato and the related mechanisms of stress resistance from the perspectives of genomics analysis, transcriptomics analysis, genetic engineering, and physiological and biochemical indicators. The mechanisms of stress resistance provide a reference for analyzing the molecular breeding of disease resistance mechanisms and biotic stress resistance in sweet potato.

Genome-wide identification of IbGRFs in sweetpotato and functional analysis of IbGRF9 in anthocyanin biosynthesis

Growth-regulating factors (GRFs), a small transcription factor family in plant, hold vital biological roles during developmental processes and plant responses. However, little is known about GRF genes in sweetpotato (Ipomoea batatas L.). Here, 10 IbGRFs were identified and cloned from the sweetpotato genome. Four IbGRF genes contained miR396-binding sites. IbGRF9 had a higher expression level in the transgenic sweetpotato line MIM396. The anthocyanin contents increased in both MIM396 and transgenic Arabidopsis and in the hairy roots of sweetpotato overexpressing IbGRF9. The IbGRF9 protein bound to the promoters of anthocyanin-biosynthesis related genes to increase anthocyanin content. These results raise new insights for the biological function of GRF genes in regulating anthocyanin biosynthesis in sweetpotato.

Transcriptome analysis and identification of leaf, tuberous root and fibrous root tissue-specific high temperature stress-responsive genes in sweet potato

Sweet Potato is an important food crop, and its production is affected by environmental stresses, including high temperature. The gene expression patterns and molecular responses in different tissues of sweet potato under high temperature stress were studied using microarray data sets. Analysis revealed that modulation in the expression of key genes and pathways associated with various proteins including enzymes under high temperature stress in leaf, fibrous root and storage root tissues. Tissue-specific responses, with both common and unique cellular responses were observed among the tissues. Pathway analysis revealed the differential regulation of genes involved in DNA replication, metabolism, transport, signaling, and stress response during high temperature stress. Six genes viz., DnaJ-domain protein (IpDnaJ), nuclear protein (IpELF5), heat shock protein 90.1 (IpHsp90.1), ABC transporter (IpABC) hydrolase (IpNUDX1) and alternative oxidase 1a (IpAO1a), were up-regulated in the leaf, fibrous root and tuberous root tissues. These six genes might play an important role in imparting high temperature stress tolerance in the leaf, fibrous root and tuberous root tissues of sweet potato. The information generated provides valuable insights on leaf, tuberous root and fibrous root tissue-specific high temperature stress-responsive genes in sweet potato. These datasets will be helpful in selecting candidate genes and pathways for further functional and genomic analyses, facilitating the genetic improvement of sweet potato with enhanced stress tolerance.

Regulatory and functional divergence among members of Ibβfruct2, a sweet potato vacuolar invertase gene controlling starch and glucose content.

Sweet potato [Ipomoea batatas (L.) Lam.] is an important food and industrial crop. Its storage root is rich in starch, which is present in the form of granules and represents the principal storage carbohydrate in plants. Starch content is an important trait of sweet potato controlling the quality and yield of industrial products. Vacuolar invertase encoding gene Ibβfruct2 was supposed to be a key regulator of starch content in sweet potato, but its function and regulation were unclear. In this study, three Ibβfruct2 gene members were detected. Their promoters displayed differences in sequence, activity, and cis-regulatory elements and might interact with different transcription factors, indicating that the three Ibβfruct2 family members are governed by different regulatory mechanisms at the transcription level. Among them, we found that only Ibβfruct2-1 show a high expression level and promoter activity, and encodes a protein with invertase activity, and the conserved domains and three conserved motifs NDPNG, RDP, and WEC are critical to this activity. Only two and six amino acid residue variations were detected in sequences of proteins encoded by Ibβfruct2-2 and Ibβfruct2-3, respectively, compared with Ibβfruct2-1; although not within key motifs, these variations affected protein structure and affinities for the catalytic substrate, resulting in functional deficiency and low activity. Heterologous expression of Ibβfruct2-1 in Arabidopsis decreased starch content but increased glucose content in leaves, indicating Ibβfruct2-1 was a negative regulator of starch content. These findings represent an important advance in understanding the regulatory and functional divergence among duplicated genes in sweet potato, and provide critical information for functional studies and utilization of these genes in genetic improvement.

Genome-wide comparative analysis of the valine glutamine motif containing genes in four Ipomoea species

BackgroundGenes with valine glutamine (VQ) motifs play an essential role in plant growth, development, and resistance to biotic and abiotic stresses. However, little information on the VQ genes in sweetpotato and other Ipomoea species is available.ResultsThis study identified 55, 58, 50 and 47 VQ genes from sweetpotato (I. batatas), I.triflida, I. triloba and I. nil, respectively. The phylogenetic analysis revealed that the VQ genes formed eight clades (I–VII), and the members in the same group exhibited similar exon–intron structure and conserved motifs distribution. The distribution of the VQ genes among the chromosomes of Ipomoea species was disproportional, with no VQ genes mapped on a few of each species' chromosomes. Duplication analysis suggested that segmental duplication significantly contributes to their expansion in sweetpotato, I.trifida, and I.triloba, while the segmental and tandem duplication contributions were comparable in I.nil. Cis-regulatory elements involved in stress responses, such as W-box, TGACG-motif, CGTCA-motif, ABRE, ARE, MBS, TCA-elements, LTR, and WUN-motif, were detected in the promoter regions of the VQ genes. A total of 30 orthologous groups were detected by syntenic analysis of the VQ genes. Based on the analysis of RNA-seq datasets, it was found that the VQ genes are expressed distinctly among different tissues and hormone or stress treatments. A total of 40 sweetpotato differentially expressed genes (DEGs) refer to biotic (sweetpotato stem nematodes and Ceratocystis fimbriata pathogen infection) or abiotic (cold, salt and drought) stress treatments were detected. Moreover, IbVQ8, IbVQ25 and IbVQ44 responded to the five stress treatments and were selected for quantitative reverse-transcription polymerase chain reaction (qRT-PCR) analysis, and the results were consistent with the transcriptome analysis.ConclusionsOur study may provide new insights into the evolution of VQ genes in the four Ipomoea genomes and contribute to the future molecular breeding of sweetpotatoes.

Genome-Wide Characterization of the PIFs Family in Sweet Potato and Functional Identification of IbPIF3.1 under Drought and Fusarium Wilt Stresses.

Phytochrome-interacting factors (PIFs) are essential for plant growth, development, and defense responses. However, research on the PIFs in sweet potato has been insufficient to date. In this study, we identified PIF genes in the cultivated hexaploid sweet potato (Ipomoea batatas) and its two wild relatives, Ipomoea triloba, and Ipomoea trifida. Phylogenetic analysis revealed that IbPIFs could be divided into four groups, showing the closest relationship with tomato and potato. Subsequently, the PIFs protein properties, chromosome location, gene structure, and protein interaction network were systematically analyzed. RNA-Seq and qRT-PCR analyses showed that IbPIFs were mainly expressed in stem, as well as had different gene expression patterns in response to various stresses. Among them, the expression of IbPIF3.1 was strongly induced by salt, drought, H2O2, cold, heat, Fusarium oxysporum f. sp. batatas (Fob), and stem nematodes, indicating that IbPIF3.1 might play an important role in response to abiotic and biotic stresses in sweet potato. Further research revealed that overexpression of IbPIF3.1 significantly enhanced drought and Fusarium wilt tolerance in transgenic tobacco plants. This study provides new insights for understanding PIF-mediated stress responses and lays a foundation for future investigation of sweet potato PIFs.

Genome-wide identification and expression analysis of two-component system genes in sweet potato (Ipomoea batatas L.).

Two-component system (TCS), which comprises histidine kinases (HKs), histidine phosphotransfer proteins (HPs), and response regulators (RRs), plays essential roles in regulating plant growth, development, and response to various environmental stimuli. TCS genes have been comprehensively identified in various plants, while studies on the genome-wide identification and analysis of TCS in sweet potato were still not reported. Therefore, in this study, a total of 90 TCS members consisting of 20 HK(L)s, 11 HPs, and 59 RRs were identified in the genome of Ipomoea batatas. Furthermore, their gene structures, conserved domains, and phylogenetic relationships were analyzed in detail. Additionally, the gene expression profiles in various organs were analyzed, and response patterns to adverse environmental stresses were investigated. The results showed that these 90 TCS genes were mapped on 15 chromosomes with a notably uneven distribution, and the expansion of TCS genes in sweet potato was attributed to both segmental and tandem duplications. The majority of the TCS genes showed distinct organ-specific expression profiles, especially in three types of roots (stem roots, fibrous roots, tuberous roots). Moreover, most of the TCS genes were either induced or suppressed upon treatment with abiotic stresses (drought, salinity, cold, heat) and exogenous phytohormone abscisic acid (ABA). In addition, the yeast-two hybrid system was used to reveal the HK-HP-RR protein-protein interactions. IbHP1, IbHP2, IbHP4, and IbHP5 could interact with three HKs (IbHK1a, IbHK1b, and IbHK5), and also interact with majority of the type-B RRs (IbRR20-IbRR28), while no interaction affinity was detected for IbHP3. Our systematic analyses could provide insights into the characterization of the TCS genes, and further the development of functional studies in sweet potato.

A systematical genome-wide analysis and screening of WRKY transcription factor family engaged in abiotic stress response in sweetpotato

BackgroundWRKY transcription factors play pivotal roles in regulating plant multiple abiotic stress tolerance, however, a genome-wide systematical analysis of WRKY genes in sweetpotato is still missing.ResultsHerein, 84 putative IbWRKYs with WRKY element sequence variants were identified in sweetpotato reference genomes. Fragment duplications, rather than tandem duplications, were shown to play prominent roles in IbWRKY gene expansion. The collinearity analysis between IbWRKYs and the related orthologs from other plants further depicted evolutionary insights into IbWRKYs. Phylogenetic relationships displayed that IbWRKYs were divided into three main groups (I, II and III), with the support of the characteristics of exon-intron structures and conserved protein motifs. The IbWRKY genes, mainly from the group Ib, displayed remarkable and diverse expression profiles under multiple abiotic stress (NaCl, PEG6000, cold and heat) and hormone (ABA, ACC, JA and SA) treatments, which were determined by RNA-seq and qRT-PCR assays, suggesting their potential roles in mediating particular stress responses. Moreover, IbWRKY58L could interact with IbWRKY82 as revealed by yeast two-hybrid based on the protein interaction network screening. And abiotic stress-remarkably induced IbWRKY21L and IbWRKY51 were shown to be localized in the nucleus and had no transactivation activities.ConclusionThese results provide valuable insights into sweetpotato IbWRKYs and will lay a foundation for further exploring functions and possible regulatory mechanisms of IbWRKYs in abiotic stress tolerance.

Genome-Wide Identification and Expression Analysis of SWEET Family Genes in Sweet Potato and Its Two Diploid Relatives.

Sugar Will Eventually be Exported Transporter (SWEET) proteins are key transporters in sugar transportation. They are involved in the regulation of plant growth and development, hormone crosstalk, and biotic and abiotic stress responses. However, SWEET family genes have not been explored in the sweet potato. In this study, we identified 27, 27, and 25 SWEETs in cultivated hexaploid sweet potato (Ipomoea batatas, 2n = 6x = 90) and its two diploid relatives, Ipomoea trifida (2n = 2x = 30) and Ipomoea triloba (2n = 2x = 30), respectively. These SWEETs were divided into four subgroups according to their phylogenetic relationships with Arabidopsis. The protein physiological properties, chromosome localization, phylogenetic relationships, gene structures, promoter cis-elements, protein interaction networks, and expression patterns of these 79 SWEETs were systematically investigated. The results suggested that homologous SWEETs are differentiated in sweet potato and its two diploid relatives and play various vital roles in plant growth, tuberous root development, carotenoid accumulation, hormone crosstalk, and abiotic stress response. This work provides a comprehensive comparison and furthers our understanding of the SWEET genes in the sweet potato and its two diploid relatives, thereby supplying a theoretical foundation for their functional study and further facilitating the molecular breeding of sweet potato.

Expression Analysis of Sporamin and Peroxidase Genes in Sweetpotato under Wounding and Bacterial Pathogen Infection

Expression Analysis of Sporamin and Peroxidase Genes in Sweetpotato under Wounding and Bacterial Pathogen Infection

Genome-Wide Identification of the A20/AN1 Zinc Finger Protein Family Genes in Ipomoea batatas and Its Two Relatives and Function Analysis of IbSAP16 in Salinity Tolerance.

Stress-associated protein (SAP) genes—encoding A20/AN1 zinc-finger domain-containing proteins—play pivotal roles in regulating stress responses, growth, and development in plants. They are considered suitable candidates to improve abiotic stress tolerance in plants. However, the SAP gene family in sweetpotato (Ipomoea batatas) and its relatives is yet to be investigated. In this study, 20 SAPs in sweetpotato, and 23 and 26 SAPs in its wild diploid relatives Ipomoea triloba and Ipomoea trifida were identified. The chromosome locations, gene structures, protein physiological properties, conserved domains, and phylogenetic relationships of these SAPs were analyzed systematically. Binding motif analysis of IbSAPs indicated that hormone and stress responsive cis-acting elements were distributed in their promoters. RT-qPCR or RNA-seq data revealed that the expression patterns of IbSAP, ItbSAP, and ItfSAP genes varied in different organs and responded to salinity, drought, or ABA (abscisic acid) treatments differently. Moreover, we found that IbSAP16 driven by the 35 S promoter conferred salinity tolerance in transgenic Arabidopsis. These results provided a genome-wide characterization of SAP genes in sweetpotato and its two relatives and suggested that IbSAP16 is involved in salinity stress responses. Our research laid the groundwork for studying SAP-mediated stress response mechanisms in sweetpotato.