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Abscisic acid (ABA), a critical phytohormone that regulates plant development and stress response, is sensed by the ABA receptors PYR/PYL/RCAR (PYLs). The PYL genes have been widely studied in multiple plant species, while a systematic analysis of PYL genes in the genus Ipomoea remains unperformed. Here, a total of 13, 14, and 14 PYLs were identified in Ipomoea batatas, Ipomoea trifida, and Ipomoea triloba, respectively. Fragment duplication was speculated to play prominent roles in Ipomoea PYL gene expansions. These Ipomoea PYLs were classified into three subfamilies via phylogenetic analysis, which was supported by exon–intron structures and conserved motif analyses. Additionally, the interspecies collinearity analysis further depicted a potential evolutionary relationship between them. Moreover, qRT-PCR analysis showed that multiple IbPYLs are highly and differentially responsive to abiotic stress treatments, suggesting their potential roles in sweetpotato stress responses. Taken together, these data provide valuable insights into the PYLs in the genus Ipomoea, which may be useful for their further functional analysis of their defense against environmental changes. [ABSTRACT FROM AUTHOR]

The AP2/ERF transcription factors (TFs) regulate various processes of plant growth, development, and response to environmental stimuli. Although they have been extensively documented in many plants, little is known about stress responsive APETALA2/ethylene response factor (AP2/ERF) genes in sweetpotato (Ipomoea batatas L.). In this study, 20 putative AP2/ERF genes, named IbERF1, IbERF2, and IbERF5–IbERF23 were identified based on the salt‐treated RNA‐seq data from two sweetpotato cultivars with different salt tolerance. Phylogenetic analysis and sequence characterization identified that all the screened IbERF proteins contained a conserved AP2 domain, which belonged to dehydration‐responsive element binding proteins (DREB; 7 members) or ERF (13 members) subfamily. The systematic expression analysis of 12 mainly salt‐induced IbERFs by quantitative real‐time polymerase chain reaction (qRT‐PCR) revealed that most IbERFs were remarkably increased by multiple abiotic stresses, such as NaCl, dehydration, and cold stress. Furthermore, varying degrees of upregulation were also detected in the expression of most IbERFs when treated with hormone abscisic acid, jasmonic acid, and salicylic acid. The expression profiles of IbERFs corroborate their involvement in diverse biological processes. In addition, the IbERF5, which was exclusively upregulated by the treatments, was identified as a nuclear protein without transcriptional activation activity. Collectively, the data of stress responsive IbERFs will provide valuable knowledge for further functional studies of IbERFs in sweetpotato stress tolerance. [ABSTRACT FROM AUTHOR]

Siyuan Liu, Chengbin Zhang and Fen Guo contributed equally to this work. Reference 1 Liu S, Zhang C, Guo F. A systematical genome-wide analysis and screening of WRKY transcription factor family engaged in abiotic stress response in sweetpotato. [Extracted from the article]

Basic region/leucine zipper (bZIP) transcription factors function as critical regulators in numerous abiotic stress responses. Massive bZIPs have been systematically identified in plants, but not in sweetpotato. In this study, 87 sweetpotato IbbZIPs unevenly distributed onto 15 chromosomes were identified, and segmental duplications were shown to play dominant roles in the diversity of IbbZIPs. The collinearity between IbbZIPs and the related orthologs from nine plants depicted evolutionary insights into bZIP gene family. Additionally, IbbZIP proteins were clustered into 11 subfamilies while no members were found in the M subfamily, and the regularity of gene structures and conserved motifs was consistent with the subgroup classification. Evidence from transcriptome data and qRT-PCR analysis of 12 selected IbbZIPs revealed that they were significantly and varyingly induced under multiple abiotic stresses (salt, drought, heat and cold) and hormone treatments (ABA, ACC, JA and SA). Consistently, the promoters of IbbZIPs harbored multiple stress- and hormone-related cis-acting elements. Besides, IbbZIP17 and IbbZIP61 exhibited transactivation activity in yeasts, while IbbZIP-14/-69/-84 did not. These findings supply worthy foundations for further functional investigation of IbbZIPs , and multiple members may serve as promising regulators to enhance the abiotic stress tolerance of transgenic plants. [ABSTRACT FROM AUTHOR]

• 175 sweetpotato IbANCs were identified and clustered into 22 subgroups including 4 specific subgroups. • Tandem duplications and segmental duplications played critical roles in the diversity of IbANCs. • Collinearity between IbANCs and related orthologs from other plants depicted evolutionary insights into NACs. • Transcriptome and qRT-PCR data provided multiple promising IbNAC regulators for breeding tolerant sweetpotato. • IbNAC006 and IbNAC143 exhibited transactivation activities in yeasts. Sweetpotato is a pivotal crop that can tolerate various edaphic and climatic conditions. The plant-specific NAC transcription factors are involved in regulating various adverse environmental conditions, while currently NAC genes have not been systematically characterized in sweetpotato. Herein, 175 putative NAC or NAC-like genes (IbNACs) were identified in sweetpotato. These genes were unevenly scattered onto all 15 chromosomes, among which 12 pairs of tandem duplications and 12 groups of fragment duplications existed. The collinearity analysis between IbNACs and the related orthologs from nine other plant species further depicted evolutionary insights into NAC gene family. Phylogenetic analysis displayed that IbNAC proteins were classified into 22 subfamilies including four sweetpotato-specific subfamilies, with the support of gene structure and motif analyses. Transcriptome analysis showed that IbNAC genes differed significantly in expression under salt stress, and significant and varying expression of ten selected genes under multiple abiotic stresses was detected by qRT-PCR. Moreover, IbNAC006 and IbNAC143, which were significantly induced by abiotic stress, exhibited obvious transactivation activities, while IbNAC-029/-138/-148 did not. These results will lay the foundation for further evolutionary analysis and functional characterization of IbNACs , particularly with regards to the potential applications of multiple IbNAC regulators in the breeding of tolerant sweetpotato. [ABSTRACT FROM AUTHOR]