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

Transcriptomic analysis for the gamma-ray-induced sweetpotato mutants with altered stem growth pattern

Introduction

Sweetpotato faces breeding challenges due to physiological and genomic issues. Gamma radiation is a novel approach for inducing genetic variation in crops. We analyzed the transcriptomic changes in gamma ray-induced sweetpotato mutants with altered stem development compared with those in the wild-type 'Tongchaeru' cultivar.

Methods

RNA sequencing analyses were performed to identify changes in the expression of genes related to stem development.

Results

Transcriptomic analysis identified 8,931 upregulated and 6,901 downregulated genes, including the upregulation of the auxin-responsive SMALL AUXIN UP RNA (SAUR) and three PHYTOCHROME INTERACTING FACTOR 4 (PIF4) genes. PIF4 is crucial for regulating the expression of early auxin-responsive SAUR genes and stem growth in Arabidopsis thaliana. In the mutant, several genes related to stem elongation, including PIF4 and those involved in various signaling pathways such as auxin and gibberellin, were upregulated.

Discussion

Our results suggest that gamma ray-induced mutations influence auxin-dependent stem development by modulating a complex regulatory network involving the expression of PIF4 and SAUR genes, and other signaling pathways such as gibberellin and ethylene signaling genes. This study enhances our understanding of the regulatory mechanisms underlying stem growth in sweetpotato, providing valuable insights for genomics-assisted breeding efforts.

A comprehensive overview of omics-based approaches to enhance biotic and abiotic stress tolerance in sweet potato

Biotic and abiotic stresses negatively affect the yield and overall plant developmental process, thus causing substantial losses in global sweet potato production. To cope with stresses, sweet potato has evolved numerous strategies to tackle ever-changing surroundings and biological and environmental conditions. The invention of modern sequencing technology and the latest data processing and analysis instruments has paved the way to integrate biological information from different approaches and helps to understand plant system biology more precisely. The advancement in omics technologies has accumulated and provided a great source of information at all levels (genome, transcript, protein, and metabolite) under stressful conditions. These latest molecular tools facilitate us to understand better the plant's responses to stress signaling and help to process/integrate the biological information encoded within the biological system of plants. This review briefly addresses utilizing the latest omics strategies for deciphering the adaptive mechanisms for sweet potatoes' biotic and abiotic stress tolerance via functional genomics, transcriptomics, proteomics, and metabolomics. This information also provides a powerful reference to understand the complex, well-coordinated stress signaling genetic regulatory networks and better comprehend the plant phenotypic responses at the cellular/molecular level under various environmental stimuli, thus accelerating the design of stress-resilient sweet potato via the latest genetic engineering approaches.

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.

Light signaling as cellular integrator of multiple environmental cues in plants

Plants being sessile need to rapidly adapt to the constantly changing environment through modifications in their internal clock, metabolism, and gene expression. They have evolved an intricate system to perceive and transfer the signals from the primary environmental factors namely light, temperature and water to regulate their growth development and survival. Over past few decades rigorous research using molecular genetics approaches, especially in model plant Arabidopsis, has resulted in substantial progress in discovering various photoreceptor systems and light signaling components. In parallel several molecular pathways operating in response to other environmental cues have also been elucidated. Interestingly, the studies have shown that expression profiles of genes involved in photomorphogenesis can undergo modulation in response to other cues from the environment. Recently, the photoreceptor, PHYB, has been shown to function as a thermosensor. Downstream components of light signaling pathway like COP1 and PIF have also emerged as integrating hubs for various kinds of signals. All these findings indicate that light signaling components may act as central integrator of various environmental cues to regulate plant growth and development processes. In this review, we present a perspective on cross talk of signaling mechanisms induced in response to myriad array of signals and their integration with the light signaling components. By putting light signals on the central stage, we propose the possibilities of enhancing plant resilience to the changing environment by fine-tuning the genetic manipulation of its signaling components in the future.

PIF1, a phytochrome-interacting factor negatively regulates drought tolerance and carotenoids biosynthesis in tobacco

The phytochrome-interacting factors (PIFs) function crucially in multiple physiological processes, but the biological functions of some PIFs remain elusive in some species. Here, a PIF transcription factor NtPIF1 was cloned and characterized in tobacco (Nicotiana tabacum L.). The transcript of NtPIF1 was significantly induced by drought stress treatments, and it localized in the nuclear. Knockout of NtPIF1 by CRISPR/Cas9 system led to the improved drought tolerance of tobacco with increased osmotic adjustment, antioxidant activity, photosynthetic efficiency and decreased water loss rate. On the contrary, NtPIF1-overexpression plants displays drought-sensitive phenotypes. In addition, NtPIF1 reduced the biosynthesis of abscisic acid (ABA) and its upstream carotenoids by regulating the expression of genes involved in ABA and carotenoids biosynthetic pathway upon drought stress. Electrophoretic mobility shift and dual-luciferase assays illustrated that, NtPIF1 directly bind to the E-box elements within the promoters of NtNCED3, NtABI5, NtZDS and Ntβ-LCY to repress their transcription. Overall, these data suggested that NtPIF1 negatively regulate tobacco adaptive response to drought stress and carotenoids biosynthesis; moreover, NtPIF1 has the potential to develop drought-tolerant tobacco plants using CRISPR/Cas9 system.

Functions of Plant Phytochrome Signaling Pathways in Adaptation to Diverse Stresses

Phytochromes are receptors for red light (R)/far-red light (FR), which are not only involved in regulating the growth and development of plants but also in mediated resistance to various stresses. Studies have revealed that phytochrome signaling pathways play a crucial role in enabling plants to cope with abiotic stresses such as high/low temperatures, drought, high-intensity light, and salinity. Phytochromes and their components in light signaling pathways can also respond to biotic stresses caused by insect pests and microbial pathogens, thereby inducing plant resistance against them. Given that, this paper reviews recent advances in understanding the mechanisms of action of phytochromes in plant resistance to adversity and discusses the importance of modulating the genes involved in phytochrome signaling pathways to coordinate plant growth, development, and stress responses.

Sweet Potato as a Key Crop for Food Security under the Conditions of Global Climate Change: A Review

Sweet potato is one of the most economically important crops for addressing global food security and climate change issues, especially under conditions of extensive agriculture, such as those found in developing countries. However, osmotic stress negatively impacts the agronomic and economic productivity of sweet potato cultivation by inducing several morphological, physiological, and biochemical changes. Plants employ many signaling pathways to respond to water stress by modifying their growth patterns, activating antioxidants, accumulating suitable solutes and chaperones, and making stress proteins. These physiological, metabolic, and genetic modifications can be employed as the best indicators for choosing drought-tolerant genotypes. The main objective of sweet potato breeding in many regions of the world, especially those affected by drought, is to obtain varieties that combine drought tolerance with high yields. In this regard, the study of the physiological and biochemical features of certain varieties is important for the implementation of drought resistance measures. Adapted genotypes can be selected and improved for particular growing conditions by using suitable tools and drought tolerance-related selection criteria. By regulating genetics in this way, the creation of drought-resistant varieties may become cost-effective for smallholder farmers. This review focuses on the drought tolerance mechanisms of sweet potato, the effects of drought stress on its productivity, its crop management strategies for drought mitigation, traditional and molecular sweet potato breeding methods for drought tolerance, and the use of biotechnological methods to increase the tolerance of sweet potato to drought.

Transcriptome Characterization and Gene Changes Induced by Fusarium solani in Sweetpotato Roots

Sweetpotato (Ipomoea batatas) is an important root crop that is infected by Fusarium solani in both seedling and root stages, causing irregular black or brown disease spots and root rot and canker. This study aims to use RNA sequencing technology to investigate the dynamic changes in root transcriptome profiles between control check and roots at 6 h, 24 h, 3 days, and 5 days post-inoculation (hpi/dpi) with F. solani. The results showed that the defense reaction of sweetpotato could be divided into an early step (6 and 24 hpi) without symptoms and a late step to respond to F. solani infection (3 and 5 dpi). The differentially expressed genes (DEGs) in response to F. solani infection were enriched in the cellular component, biological process, and molecular function, with more DEGs in the biological process and molecular function than in the cellular component. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis showed that the main pathways were metabolic pathways, the biosynthesis of secondary metabolites, and carbon metabolism. More downregulated genes were identified than upregulated genes in the plant-pathogen interaction and transcription factors, which might be related to the degree of host resistance to F. solani. The findings of this study provide an important basis to further characterize the complex mechanisms of sweetpotato resistance against biotic stress and identify new candidate genes for increasing the resistance of sweetpotato.