Comparative Genomic and Expression Analysis Insight into Evolutionary Characteristics of PEBP Genes in Cultivated Peanuts and Their Roles in Floral Induction

Genome-Wide Analysis and Expression Profiles of AhCOLs Family in Peanut (Arachis hypogaea L.)

The CONSTANS-like (COL) gene family plays critical roles in plant growth, development, stress responses, and light signal transduction. However, its functions in peanut (Arachis hypogaea) remain poorly understood. In this study, we identified 18 AhCOL genes in the peanut genome, all localized in the nucleus. Phylogenetic analysis classified these genes into three subfamilies, with Group I containing eight members and Groups II and III each comprising five. Conserved domain analysis revealed that all AhCOL proteins possess at least one B-box and one CCT domain. Most of the AhCOL members in peanuts contain a large number of ABA and MeJA elements. Additionally, some members have low-temperature response elements, anaerobic induction, circadian control, and defense stress elements. Expression profiling indicated that most AhCOL genes are abundantly expressed in leaves, flowers, and fruit needles. Notably, genes such as AhCOL4, AhCOL8, AhCOL13, and AhCOL14 were upregulated under light induction and mechanical stress, highlighting their involvement in pod development. AhCOL1 interacts with AhNF-YC1, while AhCOL3 interacts with both AhNF-YC1 and AhCOP1 proteins. This study identifies key AhCOL genes implicated in light and mechanical stress responses, offering insights into their potential roles in peanut flowering and abiotic stress tolerance.

Colonization of Serendipita indica enhances resistance against Phoma arachidicola in Arachis hypogaea L

The endophytic fungus Serendipita indica (Si) could suppress Phoma arachidicola (Pa) and control peanut web blotch disease. The study evaluated its growth-promoting and disease-resistant effects in two peanut cultivars, Luhua11 and Baisha1016. In vitro experiments and microscopy analysis demonstrated that S. indica suppressed the growth of P. arachidicola. Additionally, scanning electron microscopy illustrated that S. indica adversely affected the pathogen's hyphae. LSi treatment showed the highest stem height (35 cm), root length (15.533 cm), shoot fresh weight (9.33 g), shoot dry weight (1.30085 g), root dry weight (0.1990 g), and chlorophyll a (1.3253) and b (1.8316), while BPa had the lowest values of these parameters. The highest MDA value was observed at 96 h for BPa with (3.14598 nmol/g), and the highest proline value was observed at 72 h for LSi-Pa with (56.42851 µmol/g). Antioxidant enzymes, catalase, peroxidase, ascorbate peroxidase, and phenylalanine ammonia-lyase, increased significantly after 48 h in cultivar L. The most significant result is observed in salicylic acid with LSi-Pa at 72 h (702.10 µg/mL), showing a consistent significant difference. RNA-seq analysis revealed more pronounced transcriptomic changes in cultivar L, with enriched pathways related to flavonoid biosynthesis and defense responses. The LSi-Pa treatment significantly upregulated gene expression at 96 h, with AhNPR1 (0.05807), AhNPR10 (0.10536), AhPAL1 (4.30831), and Ahcapx (0.22074), demonstrating a strong regulatory effect. These results demonstrate that S. indica enhances peanut plant growth and resilience against P. arachidicola, mainly through modulation of oxidative stress and immune responses.

Genome-wide characterization of PEBP genes in Mung bean (Vigna radiata L.) with functional analysis of VrFT1 in relation to photoperiod

Mung bean (Vigna radiata L.), a widely cultivated legume, belongs to the Fabaceae family's Papilionoideae subfamily. Although Phosphatidylethanolamine-binding protein (PEBP) genes have been identified in several plant species, their presence and function in mung bean remain largely unexplored. In this study, we identified seven VrPEBP genes from mung bean and classified them into four clades: FT, MFT, TFL and FT-like. Cis-regulatory element analysis revealed that VrPEBP genes may play a role in light, hormone, and stress responses. Quantitative real-time PCR (qRT-PCR) analysis indicated that VrPEBPs were constitutively expressed in various tissues. However, tissue-specific expression patterns were observed among VrPEBP genes. Under short-day (SD) conditions, VrFT1 and VrMFT1 exhibited significantly higher expression levels than under long-day (LD) conditions at 8 and 4 h, respectively. Conversely, VrTFL2 and VrTFL3 showed significantly higher expression levels under LD conditions compared to SD conditions at 8 and 12 h, respectively. The varied expression patterns of these genes under different photoperiod suggest their potential involvement in the photoperiodic regulation of flowering in mung bean. Additionally, phenotypic analysis of transgenic Arabidopsis plants overexpressing VrFT1 revealed higher expression levels under SD conditions and predicted its role in promoting flowering. These results provide valuable insights into the evolution and function of PEBP genes in mung bean and lay the foundation for further research on their regulatory mechanisms and potential applications in mung bean improvement.

Evolutionary origin and functional investigation of the widely conserved plant PEBP gene STEPMOTHER OF FT AND TFL1 (SMFT)

Genes of the family PHOSPHATIDYLETHANOLAMINE-BINDING PROTEINS (PEBP) have been intensely studied in plants for their role in cell (re)programming and meristem differentiation. Recently, sporadic reports of the presence of a new type of PEBP in plants became available, highly similar to the YY-PEBPs of prokaryotes. A comprehensive investigation of their spread, origin, and function revealed conservation across the plant kingdom. The YY-PEBP clade in plants seems to have resulted from a single Horizontal Gene Transfer (HGT) episode from a prokaryotic organism to an ancestral streptophyte. YY-PEBPs are also present in other eukaryotes, such as certain fungi, diatoms, and rotifers, and these cases derive from independent HGT events. Reciprocally, the occurrence of the eukaryotic CETS/RKIP type PEBPs (CR-PEBPs) was noticed in bacteria of the genus Nocardia, showing that HGT has occurred as well from eukaryotes to prokaryotes. Based on these observations, we propose that the current model of the PEBP family in plants needs to be updated with the clade STEPMOTHER OF FT AND TFL1 (SMFT). SMFT genes not only share high sequence conservation but also show specific expression in homologous plant structures that serve as propagules. Functional analysis of Arabidopsis smft mutant lines pointed to a function for this gene in regulating seed germination, both concerning primary dormancy release and in response to adverse high-temperature conditions. Overall, our study reveals an increasing complexity in the evolutionary history of the PEBP gene family, unlocking new potential in understanding the evolution and functional spectrum of these important key regulatory genes.

Genome-wide identification, subcellular localization, and expression analysis of the phosphatidyl ethanolamine-binding protein family reveals the candidates involved in flowering and yield regulation of Tartary buckwheat (Fagopyrum tataricum)

Background

PEBP (phosphatidyl ethanolamine-binding protein) is widely found in eukaryotes including plants, animals and microorganisms. In plants, the PEBP family plays vital roles in regulating flowering time and morphogenesis and is highly associated to agronomic traits and yields of crops, which has been identified and characterized in many plant species but not well studied in Tartary buckwheat (Fagopyrum tataricum Gaertn.), an important coarse food grain with medicinal value.

Methods

Genome-wide analysis of FtPEBP gene family members in Tartary buckwheat was performed using bioinformatic tools. Subcellular localization analysis was performed by confocal microscopy. The expression levels of these genes in leaf and inflorescence samples were analyzed using qRT-PCR.

Results

Fourteen Fagopyrum tataricum PEBP (FtPEBP) genes were identified and divided into three sub-clades according to their phylogenetic relationships. Subcellular localization analysis of the FtPEBP proteins in tobacco leaves indicated that FT- and TFL-GFP fusion proteins were localized in both the nucleus and cytoplasm. Gene structure analysis showed that most FtPEBP genes contain four exons and three introns. FtPEBP genes are unevenly distributed in Tartary buckwheat chromosomes. Three tandem repeats were found among FtFT5/FtFT6, FtMFT1/FtMFT2 and FtTFL4/FtTFL5. Five orthologous gene pairs were detected between F. tataricum and F. esculentum. Seven light-responsive, nine hormone-related and four stress-responsive elements were detected in FtPEBPs promoters. We used real-time PCR to investigate the expression levels of FtPEBPs among two flowering-type cultivars at floral transition time. We found FtFT1/FtFT3 were highly expressed in leaf and young inflorescence of early-flowering type, whereas they were expressed at very low levels in late-flowering type cultivars. Thus, we deduced that FtFT1/FtFT3 may be positive regulators for flowering and yield of Tartary buckwheat. These results lay an important foundation for further studies on the functions of FtPEBP genes which may be utilized for yield improvement.

Comparative Genomics and Functional Genomics Analysis in Plants

Comparative genomics and functional genomics are two basic branches of plant genomics [...].