Flower Development in Arabidopsis

The MADS-box transcription factor CmFYF promotes the production of male flowers and inhibits the fruit development in melon (Cucumis melo L.)

The FOREVER YOUNG FLOWER (FYF/AGL42) gene plays an important role in regulating the flower development especially the flowering time, and senescence and abscission of floral organs. Melon is an important horticultural crop, and the flower development has an important influence on pollination, fertilization and final fruit yield. However, the function of FYF homolog is still unknown in melon. In this study, the characteristic of melon CmFYF was analyzed combining with molecular biology, developmental biology and biochemical tools. CmFYF was present in all detected tissues of melon, but its expression level was significantly higher in shoot apex of lateral branches and male flowers than that in other tissues. Subcellular localization revealed that CmFYF was located in the nucleus. CmFYF was able to respond to multiple hormone and environmental signals including GA3, SA, MeJA, cold and drought. Ectopic expression of CmFYF in Arabidopsis resulted in the early flowering phenotype and increased plant height, but had no effect on the flower organs or fruits development. In melon, overexpression of CmFYF increased the number of male flowers, but inhibited the size of fruit. These results suggested that CmFYF of melon was partially equivalent to AtFYF of Arabidopsis. Further biochemical analyses indicated that CmFYF directly interacted with CmAGb (a homolog of Arabidopsis AGAMOUS), CmKNAT7 (KNOTTED-LIKE HOMEOBOX OF ARABIDOPSIS THALIANA 7) and itself at the protein level. Therefore, this study enriched the function of FYF homologs and revealed a preliminary molecular mechanism underlying the male flower production and fruit development in melon.

Regulation of cell cycle in plant gametes: when is the right time to divide?

Cell division is a fundamental process shared across diverse life forms, from yeast to humans and plants. Multicellular organisms reproduce through the formation of specialized types of cells, the gametes, which at maturity enter a quiescent state that can last decades. At the point of fertilization, signalling lifts the quiescent state and triggers cell cycle reactivation. Studying how the cell cycle is regulated during plant gamete development and fertilization is challenging, and decades of research have provided valuable, yet sometimes contradictory, insights. This Review summarizes the current understanding of plant cell cycle regulation, gamete development, quiescence, and fertilization-triggered reactivation.

The characterization of OfRGA in regulation of flower size through tuning cell expansion genes

Flower appearance stands as a key characteristic of flowering plants and is closely linked to their ornamental value. Phytohormone Gibberellin (GA), essential for plant growth and development are widely reported for expansion in flower. DELLA proteins are known to negatively regulate GA signaling and influences plant growth and development through the regulation of cell expansion. However, the specific biological function of DELLA proteins in the woody plant Osmanthus fragrans remains unclear. In this study, O. fragrans 'Sijigui' was utilized as the experimental material, and OfRGA was isolated using the PCR method. OfRGA is expressed in various tissues and is localized in the nucleus. A negative association was observed between OfRGA expression and petal size across four different Osmanthus fragrans cultivars. Transformation experiments in tobacco revealed that transgenic plants overexpressing OfRGA exhibited increased plant height, greater node spacing, shorter leaf length, and wider leaves during the vegetative phase. Notably, the flower organs of transgenic tobacco plants displayed noticeable alterations, including reduced petal size, shorter corolla tubes, pedicels, male and female stamens, and lighter petal color. Furthermore, a decrease in the length and area of petal and corolla tube cells was observed as well. DEGs were found in RNA-seq studies of OfRGA transgenic plants. Subsequent investigation revealed a considerable quantity of down-regulated genes were associated with cell wall synthesis genes and expansion genes, such as CesA1, XEH, and EXPB1, as well as genes related to anthocyanin biosynthesis. Overall, our findings suggest that OfRGA undermines tobacco petal size by influencing cell expansion. The present study offers a fundamental comprehension of the role of DELLA protein in the organ development in Osmanthus fragrans.

Characterization and expression analysis of the MADS-box gene AGL8 in cotton: insights into gene function differentiation in plant growth and stress resistance

BACKGROUND

AGAMOUS-LIKE 8 (AGL8) belongs to the MADS-box family, which plays important roles in transcriptional regulation, sequence-specific DNA binding and other biological processes and molecular functions. The genome of cotton, a representative polyploid plant, contains multiple AGL8 genes. However, their functional differentiation is still unclear.

METHODS AND RESULTS

In this study, a comprehensive genomic analysis of AGL8 genes was conducted. Cotton AGL8s were subdivided into four subgroups (Groups 1, 2, 3, and 4) based on phylogenetic analysis, and different subgroups of AGL8s presented different characteristics, including different structures and conserved motifs. With respect to the promoter regions of the GhAGL8 genes, we successfully predicted cis-elements that respond to phytohormone signal transduction and the stress response of plants. Transcriptome data and real-time quantitative PCR validation indicated that three genes, namely, GH_D07G0744, GH_A03G0856 and GH_A07G0749, were highly induced by methyl jasmonate (MeJA), salicylic acid (SA), and abscisic acid (ABA), which indicated that they function in plant resistance to abiotic and biotic stresses.

CONCLUSIONS

The information from the gene structure, number and types of conserved domains, tissue-specific expression levels, and expression patterns under different treatments highlights the differences in sequence and function of the cotton AGL8 genes. Different AGL8s play roles in vegetative growth, reproductive development, and plant stress resistance. These results lay a foundation for further study of GhAGL8s in cotton.

Genome-wide identification of the E-class gene family in wheat: evolution, expression, and interaction

Introduction

Wheat (Triticum aestivum L.) is among themost important crop worldwide. Given a growing population and changing climate, enhancing wheat yield is of great importance. Yield is closely associated with flower and spike development, and E-class genes play important roles in the flower and kernel development of plants. Currently, the absence of systematic analysis on the E gene family hinders our comprehension of their roles in plant growth and development.

Methods

Identify E-class genes based on homologous sequence searches. Analyze the identified E-class genes through a series of gene family analyses. Determine the expression levels of wheat E-class genes by searching public databases. Validate the functions of these genes by transforming them into Arabidopsis. Finally, determine the interactions between the genes through yeast two-hybrid experiments.

Results

Fifteen E-class genes (TaEs) were identified in common wheat. Nine E-class genes were detected in five ancestral/closely related species, including one in Aegilops tauschii (AtE), one in T. Urartu (TuEs), two in T. turgidum (TtEs), two in T. dicoccoides (TdEs), and three in T. spelta (TsEs). The 24 E-class genes were classified into three subgroups using a phylogenetic approach. All genes were highly expressed in spikes, and most were only highly expressed at the floret meristem stage. The effects of TaSEP5-A on flowering and growth cycles were confirmed in homologous mutants and transgenic Arabidopsis thaliana. The E-class genes were able to regulate the growth cycle of Arabidopsis. Finally, we confirmed the interactions between TaSEP5-A and other wheat E-class genes based on yeast two-hybrid assays.

Discussion

Our findings provide information regarding the E-class genes in wheat and will potentially promote the application of these genes in wheat improvement.