Strictosidine Synthase-like Gene NMS1 Is Required for Male Fertility in Rice by Regulating Tapetal Degradation

Functional divergence of MADS-box genes and the dual regulatory role of a long noncoding RNA underlie sex determination in Ginkgo biloba.

BACKGROUND Ginkgo biloba is a dioecious gymnosperm that has remained morphologically stable for over 200 million years, offering a unique system for studying early plant reproductive evolution. However, the molecular mechanisms underlying its sex determination remain largely unknown due to its large genome and the lack of genetic transformation tools. The purpose of this study was to precisely map the sex-determining region and decipher the gene regulatory network governing sexual differentiation in this ancient species. RESULTS Through bulked segregant analysis sequencing (BSA-seq) and transcriptomic profiling of male and female pools, we mapped a sex-determining region (SDR) to a nine-megabase interval on chromosome two. Within this region, a B-class MADS-box transcription factor, GbAP3a, was identified as a core candidate promoting male development. It exhibits strict male-specific expression in microstrobili, and its sequence and function are highly conserved due to tandem duplication and strong purifying selection. We also characterized a male-specific long noncoding RNA, GbLINC-CNR1 (Cellular Negative Regulator 1), located within this region. This long noncoding RNA regulates sex differentiation via two parallel pathways: it represses the MADS transcription factor GbAGL32a to abort ovule development, and it acts as a competing endogenous RNA for microRNA 159 to prevent the degradation of GbMYB33 transcripts, thereby sustaining pollen development. CONCLUSIONS Sex determination in Ginkgo is orchestrated by the functional divergence of two MADS-box genes, tightly integrated with dual regulatory inputs from a sex-linked long noncoding RNA. These findings provide mechanistic insights into the evolution of sex chromosomes and reproductive strategies in gymnosperms, offering potential molecular targets for early sex identification and marker-assisted breeding in dioecious trees.

AcoPMEI acts as a dual-function effector that promotes pollen tube growth and buffers against pistil-derived inhibition in pineapple.

Self-incompatibility (SI) severely restricts breeding efficiency and genetic improvement in cultivated pineapple (Ananas comosus (L.) Merr.), yet its molecular basis remains poorly understood. Here, we investigated the molecular processes associated with gametophytic SI (GSI) and compatible pollination using pineapple cultivars 'MD2' and 'BaLi' ('BL') using integrated transcriptomic analyses and functional validation. Our comparative transcriptomic analysis identified AcoPMEI, a gene encoding a pectin methylesterase inhibitor, as a compatibility-associated factor specifically upregulated during compatible pollination in pineapple. Functional assays demonstrated that AcoPMEI promotes pollen tube growth by inhibiting the enzymatic activity of AcoPME14, thereby maintaining a highly methylesterified and extensible apical cell wall. Furthermore, in vitro co-treatment and in vivo heterologous expression assays showed that AcoPMEI partially alleviates AcoRNase-mediated inhibition of pollen tube growth. Yeast two-hybrid (Y2H) and bimolecular fluorescence complementation (BiFC) assays did not support a direct interaction between AcoPMEI and AcoRNase, suggesting that AcoPMEI counteracts pistil-derived inhibition through an indirect, cell wall-mediated mechanism. Baed on SI-responsive gene expression patterns, we propose a transcriptome-informed regulatory model for GSI-associated responses in pineapple. Collectively, these findings identify AcoPMEI as a pollen-derived compatibility-associated factor that promotes pollen tube growth and mitigates RNase-associated inhibition through cell wall modulation, providing insight into the molecular control of pollination compatibility in monocots.

A minimal two-amino-acid deletion in SmMYB1 converts an activator into a dominant repressor, reshaping global eggplant anthocyanin pigmentation during domestication.

This study uncovers a rare case in which a deletion of just two amino acids is sufficient to generate a potent dominant-negative regulator, designated SmMYB1alf-D, which enables reliable prediction of fruit color and provides a breeding strategy to precisely manipulate anthocyanin metabolism.

The WD40 repeat protein OsDPMS1 controls pistil development and female fertility in rice.

The pistil, a key female reproductive organ in flowering plants, plays a critical role in sexual reproduction. Although pistil function has been well studied in some species, the molecular mechanisms governing its development in rice (Oryza sativa) remain unclear. Here, we isolated and characterized a female-sterile rice mutant, Osdpms1, that exhibits pleiotropic reproductive defects, including greater stigma number and aberrant gametophyte development, while maintaining normal vegetative growth and male fertility. Using map-based cloning, genetic complementation, and CRISPR-Cas9 knockout experiments, we determined that LOC_Os07g03160 (named OsDPMS1), encoding a protein containing a WD40 repeat domain, is the causal gene underlying the mutant phenotype. OsDPMS1 was predominantly expressed during the flowering stage, and subcellular localization experiments revealed that OsDPMS1 localizes to both the nucleus and the cytoplasm. Using yeast two-hybrid, bimolecular fluorescence complementation, and GST-pulldown assays, we demonstrated that OsDPMS1 physically interacts with three components of the 26S proteasome pathway: OsUBQ, OsCDC48, and OsCDC48E. Furthermore, we showed that the female sterility of Osdpms1 can be efficiently maintained via seed production technology. When we combined Osdpms1 with male-sterile lines for hybrid seed production in a mixed planting manner, we achieved yield potentials comparable to those using conventional row-planting methods. Our findings establish OsDPMS1 as a critical regulator of pistil development and female fertility in rice and highlight its potential application in hybrid rice breeding programs.

Deciphering a Novel Function of the WOX Family: SpWOX1-Mediated Male Suppression in Dioecious Spinach.

Spinach, a dioecious species, serves as an important model for studying sex determination and differentiation in plants. However, the molecular mechanisms underlying these processes remain largely unresolved. The WUSCHEL-related homeobox (WOX) gene family plays critical roles in meristem maintenance, cell fate determination, and plant development, yet remains uncharacterized in spinach. In this study, a genome-wide comparative analysis identified 10-11 WOX genes across the genus Spinacia. Transcriptome analysis across floral developmental stages, combined with weighted gene co-expression network analysis, revealed that SpWOX1 exhibits female-biased expression and is associated with transcription factors involved in floral development. Functional analysis showed that silencing of SpWOX1 using virus-induced gene silencing resulted in the conversion of female flowers into hermaphroditic flowers in spinach, whereas ectopic expression in Arabidopsis thaliana led to reduced pollen viability and impaired stamen development. Furthermore, yeast two-hybrid and bimolecular fluorescence complementation assays demonstrate that SpWOX1 interacts with the masculine factor SpMS1 and three key regulators of floral development, including AFO, AS2 and ARF3. Collectively, these findings suggest that SpWOX1 functions as a suppressor of male organ development and may play a central role in the spinach sex-determination pathway. This study provides new insights into the molecular basis of sex differentiation in spinach.

The mutation of pseudouridine synthase gene BrTRUD1 resulted in glossy leaf in Chinese cabbage