Auxin Efflux Transporters OsPIN1c and OsPIN1d Function Redundantly in Regulating Rice (Oryza sativa L.) Panicle Development

The essential role of auxin in plant growth and development is well known. Pathways related to auxin synthesis, transport, and signaling have been extensively studied in recent years, and the PIN-FORMED (PIN) protein family has been identified to be pivotal for polar auxin transport (PAT) and distribution. However, research focused on the functional characterization of PIN proteins in rice is still lacking. In this study, we investigated the expression and function of OsPIN1c and OsPIN1d in the japonica rice variety (Nipponbare) using gene knockout and high-throughput RNA sequencing (RNA-Seq) analysis. Results showed that OsPIN1c and OsPIN1d were mainly expressed in young panicles and exhibited a redundant function. Furthermore, OsPIN1c or OsPIN1d loss-of-function mutants presented a mild phenotype compared with the wild type. In addition to significantly decreased plant height and tiller number, panicle development was severely disrupted in double mutant lines of OsPIN1c and OsPIN1d. Severe defects included smaller inflorescence meristem (IM) and panicle sizes, fewer primary branches, elongated bract leaves, non-degraded hair, and no spikelet growth. Interestingly, ospin1cd-3, a double mutant line with functional retention of OsPIN1d, showed milder defects than those observed in other mutants. Additionally, several critical regulators of reproductive development, such as OsPID, LAX1, OsMADS1, and OsSPL14/IPA1, were differentially expressed in ospin1c-1 ospin1d-1, supporting the hypothesis that OsPIN1c and OsPIN1d are involved in regulating panicle development. Therefore, this study provides novel insights into the auxin pathways that regulate plant reproductive development in monocots.

Male fire ant neurotransmitter precursors trigger reproductive development in females after mating

Social insect queens have evolved mechanisms to prevent competition from their sexual daughters. For Solenopsis invicta, the fire ant, queens have evolved a primer pheromone that retards reproductive development in their winged reproductive daughters. If these daughters are removed from the influence of the queen, it takes about a week to start reproductive development; however, it starts almost immediately after mating. This dichotomy has been unsuccessfully investigated for several decades. Here we show that male fire ants produce tyramides, derivatives of the biogenic amine tyramine, in their reproductive system. Males transfer tyramides to winged females during mating, where the now newly mated queens enzymatically convert tyramides to tyramine. Tyramine floods the hemolymph, rapidly activating physiological processes associated with reproductive development. Tyramides have been found only in the large Myrmicinae ant sub-family (6,800 species), We suggest that the complex inhibition/disinhibition of reproductive development described here will be applicable to other members of this ant sub-family.

Effects of Maternal Nutrition on Female Offspring Weight Gain and Sexual Development

Maternal nutrition during pregnancy influences postnatal life of animals; nevertheless, few studies have investigated its effects on the productive performance and reproductive development of heifers. This study evaluated the performance, reproductive development, and correlation between reproduction × fat thickness and performance × ribeye area (REA) traits of heifers. We also performed an exploratory genomic association during the rearing period in heifers submitted to fetal programming. The study comprised 55 Nellore heifers born to dams exposed to one of the following nutritional planes: control, without protein-energy supplementation; PELT, protein-energy last trimester, protein-energy supplementation offered in the final third of pregnancy; and PEWG, protein-energy whole gestation, protein-energy supplementation upon pregnancy confirmation. Protein-energy supplementation occurred at the level of 0.3% live weight. After weaning, heifers were submitted to periodic evaluations of weight and body composition by ultrasonography. From 12 to 18 months, we evaluated the reproductive tract of heifers to monitor its development for sexual precocity and ovarian follicle population. The treatments had no effect (p > 0.05) on average daily gain; however, the weight of the animals showed a significant difference over time (p = 0.017). No differences were found between treatments for REA, backfat, and rump fat thickness, nor for puberty age, antral follicular count, and other traits related to reproductive tract development (p > 0.05). The correlation analysis between performance traits and REA showed high correlations (r > 0.37) between REA at weaning and year versus weight from weaning until yearling; however, no correlation was found for reproductive development traits versus fat thickness (p > 0.05). The exploratory genomic association study showed one single-nucleotide polymorphism (SNP) for each treatment on an intergenic region for control and PEWG, and the one for PELT on an intronic region of RAPGEF1 gene. Maternal nutrition affected only the weight of the animals throughout the rearing period.

Interactions Between Environment and Genetic Diversity in Perennial Grass Phenology: A Review of Processes at Plant Scale and Modeling

In perennial grasses, the reproductive development consists of major phenological stages which highly determine the seasonal variations of grassland biomass production in terms of quantity and quality. The reproductive development is regulated by climatic conditions through complex interactions subjected to high genetic diversity. Understanding these interactions and their impact on plant development and growth is essential to optimize grassland management and identify the potential consequences of climate change. Here, we review the main stages of reproductive development, from floral induction to heading, i.e., spike emergence, considering the effect of the environmental conditions and the genetic diversity observed in perennial grasses. We first describe the determinants and consequences of reproductive development at individual tiller scale before examining the interactions between plant tillers and their impact on grassland perenniality. Then, we review the available grassland models through their ability to account for the complexity of reproductive development and genetic × environmental interactions. This review shows that (1) The reproductive development of perennial grasses is characterized by a large intraspecific diversity which has the same order of magnitude as the diversity observed between species or environmental conditions. (2) The reproductive development is determined by complex interactions between the processes of floral induction and morphogenesis of the tiller. (3) The perenniality of a plant is dependent on the reproductive behavior of each tiller. (4) Published models only partly explain the complex interactions between morphogenesis and climate on reproductive development. (5) Introducing more explicitly the underlying processes involved in reproductive development in models would improve our ability to anticipate grassland behavior in future growth conditions.

From Single Cells to Flowers – Biological Complexity Driving Plant Reproductive Development

The rise of data science in biology stimulates interdisciplinary collaborations to address fundamental questions. Here, we report the outcome of the first SINFONIA symposium focused on revealing the mechanisms governing plant reproductive development across biological scales. The intricate and dynamic target networks of known regulators of flower development remain poorly understood. To analyze development from the genome to the final floral organ morphology, high-resolution data that capture spatiotemporal regulatory activities are necessary and require advanced computational methods for analysis and modeling. Moreover, frameworks to share data, practices and approaches that facilitate the combination of varied expertise to advance the field are called for. Training young researchers in interdisciplinary approaches and science communication offers the opportunity to establish a collaborative mindset to shape future research.