Signaling pathways that control the activities in non-photosynthetic plastids, important sites of plant metabolism, are largely unknown. Previously, we demonstrated that WRKY2 and WRKY34 transcription factors play an essential role in pollen development downstream of mitogen-activated protein kinase 3 (MPK3) and MPK6 in Arabidopsis. Here, we report that GLUCOSE-6-PHOSPHATE/PHOSPHATE TRANSLOCATOR 1 (GPT1) is a key target gene of WRKY2/WRKY34. GPT1 transports glucose-6-phosphate (Glc6P) into plastids for starch and/or fatty acid biosynthesis depending on the plant species. Loss of function of WRKY2/WRKY34 results in reduced GPT1 expression, and concomitantly, reduced accumulation of lipid bodies in mature pollen, which leads to compromised pollen viability, germination, pollen tube growth, and male transmission in Arabidopsis. Pollen-specific overexpression of GPT1 rescues the pollen defects of wrky2 wrky34 double mutant. Furthermore, gain-of-function activation of MPK3/MPK6 enhances GPT1 expression; whereas GPT1 expression is reduced in mkk4 mkk5 double mutant. Together, this study revealed a cytoplasmic/nuclear signaling pathway capable of coordinating the metabolic activities in plastids. High-level expression of GPT1 at late stages of pollen development drives Glc6P from cytosol into plastids, where Glc6P is used for fatty acid biosynthesis, an important step of lipid body biogenesis. The accumulation of lipid bodies during pollen maturation is essential to pollen fitness and successful reproduction. Plastids are important sites of plant metabolism including fatty acid and starch biosynthesis. At present, how the activities in the plastids are coordinated with those in the cytoplasm and the signaling pathway(s) involved are largely unknown. Previously, we demonstrated that WRKY2 and WRKY34 transcription factors play an essential role in pollen development downstream of mitogen-activated protein kinase 3 (MPK3) and MPK6 in Arabidopsis. Here, we report that GLUCOSE-6-PHOSPHATE/PHOSPHATE TRANSLOCATOR 1 (GPT1) is a key target gene of WRKY2/WRKY34. GPT1 is localized on the membrane of plastids and transports glucose-6-phosphate (Glc6P) into plastids for starch and/or fatty acid biosynthesis depending on the plant species. Genetic analyses demonstrated that WRKY2/WRKY34 and their upstream MPK3/MPK6 are involved in regulating GPT1 expression, therefore, the accumulation of lipid bodies in mature pollen, which is critical to pollen viability, pollen germination, pollen tube growth, and male transmission in Arabidopsis. This study revealed a cytoplasmic/nuclear signaling pathway capable of coordinating the metabolic activities in plastids. High-level expression of GPT1 at late stages of pollen development drives Glc6P from cytosol into plastids, where Glc6P is used for fatty acid biosynthesis, an important step of lipid body biogenesis. The accumulation of lipid bodies during pollen maturation is essential to pollen fitness and successful reproduction.

Coordination between the sporophytic tissue and the gametic pollen within anthers is tightly controlled to achieve the optimal pollen fitness. Glucose-6-phosphate/phosphate translocator (GPT) transports glucose-6-phosphate, a key precursor of starch and/or fatty acid biosynthesis, into plastids. Here, we report the functional characterization of OsGPT1 in the rice anther development and pollen fertility. Pollen grains from homozygous osgpt1 mutant plants fail to accumulate starch granules, resulting in pollen sterility. Genetic analyses reveal a sporophytic effect for this mutation. OsGPT1 is highly expressed in the tapetal layer of rice anther. Degeneration of the tapetum, an important process to provide cellular contents to support pollen development, is impeded in osgpt1 plants. In addition, defective intine and exine are observed in the pollen from osgpt1 plants. Expression levels of multiple genes that are important to tapetum degeneration or pollen wall formation are significantly decreased in osgpt1 anthers. Previously, we reported that AtGPT1 plays a gametic function in the accumulation of lipid bodies in Arabidopsis pollen. This report highlights a sporophytic role of OsGPT1 in the tapetum degeneration and pollen development. The divergent functions of OsGPT1 and AtGPT1 in pollen development might be a result of their independent evolution after monocots and dicots diverged.

Fritillaria is a perennial herb with medicinal properties. There are 158 Fritillaria species worldwide, 33 of which have reported therapeutic efficacy. Alkaloids are the principal constituents in Fritillaria. Fritillaria species growing at 2700–4000 m are the sources of extract namely Chuan Beimu (the Pharmacopoeia of the People’s Republic of China, 2020 Edition), with low biomass, mainly containing more 5α-cevanine isosteroidal alkaloids with cis-configuration. In contrast, species growing below 1500 m are usually taller than 50 cm, and they mainly contain more trans-configuration isosteroidal alkaloids. There are two schemes of the biosynthetic pathways of steroidal alkaloids with different frameworks and catalytic reactions and combined high-throughput omics data. Based on the distributed elevations, Fritillaria species were divided into three major categories, which met classification features based on phylogenetic analysis or morphological features. Artificial or in vitro cultivations are effective strategies for balancing economical requirements and ecological protection. Fritillaria species growing at lower altitudes can be cultivated by bulb reproduction, but species growing at higher altitudes still rely mainly on gathering a large number of wild resources. Integration of asexual tissue culture and bulb reproduction with sexual artificial or imitated wild cultivation may create a very promising and effective way to maintain sustainable industrial development of Fritillaria.

As a medicinal and edible plant, basil (Ocimum basilicum Linn. var. pilosum (Willd.) Benth.) has rich nutrition and significant economic value. The increase in heat stress caused by global warming adversely affects the growth and yield of plants. However, the response mechanism of basil to heat stress is poorly understood. This work investigated the changes in phenotype, metabolome, and transcriptome in basil under heat stress. The results showed that heat stress triggered severe oxidative damage and photosynthesis inhibition in basil. Metabonomic analysis showed that, compared to the control group, 29 significantly differentially accumulated metabolites (DAMs) were identified after 1 d of heat treatment, and 37 DAMs after the treatment of 3 d. The DAMs were significantly enriched by several pathways such as glycolysis or gluconeogenesis; aminoacyl-tRNA biosynthesis; and alanine, aspartate, and glutamate metabolism. In addition, transcriptomic analysis revealed that 15,066 and 15,445 genes were differentially expressed after 1 d and 3 d of heat treatment, respectively. Among them, 11,183 differentially expressed genes (DEGs) were common response genes under 1 d and 3 d heat treatment, including 5437 down-regulated DEGs and 6746 up-regulated DEGs. All DEGs were significantly enriched in various KEGG (Kyoto Encyclopedia of Genes and Genomes) pathways, most dominated by glyoxylate and dicarboxylate metabolism, followed by starch and sucrose metabolism, and by the biosynthesis and metabolism of other secondary metabolites. Overall, all the above results provided some valuable insights into the molecular mechanism of basil in response to heat stress.

(1) Background: Methyl jasmonate-treated D. morbifera adventitious root extract (MeJA-DMARE), enriched with phenolics, has enhanced bioactivities. However, phenolics possess low stability and bioavailability. Substantial evidence indicates that plant extract–phospholipid complex assemblies, known as phytosomes, represent an innovative drug delivery system. (2) Methods: The phytosome complex was created by combining MeJA-DMARE with Soy-L-α-phosphatidylcholine (PC) using three different ratios through two distinct methods (co-solvency method: A1, A2, and A3; thin-layer film method: B1, B2, and B3). (3) Results: Initial evaluation based on UV-Vis, entrapment efficiency (EE%), and loading content (LC%) indicated that B2 exhibited the highest EE% (79.98 ± 1.45) and LC% (69.17 ± 0.14). The phytosome displayed a spherical morphology with a particle size of 210 nm, a notably low polydispersity index of 0.16, and a superior zeta potential value at −25.19 mV. The synthesized phytosome exhibited superior anti-inflammatory activities by inhibiting NO and ROS production (reduced to 8.9% and 55.1% at 250 μg/mL) in RAW cells and adjusting the expression of related inflammatory cytokines; they also slowed lung tumor cell migration (only 2.3% of A549 cells migrated after treatment with phytosomes at 250 μg/mL), promoting ROS generation in A549 cell lines (123.7% compared to control) and stimulating apoptosis of lung cancer-related genes. (4) Conclusions: In conclusion, the MeJA-DMARE phytosome offers stable, economically efficient, and environmentally friendly nanoparticles with superior inflammation and lung tumor inhibition properties. Thus, the MeJA-DMARE phytosome holds promise as an applicable and favorable creation for drug delivery and lung cancer treatment.

Flavonoids in plant extracts exhibit significant biological activities but are limited by their low bioavailability. This research aimed to improve the functional properties by synthesizing polyvinylpyrrolidone (PVP) nanoparticles using flavonoids derived from T. hemsleyanum. 208 flavonoids were identified using ultrahigh-performance-mass/mass spectrometry and used for nanoparticle preparation. The nanoparticles exhibited 24 % and 55 % higher equilibrium dissolution rates in simulated intestinal and gastric fluids than free flavonoids. With spherical morphologies, 100 nm size and - 26.7 mV zeta potential, these nanoparticles showed remarkable improvements in biological activities, including 1.5-fold enhancement in antioxidant capacity, HeLa cell inhibition, and antimicrobial efficacy, and a 5-fold increase in anti-inflammatory effects compared to unencapsulated flavonoids. This research has established a methodological system that could effectively enhance the utilization rate of flavonoids in plant extracts, offering promising potential for application in functional foods.