Angiosperm fertilization has been a hot topic in the field of sexual plant reproduction. In recent years, great advances have been made in the studies on some critical steps, such as pollen tube guidance, polytubey block, and fertilization recovery system. However, most of these known mechanisms are synergid cell-based for ensuring successful double fertilization, the counterpart system based on central cell remains poorly understood. A recently published paper from Hongju Li’s lab revealed that the central cell could also secrete peptides as pollen tube attractants to guide the pollen tube entering embryo sac to ensure double fertilization. Interestingly, this mechanism is not synergid-dependent. Thus, the authors revealed a novel fertilization recovery system and bridged a gap in understanding the mechanism underlying double fertilization.

The development of drought-resistant tree varieties is of great significance for maintaining forest productivity in arid and semi-arid regions of China and addressing the challenges of global climate change. Populus laurifolia is distributed in the Irtysh River Basin in Xinjiang, China, has excellent characteristics such as fast growth and cold resistance. P. simonii has the characteristics of drought resistance and barren resistance, and is widely planted in northern China. In this study, the drought resistance characteristics of P. laurifolia × P. simonii F₁ progeny were comprehensively analyzed and evaluated. We investigated seven growth parameters such as high growth and relative leaf water content, six photosynthetic parameters such as net photosynthetic rate and intercellular CO₂ concentration, and five biochemical characteristics such as SOD activity and MDA content. Based on the drought resistance coefficient and membership function analysis of 18 trait parameters, the parent and 23 F₁ progeny were divided into three drought resistance types: high, medium and low. Compared to other two drought resistance types seedlings, the highly drought-resistant F₁ progeny seedlings had larger leaf thickness, upper and lower epidermis thickness, palisade tissue thickness, and leaf tissue compactness. For highly drought-resistant F₁ progeny seedlings, the expression levels of key drought resistance genes under drought stress were significantly higher than other two drought resistance types. This study provides theoretical guidance and material basis for breeding drought-resistant poplar.

Lutein can effectively reduce incidence of atherosclerosis, diabetes, cancer and multiple eye diseases. The lutein biofortification through food crop has gained more attention with improvement of daily diet. In this paper, 194 Shanxi wheat cultivars planted in three environments were used to extract lutein by organic solvent extraction, and the content of lutein in different germplasms was determined by high performance liquid chromatography (HPLC). The broad-sense heritability of lutein content in wheat and its relationship with grain color, winter/spring types, geographical origin, accession types, and main agronomic traits were analyzed, and the genetic loci associated with lutein content were identified through genome-wide association analysis. Results showed that significant variation in lutein contents occurred among Shanxi wheat accessions, the coefficient of variation was 33.12%-48.57%. Genotype was the main factor affecting lutein content. The average lutein content in three environments was 0.67-4.03 μg·g^-1, 0.16-5.05 μg·g^-1 and 0.16-3.63 μg·g^-1, respectively. The average lutein content of winter types and irrigated-wheat accessions were higher than those of spring types and dryland-wheat, respectively. There was no significant effect of grain color and released years on lutein content. Heading date, plant height and 1 000 kernel weight were significantly negative correlated with lutein content. The other agronomic traits had no significant effect on lutein. Genome-wide association analysis found four major loci related to lutein content on chromosomes 1B, 3A and 7A, among them, QLuc.3A and QLuc.7A.1 are new loci affecting the lutein content. These results provide valuable information for breeding and cultivation of wheat lutein bioaugmentation varieties.

The PLATZ transcription factor family is a class of plant-specific zinc-dependent DNA-binding proteins that play an indispensable role in plant growth and development and stress resistance. However, the PLATZ family genes have not been systematically analyzed in foxtail millet (Setaria italica). In this study, 17 PLATZ genes in the foxtail millet genome were identified and systematically named. The SiPLATZ genes were divided into five subfamilies by phylogenetic analysis, and members of the same subfamily have similar gene structures and motifs. Cis-acting element analysis demonstrated that the SiPLATZ genes may play a role in endosperm development and various stress-resistant responses. The K_a/K_s ratio analysis indicates that duplicated genes are subject to purifying selection. There were significant differences in the expression of SiPLATZ genes in different tissues and developmental stages, which were mainly divided into two categories: high expression in roots, leaves, and stems, and in spikes and seeds. This reflects the complexity of the physiological functions of SiPLATZ genes and their possible involvement in regulating seed growth and multiple stress responses. In addition, the co-expression network constructed in combination with WGCNA analysis revealed that SiPLATZ6, SiPLATZ8, SiPLATZ9 and SiPLATZ11 may be the candidates for genetic improvement of foxtail millet yield and functional gene research. These results lay the foundation for further studies on the biological functions of PLATZ transcription factors in foxtail millet growth and development.

Borneol is one of the most important pharmacodynamic components in Artemisia argyi, which has antibacterial, anti-inflammatory, analgesic and other pharmacological activities. The synthesis and metabolism of borneol are affected by many kinds of enzymes, and borneol dehydrogenase is one of the key enzymes that oxidize borneol to camphor. In this study, the contents of borneol and camphor in 35 germplasm of A. argyi leaves were determined by Gas chromatograph-mass spectrometer (GC-MS). We found that the amount of borneol and camphor was highly varied among the varieties, and some germplasm contained more camphor than borneol, indicating that a large proportion of borneol was oxidized to camphor in A. argyi leaves. Based on the full-length transcriptome of A. argyi and homology comparison analysis, we cloned the first borneol dehydrogenase encoding gene AArBDH1 in A. argyi. The AArBDH1 contained 2 exons and 1 intron, and encoded a protein of 289 amino acids. The AArBDH1 gene expression levels were measured by real-time quantitative reverse transcription PCR (qRT-PCR) technology, which showed that AArBDH1 was differentially expressed in different tissues and in leaves at different development stages, and highly expressed in stem and 30 days old leaves. The enzymatic reactions of AArBDH1 with borneol as substrate and NAD⁺ as coenzyme showed that AArBDH1 could catalyze the dehydrogenation of borneol to camphor. Our study provides a theoretical basis and gene resource for further analyzing the regulation and potential improvement of borneol accumulation in A. argyi leaves.

Aluminum (Al) is one of the common metal contaminants in acidic soils. To reveal the effects of exogenous organic acids on the physiological characteristics and root DNA damage of Helianthus tuberosus under Al stress, we used Al resistant H. tuberosus cv. ‘Xuzhou’ and Al sensitive H. tuberosus cv. ‘Ziyang’ as materials. The effects of exogenous organic acids on the physiological responses and DNA damage of H. tuberosus at various periods (7, 14, and 21 d) under Al stress were investigated by setting 0, 350 and 700 µmol∙L^-1 Al concentration treatments and applying 0, 30, 60 and 90 µmol∙L^-1 compound organic acids, respectively. The results showed that Al stress inhibits root elongation and root activity, severely inhibited the photosynthetic and antioxidant systems of H. tuberosus, and the DNA damage in the root system increased with the increase of Al concentration. In contrast, the application of compound organic acid effectively alleviated Al stress. 60 µmol∙L^-1 compound organic acid improved the activity of the antioxidant system, maximum photochemical efficiency and organic acid secretion in root tips, secretion of citric acid was 2 times (H. tuberosus cv. ‘Xuzhou’) and 0.75 times (H. tuberosus cv. ‘Ziyang’) higher than the control, reduced root tip Al content and improved root activity. Besides, H. tuberosus cv. ‘Xuzhou’ and H. tuberosus cv. ‘Ziyang’ oliver tail moment decreased by 51.53% and 35.10%, and compound organic acid reduced the DNA trailing phenomenon and repaired DNA breaks to a greater extent. In conclusion, high concentration of Al causes serious damage to H. tuberosus, which is difficult to mitigate. 60 µmol∙L^-1 compound organic acid could enhance the H. tuberosus physiological responses under low Al stress, reduce DNA damage and thus improve the stress resistance. The alleviation effect was better in H. tuberosus cv. ‘Ziyang’. This study reveals the regulatory role of exogenous organic acids on the physiological responses of H. tuberosus under Al stress, and provides a theoretical basis for planting and production of H. tuberosus and production of other cash crops in the acid-aluminium areas of southern China.

Plasma membrane (PM) proteins are important components of cell membranes and play important roles in material transport, ion exchange, signal transduction, and metabolic process. Their movements in the PM are in response to the developmental cues and environmental stimuli. Studying the regulatory mechanism of PM protein movement is crucial for a better understanding of the plant development and adaptation to environment. In the recent years, the rapid development of microscopic technologies enables us to move one step closer to reveal the regulatory mechanism of PM protein dynamics. In this paper, we systematically summarized PM protein dynamics and the factors affecting it. We also provided an introduction to commonly-used microscopic imaging techniques applied on PM protein dynamics research. This review will serve as a useful reference for the further investigation of biological functions of PM proteins.

Tn5 is a bacterial transposon. The engineered Tn5 can efficiently tag DNA while adding the adapter sequences. Therefore, it has been widely used in the preparation of high-throughput sequencing libraries. Cleavage Under Target & Tagmentation (CUT&Tag) is an improved technology for studying the interaction between protein and DNA, which has the advantages of good repeatability, high signal-to-noise ratio, and easy operation. This technology uses Protein A (pA) or Protein G (pG) and Tn5 to form a fusion protein, which can locate specific antibodies (the antibody is used to identify the target protein) and break the DNA near the target site while introducing sequencing adapters. Then, DNA was extracted, followed by PCR amplification to obtain the sequencing library. However, different types of antibodies have different affinities for pA and pG, thus limiting the application of CUT&Tag for some antibodies. To overcome this limitation, the expression vector of pG-Tn5 was constructed by recombination, and pG-Tn5 recombinant protein was obtained by prokaryotic expression and affinity purification. We used RNA polymerase II (Pol II)-specific antibodies (Pol II Ser5P, mouse IgG1 and rabbit IgG) to compare the efficiency of pA-Tn5 and pG-Tn5 in library preparation of CUT&Tag in Arabidopsis. The results showed that the IgG1 antibody had higher affinity for pG-Tn5, and the quality of the constructed library was better when pG-Tn5 was used. The rabbit IgG antibody has comparable affinities to the two enzymes. A lower starting amount of plant material can be applicable in CUT&Tag. This study provides a reference for the selection of Tn5 fusion proteins against different antibodies in future CUT&Tag experiments.

Abstract Starch is the major storage material of rice (Oryza sativa) endosperm, and its accumulation process affects the subsequent growth and development of plants. As one of the main nutrients absorbed by human beings from rice, the synthesis and accumulation process of starch in rice has attracted increasing attention. This review mainly discusses the latest progress of endogenous factors affecting starch synthesis and accumulation, such as sucrose unloading from phloem, key enzymes of starch synthesis and hormones, and points out the unsettled questions in the field of endosperm starch accumulation to provide some reference ideas for further research in the future.

As an important environmental factor, light not only provides energy for plant photosynthesis, but also acts as a signal to regulate plant growth and development. Here, we summarize the regulatory effects of red light and far-red light on plant growth and development and abiotic stress responses. This review focuses on the mechanism of phytochrome and light signaling factor regulation of seed germination, hypocotyl growth, bud development, and flowering in plants through integration with endogenous signal transduction, such as hormones. In addition, the regulatory mechanisms of red light and far-red light on plant responses to salt, drought and temperature stress were elucidated. It is expected that on the basis of exploring the mechanism of plant’ perception and response to the light environment, we can accurately supplement light for crops to improve crop yield, quality and stress resistance by using LED spectrum technology while promoting the goal of “dual carbon” to reduce energy consumption and environmental pollution.

Riboflavin is the precursor of flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD) that serve as an indispensable cofactor to maintain normal metabolism, which plays pivotal roles in mitochondrial electron transport chain, citric acid cycle, β-oxidation of fatty acids, branched-chain amino acid catabolism, redox homeostasis, chromatin remodeling, DNA repair, apoptosis and secondary metabolite biosynthesis. Riboflavin deficiency will cause metabolic disorders and a series of defective phenotypes, and death in the most severe cases. Among the living organisms, microorganisms and plants can de novo synthesize riboflavin, but humans and animals can only obtain it from food. At present, the regulation of riboflavin biosynthesis in microorganisms has been clearly studied, but the mechanism of riboflavin transport and metabolism in plants is still not clear. Isolating riboflavin deficient mutants is crucial for analyzing the molecular mechanisms of riboflavin biosynthesis, transport, and metabolism in plants and the effect of riboflavin on plant growth and development. Here we review first the riboflavin biosynthetic pathway and its key enzymes, and then the processes of riboflavin involved in plant growth and development in detail, and finally give prospects for plant riboflavin research.

Pinoresinol-lariciresinol reductases (PLRs) are key enzymes involved in the lignan biosynthesis in plants, which convert pinoresinol to lariciresinol and then to secoisolariciresinol. PLRs are NADPH-dependent reductases with substrate stereoselectivity. The catalytic products of PLR are the sources of different types of 8-8′ lignans, and the substrate selectivity directly determines the skeleton types of lignans, such as furano, dibenzylbutane, dibenzylbutyrolactone and aryltetrahydronaphthalene lignans. Therefore, the catalytic and expression characteristics of PLRs play an important role in the composition and biodiversity of lignans in plants. This paper reviewed the research progress on the important role of PLRs in lignans biosynthesis, as well as its enantioselectivity and catalytic mechanism, thus to lay the foundation for further study on the biological function and catalytic mechanism of PLR genes, and point out the direction for the precise biosynthesis of different types of lignans enantiomers through synthetic biology.