The two main glucan polymers cellulose and callose in plant cell wall are synthesized at the plasma membrane by cellulose or callose synthase complexes. Cellulose is the prevalent glucan in cell wall and provides strength to the walls to support directed cell expansion. By contrast, callose is mainly produced in special cell wall and exercises important functions during development and stress responses. However, the structure and precise regulatory mechanism of callose synthase complex is not very clear. This review therefore compares and analyzes the regulation of callose and cellulose synthesis, and further emphasize the future research direction of callose synthesis.

Background: N6-methyladenosine (m6A) is an important epigenetic modification involved in RNA stability and translation regulation. Manipulating the expression of RNA m6A methyltransferases or demethylases makes it difficult to study the effect of specific RNA methylation. Results: In this study, we report the development of Plant m6A Editors (PMEs) using dLwaCas13a (from L. wadei) and human m6A demethylase ALKBH5 catalytic domain. PMEs specifically demethylates m6A of targeted mRNAs (WUS, STM, FT, SPL3 and SPL9) to increase mRNAs stability. In addition, we discovered that a double ribozyme system can significantly improve the efficiency of RNA editing. Conclusion: PMEs specifically demethylates m6A of targeted mRNAs to increase mRNAs stability, suggesting that this engineered tool is instrumental for biotechnological applications.

WUSCHEL (WUS) is a crucial transcription factor in regulating plant stem cell development, and its expression can also improve genetic transformation. However, the ectopic expression of WUS always causes pleiotropic effects during genetic transformation, making it important to understand the regulatory mechanisms underlying these phenomena. In our study, we found that the transient expression of the maize WUS ortholog ZmWus2 caused severe leaf necrosis in Nicotiana benthamiana. We performed transcriptomic and non-target metabolomic analyses on tobacco leaves during healthy to wilted states after ZmWus2 transient overexpression. Transcriptomic analysis revealed that ZmWus2 transformation caused active metabolism of inositol trisphosphate and glycerol-3-phosphate, while also upregulating plant hormone signaling and downregulating photosystem and protein folding pathways. Metabolomic analysis mainly identified changes in the synthesis of phenylpropanoid compounds and various lipid classes, including steroid synthesis. In addition, transcription factors such as ethylene-responsive factors (ERFs), the basic helix–loop–helix (bHLH) factors, and MYBs were found to be regulated by ZmWus2. By integrating these findings, we developed a WUS regulatory model that includes plant hormone accumulation, stress responses, lipid remodeling, and leaf necrosis. Our study sheds light on the mechanisms underlying WUS ectopic expression causing leaf necrosis and may inform the development of future genetic transformation strategies.

• EBR delayed the decline in quality of sweet corn during and after harvest. • ROS levels in sweet corn kernels were reduced by treatment with EBR. • EBR promoted the activity and transcriptions of antioxidant enzymes in kernels. • EBR retarded the soluble sugar content drops during and after harvest. • The expression of sucrose transporter genes in kernels were markedly induced by EBR.

Cadmium (Cd) is a hazardous heavy metal pollutant that poses significant risks to agricultural production and human health. Nanoparticles (NPs) can alleviate the effects of cadmium on crops by regulating the expression of stress-responsive genes, however, the mechanism of regulation is unknown. N6-methyladenosine (m6A) is a prevalent RNA modification, which determines the expression level of RNA. In this study, we performed m6A methylome analysis and gene editing to investigate the regulation of stress-responsive genes by m6A under Cd stress with ZnO nanoparticles (ZnO NPs). Firstly, we identified 16 differentially expressed genes (DEGs) with differential m6A-modification by m6A methylome seq, which included 6 stress-responsive genes. ZnO NPs treatment reduced the m6A level and stabilized the mRNAs of these stress-responsive genes. Then, we utilized the in vivo m6A modification tool, Plant m6A Editors (PMEs), specifically reduced the m6A level of NRT1 and GM35E in transgenic plants. The expression of NRT1 and GM35E was increased, and plants carrying PMEs-NRT1 and PMEs-GM35E showed stronger Cd tolerance than control. Therefore, we can conclude that NPs enhance Cd tolerance in plants by regulating the m6A methylation level of stress-responsive genes such as NRT1 and GM35E, which ultimately affects the expression of these genes. This study proposed a post-transcriptional regulatory network in vegetable soybean roots responding to Cd with ZnO NPs, potentially offering new insights into gene manipulation for controlling low Cd accumulation in crops.

Micronutrients, including vitamins, minerals, and other bioactive compounds, have tremendous impacts on human health. Much progress has been made in improving the micronutrient content of inbred lines in various crops through biofortified breeding. However, biofortified breeding still falls short for the rapid generation of high-yielding hybrids rich in multiple micronutrients. Here, we bred multi-biofortified sweet corn hybrids efficiently through marker-assisted selection. Screening by molecular markers for vitamin E and folic acid, we obtained 15 inbred lines carrying favorable alleles (six for vitamin E, nine for folic acid, and three for both). Multiple biofortified corn hybrids were developed through crossing and genetic diversity analysis.