Sugarcane mosaic virus employs 6K2 protein to impair ScPIP2;4 transport of H2O2 to facilitate virus infection

Genome-wide identification of Morus notabilis Aquaporin gene family and differential expression of plasma membrane intrinsic proteins in response to Ralstonia pseudosolanacearum infection

BACKGROUND

Aquaporins (AQPs) play crucial roles in plant water transport, growth and development, and response to biotic and abiotic stresses. Despite their essential functions, the role of AQPs in mulberry trees (Morus L.) during Ralstonia pseudosolanacearum infection remains largely unknown.

RESULTS

In this study, we performed a genome-wide identification and comprehensive characterization of AQP genes in Morus notabilis. A total of 26 AQP genes were identified and classified into four subfamilies: NIP, PIP, SIP and TIP. Furthermore, detailed analyses were conducted on gene structures, protein physicochemical properties, transmembrane domains, phylogenetic relationships, and subcellular localization. Cis-acting element analysis showed that MnAQP genes were mainly involved in hormone, light and stress response. Tissue-specific expression analysis demonstrated that the PIP1 subfamily displayed significantly higher transcript abundance in root tissues relative to leaves, while the PIP2 subfamily maintained relatively stable expression patterns across various tissue types. In addition, following R. pseudosolanacearum inoculation, the expression levels of PIP genes were significantly upregulated in the roots, stems, and leaves of mulberry seedlings. These findings indicate that MnPIP genes play a crucial role in responding to R. pseudosolanacearum infection.

CONCLUSIONS

This study provides the comprehensive characterization of the AQP gene family in mulberry, clarifying the composition and diversity. Our findings establish a solid foundation for further understanding the function roles of MnPIPs following R. pseudosolanacearum infection in mulberry trees.

CLINICAL TRIAL NUMBER

Not applicable.

A new scheme for boosting in situ Fenton-like reaction in plant pathogenic tissues for selective structural degradation of capsid proteins

Safe prevention and control of plant viruses is a global challenge. Inducing viral capsid protein (CP) degradation via hydroxyl radicals (∙OH) generated by an in situ Fenton-like reaction within plant pathogenic tissues is proposed for combating plant viruses in this study. We designed a new Fenton-like reaction inducer, tCuinter-bCDs, which utilizes an internal doping strategy that reduces copper content by 89.89% compared to conventional doping methods, while still achieving a high coexistence of multivalent copper ions. Our research demonstrated that tCuinter-bCDs possessed functional activity to specifically recognize and proximally degrade CP. tCuinter-bCDs form complexes with CP monomers through supramolecular bonds characterized by significant electrostatic components. Within 10 min, the complex induced complete degradation of tertiary structure pockets composed of α-helices and β-sheets located at residues MET1-GLU23, TYR73-ARG93, and SER147-PRO157. Based on a high-resolution 2.91 Å CP model that was constructed for the first time, this degradation process is likely driven by hydrophobic interactions between tCuinter-bCDs and CP residues MET1, VAL5, THR55, and THR58, along with hydrogen bonds formed with THR4, VAL5, GLY15, PRO57, and ALA59, thereby promoting degradation of adjacent peptide segments. This represents the first study demonstrating in situ Fenton-like reactions to combat pathogens in plant systems. Our findings provide a new, efficient, and environmentally friendly approach for plant virus control.

Aquaporin CmPIP2;3 links H2O2 signal and antioxidation to modulate trehalose-induced cold tolerance in melon seedlings

Cold stress severely restricts the growth and development of cold-sensitive crops. Trehalose (Tre), known as the "sugar of life", plays key roles in regulating plant cold tolerance by triggering antioxidation. However, the relevant regulatory mechanism remains unclear. Here, we confirmed that Tre triggers apoplastic hydrogen peroxide (H2O2) production and thus plays key roles in improving the cold tolerance of melon (Cucumis melo var. makuwa Makino) seedlings. Moreover, Tre treatment can promote the transport of apoplastic H2O2 to the cytoplasm. This physiological process may depend on aquaporins. Further studies showed that a Tre-responsive plasma membrane intrinsic protein 2;3 (CmPIP2;3) had strong H2O2 transport function and that silencing CmPIP2;3 significantly weakened apoplastic H2O2 transport and reduced the cold tolerance of melon seedlings. Yeast library and protein-DNA interaction technology were then used to screen 2 Tre-responsive transcription factors, abscisic acid-responsive element (ABRE)-binding factor 2 (CmABF2) and ABRE-binding factor 3 (CmABF3), which can bind to the ABRE motif of the CmPIP2;3 promoter and activate its expression. Silencing of CmABF2 and CmABF3 further dramatically increased the ratio of apoplastic H2O2/cytoplasm H2O2 and reduced the cold tolerance of melon seedlings. This study uncovered that Tre treatment induces CmABF2/3 to positively regulate CmPIP2;3 expression. CmPIP2;3 subsequently enhances the cold tolerance of melon seedlings by promoting the transport of apoplastic H2O2 into the cytoplasm for conducting redox signals and stimulating downstream antioxidation.

Genome-Wide Identification and Expression Pattern Profiling of the Aquaporin Gene Family in Papaya (Carica papaya L.)

Aquaporins (AQPs) are mainly responsible for the transportation of water and other small molecules such as CO2 and H2O2, and they perform diverse functions in plant growth, in development, and under stress conditions. They are also active participants in cell signal transduction in plants. However, little is known about AQP diversity, biological functions, and protein characteristics in papaya. To better understand the structure and function of CpAQPs in papaya, a total of 29 CpAQPs were identified and classified into five subfamilies. Analysis of gene structure and conserved motifs revealed that CpAQPs exhibited a degree of conservation, with some differentiation among subfamilies. The predicted interaction network showed that the PIP subfamily had the strongest protein interactions within the subfamily, while the SIP subfamily showed extensive interaction with members of the PIP, TIP, NIP, and XIP subfamilies. Furthermore, the analysis of CpAQPs' promoters revealed a large number of cis-elements participating in light, hormone, and stress responses. CpAQPs exhibited different expression patterns in various tissues and under different stress conditions. Collectively, these results provided a foundation for further functional investigations of CpAQPs in ripening, as well as leaf, flower, fruit, and seed development. They also shed light on the potential roles of CpAQP genes in response to environmental factors, offering valuable insights into their biological functions in papaya.