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This article discusses the role of reactive oxygen species (ROS) and phosphatidic acid (PA) as important second messengers in plant immunity. The authors focus on the interaction between DGK5, a lipid kinase that regulates PA production, and RBOHD, an NADPH oxidase responsible for ROS production. They found that DGK5-derived PA stabilizes RBOHD, leading to enhanced ROS production and promoting plant immune responses. The authors also identified specific kinases that phosphorylate DGK5, regulating its enzymatic activity and maintaining PA homeostasis. These findings contribute to our understanding of the complex signaling network involved in plant immune responses. [Extracted from the article]

Amino acid permeases (AAPs) are proteins of the integral membrane that play important roles in plant growth, development, and responses to various stresses. The molecular functions of several AAPs were characterized in Arabidopsis and rice, but there is still limited information on wheat. Here, we identified 51 AAP genes (TaAAPs) in the wheat genome, classified into six groups based on phylogenetic and protein structures. The chromosome location and gene duplication analysis showed that gene duplication events played a crucial role in the expansion of the TaAAPs gene family. Collinearity relationship analysis revealed several orthologous AAPs between wheat and other species. Moreover, cis-element analysis of promoter regions and transcriptome data suggested that the TaAAPs can respond to salt stress. A TaAAP1 gene was selected and transformed in wheat. Overexpressing TaAAP1 enhanced salt tolerance by increasing the expression of ethylene synthesis genes (TaACS6/TaACS7/TaACS8) and accumulating more ethylene. The present study provides an overview of the AAP family in the wheat genome as well as information on systematics, phylogenetics, and gene duplication, and shows that overexpressing TaAAP1 enhances salt tolerance by regulating ethylene production. These results serve as a theoretical foundation for further functional studies on TaAAPs in the future. [ABSTRACT FROM AUTHOR]

Background and Aims The precise control of brassinosteroid (BR) homeostasis and signalling is a prerequisite for hypocotyl cell elongation in plants. Arabidopsis MYB42 and its paralogue MYB85 were previously identified to be positive regulators of secondary cell wall formation during mature stages. Here, we aim to reveal the role of MYB42 and MYB85 in hypocotyl elongation during the seedling stage and clarify how MYB42 coordinates BR homeostasis and signalling to regulate this process. Methods Histochemical analysis of proMYB42-GUS transgenic plants was used for determination of the MYB42 expression pattern. The MYB42 , 85 overexpression, double mutant and some crossing lines were generated for phenotypic observation and transcriptome analysis. Transcription activation assays, quantitative PCR (qPCR), chromatin immunoprecipitation (ChIP)-qPCR and electrophoretic mobility shift assays (EMSAs) were conducted to determine the relationship of MYB42 and BRASSINAZOLE-RESISTANT 1 (BZR1), a master switch activating BR signalling. Key Results MYB42 and MYB85 redundantly and negatively regulate hypocotyl cell elongation. They function in hypocotyl elongation by mediating BR signalling. MYB42 transcription was suppressed by BR treatment or in bzr1-1D (a gain-of-function mutant of BZR1), and mutation of both MYB42 and MYB85 enhanced the dwarf phenotype of the BR receptor mutant bri1-5. BZR1 directly repressed MYB42 expression in response to BR. Consistently, hypocotyl length of bzr1-1D was increased by simultaneous mutation of MYB42 and MYB85 , but was reduced by overexpression of MYB42. Expression of a number of BR-regulated BZR1 (non-)targets associated with hypocotyl elongation was suppressed by MYB42, 85. Furthermore, MYB42 enlarged its action in BR signalling through feedback repression of BR accumulation and activation of DOGT1/UGT73C5, a BR-inactivating enzyme. Conclusions MYB42 inhibits hypocotyl elongation by coordinating BR homeostasis and signalling during primary growth. The present study shows an MYB42, 85-mediated multilevel system that contributes to fine regulation of BR-induced hypocotyl elongation. [ABSTRACT FROM AUTHOR]

Summary: Wood (secondary xylem) formation in tree species is dependent on auxin‐mediated vascular cambium activity in stems. However, the complex regulatory networks underlying xylem formation remain elusive.Xylem development in Populus was characterized based on microscopic observations of stem sections in transgenic plants. Transcriptomic, quantitative real‐time PCR, chromatin immunoprecipitation PCR, and electrophoretic mobility shift assay analyses were conducted to identify target genes involved in xylem development. Yeast two‐hybrid, pull‐down, bimolecular fluorescence complementation, and co‐immunoprecipitation assays were used to validate protein–protein interactions.PaC3H17 and its target PaMYB199 were found to be predominantly expressed in the vascular cambium and developing secondary xylem in Populus stems and play opposite roles in controlling cambial cell proliferation and secondary cell wall thickening through an overlapping pathway. Further, PaC3H17 interacts with PaMYB199 to form a complex, attenuating PaMYB199‐driven suppression of its xylem targets. Exogenous auxin application enhances the dual control of the PaC3H17‐PaMYB199 module during cambium division, thereby promoting secondary cell wall deposition.Dual regulation of xylem formation by an auxin‐mediated PaC3H17‐PaMYB199 module represents a novel regulatory mechanism in Populus, increasing our understanding of the regulatory networks involved in wood formation. [ABSTRACT FROM AUTHOR]