Plant Communications最新文献

Rhizobial type-Ⅲ effectors (T3Es) contribute to establishing symbiotic interactions with legume host plants, alongside Nod factors. However, the functions of most rhizobial T3Es, as well as the regulatory and molecular mechanisms underlying their symbiotic effects on hosts, particularly in soybean, are poorly documented. Here, we characterize the function of the T3E Nodulation Outer Protein C (NopC) in the broad-host-range rhizobium Sinorhizobium fredii HH103 for promoting symbiosis in soybean. NopC genotype influences root nodulation across diverse host germplasm and this is further influenced by GmRAC1, encoding a ROP/RAC family GTPase in soybean. GmRAC1 physically interacts with NopC to subsequently induce the expression of the essential symbiotic genes GmNIN2a/2b and GmENOD40. Knock-down of GmNIN2a/2b results in NopC failing to promote symbiosis, and Gmrac1 mutants have fewer nodules than the wild type. NopC facilitates multiple infection stages whereas the requirement for GmRAC1 is pronounced for infection-thread progression and nodule-primordia initiation. Natural variation in the GmRAC1 promoter largely dictates the symbiotic contribution of NopC during symbiotic establishment, and elite GmRAC1 haplotypes with strong expression were artificially selected in soybean breeding. Transgenic over-expression level and elite GmRAC1 haplotypes increase plant height, 100-seed weight and soybean yield. GmRAC1 serves as a key regulator of NopC-mediated symbiosis promotion and offers translational potential for enhanced symbiotic nitrogen fixation in molecular breeding of soybean.

Rice (Oryza sativa), a staple food for over half the global population, has evolved unique physiological mechanisms to adapt to its semi-aquatic environment, among which root development is critical for nutrient acquisition, stress tolerance, and grain yield. Ethylene, a gaseous phytohormone, regulates rice root elongation. Calcium (Ca²⁺), an essential nutrient and universal second messenger, mediates various plant physiological pathways. However, the molecular link between ethylene signaling and Ca²⁺ dynamics in rice, especially in root growth regulation that impacts agricultural productivity, remains unclear. Here, we identified a calcium-dependent antagonism to ethylene-induced response (CAER) that specifically modulates root elongation in the model cereal rice. Interestingly, we demonstrate that rice ethylene receptors OsERS1/2 function as Ca²⁺-permeable channels. In particular, OsERS1 exhibits permeability to both monovalent and divalent cations. Further mutagenesis analysis reveals that OsERS1 channel activity relies on homomeric assembly sites (Cys4 and Cys6) rather than its ethylene-binding site (Cys65), indicating a clear decoupling of the molecular modules governing receptor signaling and ion channel function. Loss-of-function mutant Osers1 and Osers2 failed to exhibit the CAER phenotype observed in the wild type (WT), confirming that this calcium-dependent regulatory mechanism is dependent on OsERS1/2. Collectively, these findings uncover an unexpected ion-channel function of ethylene receptors, redefining their molecular identity beyond canonical signaling receptors. Moreover, our work introduced the concept of "hormone receptor-type ion channel (HRIC)" as a new functional category, which enriches our understanding of how plant hormones transduce signals at the molecular level.

Oxyresveratrol is a bioactive stilbenoid with strong antioxidant, anti-inflammatory, and tyrosinase-inhibitory activities that accumulates in mulberry (Morus alba L.) tissues. Despite its relevance, the biosynthetic origin of oxyresveratrol has remained unclear, with competing hypotheses proposing either hydroxylation of resveratrol or synthesis from a distinct precursor. Moreover, resveratrol and oxyresveratrol naturally accumulate in non-renewable parts of mulberry trees, limiting their efficient extraction. To bypass these spatiotemporal constraints, we established cell suspension cultures from mulberry twigs and demonstrated that combined treatment with methyl jasmonate and methyl- or hydroxypropyl-β-cyclodextrins elicits high levels of both resveratrol and oxyresveratrol, accumulating intra- and extracellularly. Using this system, we addressed the biological question of how oxyresveratrol is synthesized at the molecular level in mulberry. We first improved the structural and functional annotation of the mulberry genome by integrating short- and long-read sequencing data derived from elicited cell suspension transcriptomes. By combining these resources with integrative transcriptomic, proteomic, and metabolomic analyses, we identified a coordinated induction of several stilbene synthases (STSs) and a group of p-coumaroyl-CoA 2'-hydroxylases (C2'Hs) that were strongly co-expressed with resveratrol and oxyresveratrol accumulation. Functional validation in Nicotiana benthamiana, grapevine cell cultures, and in vitro enzyme assays demonstrated that C2'Hs catalyze the hydroxylation of p-coumaroyl-CoA upstream of the STS reaction, generating 2',4'-dihydroxycinnamoyl-CoA as an alternative substrate for STSs. These findings reveal that oxyresveratrol is produced through a biosynthetic pathway parallel to resveratrol formation rather than via post-synthetic hydroxylation. In addition, we provide genomic and transcriptomic resources contextualized within jasmonate-mediated elicitation, enabling the discovery of novel phenylpropanoid structural and regulatory genes in the Morus genus. Together, our work establishes a new biosynthetic paradigm for stilbenoid diversification in plants and delivers molecular tools and resources for the biotechnological production of oxyresveratrol.

The evolutionary arms race between plants and viruses hinges on the sophistication of host defense mechanisms and viral counter-defenses. RNA silencing serves as a fundamental antiviral strategy in plants, primarily mediated by Dicer-like (DCL) proteins such as DCL4, which is stabilized by its canonical cofactor dsRNA-binding protein 4 (DRB4). Interestingly, residual DCL4 activity persists in drb4 mutants, suggesting compensatory pathways. Here, we identify the single-dsRNA-binding motif (dsRBM) proteins DRB7.1 and DRB7.2 as essential cofactors that sustain DCL4-dependent antiviral defense in the absence of DRB4. This functional compensation occurs despite a lack of sequence homology with DRB4, illustrating a novel mechanism of "structural substitution" wherein functional redundancy is achieved through divergent domain architecture rather than sequence conservation. Furthermore, we show that Turnip crinkle virus (TCV) actively subverts this backup defense through its coat protein (CP), which directly interacts with both DRB7.1 and DRB7.2 and promotes their degradation via the ubiquitin-proteasome system. Our findings reveal a multi-layered molecular arms race centered on cofactor homeostasis, highlighting how plants employ structural plasticity to maintain antiviral silencing and how viruses dynamically adapt by hijacking host degradation system. This study redefines conventional notions of functional redundancy in antiviral defense and underscores the intricate co-evolution between RNA silencing components and viral counter-defense strategies.

In wheat, exposure to low temperatures (LT) during the middle and late stages of seed development induces the release of dormancy. However, the underlying regulatory mechanism remains unclear. Here, we identified a novel microRNA (miR1832), which is downregulated by LT and located at a key node of the related regulatory network, using the whole-transcriptome sequencing technology. Germination experiments showed that overexpression of miR1832 enhanced seed dormancy (SD), while its silencing repressed seed dormancy. Further sequence variation and association analysis indicated that an A/G mutation at -670 bp in the miR1832 promoter was significantly associated with phenotypic difference in seed dormancy across wheat varieties, with A associated with strong dormancy. Combining yeast one-hybrid (Y1H), electrophoretic mobility shift assay (EMSA), and dual-luciferase (LUC) reporter assays, we found that the LT-responsive Dof transcription factor TaDof-2D binds directly to the A site in the miR1832 promoter and inhibits its transcription. Subsequently, through expression analysis, dual-LUC assay, and 5'-rapid amplification of cDNA ends (5'-RACE), we confirmed that miR1832 targets the cytochrome P450 gene TaP450-7A, which is upregulated by LT and negatively regulates SD. Finally, physiological and biochemical analysis further demonstrated that the TaDof-2D-miR1832-TaP450-7A module appears to participate in LT-induced dormancy release by influencing α-amylase activity as well as the abscisic acid (ABA) and gibberellin (GA) pathways. These findings not only demonstrate a new regulatory mechanism underlying LT-induced dormancy release, but also provide promising genetic resources and molecular markers for breeding wheat varieties with optimal dormancy levels.

Polyploidy, the condition of possessing more than two sets of chromosomes, is prevalent across the tree of life, particularly in green plants (Viridiplantae). It plays a crucial role in plant evolution, speciation, and adaptation. This review explores the intricate relationship between polyploidy and plant interactions with environmental stresses, focusing on recent studies that demonstrate how polyploid plants often exhibit enhanced stress tolerance compared to related diploids, including various biochemical and physiological responses. We also review the role of epigenetic modifications in diploid versus polyploid responses to stress. The genetic redundancy afforded by polyploidy often results in the up-regulation of stress-responsive genes and pathways, as well as neofunctionalization. Additionally, we highlight multi-omics approaches, comparing polyploids and their diploid progenitors with emphasis on the complex interactions between ploidy and stress responses. These recent results collectively enhance our understanding of how polyploid plants, including crops, rewire metabolic pathways and protein networks, thereby optimizing their survival in challenging environments. This improved knowledge of polyploids and their stress responses is essential for understanding the success of polyploid plants in nature, as well as future practical research applications; harnessing polyploid traits through breeding programs could enhance crop resilience and promote sustainable agriculture. We propose key areas for further investigation, emphasizing the potential of traits in polyploid plants for mitigating the impacts of altered climatic conditions on global food security.

Tiller angle is a critical agronomic trait influencing rice plant architecture and yield potential. However, the molecular mechanisms underlying its regulation remain incompletely understood. Here, we report that ITA1 (LOC_Os01g51260), encoding a MYB family transcription factor, positively regulates shoot gravitropism and restricts tiller angle in rice. The ita1 mutant, characterized by a 740-bp deletion in the ITA1 promoter, displays an enlarged tiller angle due to elevated ITA1 expression. Functional assays demonstrate that ITA1 directly activates BRXL4, a gene that modulates auxin transport by influencing the subcellular localization of LAZY1, a key regulator of shoot gravitropism. Yeast one-hybrid, ChIP-qPCR, EMSA, and luciferase assays reveal that the transcriptional repressor LPA1, a member of the IDD family, directly binds to the 740-bp region of the ITA1 promoter to repress its expression. Genetic evidence shows that the lpa1 mutant phenocopies ita1 and that the lpa1/ita1-c1 double mutant partially rescues the large tiller angle phenotype. Together, our findings define a previously unknown LPA1-ITA1-BRXL4 regulatory cascade that controls shoot gravitropism and tiller angle by modulating auxin distribution. This study provides new insights into plant architectural regulation and offers potential genetic targets for optimizing rice planting density and yield.

N⁴-acetylcytidine (ac⁴C) is a conserved acetylation modification on messenger RNA (mRNA) recently identified in plants. It is deposited by the N-ACETYLTRANSFERASE FOR CYTIDINE IN RNA (ACYR) protein, which is homologous to mammalian N-ACETYLTRANSFERASE (NAT10) (Wang et al., 2023; Li et al., 2023). Here, we describe the defining features and functional landscape of ACYR-dependent ac⁴C marks, their effects on mRNA expression, stability, splicing, and translation, and their roles in leaf development (Wang et al., 2023), photosynthesis (Zhao et al., 2025; Cai et al., 2025), thermosensory flowering (Wu et al., 2025), and plant defense (Lu et al., 2024). We highlight current methods for ac⁴C profiling and discuss future directions in ac⁴C research.mRNA acetylation occurs in plants.

The interactions between the roots of plants and the nitrogen-fixing microorganisms in the rhizosphere are crucial for plant growth and development. However, the contribution of rhizosphere microbial nitrogen fixation to peach trees growth and the underlying interaction mechanisms remain unclear. Our study demonstrated that the peach trees under bag-controlled precise and stabilized low-nitrogen (BCLN) fertilization exhibited a significant increase in root microbial abundance and soil nitrogen fixation. The peach rhizosphere soil exhibited significantly enhanced microbial α-diversity, increased nitrogen-fixing microbial abundance, and elevated nitrogenase activity under BCLN fertilization. Further analysis showed that the BCLN fertilization induced peach roots to secrete arbutin, which mediated the enrichment of the Pseudomonas strain DT33X, a nitrogen-fixing bacterium, and thereby enhanced plant nitrogen-use efficiency. Arbutin, a component of the root exudate, enhanced the growth, colonization, and nitrogen-fixing capacity of DT33X, as evidenced by the increased copy number of the nifH gene in soil. Thus, we elucidated the mechanistic link between peach roots and nitrogen-fixing microbes under BCLN fertilization and found that specific root-derived signaling molecules regulated nitrogen-fixing bacteria, thereby improving nitrogen-use efficiency of the peach trees.