Plant Communications最新文献

SUMO PROTEASE RELATED TO FERTILITY 1 (SPF1) and SPF2 are responsible for deSUMOylation of SUMO-conjugated protein substrates and for maintaining protein SUMOylation homeostasis. To date, the role of SUMO proteases in fatty acid biosynthesis and lipid accumulation remains unclear. Here, we demonstrate that the Arabidopsis thaliana mutantsspf1-1, spf2-1, and spf1-1 spf2-1 exhibit increased seed size and elevated seed oil content (SOC). We further show that SPF1 and SPF2 interact with WRINKLED1 (WRI1), a master regulator of the transcriptional control of plant oil synthesis. Genetic analyses indicate that the spf1-1 wri1-3 and spf2-1 wri1-3 double mutants, as well as the spf1-1 spf2-1 wri1-3 triple mutant, phenocopy wri1-3 and display severe seed shriveling, indicating that SPF1 and SPF2 act upstream of WRI1. WRI1 was identified as a SUMO1 substrate with two conserved SUMOylation sites, lysine 257 (K257) and K266, in cruciferous plants, with K257 acting as the dominant site required for seed oil synthesis. SUMOylation enhances WRI1 stability, whereas SPF1- and SPF2-mediated deSUMOylation promotes WRI1 degradation. In spf1-1, spf2-1, and spf1-1 spf2-1 mutants, the abundance of SUMOylated WRI1 increases during seed development and correlates with elevated seed oil accumulation. Together, these results indicate that SPF1 and SPF2 negatively regulate oil synthesis by deSUMOylating WRI1, establishing a dynamic SUMOylation and deSUMOylation switch centered on the SPF1/SPF2-WRI1 module that fine-tunes seed development and oil synthesis.

Genetic transfers are pervasive across both prokaryotes and eukaryotes, primarily involving canonical genomic introgression between species or genera and horizontal gene transfer (HGT) across kingdoms. However, DNA transfer between phylogenetically distant species, which differs from canonical introgression and HGT in certain aspects of its temporal scale and mechanistic features, here defined as remote introgression (RI), has received less attention in evolutionary genomics. In this study, we present RIFinder, a novel phylogeny-based method for the detection of RI events, and apply it to a comprehensive dataset of 122 grass genomes. Our analysis identifies 622 RI events originating from 543 distinct homologous genes, revealing distinct characteristics among grass subfamilies. Specifically, the subfamily Pooideae contains the largest number of introgressed genes, whereas Bambusoideae contains the fewest. Comparisons among the accepted genes, their donor copies, and native homologs demonstrate that introgressed genes undergo post-transfer localized adaptation and show significant functional enrichment in stress-response pathways. Notably, we identify a large Triticeae-derived segment in the Chloridoideae species Cleistogenes songorica, which is potentially associated with its exceptional drought tolerance. Furthermore, we provide compelling evidence that RI has contributed to the origin and diversification of biosynthetic gene clusters for gramine, a defensive alkaloid chemical, across grass species. Our study establishes a robust method for RI detection and highlights its critical role in adaptive evolution. The Python implementation of RIFinder is publicly available at https://github.com/Ne0tea/RIFinder.

Soil salinization and blast disease are major constraints on global rice production. Although plants modulate oxidative homeostasis to withstand such stresses, the genetic components that coordinate abiotic and biotic stress responses through reactive oxygen species scavenging remain poorly defined. Here, we identify STBR1, a BAHD acyltransferase-encoding gene, as a key regulator that confers both saline-alkali stress tolerance and blast resistance. Through association analysis and transgenic validation, we show that STBR1 overexpression enhances stress tolerance and increases grain yield. Mechanistically, yeast two-hybrid, co-immunoprecipitation, and biochemical analyses reveal that STBR1 physically interacts with and stabilizes the non-canonical catalase CATA, thereby promoting H₂O₂ scavenging and mitigating oxidative damage. We further identified a natural elite haplotype, STBR1-T, which harbors a promoter mutation that weakens binding by the transcriptional repressor NAC2-as confirmed by electrophoretic mobility shift assay and chromatin immunoprecipitation-qPCR-resulting in elevated STBR1 expression and enhanced stress resilience in rice. Together, our findings define the NAC2-STBR1-CATA regulatory module as a central hub that coordinates oxidative homeostasis under combined abiotic and biotic stresses. The STBR1-T allele represents a valuable genetic resource for breeding high-yielding rice cultivars with robust, broad-spectrum stress resistance.

In plants, multiple hormone pathways orchestrate thermomorphogenesis in response to warm temperatures, yet the mechanism that coordinates these pathways remains elusive. Here, we identify INTERACT WITH SPT6 (IWS1) as an essential transcription elongation factor that coordinates the brassinosteroid (BR) and gibberellin (GA) pathways to promote thermomorphogenesis in Arabidopsis. During prolonged exposure to warm temperatures, IWS1 transcript and protein levels increase; under these conditions, the iws1 loss-of-function mutant exhibits severe hypocotyl elongation defects comparable to those of pif4-2, a mutant of the central thermomorphogenesis regulator PIF4. Mechanistically, IWS1 forms a complex with the BR transcription factor BRASSINAZOLE RESISTANT 1 (BZR1) and directly binds to the PHYTOCHROME-INTERACTING FACTOR 4 (PIF4) promoter in a temperature-dependent manner, thereby facilitating BZR1 chromatin occupancy and activating PIF4 transcription. This IWS1-BZR1 module also enhances BR biosynthesis by upregulating the BR biosynthetic gene BR6ox2. IWS1 also interacts with the GA-associated transcription factors TCP14 and TCP15 to activate expression of the GA biosynthetic gene GA20ox2 and promotes DELLA degradation to alleviate GA-mediated growth repression. Thus, IWS1 coordinates the BR and GA pathways by concurrently promoting PIF4-mediated transcription and relieving DELLA-mediated growth repression, thereby enhancing thermomorphogenesis. Our findings identify IWS1 as a central coordinator that integrates hormonal signals to positively regulate thermal acclimation in plants.

Agrobacterium transfers single-stranded T-DNA (T-strands) and virulence effector proteins into plant cells. VirE2, a key effector protein, enters the plant cell and is thought to bind T-strands, protecting them from nuclease degradation and guiding them to the nucleus. However, the intracellular trafficking mechanisms of VirE2 remain unclear. Using bimolecular fluorescence complementation, in vitro pull-down, yeast two-hybrid, and in vivo co-immunoprecipitation assays, we found that VirE2 binds directly to the cargo-binding domains (CBDs) of several myosin VIII family members and to myosin XI-K. We observed reduced susceptibility to Agrobacterium-mediated transformation of several Arabidopsis actin mutants and in a myosin VIII-1/2/a/b quadruple mutant. Expression of the CBDs of myosin VIII-1, VIII-2, VIII-A, or VIII-B in transgenic plants will inhibit Arabidopsis root transformation. However, none of the myosin VIII proteins contributes to the intracellular trafficking of VirE2. Expression of myosin VIII-2, VIII-A, and VIII-B, but not VIII-1, cDNAs in the myosin VIII-1/2/a/b mutant can partially restore transformation efficiency. Furthermore, functional fluorescent protein-tagged VirE2 synthesized in plant cells relocalizes from the cell periphery to the cytoplasm following T-strand delivery from Agrobacterium. Surprisingly, an Arabidopsis myosin XI-k mutant, transgenic plants expressing the myosin XI-K CBD, and plants subjected to RNAi targeting myosin XI-k all remain highly transformable, even though VirE2 movement along actin filaments is blocked. We hypothesize that myosin VIII proteins facilitate VirE2 tethering to the plasma membrane and are required for its efficient localization to membrane sites where it binds incoming T-strands, whereas myosin XI-K is important for VirE2 movement through the cytoplasm toward the nucleus.

The initiation of light signaling involves the formation of phyB nuclear photobodies (PBs). The nuclear pore complex (NPC) is the sole gate for macromolecule transport between the cytoplasm and nucleus; however, its role in phyB PB formation and light signal transduction remains unclear. Here, we identify Nup96, a nucleoporin in the NPC subcomplex Nup107-160, as a key regulator that promotes plant photomorphogenesis. Nup96 interacts with phyB at the nuclear envelope to facilitate phyB PB formation and enhance phyB activity. Moreover, this interaction promotes phyB-PIF5 association, thereby facilitating PIF5 degradation. Notably, knocking out PIF5 fully rescues the hypocotyl phenotype of nup96-1. Further analyses identify an E3 ligase, HIGH EXPRESSION OF OSMOTICALLY RESPONSIVE GENES 1 (HOS1), which interacts with PIF5 to promote its degradation via the 26S proteasome pathway. Collectively, our study elucidates a mechanism by which Nup96 promotes PIF5 degradation by enhancing phyB activity and stabilizing HOS1, thereby ensuring precise light-regulated growth in plants.

Optimization of plant architecture requires precise regulation of internode elongation; however, the post-translational mechanisms that integrate microRNA and phytohormone signaling remain poorly understood. Here, we describe a hierarchical miR164e-NAC32-DELLA regulatory network that controls stem development in maize. Genetic analyses demonstrate that ZmmiR164e negatively regulates its target gene ZmNAC32, with ZmmiR164e overexpression enhancing internode cell elongation and loss-of-function resulting in dwarfism. Notably, ZmNAC32 physically interacts with and stabilizes the DELLA protein ZmD8, as evidenced by increased ZmD8 protein levels in ZmNAC32-overexpressing plants compared with the wild type. Transcriptome profiling reveals that ZmNAC32-mediated regulation of plant height occurs primarily through post-translational stabilization rather than extensive transcriptional reprogramming, with downstream cell wall biosynthesis genes (EXP, XTH, and LAC) showing GA-responsive suppression. Structural analyses further reveal that ZmNAC32 binding stabilizes ZmD8 by shielding the key interaction residue K399, thereby suppressing its degradation. Together, these results identify a miRNA-NAC-DELLA module that governs post-translational protein stability during stem development and provides strategic targets for precision breeding of plant architecture.

Plant roots have evolved adaptive strategies mediated by transcriptional networks to cope with fluctuating nitrogen (N) forms and availability. However, the mechanisms linking root-foraging responses to N use efficiency (NUE) in crops remain poorly understood. Here, we show that rice exhibits enhanced root elongation under nitrate compared with ammonium, particularly under low N supply, suggesting a specific regulatory role for nitrate in root morphogenesis. We identify the transcription factor OsMADS61 as a key regulator of nitrate-dependent root morphological and physiological responses, as well as NUE, especially under N-limited conditions. OsMADS61 acts as a transcriptional activator of nitrate metabolism by directly binding to OsNRT2.1 and OsNR2 promoters. Nitric oxide produced via the nitrate reductase pathway, under the control of nitrate-responsive OsMADS61, precisely triggers cell proliferation in the root meristem. Moreover, single-nucleotide polymorphisms in the OsMADS61 promoter may be associated with differential root-foraging responses to nitrate availability. Therefore, enhancing N-adaptive root responses to optimize N uptake and assimilation represents a promising strategy for breeding crops with high NUE.