Journal of Integrative Plant Biology最新文献

In poplar trees, a molecular switch involving phytochrome B and PHYTOCHROME-INTERACTING FACTOR 4 responds to cool temperatures by keeping growth active, preventing premature dormancy. This mechanism, which differs from that in Arabidopsis, helps trees adapt to cool summers and ensures survival in seasonal environments.

While plant salicylic acid (SA) signaling via NPR1-PR1 is well-characterized in pathogen resistance, its role against piercing-sucking insects remains unclear in rice. Here, we demonstrate that leafhopper infestation in rice induces SA-mediated resistance, which defends against insect infestation via pathogenesis-related protein OsPR1a. However, prolonged infestation triggers autophagy-dependent degradation of OsPR1a through its interaction with OsATG8b, fine-tuning immunity to prevent excessive defense activation. Strikingly, this autophagy-mediated OsPR1a degradation represents a conserved regulatory mechanism in rice during brown planthopper infestation. A rice rhabdovirus in leafhopper vectors secretes glycoprotein on virion envelopes to rice phloem, where it binds OsATG6b and OsPR1a to enhance autophagic OsPR1a turnover, ultimately facilitating insect vector feeding and viral transmission by leafhopper vectors. Our work reveals an adaptive mechanism by which a vector-borne virus hijacks plant autophagy to evade SA immunity, highlighting OsPR1a as a critical convergence point in plant-insect-virus interactions.

This commentary highlights emerging strategies for efficient plant regeneration through control of morphogenic regulators that govern cell identity. Synthetic expression systems, enabled by high-throughput discovery platforms, can direct plant cells to form new tissues or organs, opening new possibilities for efficient genetic engineering of agronomically important crops.

Global warming imposes a major threat to plant survival by disrupting growth homeostasis, yet plants adapt to elevated temperatures through thermomorphogenesis. Although auxin signaling is known to orchestrate these adaptive responses, how temperature perception is integrated with auxin remains poorly understood. Here, we identify the CrRLK1L-family receptor kinase FERONIA (FER) as a central regulator of thermomorphogenesis in Arabidopsis thaliana. Under warm-temperature conditions, FER undergoes proteolytic cleavage, releasing its cytosolic domain FER^CD, which translocates into the nucleus via an importin-dependent pathway. Once in the nucleus, FER^CD phosphorylates the non-canonical AUX/IAA protein IAA29, thereby relieving its inhibition of ARF19 and promoting hypocotyl elongation. Transcriptomic analyses further reveal that FER and ARF19 co-regulate thermo-inducible genes involved in auxin signaling and cell wall remodeling. Together, these findings uncover the mechanism by which FER integrates thermal cues through proteolytic activation and phosphorylation-dependent modulation of auxin signaling, establishing a new paradigm for receptor kinase-mediated environmental adaptation in plants.

CRISPR/Cas12i3 belongs to the type V-I Cas system, characterized by its smaller protein size and less restricted canonical "TTN" protospacer adjacent motif. Developments of Cas12i3-mediated base editing systems for either C-to-T or A-to-G transitions will expand the editing scope and enrich the plant base editing toolkits for crop improvement. However, while the Cas12i3-based cytosine base editor (CBE) only shows very low editing efficiency in plants, its adenine base editor (ABE) has not been documented as yet. Here, we engineered a series of Cas12i3 (5M)-based CBEs (V0-V5) and ABEs (V0-V5) by fusing a deactivated dCas12i3 (5M) with a transactivation module VP64, a single-stranded DNA-binding domain Rad51, or a double-stranded DNA-binding domain HMG-D, or in combinations, and systemically evaluated their performance in rice protoplasts. Our results demonstrated that synergistic combinations of both VP64 and HMG-D outperformed other architectures and significantly boosted the efficiencies of Cas12i3 (5M)-based CBE and ABE for C-to-T and A-to-G base editing and expanded the editing window. In stable lines, in comparison to the non-fusion control, the optimized Cas12i3 (5M)-based CBE-V5 and ABE-V5 enabled up to 4.78- and 3.35-fold higher editing efficiencies, with the maximum C-to-T and A-to-G efficiencies reaching 32.35% and 38.24%, respectively, and a higher proportion of homozygous mutants in the T₀ generation. Furthermore, we generated herbicide-resistant rice germplasm by using CBE-V5 and ABE-V5, demonstrating their potential for precision breeding in crops. Together, here, we report novel Cas12i3 (5M)-based CBE and ABE that substantially enrich base editing toolkits for improvement of rice and potentially other crops.

Small G proteins, functioning as monomeric GTPases, are critical molecular switches that regulate diverse processes in plants. However, little is known about their protein homeostasis during immune responses. Here, we demonstrate that OsRab11C1, encoding a Rab-type GTPase, is transcriptionally upregulated upon Magnaporthe oryzae infection. Strikingly, loss of OsRab11C1 enhances rice blast resistance, concomitant with increased defense gene expression, MAPK activation, and ROS burst. Mechanistically, we identify the E3 ubiquitin ligase EL5 as an interactor that ubiquitinates and targets OsRab11C1 for degradation via the 26S proteasome. Consistently, EL5 acts upstream of OsRab11C1 and positively regulates rice immunity. Further analysis reveals that OsRab11C1 interacts with and stabilizes mitogen-activated protein kinase kinase OsMKK6, thereby facilitating its autophosphorylation activity. In return, OsMKK6 acts as a negative regulator of rice programmed cell death and immunity. Collectively, our findings unveil a dynamic EL5-OsRab11C1-OsMKK6 signaling module that orchestrates rice immunity against pathogen invasion.

Jasmonic acid (JA), a key phytohormone in plant defense, plays essential roles in regulating plant stress responses and growth. However, how JA signaling and nitrate signaling regulate nitrate uptake in maize (Zea mays L.) remains elusive. Here, we report that low-nitrate stress promotes JA accumulation in maize roots, and JA treatment leads to a low-nitrate phenotype. JA triggers ZmbHLH99 expression, encoding a transcription factor that binds to ZmNLP3.2 promoter and inhibits ZmNLP3.2 expression, thereby regulating nitrate uptake. In addition, the JA ZIM-domain (JAZ) transcriptional repressor ZmZIM13 interacts with ZmbHLH99 to release its inhibitory effect on the ZmNLP3.2-ZmNRT cascade and promotes ZmNLP3.2 expression. Furthermore, loss of ZmbHLH99 or overexpression of ZmZIM13 promotes plant growth and nitrate uptake, leading to higher grain yield. These findings reveal the transcriptional regulatory landscape of how JA signaling regulates nitrate uptake via the ZmZIM13-ZmbHLH99-ZmNLP3.2 module and integrates with nitrate signaling to coordinate plant growth and stress responses.

CRISPR-Cas9 is a widely used platform for plant genome editing, but its outcomes are typically dominated by small insertions and deletions (indels). Such limited mutation profiles restrict its utility in functional studies of non-coding RNAs and regulatory elements, such as microRNAs (miRNAs), untranslated regions (UTRs), and promoter sequences, where larger sequence disruptions are often required. Here, we developed enhanced exonuclease-Cas9 platforms, termed multiple nucleotide deletion Cas9 (MND-Cas9) systems, for efficient generation of large deletions in rice. By screening four exonucleases (RecJ, T5, TREX2, and SbcB), we established MND-Cas9v1 systems based on TREX2 or SbcB that produced substantially larger deletions without reducing editing efficiency. Further optimization with an inserted DNA-binding domain (DBD) between Cas9 and exonuclease yielded MND-Cas9v2, which simultaneously enhanced efficiency and deletion size. To expand PAM compatibility, we introduced PAM-relaxed Cas9-NG and SpG variants, generating MND-Cas9-NG/SpGv2 systems with broader targeting scope and superior performance compared to their parental nucleases. Finally, we demonstrated the utility of these systems in two applications: MND-Cas9v2 efficiently knocked out the miRNA gene OsMIR530, producing larger seeds, and generated extended deletions in the 3'UTR of OsGhd2, which upregulated its expression and increased grain size. These results demonstrate that MND-Cas9 systems enable high-efficiency generation of extended deletions and facilitate functional analyses of non-coding RNAs and regulatory sequences. Overall, this work establishes a versatile and expandable exonuclease-Cas9 platform that substantially broadens the mutational spectrum and application potential of CRISPR-Cas9 for plant genome engineering.

Understanding cellular events in three dimensions (3D) is of great importance for the annotation and illustration of biological processes in a contextual way. Imaging techniques based on electron microscopy (EM), such as those derived from scanning electron microscopy (SEM) and transmission electron microscopy (TEM), provide various options to visualize biological samples at scales ranging from cells to macromolecules in situ. Recently, a series of cryogenic techniques has brought EM-based imaging to a new level, enabling specimens to retain their hydrated state throughout the sample preparation and imaging steps, thereby offering a near-native visualization of cellular events. The application of dual-beam focused ion beam (FIB)-SEM to biological samples has enabled high-resolution reconstructions in 3D and streamlined sample preparation workflows for downstream cryo-electron tomography (cryo-ET) imaging. However, applications of these technologies to plant materials are limited due to intrinsic characteristics of plant cells (e.g., non-adhesive growth, large size with a central vacuole, and the presence of cell walls). For the timely application of dual-beam FIB-SEM in three-dimensional subcellular imaging of plant materials, we have recently tested and developed three major workflows with proof-of-concept evidence using developing anthers and in vitro-cultured pollen tubes based on Aquilos 2 Cryo-FIB, including (1) room-temperature FIB-SEM volume imaging, (2) cryo-lamellae preparation from cell suspension culture or high-pressure-frozen organs for cryo-ET imaging, and (3) cryo-FIB-SEM volume imaging, which will facilitate structural studies of plant materials and provide technical guidance for the broader plant cell biology research community.

Supplementation of Driver and Kuniyuki Walnut Medium with phloroglucinol enhanced regeneration efficiency in tomato tissue culture. Heterologous expression of an Arabidopsis growth-regulating factor gene, GROWTH-REGULATING FACTOR5 (GRF5), in tomato improved regeneration and transformation efficiency, suggesting a synergistic effect between phloroglucinol treatment and GRF-mediated pathways.