aBIOTECH最新文献

Noncanonical nucleotide-binding leucine-rich repeat (NLR) genes, which lack typical N-terminal domains, are abundant in plants but their functions remain poorly understood. Two recent studies have cloned members of this family and offer clues into the role of this family in plant immunity. Independently, these workers cloned two noncanonical NLR genes, RMES1A and RMES1B, that confer resistance to the aphid Melanaphis sorghi in sorghum (Sorghum bicolor). Furthermore, their cognate insect effector MsEF1, a phosphatase-like protein, was identified. These studies establish that NLRs lacking clear functional domains can mediate insect resistance and provide a new genetic resource for engineering pest-resilient crops.

The plant immune system plays crucial roles in interactions with microbes- both pathogenic and beneficial. During the past few decades, great progress has been made in understanding the molecular mechanisms of plant immune responses, including during legume-rhizobium mutualism. Here, we summarize recent progress uncovering the roles of the two layers of plant immunity, pathogen-triggered immunity (PTI) and effector-triggered immunity (ETI), in the association between legumes and rhizobia. We propose that crosstalk occurs between PTI and ETI in legumes to regulate symbiotic interactions with rhizobia. This concept enhances our understanding of the molecular mechanisms underlying the relationships between plant immunity and legume-rhizobium mutualism.

Soybean (Glycine max) is an important protein and oil crop whose yield is significantly affected by salinity stress. N⁶-methyladenine (m⁶A), a prominent epigenetic modification of RNA, exerts crucial regulatory functions in plant development and stress responses. Through genome-wide analysis, we identified 55 m⁶A modification-regulatory genes in soybean across 19 soybean chromosomes, categorized into writers, readers, and erasers. The promoters of these genes are enriched in light-, phytohormone-, and stress-responsive cis-elements and display diurnal and tissue-specific expression patterns, suggesting multifaceted regulation. Chromatin immunoprecipitation revealed distinct histone modification signatures associated with these genes, including H3K4me3, H3K36me3, and H2A.Z. Protein-protein interaction analysis confirmed the assembly of core GmMTA-GmMTB-GmFIP37 writer components, with GmFIP37 forming homodimers and heterodimers. Evolutionary analysis showed that GmMTBa underwent strong selection pressure with genetic conservation, while GmMTBb experienced selection during domestication, showing an association with flowering and yield traits. Notably, we discovered that GmMTBa, a core subunit of the m⁶A methyltransferase complex, functions as a critical determinant of salinity stress tolerance in soybean, as Gmmtba mutants exhibited pronounced salinity sensitivity. Mechanistically, GmMTBa regulates the m⁶A modification of GmMSH1 transcripts, a key suppressor of stress signal transduction. GmMSH1 knockdown lines were more tolerant to salinity stress, under which conditions GmMSH1 expression was significantly elevated in Gmmtba mutants. These results indicate that GmMTBa influences salinity stress tolerance by modulating MSH1-dependent stress signaling pathways. Our findings reveal an m⁶A-mediated regulatory mechanism in plant stress acclimation and establish GmMTBa as a promising candidate for improving soybean resilience to salinity stress.

Photosynthesis, as the primary biochemical reaction for carbon fixation, provides the carbon skeletons for diverse secondary metabolites in plants. Here, we report that the transcription factors GmSTF1 and GmSTF2 regulate both photosynthesis and lignin biosynthesis in soybean (Glycine max). GmSTF1 and GmSTF2 directly bound to a TGACG motif in the promoter of the photosynthetic gene GmLHCA4 and a Z-box element in the promoter of the lignin biosynthetic gene GmCAD1, activating their transcription. Loss-of-function mutants (gmstfs-dm) displayed light-green leaves with reduced chlorophyll levels, photosynthetic rates, soluble sugar contents, and lignin contents. Conversely, transgenic soybean plants overexpressing these genes (GmSTF1-YFP and GmSTF2-YFP) showed enhanced chlorophyll accumulation, photosynthetic efficiency, soluble sugar production, and lignin deposition. Our findings identify GmSTF1 and GmSTF2 as critical regulators of carbon assimilation and lignin production in soybean.

Plants possess a multilayered immune system that detects and responds to pathogen invasion through pattern-triggered immunity (PTI) and effector-triggered immunity (ETI). We recently developed a high-throughput screening platform using transgenic Arabidopsis thaliana expressing the β-glucuronidase (GUS) reporter gene under the control of the promoter of the PTI marker gene FRK1 (pFRK1::GUS) to identify chemical inducers of plant immunity. Among the ∼10,000 screened compounds, we identified 10 candidate compounds with the potential to activate FRK1 expression. In this study, we focused on one of these small molecules, designated Agrivax, for analysis. Agrivax is a previously unreported small molecule that activates immune signaling. Agrivax induces FRK1 expression in a dose-dependent manner, triggers the transient phosphorylation of MAPKs, and enhances resistance against Pseudomonas syringae pv. tomato DC3000 (Pst DC3000). While Agrivax alone did not elicit reactive oxygen species (ROS) production, it synergistically amplified flg22-and chitin-induced ROS bursts and root growth inhibition. Furthermore, Agrivax pretreatment potentiated the ETI-associated hypersensitive response upon challenge with Pst DC3000 carrying AvrRpt2. These findings demonstrate that Agrivax functions as an immune priming chemical to activate immune responses and disease resistance, making it a promising lead compound for developing plant immune inducers and a valuable tool for dissecting immune signaling pathways.

Male sterility affects various agronomic traits. Although jasmonate (JA) has been shown to influence fertility in several plant species, most research on JA-mediated regulation of fertility has focused on bisexual flowers, leaving the role of this phytohormone in unisexual flowering plants largely unexplored. Cucumber (Cucumis sativus) has unisexual flowers and is an ideal model plant for studying male and female gametophyte development. In this study, we determined that JA regulates male and female flower development as well as male fertility in cucumber. In the JA biosynthesis-deficient mutant Csopr3, both female and male flower petals failed to open properly, anthers showed defective dehiscence, and pollen in male flowers ruptured and was nonviable. MeJA treatment restored normal petal opening and anther dehiscence in Csopr3, and the pollen regained the ability to germinate. Further analysis revealed that CsXTH33, a gene involved in cell-wall structure, negatively regulates stamen fertility in cucumber. Transcriptional regulation assays indicated that CsMYC2 binds to the promoters of CsWRKY45 and CsWRKY57 and activates their expression. In turn, CsWRKY45 and CsWRKY57 bind to the promoter of CsXTH33, inhibiting its expression and promoting normal stamen development. This study thus reveals the role of JA in cucumber unisexual flower development and deepens our understanding of the mechanisms by which JA regulates plant fertility.

Hi-C technology has become indispensable for studying three-dimensional (3D) genome organization; however, the substantial variability in existing genome analysis tools poses challenges for efficient, accurate data processing. Here, we present Motif-Hi-C, an innovative computational framework that leverages the intrinsic sequence signatures of Hi-C chimeric reads to enable rapid, reliable quality control. Through systematic benchmarking of four mainstream tools (HiC-Pro, HiCUP, Juicer, and HiCExplorer) across diverse Hi-C datasets, we identified critical trade-offs between processing speed and analytical precision. Motif-Hi-C addresses these limitations by implementing a motif-aware classification system that achieves faster processing with more valid interacting rmdup/total read pairs. Key innovations include (1) automated detection of ligation-motif signatures in raw sequencing data, (2) category-specific parallel processing pipelines, and (3) dynamic quality thresholds adapted to different experimental protocols. Validation across multiple cell types and restriction enzymes demonstrated robust performance, with particular advantages for large-scale consortium datasets. This framework establishes a new paradigm for efficient quality assessment in 3D genomics studies, seamlessly integrating with downstream chromatin interaction analyses.

Rice (Oryza sativa) grain quality is an important breeding target, yet its genetic basis remains incompletely understood. In this study, we integrated hyperspectral phenotyping with genome-wide association study (GWAS) to investigate apparent amylose content (AAC) and protein content (PC) in 241 modern rice varieties. Using a visible-shortwave infrared hyperspectral system combined with optimized preprocessing and machine-learning pipelines, we achieved accurate predictions for AAC (R ² = 0.97) and PC (R ² = 0.92). Hyperspectral-based GWAS identified both known loci and previously unreported genetic associations. For AAC, qAAC _(780.791nm) -1-3 was mapped to the Green Revolution gene SD1, showing that the sd1 allele increases AAC while conferring high yields. For PC, we identified qPC _(1998.98nm) -5-1 and confirmed GW5 as the causal gene, linking the high-yielding gw5 allele with high grain PC. Hyperspectral features outperformed traditional measurements, enhancing the detection of genetic signals. This study provides an efficient strategy for elucidating the genomic architecture of complex grain-quality traits.