The Plant Journal最新文献

The wheat "Green Revolution (GR)" that occurred from the 1960s to the 1970s significantly enhanced the harvest index and resistance to lodging, thereby increasing grain production, but at the cost of reduced nitrogen (N) use efficiency (NUE) in wheat. The NUE of wheat is mainly regulated by N metabolism genes (NMGs). However, the evolutionary process of NMGs during GR and post-GR wheat breeding, as well as which of them affect NUE, remains unclear. Here, we collected 265 wheat varieties that were released before, during, and after the GR and investigated grain yield per plant and 24 other traits under different N supply conditions. Next, we identified the genotypes of these wheat varieties using a 100 K targeted sequencing array. Then, we systematically analyzed the signatures in the genomes of GR and post-GR released varieties compared with pre-GR released varieties through population divergence (Fst) and nucleotide diversity (π) ratio analyses, and found that 41 NMGs were located within the selective sweep regions during the GR and post-GR breeding. We further identified 118 quantitative trait loci (QTLs) involved in regulating NUE through genome-wide association studies (GWAS). Four NMGs-NRT1 AND PEPTIDE TRANSPORTER FAMILY 2.7-D (TaNPF2.7-D), TaNPF2.3-D, TaNPF2.7 L-D, and QUASIMODO2-B (TaQUA2-B)-were located within overlapping regions of selective sweeps and NUE-related QTLs. Notably, the elite haplotypes of these genes for NUE are less utilized in GR and post-GR released cultivars. Furthermore, we found that TaNPF2.7-D positively regulates nitrate exudation as well as the wheat development. Collectively, our findings uncover an important reason for the reduction in NUE in modern cultivars and provide a valuable resource for improving wheat NUE.

NUCLEOPORIN1 (NUP1/NUP136), a member of the Nuclear Pore Complex (NPC), is located on the inner side of the nuclear membrane. It is highly expressed in seeds; however, its role in seed germination and seedling establishment has not yet been explored. Here, we identified an abscisic acid (ABA) hypersensitive phenotype of nup1 during seedling establishment in two nup1 mutant alleles. ABA treatment drastically changes the expression pattern of thousands of genes in nup1, including the major transcription factors (TFs) involved in germination, ABI3, ABI4, and ABI5. Double mutant analysis of NUP1 and these ABA-related genes showed that mutations in ABI5 can rescue the phenotype of nup1, suggesting that abi5-8 is epistatic to nup1-1 in seedling establishment. ABI5, a key negative regulator of germination, is abundant in dry seeds and rapidly degraded during germination. However, its spatiotemporal regulation and interaction with other molecular players during the degradation remain to be fully elucidated. We found that NUP1 is physically associated with ABI5 and the 26S proteasome. Mutation in NUP1 delayed ABI5 degradation through its post-translational retention in the nucleolus under ABA stress. Taken together, our findings suggest that NUP1 anchors the proteasome to NPC and modulates seedling establishment through proteasome-mediated degradation of ABI5 in the vicinity of NPC in the nucleoplasm.

Receptor-like proteins (RLPs) are key components in the plant immune system. Loss of the RLP SUPPRESSOR OF NPR1-1, CONSTITUTIVE 2 (SNC2) in Arabidopsis results in enhanced disease susceptibility, whereas the gain-of-function mutant snc2-1D exhibits autoimmunity including a dwarfed morphology and constitutively activated defense responses. SNC2 function is fully dependent on the transmembrane protein BIAN DA 1 (BDA1). SYSTEMIC ACQUIRED RESISTANCE DEFICIENT 1 (SARD1) and CALMODULIN-BINDING PROTEIN 60 g (CBP60g) are two transcription factors required for the autoimmunity of snc2-1D. Constitutive defense responses in snc2-1D are attenuated by the cbp60g single mutant, but fully abolished by the sard1 cbp60g double mutant. In this study, we identified and characterized the ADAPTOR PROTEIN 4 (AP4) complex in SNC2-mediated plant immunity. By performing a suppressor screen in the cbp60g-1 snc2-1D background, mutations in AP4μ, a subunit of the AP4 complex, were identified. Interestingly, AP4μ associates with BDA1, and Y18 and Y257 of BDA1 seem to play important roles in such interaction. Knocking out genes of other subunits in the AP4 complex consistently suppressed cbp60g-1 snc2-1D autoimmunity, suggesting that the AP4 complex is required for SNC2 signaling. Furthermore, mutating AP4μ in wild-type plants compromises basal defense and pattern- and effector-triggered immunity, indicating a broader role of the AP4 complex in plant immunity.

Brassica napus is one of the most important oilseed crops worldwide and improving its oil content is a key research focus. The transcription factor (TF) BnMYB96 was found to be upregulated during oil accumulation under drought conditions, but the molecular regulation pathway remains unclear. Here, a cDNA library was constructed in a B. napus line with high oil content. BnLEA4 was first screened using BnMYB96 as bait, which was confirmed by yeast two-hybrid (Y2H), co-immunoprecipitation (Co-IP), bimolecular fluorescence complementation (BiFC), and pull-down assays. BnMYB96 can interact with BnLEA4 and regulate downstream BnLTP2, as confirmed by yeast one-hybrid (Y1H), dual-luciferase reporter (LUC) assay, electrophoretic mobility shift assay (EMSA), and β-glucuronidase (GUS) assay. Overexpression of BnMYB96 and BnLTP2 increased oil content and drought resistance through photosynthetic physiological processes and reactive oxygen species (ROS) metabolism. In contrast, opposite trends were observed in the CRISPR/Cas9 knockout lines. Hybrids (six-line crosses) between the two genes (BnMYB96 and BnLTP2) with increased or reduced expression showed stronger trends in drought tolerance and lipid accumulation. Single-cell and bulk transcriptome sequencing analyses showed that genes involved in carbon fixation and fatty acid (FA) synthesis in photosynthetic organisms were upregulated by BnMYB96 and BnLTP2, enhancing photosynthesis and FA synthesis. This study elucidates the BnLEA4-BnMYB96-BnLTP2 regulatory pathway that coordinates oil accumulation and drought resistance in B. napus. These findings provide a theoretical basis for improving the drought resistance and oil content of plants.

Long-term domestication and cultivation have led to the differentiation of Salvia miltiorrhiza genetic resources in different regions of China, accompanied by differences in the accumulation of pharmacological components represented by tanshinones in the roots. Tanshinone, as a key biomarker with significant therapeutic effects on cardiovascular and cerebrovascular diseases, has become the primary target for improvement in S. miltiorrhiza breeding. It is particularly important to deeply analyze the differentiation of tanshinones biosynthetic pathways in S. miltiorrhiza of different ecotypes, systematically revealing the evolution mechanism of geoherbs driven by metabolic networks. Based on integrated omics strategies, the metabolic regulatory network of tanshinones was constructed in different ecotypes, and WRKY70 was identified as a core transcription factor in the regulatory network of tanshinones metabolism. Transgene, Yeast-one-hybrid, EMSA, and Dual-LUC demonstrated that WRKY70 positively regulates tanshinones biosynthesis by targeting the promoter of CYP76AK1 and ABCG1. Yeast-two-hybrid, BiFC, Luciferase complementation, and Co-IP confirmed that WRKY70 formed a stable protein complex with SnRK2.6, which in turn mediated the ABA signaling pathway dependent tanshinones metabolic regulation and drought stress adaptation. Overall, we report that a bifunctional transcription factor, WRKY70, promotes tanshinones synthesis while enhancing plant adaptation to drought, which is expected to be used as a breeding target to save the deficiency of tanshinones and enhance stress resistance in specific ecotype S. miltiorrhiza.

Drought is a major environmental factor that hinders plant growth and development, thereby threatening crop yields. The major latex protein (MLP) plays an important role in modulating plant stress responses and development. However, the roles and molecular mechanism of MLP in drought stress response remain unclear. Here, we identified a wheat MLP member TaSTP, and its overexpression in wheat exhibited enhanced drought tolerance, whereas silencing TaSTP increased drought sensitivity. Additionally, TaSTP-overexpressing lines exhibited higher yields under drought conditions. Transcriptome sequencing analysis revealed that TaSTP significantly upregulates genes involved in the osmotic regulatory and sugar metabolism pathway, thereby increasing antioxidant capacity and sugar content. Moreover, we also found that exogenous application of glucose and sucrose effectively enhanced drought tolerance in wheat. A 172 bp fragment insertion in the TaSTP-2A promoter created two allelic variants, Hap-2A-I and Hap-2A-II, which differ in transcriptional levels and drought tolerance. This insertion allows binding of the zinc finger transcription factor TaZAT5L, strongly repressing TaSTP expression in Hap-2A-I, but not in Hap-2A-II. The superior allele Hap-2A-II has been preferentially selected during wheat breeding in China. Collectively, our results demonstrate that TaSTP enhances drought tolerance by promoting reactive oxygen species (ROS) scavenging and sugar accumulation. These findings provide novel insights into the roles and molecular mechanisms of TaSTP in plants.

SQUAMOSA PROMOTER BINDING PROTEIN-LIKE (SPL) genes encode plant-specific transcription factors that are widely distributed across the plant kingdom. In angiosperms, the multimember SPL family regulates various biological processes, including vegetative-to-reproductive phase transition, inflorescence architecture, and lateral organ development. In contrast, the liverwort Marchantia polymorpha genome encodes only four SPL genes, with functional studies available only for microRNA-targeted members, MpSPL1 and MpSPL2. MpSPL1 was shown to control the meristem dormancy to modulate the thallus architecture, whereas MpSPL2 was found to promote the transition from vegetative-to-reproductive phase. Here, we investigate the impact of the MpSPL3 gene on M. polymorpha development. We demonstrate that MpSPL3 influences coordination of the vegetative growth and the reproductive phase transition. Knockout of MpSPL3 leads to strong growth retardation with disordered thallus morphology, reduced gemma cup number, and, most strikingly, complete loss of gametangiophore formation. Interestingly, overexpression of MpSPL3.2, the shorter isoform, has no detectable morphological effect, whereas the overexpression of MpSPL3.1, the longer isoform encoding a protein with an additional 61-aa long fragment, results in a delay in timing and reduced efficiency of gametangiophore production. Moreover, all the observed developmental abnormalities might be a consequence of the altered expression of genes essential for proper vegetative development and responsible for germ cell specification in MpSPL3 knockout and overexpression plants. Altogether, our findings demonstrate that MpSPL3 is important in regulating gametophyte development and ensuring reproductive success in M. polymorpha.

The use of wild relatives to introduce original diversity in the genome of bread wheat (Triticum aestivum L.) is an interesting approach to face the challenges of sustainable agriculture and the impact of climate change on wheat production. However, the influence of these wild-species introgressions on meiosis in inter-varietal wheat hybrids remains poorly understood. We analyzed the French wheat variety Renan (Re) carrying Aegilops ventricosa (Aev)-derived 2AS/2NS and 7DL/7DvL introgressions, the reference cultivar Chinese Spring (CS), which lacks these introgressions, and their inter-varietal hybrid Chinese Spring × Renan (CSRe). This analysis combined cytogenetic approaches with the assessment of reproductive performance. Furthermore, we generated a cytological atlas of meiosis in wild tetraploid Aev, quantifying bivalent configurations and chiasma frequency. We observed a reduced pollen viability and a slight decrease in floret fertility in the hybrid CSRe. Exploration of the meiotic behavior showed that CSRe exhibited increased numbers of rod bivalents and univalents, leading to a reduced average chiasma number and frequent chromosome bridges and fragmentations, whereas the parental lines maintained stable chromosome pairing. These rearrangements indicate that homologous chromosome pairing and recombination are affected in CSRe. We applied introgression-specific oligo-Fluorescent In Situ Hybridization to localize alien segments in CSRe, providing a novel strategy to investigate the meiotic behavior of introgressed regions. The 2AS/2NS introgressed segments in CSRe were frequently located on rod bivalents or univalents, while 7DL/7DvL segments consistently formed ring bivalents. Our results provide a foundation for guiding alien gene introgression and for understanding the behavior of chromosomes with introgressions in the wheat genome.

MicroRNAs (miRNAs) are key regulators of plant growth, development, and immunity. However, their role in kiwifruit and other perennial fruit trees remains poorly characterized. Here, we demonstrate that Ac-miR156a functions as a negative regulator of kiwifruit resistance to Pseudomonas syringae pv. actinidiae (Psa). In the resistant cultivar "Jinkui," Ac-miR156a expression was significantly suppressed upon Psa infection, whereas it was markedly induced in the susceptible cultivar "Hongyang." Overexpression of miR156a increased kiwifruit susceptibility to Psa, while silencing miR156a via short-tandem target mimic (STTM) constructs enhanced resistance. We identified 14 SQUAMOSA-PROMOTER-BINDING PROTEIN-LIKE (SPL) transcription factors as direct targets of Ac-miR156a, among which AcSPL6c and AcSPL14c were rapidly upregulated in the resistant cultivar and shown to positively regulate immunity against Psa. Furthermore, we revealed that the Ac-miR156a-SPL module regulates kiwifruit immunity by reprogramming the hormonal levels between salicylic acid (SA) and jasmonic acid (JA) signaling pathways, favoring SA-dominated defense against the biotrophic pathogen Psa. Collectively, our study elucidates a complete Ac-miR156a-AcSPL6c/14c regulatory pathway that fine-tunes kiwifruit immune outcomes through hormonal redistribution, providing both mechanistic insights and potential genetic targets for improving disease resistance in kiwifruit breeding programs.

Both abscisic acid (ABA) and brassinosteroids (BRs) antagonistically regulate growth and abiotic stress responses; however, the mechanisms by which these phytohormones synergistically influence growth and salt tolerance in halophytes have not yet been fully elucidated. In this study, an NAC gene from Reaumuria trigyna, RtNAC081, was found to enhance growth and salt tolerance in transgenic poplar via the ABA and BR pathways, and its suppression led to decreased callus growth and greater sensitivity to salt stress. Under normal conditions, RtNAC081 increased wood formation and shoot growth, whereas saline conditions induced RtNAC081 transcription. RtNAC081 activated RtNCED1.1 expression and promoted BR synthesis through the RtNAC081-RtBZR1 axis, and also activated BR signaling. Synergistic interactions between ABA and BR were rapidly disrupted under extreme stress. Higher ABA levels inhibited RtBZR1 expression, causing growth retardation that improved salt tolerance through physical interaction with RtNAC081. RtNAC081 activated RtAPX5 to modulate reactive oxygen species balance and photosynthetic efficiency, which ultimately improved salt tolerance. Together, our results demonstrate the intricate interplay between the BR and ABA signaling pathways in modulating the balance between plant growth and salt stress adaptation, highlighting the pivotal role of RtNAC081 in this regulatory network.