Journal of Integrative Plant Biology最新文献

Soil salinization is a global challenge threatening agricultural production, food security, and sustainable development. As a pioneer crop on saline-alkali land, sunflower plays a crucial role in the improvement and utilization of salt-affected soils. However, the molecular mechanisms underlying sunflower salt tolerance remain poorly understood. In this study, we identified a key R2R3-MYB gene, HaMYB22, through a combination of genome and transcriptome analyses. Functional characterization demonstrates that overexpression of HaMYB22 significantly enhances salt tolerance in both Arabidopsis and sunflower, whereas its silencing decreases salt resistance. Protein interaction assays revealed that HaMYB22 interacts with HaMYB120 and HaMYB181. Glutathione S-transferase HaGST3.2 was identified as a direct target of HaMYB22, and superior haplotype HaMYB22^hap1 can strongly increase HaGST3.2 transcripts. Moreover, HaMYB120 and HaMYB181 synergistically strengthen HaMYB22-mediated HaGST3.2 activation. HaGST3.2 silencing in sunflower decreases salt tolerance. Our findings revealed the importance of the HaMYB22-HaGST3.2 module in sunflower salt tolerance.

Calcium (Ca²⁺), a dual-functional mineral that serves both as an essential structural factor and a signaling molecule, plays a critical role in regulating fundamental physiological processes in plants, including development, stress response, and fruit quality traits. However, a comprehensive and systematic summary of calcium's regulatory functions in fruit quality is still lacking. This review aims to clarify the pivotal roles of calcium in regulating key fruit quality attributes, including external traits such as morphology and coloration; internal nutritional properties, such as flavor-related metabolites and bioactive compounds; and physiological disorders such as cracking, softening, browning, chilling injury, blossom-end rot, water core, and bitter pit. Considering its diverse regulatory functions, genetic manipulation of Ca²⁺ signaling pathways and the application of nano-calcium formulations offer promising strategies for improving fruit yield and quality in commercial production systems. This review further outlines the underlying mechanisms through which calcium influences fruit quality and suggests future research directions to address existing knowledge gaps.

Auxin plays a pivotal role in regulating crop nitrogen (N)-use efficiency (NUE), coordinating both N-responsive root development and the expression of N metabolism genes. In our previous work, we identified DULL NITROGEN RESPONSE1 (DNR1) as a repressor within the auxin-mediated NUE network in rice. Here, we further delineate this pathway by identifying the SUMO E3 ligase OsSIZ1 as a key upstream regulator of DNR1. Contrary to its canonical role, we discovered that OsSIZ1 exhibits ubiquitin E3 ligase activity toward DNR1, facilitating its polyubiquitination at lysine 314 and subsequent degradation. This degradation promotes auxin accumulation, thereby enhancing NUE and grain yield. Notably, the yield advantage driven by OsSIZ1 is most pronounced under low-N conditions, underscoring its potential as a breeding target for developing resilient crops that require less N fertilizer, enabling a more sustainable agriculture.

Alkaline stress is a major constraint on crop growth and development and negatively impacts soybean (Glycine max) production and yield. Despite the remarkable progress that has been made in investigating beneficial microbes that facilitate plant growth and development, the role of rhizobacteria in regulating alkaline tolerance in soybean remains poorly understood. Here, we isolated Klebsiella sp. strain B7 from the Suaeda glauca roots and found that it enhances the alkaline tolerance of soybean by secreting pyruvic acid. Metabolome and RT-qPCR analysis of soybean roots indicated that high levels of pyruvic acid secreted by B7 activated the expression of genes involved in pyruvic acid metabolism and increased L-malic acid accumulation in soybean roots, thereby effectively mitigating reactive oxygen species induced by alkaline stress. Overexpression of these pyruvic acid metabolism-associated genes greatly enhanced alkaline tolerance of soybean and ATP-citrate lyase activity, further confirming the positive role of pyruvic acid in L-malic acid biosynthesis and alkaline tolerance in soybean. Notably, the B7 application to alkaline soil enhanced the soybean yield. Moreover, B7 recruited more beneficial microbes and shaped the composition of the rhizosphere bacterial community of soybean plants. These findings highlight the vital function of rhizobacteria strain B7 in enhancing alkaline tolerance in soybean, thus providing further evidence for the crucial role of plant growth-promoting rhizobacteria in the abiotic stress response of soybean.

The rice blast fungal effector AVR-PikC binds to the rice protein HIPP19, which may contribute to plant susceptibility. The compound B93 induces the interaction between the rice E3 ligase APIP6 and AVR-PikC, which results in the ubiquitination and degradation of AVR-PikC, thereby facilitating plant resistance.

Seed dormancy (SD) is the primary genetic determinant of pre-harvest sprouting (PHS) resistance. However, the molecular mechanisms underlying SD remain incompletely understood. Here, we identified a wheat cytochrome P450 gene, TaCYP94-A1, that is expressed at significantly higher levels in weak-dormancy varieties than in strong-dormancy varieties. TaCYP94-A1 expression increased during SD release and decreased during dormancy establishment. Knockout of TaCYP94-A1 markedly enhanced SD and PHS resistance without adversely affecting yield-related traits. Two key single-nucleotide polymorphisms (T/C at -1,895 bp and T/C at -1,225 bp) in the TaCYP94-A1 promoter were significantly associated with SD variation, with the TaCYP94-A1^1,895C and TaCYP94-A1^1,225C allele combination (haplotype Hap4) strongly associated with enhanced dormancy. Two transcription factors, TaABI4 and TaNAC-A1, bind directly to the 5'-ACCGC-3' (C, -1,895 bp) and 5'-GACTTC-3' (C, -1,225 bp) motifs in the TaCYP94-A1 promoter, respectively, and regulate its transcription through antagonistic protein-protein interactions in the nucleus. Physiological, biochemical, and gene expression analyses revealed that the TaABI4/TaNAC-A1-TaCYP94-A1 module regulates SD through crosstalk with the gibberellic acid, abscisic acid, and jasmonic acid pathways. Together, these findings uncover a previously uncharacterized regulatory module controlling SD and provide valuable genetic resources and molecular markers for developing PHS-resistant wheat cultivars through molecular design breeding.

Leaf angle is a key agronomic trait for improving planting density and yield in lettuce, particularly in controlled-environment agriculture and high-density field cultivation. Leaf angle regulation is well studied in monocots; however, the genetic and molecular mechanisms in dicots remain largely unknown. Here, we genetically clone and functionally characterize LsOFP6a, an OVATE family protein gene, as a key regulator of leaf angle in lettuce. A nonsense mutation in LsOFP6a in large-leaf-angle cultivars produces a truncated protein with impaired function. CRISPR/Cas9 knockout and complementary tests confirmed that LsOFP6a negatively regulates leaf angle in lettuce. LsOFP6a physically interacts with the BELL-like homeodomain transcription factor LsBLH2. Genetic analyses revealed that LsOFP6a regulates leaf angle through an LsBLH2-dependent pathway, and LsBLH2 is recessive-epistatic to LsOFP6a. LsBLH2 directly upregulates the expression of the cytokinin oxidase gene LsCKX5a. LsOFP6a represses the transcriptional activity of LsBLH2 on LsCKX5, leading to elevated cytokinin levels and small leaf angle. Furthermore, LsOFP6a inhibits the effects of LsBLH2 on repressing abaxial gene LsYAB1, leading to enhanced abaxial cell elongation and erect leaves. Loss of function of LsOFP6a decreases the cytokinin level and represses abaxial cells, resulting in large leaf angles. In summary, the LsOFP6a-LsBLH2 module orchestrates cytokinin catabolism and leaf dorsiventrality to regulate lettuce leaf angle. Our study suggests potential novel strategies for the breeding of lettuce with compact architecture and suitable for high-density planting in the open field and plant factories.

O-Methyltransferases (OMTs) play crucial roles in plant defense, environmental adaptation, and quality formation by catalyzing the biosynthesis of diverse methylated metabolites. Although OMT (COMT and CCoAOMT) genes have been functionally characterized in various plant species, the evolutionary trajectory of the entire OMT gene family and the functional divergence of the CCoAOMT subfamily remain to be systematically elucidated. In this study, we performed pan-genome analysis of the OMT gene family in 61 tomato (Solanum spp.) accessions and conducted phylogenetic analysis across 20 plant species (from algae to angiosperms), identifying 2,882 OMT genes. Phylogenetic reconstruction revealed that all extant plant CCoAOMT genes evolved from a single ancestral lineage (Clade I) originating before the divergence of red and green algae. In tomato, 2,199 OMT genes were classified into 42 orthogroups: nine core, five soft-core, 22 dispensable, and six private orthogroups, with 52.4% classified as dispensable genes. OMT genes in the Solanum genus have predominantly undergone purifying selection. Among all COMT orthogroups, a single tandem duplicate cluster stands out as exclusively conserved. Members of this cluster have evolved a distinct catalytic role, as evidenced by the finding that SlCOMT2c exclusively catalyzes the formation of kaempferide via the 4'-O-methylation of kaempferol. Ion mobility spectrometry showed that SlAOMT, a member of the CCoAOMT-like subfamily, catalyzes the methylation of luteolin to produce two isomeric products identified as diosmetin and chrysoeriol while losing the canonical catalytic function of the CCoAOMT subfamily. In addition, we identified a potential gene regulatory network associated with methylated flavonoid biosynthesis. This study establishes an integrative framework for elucidating OMT evolution and provides analytical tools for identifying genes involved in isomeric methylated flavonoid biosynthesis, paving the way for studying adaptive evolution and specialized metabolic pathways in plants.

The brown planthopper (Nilaparvata lugens Stål, BPH) is a major rice pest that feeds on sieve tubes, where plants respond by depositing callose to restrict phloem sap ingestion. However, the molecular basis of how rice stabilizes callose at plasmodesmata and how BPH overcomes this defense remains poorly understood. Here, we identify OsPDCB1, a plasmodesmal callose-binding protein that positively regulates BPH resistance by anchoring callose through its X8 domain. Loss- and gain-of-function analyses demonstrate that OsPDCB1 is essential for callose accumulation and effective phloem defense. We further identified NlVRSP1, a BPH salivary effector that is highly conserved across rice planthopper species. This effector directly interacts with OsPDCB1 and disrupts its callose-binding activity, revealing a previously uncharacterized effector-host interaction module at the plasmodesmal interface. Importantly, haplotype analysis uncovered a resistance-associated allele (OsPDCB1^Hap1), enriched in Indica rice, which enhances resistance when introgressed into susceptible Japonica backgrounds. Collectively, these findings identify OsPDCB1 as a key mediator of callose-based defense and a promising genetic target for breeding BPH-resistant rice cultivars, while providing mechanistic insight into how insect effectors subvert plasmodesmal immunity.