Journal of Integrative Plant Biology最新文献

Low light is one of the main environmental factors influencing the content of soluble sugar in oriental melon fruit under protected cultivation. As a supplementary light source, light-emitting diodes have been widely used to improve fruit quality. However, the regulatory mechanism of light quality on oriental melon fruit quality remains unclear. Here, the high sucrose melon fruit was treated with different light qualities during the development stage in a greenhouse, and the results showed that red light significantly increased the sucrose content and upregulated the expression of sucrose transport and metabolism-related genes (CmSUT2, CmSWEET10, and CmSUS2) in melon fruit. In addition, CmWRKY28 was found using a yeast single-hybrid cDNA library, which responded to red light treatment and could bind to the promoters of CmSUT2, CmSWEET10, and CmSUS2 to activate their expression. Moreover, CmHY5 acted as a positive regulator of sucrose accumulation by directly binding to CmSUT2 and CmWRKY28 promoters. CmHY5 also interacted with CmWRKY28 at the protein level to participate in the regulation of sucrose accumulation. Taken together, these findings revealed that red light induced CmHY5 and CmWRKY28 to positively regulate the expression of target genes, promoting the accumulation of more sucrose in melon fruit. This study provided new insights into alleviating the effects of low-light conditions on melon fruit quality.

Plant cells can undergo cellular reprogramming, enabling pluripotent callus formation from excised leaves. Despite this pluripotency, organs regenerated from leaf callus have predominantly been confined to conventional shoots and roots, leaving the potential to regenerate other specialized organs unknown. In this study, we identified that stolons can be regenerated from potato leaf callus. Furthermore, we demonstrate that Agrobacterium tumefaciens stimulation efficiently induces stolon regeneration and subsequent tuber development from potato leaf callus. The induction of stolon regeneration is abolished when biological activity is removed from the bacterial cultures, indicating that viable bacterial cells are required for this process. Comparative assays using various strains reveal that the C58 chromosomal background is essential for this enhancement. Integrating transcriptome analysis with transgenic functional validation, we find that phosphatidylethanolamine-binding protein (PEBP) family genes are closely involved in this response. Furthermore, we observe that viruses do not readily spread to regenerated stolons through the callus, which lacks a continuous vascular system to serve as a pathway for virus movement. Our findings demonstrate that bacterial stimulation triggers stolon regeneration from pluripotent leaf callus, offering a potential approach for the production of virus-free storage organs in potato.

Biomass allocation is crucial for predicting ecosystem responses to global change, and yet, whether patterns follow the plastic optimal partitioning theory (OPT) or the constrained allometric partitioning theory (APT) remains contentious across different biomes. A key uncertainty is whether vast, functionally distinct ecosystems, such as temperate and alpine drylands, show different allocation strategies. Here, we investigated root:shoot ratio (R/S) patterns across 120 sites spanning temperate and alpine drylands in northern China. Significant differences in allocation were observed, with temperate drylands showing lower R/S than alpine regions. In temperate drylands, R/S scaled allometrically with plant community size, consistent with APT, with key soil factors exerting only an indirect influence through their effects on plant community size. Conversely, in alpine drylands, R/S was insensitive to plant community size and instead responded directly to the mean annual temperature, a pattern indicative of OPT. We propose that this strategic divergence is linked to their underlying community functional structures. Communities with greater functional dissimilarity may achieve higher niche complementarity, providing the necessary capacity to optimize allocation in response to environmental constraints. Our findings demonstrate that climatic regimes drive alternative biomass allocation strategies, providing both a predictive framework for vegetation responses and a theoretical basis for dryland ecosystem restoration under climate change.

Transposable elements (TEs) are abundant and evolutionarily important components of plant genomes, yet the population-scale landscape of TE insertion polymorphisms (TIPs) and their regulatory roles in gene expression and trait variation remain insufficiently understood. In this study, genomic resequencing, RNA-seq, and agronomic trait data from a panel of 381 Brassica napus accessions were integrated to characterize population-level TIP dynamics and assess their impacts on gene regulation, ecotype differentiation, and phenotypic innovation. Using a developed computational pipeline, a robust pan-TE library was constructed based on 28 diverse reference genomes, and 77,603 TIP loci were profiled by mapping resequencing data from 381 accessions. Most TE insertions were found to be dispensable and weakly linked to neighboring SNPs, suggesting that they represent recent or ecotype-specific variants that serve as independent sources of regulatory and adaptive diversity in B. napus. The regulatory roles of TEs were examined through two complementary strategies (direct-effect analyses and TIP-based eQTL mapping), which together revealed that TEs modulate gene expression via both cis- and long-range trans-effects. Notably, TE-mediated trans-regulation, rarely investigated in previous studies, was found to be widespread, with trans-effects predominating and displaying strong tissue specificity, emphasizing the extensive regulatory influence of TEs on the plant transcriptome. Furthermore, selective sweep analyses identified ecotype-specific TIPs associated with adaptive divergence, particularly those contributing to semi-winter type diversification. TIP-based genome-wide association studies (GWAS) revealed 1,102 candidate insertions significantly associated with key agronomic traits, including flowering time, fatty acid composition, and glucosinolate content, some of which were not detected by SNP-based analyses. This study provides the population-scale atlas of TE insertions in B. napus, uncovers their extensive regulatory roles, and demonstrates their contribution to adaptation and trait variation, offering valuable resources for breeding and functional genomics.

Plants must coordinate chloroplast biogenesis with environmental conditions during seedling establishment, as failure to do so results in impaired phototrophic growth. Despite the biological importance of this early developmental stage, the influence of environmental factors on chloroplast biogenesis remains poorly understood. Here, we reveal a crucial role for GENOMES UNCOUPLED1 (GUN1)-mediated biogenic retrograde signaling in safeguarding chloroplast development and supporting seedling growth under heat stress. Loss of GUN1 causes severe bleaching and impaired photomorphogenesis at elevated temperatures. Genetic interaction analyses show that EXECUTER1 (EX1) and EXECUTER2 (EX2), key components of chloroplast ROS-associated operational retrograde signaling, modulate the heat-sensitive phenotype of gun1 mutants, indicating crosstalk between biogenic and operational retrograde pathways. We further demonstrate that the de-repressed expression of photosynthesis-associated nuclear genes, that is, genomes uncoupled expression, is a major contributor to the heat sensitivity and failed chloroplast biogenesis in gun1 seedlings under heat stress. These findings extend the current understanding of GUN1 function by showing its contribution to chloroplast development and thermotolerance through biogenic retrograde signaling during early seedling growth.

The inhibited growth of primary roots (PRs) is a typical adaptive response of Arabidopsis to low phosphate (LP) stress. The role of auxin and its relationship with iron (Fe) in this process, however, remains unclear. In this study, we demonstrated that auxin acts as a positive regulator. A high concentration of auxin at the tips of PRs stimulates vigorous PR growth in both LP-arf7 arf19 and LP-yucca mutants. The application of a low dose of exogenous auxin can partially mitigate LP-induced PR growth inhibition. Enhanced auxin signaling, achieved through overexpression of ARF7 or ARF19, also promotes PR growth in LP-transgenic plants. Conversely, LP stress negatively regulates the polar transport of auxin, leading to reduced PIN activity at PRs. Mutations of PINs and application of NPA, therefore, exacerbate the impact of LP stress on PR growth. Consistently, PIN activity remains stable in the PRs of LP-arf7 arf19 mutants, and mutation of PINs normalizes the inhibited growth of these mutants. Furthermore, a correlation is observed between decreased auxin activity and increased Fe at LP-PRs. Fe accumulation triggers a burst of reactive oxygen species (ROS), which inhibits polar auxin transport and distribution at the tips of PRs. Changes in Fe and ROS levels influence auxin activity at LP-PRs, while auxin conversely affects Fe accumulation at these sites. Consequently, Fe levels are low at the PRs of LP-arf7 arf19 mutants, LP-yucca mutants, and auxin-treated LP-WT plants. Conversely, they are high in PRs of LP-pin2 mutant and NPA-treated LP-WT plants. In conclusion, accumulated Fe triggers a burst of ROS, disrupting auxin transport by decreasing PIN activity at LP-PRs. This disruption subsequently inhibits cell division and overall PR growth.

Argonaute (AGO) proteins are important components of the RNA silencing machinery and play core roles in plant antiviral defenses. OsAGO2 was significantly induced by infection with Rice stripe virus and Rice dwarf virus. Loss-of-function ago2 mutant lines lack antiviral activity, and AGO2 over-expression lines show increased antiviral activity.

Sphingolipids, including ceramides, are structural membrane lipids that function in membrane trafficking and cell polarity. Very-long-chain (VLC) ceramide synthases are essential for plant growth and development, but how VLC ceramide synthases affect developmental programs and their exact roles in plant growth remain unclear. Here, we report that two VLC ceramide synthases, LONGEVITY ASSURANCE GENE ONE HOMOLOG 1 (LOH1) and LOH3, link sphingolipid metabolism and thermomorphogenesis, that is, plant morphogenesis in response to higher temperatures. We found that high ambient temperature (28°C) induced an increase in plant VLC ceramide contents, and defects in LOH1 or LOH3 function inhibited hypocotyl elongation at this temperature. PHYTOCHROME-INTERACTING FACTOR 4 (PIF4) potentiates the thermal sensitivity of hypocotyl morphogenesis in a LOH1- and LOH3-dependent manner, directly binding to the LOH1 and LOH3 promoters to enhance their expression. Strikingly, LOH1 and LOH3 also enhance PIF4-dependent transcriptional activation of downstream genes, including PIF4 itself, LOH1, and LOH3. Our study reveals a regulatory mechanism in which PIF4 activates the transcription of LOH1 and LOH3; in turn, LOH1 and LOH3 enhance PIF4 signaling by supporting PIF4-mediated transcriptional responses, thereby controlling plant growth in response to temperature.

Climate change poses an increasing threat to global biodiversity and food security. As a wild relative of cultivated apples, Malus baccata exhibits broad environmental adaptability and robust stress tolerance. However, its effective utilization in breeding is constrained by the absence of a complete reference genome and insufficient population-level genomic characterization. In this study, we assembled a haplotype-resolved, telomere-to-telomere genome for M. baccata, providing unprecedented resolution for a wild apple reference genome. Population genomic analyses revealed four distinct genetic clusters. Among these, the Hebei Group 2 harbors the highest genetic diversity and heterozygosity, alongside the lowest runs of homozygosity, suggesting a complex history of genetic admixture in this population. By integrating population genomics with genotype-environment association analyses, we identified a series of climate-associated single-nucleotide polymorphisms and structural variants. A substantial proportion of these adaptive variants is localized within the coding and regulatory regions of candidate genes, providing a genomic basis for their roles in environmental adaptation. Notably, DREB1A/D and NAC6 are associated with temperature seasonality and annual precipitation, respectively. Furthermore, future climate projections indicate that the Northeastern (NE) clusters face the highest risk of maladaptation, especially under high-emission scenarios. Collectively, these findings provide critical insights into the genetic basis of climatic adaptation in wild apples, establishing a solid foundation for the conservation of crop wild relatives and the breeding of climate-resilient cultivars.