Journal of Integrative Plant Biology最新文献

Using an optimized CRISPR/Cas9 system to knock out the BTB-POZ and MATH domain gene BoBPM6 and the DOWNY MILDEW RESISTANCE 6 gene in Brassica oleracea resulted in new lines with broad-spectrum disease resistance.

Reactive oxygen species (ROS) plays critical roles in modulating plant growth and stress response and its homeostasis is fine tuned using multiple peroxidases. H₂O₂, a major kind of ROS, is removed rapidly and directly using three catalases, CAT1, CAT2, and CAT3, in Arabidopsis. Although the activity regulations of catalases have been well studied, their degradation pathway is less clear. Here, we report that CAT2 and CAT3 protein abundance was partially controlled using the 26S proteasome. To further identify candidate proteins that modulate the stability of CAT2, we performed yeast-two-hybrid screening and recovered several clones encoding a protein with RING and vWA domains, CIRP1 (CAT2 Interacting RING Protein 1). Drought and oxidative stress downregulated CIRP1 transcripts. CIRP1 harbored E3 ubiquitination activity and accelerated the degradation of CAT2 and CAT3 by direct interaction and ubiquitination. The cirp1 mutants exhibited stronger drought and oxidative stress tolerance, which was opposite to the cat2 and cat3 mutants. Genetic analysis revealed that CIRP1 acts upstream of CAT2 and CAT3 to negatively regulate drought and oxidative stress tolerance. The increased drought and oxidative stress tolerance of the cirp1 mutants was due to enhanced catalase (CAT) activities and alleviated ROS levels. Our data revealed that the CIRP1-CAT2/CAT3 module plays a vital role in alleviating ROS levels and balancing growth and stress responses in Arabidopsis.

Seed color is a key agronomic trait in crops such as peanut, where it is a vital indicator of both nutritional and commercial value. In recent years, peanuts with darker seed coats have gained market attention due to their high anthocyanin content. Here, we used bulk segregant analysis to identify the gene associated with the purplish-red coat trait and identified a novel gene encoding a basic/helix-loop-helix transcription factor, PURPLE RED SEED COAT1 (PSC1), which regulates the accumulation of anthocyanins in the seed coat. Specifically, we found that a 35-bp insertion in the PSC1 promoter increased the abundance of PSC1 mRNA. Transcriptomic and metabolomic analyses indicated that the purplish-red color of the seed coat was the result of decreased expression of anthocyanidin reductase (ANR), leading to increased accumulation of delphinidin, cyanidin, and pelargonidin derivatives. Further analysis revealed that PSC1 interacts with AhMYB7 to form a complex that specifically binds to the ANR promoter to suppress its expression, resulting in increased anthocyanin accumulation. Moreover, overexpression of PSC1 increased anthocyanin content in Arabidopsis thaliana and peanut callus. Our study reveals a new gene that controls seed coat color by regulating anthocyanin metabolism and provides a valuable genetic resource for breeding peanuts with a purplish-red seed coat.

Plants, algae and photosynthetic bacteria convert light into chemical energy by means of photosynthesis, thus providing food and energy for most organisms on Earth. Photosynthetic pigments, including chlorophylls (Chls) and carotenoids, are essential components that absorb the light energy necessary to drive electron transport in photosynthesis. The biosynthesis of Chl shares several steps in common with the biosynthesis of other tetrapyrroles, including siroheme, heme and phycobilins. Given that many tetrapyrrole precursors possess photo-oxidative properties that are deleterious to macromolecules and can lead to cell death, tetrapyrrole biosynthesis (TBS) requires stringent regulation under various developmental and environmental conditions. Thanks to decades of research on model plants and algae, we now have a deeper understanding of the regulatory mechanisms that underlie Chl synthesis, including (i) the many factors that control the activity and stability of TBS enzymes, (ii) the transcriptional and post-translational regulation of the TBS pathway, and (iii) the complex roles of tetrapyrrole-mediated retrograde signaling from chloroplasts to the cytoplasm and the nucleus. Based on these new findings, Chls and their derivatives will find broad applications in synthetic biology and agriculture in the future.

Circular RNAs (circRNAs), a type of head-to-tail closed RNA molecules, have been implicated in various aspects of plant development and stress responses through transcriptome sequencing; however, the precise functional roles of circRNAs in plants remain poorly understood. In this study, we identified a highly expressed circular RNA, circZmMED16, derived from exon 8 of the mediator complex subunit 16 (ZmMED16) across different maize (Zea mays L.) inbred lines using circRNA-seq analysis. This circRNA is predominantly expressed in maize tassels and functions in the cytoplasm. Overexpression of circZmMED16 resulted in increased expression of ZmMED16/AtMED16 and delayed flowering in both maize and Arabidopsis thaliana, compared with that in wild-type plants. In contrast, overexpression of the parent gene ZmMED16 did not alter the flowering time of transgenic plants in Arabidopsis, suggesting that circZmMED16 plays a specific role in regulating flowering, distinct from that of linear ZmMED16. To further understand the mechanisms underlying the regulation of flowering time by circZmMED16, we performed RNA pull-down, dual-luciferase, RNA interference (RNAi), and ribonuclease protection assays (RPA). These results indicate that circZmMED16 interacts with small subunit 1 of ADP-glucose pyrophosphorylase (APS1) mRNA in both maize and Arabidopsis. The knockdown of circZmMED16 increased the expression of ZmAPS1, whereas the overexpression of circZmMED16 led to the downregulation of ZmAPS1 RNA and protein. By affecting ZmAPS1 expression, circZmMED16 reduced ADP-glucose pyrophosphorylase (AGPase) activity and led to delayed flowering. These results revealed a novel regulatory mechanism for circRNAs in flowering time and shed light on their functional and regulatory roles in plants.

A synthetic biology approach using a robust reconstitution system in Escherichia coli enables the identification of plant ubiquitin-like proteases responsible for removing the small ubiquitin-like modifier (SUMO) post-translational modifications from specific protein substrates.

Heat stress (HS) at the reproductive stage detrimentally affects crop yields and seed quality. However, the molecular mechanisms that protect reproductive processes in plants under HS remain largely unknown. Here, we report that Acetylation Lowers Binding Affinity 3 (ALBA3) is crucial for safeguarding male fertility against HS in Arabidopsis. ALBA3 is highly expressed in pollen, and ALBA3 is localized in the cytoplasm of both sperm and vegetative cells. Mutants lacking functional ALBA3 exhibit hypersensitivity to HS, with reduced silique length and fertility due to defects in pollen germination, pollination, pollen tube growth, and fertilization under HS. ALBA3 binds and stabilizes a subset of messenger RNAs (mRNAs) essential for pollen function, thereby protecting male fertility. Two residues in the Alba domain, K46 and L90, are critical for ALBA3's ability to bind and stabilize mRNAs and are necessary for its proper function. Interestingly, the loss of rice ALBA3 also leads to severe pollen abortion and male sterility under HS, highlighting the conserved role of ALBA3 in protecting male fertility across plant species. This study uncovers a conserved mechanism by which ALBA3 safeguards male fertility during HS by stabilizing specific mRNAs crucial for pollen function.

Plant oils play a crucial role in human nutrition, industrial applications and biofuel production. While the enzymes involved in fatty acid (FA) biosynthesis are well-studied, the regulatory networks governing these processes remain largely unexplored. This review explores the intricate regulatory networks modulating seed oil biosynthesis, focusing on key pathways and factors. Seed oil content is determined by the efficiency of de novo FA synthesis as well as influenced by sugar transport, lipid metabolism, FA synthesis inhibitors and fine-tuning mechanisms. At the center of this regulatory network is WRINKLED1 (WRI1), which plays a conserved role in promoting seed oil content across various plant species. WRI1 interacts with multiple proteins, and its expression level is regulated by upstream regulators, including members of the LAFL network. Beyond the LAFL network, we also discuss a potential nuclear factor-Y (NF-Y) regulatory network in soybean with an emphasis on NF-YA and NF-YB and their associated proteins. This NF-Y network represents a promising avenue for future efforts aimed at enhancing oil accumulation and improving stress tolerance in soybean. Additionally, the application of omics-based approaches is of great significance. Advances in omics technologies have greatly facilitated the identification of gene resources, opening new opportunities for genetic improvement. Importantly, several transcription factors involved in oil biosynthesis also participate in stress responses, highlighting a potential link between the two processes. This comprehensive review elucidates the complex mechanisms underlying the regulation of oil biosynthesis, offering insights into potential biotechnological strategies for improving oil production and stress tolerance in oil crops.

The development of rapeseed with high resistance against the pathogen Sclerotinia sclerotiorum is impeded by the lack of effective resistance resources within host species. Unraveling the molecular basis of nonhost resistance (NHR) holds substantial value for resistance improvement in crops. In the present study, small RNA sequencing and transcriptome sequencing were carried out between rice (a nonhost species of S. sclerotiorum) and rapeseed during infection, revealing the involvement of rice miRNAs on translation-related processes in both rice and the pathogen. Specifically, rice-specific miRNAs with potential capability for cross-kingdom RNAi against S. sclerotiorum were explored, of which Os-miR169y was selected as a representative case to elucidate its role in resistance to S. sclerotiorum. The silence of Os-miR169y decreased the resistance level of rice to S. sclerotiorum, and heterologous expression of Os-miR169y in Arabidopsis and rapeseed significantly enhanced the host resistance. The dual-luciferase reporter assay indicates that Os-miR169y targets S. sclerotiorum 60S ribosomal protein L19 (SsRPL19). Overexpressing Os-miR169y (OE_ss-miR169y) and RNAi of SsRPL19 (RNAi_ss-RPL19) in S. sclerotiorum significantly impaired the growth and pathogenicity of the pathogen, while overexpressing SsRPL19 exhibited a contrast effect. Yeast-two-hybridization revealed an interlinking role of SsRPL19 with multiple large and small ribosomal subunits, indicating its important role in translation. Proteome sequencing detected a decreased amount of proteins in transformants OE_ss-miR169y and RNAi_ss-RPL19 and significant suppression on key metabolic pathways such as carbon and nitrogen metabolisms. Collectively, this study suggests that rice can secrete specific miRNAs to suppress genes essential for S. sclerotiorum, such as Os-miR169y, which targets and suppresses SsRPL19 and thus impairs protein synthesis in the pathogen. This study sheds light on the intrinsic mechanisms of rice NHR against S. sclerotiorum, and further demonstrates the potential of using nonhost-specific "pathogen-attacking" miRNAs in improving resistance in host species.

As sessile organisms, plants must directly face various stressors. Therefore, plants have evolved a powerful stress resistance system and can adjust their growth and development strategies appropriately in different stressful environments to adapt to complex and ever-changing conditions. Nevertheless, prioritizing defensive responses can hinder growth; this is a crucial factor for plant survival but is detrimental to crop production. As such, comprehending the impact of adverse environments on plant growth is not only a fundamental scientific inquiry but also imperative for the agricultural industry and for food security. The traditional view that plant growth is hindered during defense due to resource allocation trade-offs is challenged by evidence that plants exhibit both robust growth and defensive capabilities through human intervention. These findings suggest that the growth‒defense trade-off is not only dictated by resource limitations but also influenced by intricate transcriptional regulatory mechanisms. Hence, it is imperative to conduct thorough investigations on the central genes that govern plant resistance and growth in unfavorable environments. Recent studies have consistently highlighted the importance of WRKY transcription factors in orchestrating stress responses and plant-specific growth and development, underscoring the pivotal role of WRKYs in modulating plant growth under stressful conditions. Here, we review recent advances in understanding the dual roles of WRKYs in the regulation of plant stress resistance and growth across diverse stress environments. This information will be crucial for elucidating the intricate interplay between plant stress response and growth and may aid in identifying gene loci that could be utilized in future breeding programs to develop crops with enhanced stress resistance and productivity.