Regulon: An overview of plant abiotic stress transcriptional regulatory system and role in transgenic plants

Marine and terrestrial biostimulant elicitors of tolerance to cold stress

The increasing frequency of adverse environmental events, driven by ongoing climate change, has intensified the search for new technological alternatives in crop production and plant protection. Thermal stress can limit plant adaptation and negatively impact metabolism, physiology, morphology, and yield. Cold stress in plants has been extensively studied and can affect various stages of plant's life cycle, from seed formation to development, causing damage to cell membranes, impairing cell division, and disrupting water absorption. Consequently, researchers have focused on mitigating the impacts of abiotic stress by investigating bioactive molecules and biostimulants derived from various organisms, which enhance tolerance mechanisms in plants. In aquatic environments, macro- and microalgae have emerged as key sources of plant elicitors, providing extractable molecules such as polysaccharides, polyamines, polyphenols, and amino acids that enhance plant defense responses. Similarly, certain terrestrial plants have shown potential as sources of biostimulant compounds. Thus, this study aims to highlight advancements in crop systems by emphasizing the potential of algae-based and terrestrial biostimulant elicitors in enhancing tolerance to cold stress. Ultimately, the goal is to improve understanding of promising biological models for food production, fostering innovative developments that can contribute to economically and ecologically sustainable technologies.

Potential impact and mechanism of aged polyethylene microplastics on nitrogen assimilation of Lactuca sativa L

Nitrogen (N) is the driving factor for crop yield and quality, and more research is needed on the mechanisms of aged micro/nano plastics (MNPs) on N assimilation in edible crops. In this study, pot experiments were conducted to investigate the potential effect of aged polyethylene (PE) microplastic addition (particle sizes: 20 and 0.1 µm, addition levels: 0.5 % [w/w], referred to as the control (CK), P20 (20-µm PE), AP20 (20-µm aged PE), P0.1 (0.1-µm PE), AP0.1 (0.1-µm aged PE) on MNPs accumulation and N assimilation in romaine lettuce (Lactuca sativa L.). The results showed that the particle size of MNPs accumulated in lettuce decreased from root > stem > leaf. Compared to CK, the fresh plant weight significantly decreased by 40.84 and 51.62 % in AP20 and AP0.1, respectively. The results indicated that MNPs could affect lettuce growth via soil nutrient availability, and aged 100-nm PE decreased soil NH4+ and plant TN concentrations by 9.10 and 21.99 %, respectively, compared to that in CK. N assimilation in lettuce was significantly inhibited by aged MNPs, which manifested as the soluble protein content in lettuce under AP20 and AP0.1 treatments being significantly reduced by 30.59 and 42.11 %, respectively (P < 0.01). Possible mechanisms included inhibition of carbon assimilation, photosynthesis, and Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco). The toxic effect of aged MNPs on growth and N assimilation in lettuce was much greater than that of the particle size, which was attributed to the carbonyl and hydroxyl groups caused by aging. Structural equation modeling showed that soil nitrogen positively affected total nitrogen (TN) (0.359), chlorophyll (0.665), Rubisco (0.441), soluble protein (0.383), and biomass (0.460), and negatively affected phosphoenolpyruvate carboxylase (PEPC) (-0.325), soluble sugar (-0.134). This study enhances current understandings of the effects of microplastics on N assimilation in edible crops. The findings indicated that aged MNPs accumulation in vegetables may negatively affect agricultural sustainability and food safety.

Floristic survey, trace element transfers between soil and vegetation and human health risk at an urban industrial wasteland

This study aimed to determine the trace element accumulation in the soil and plants in an industrial wasteland and to estimate the extent of transfer to humans to measure the effects on and risks to vegetation and human health and find bioindicator plants representative of the levels of the main contaminants. In areas with the highest extractable trace element levels, we observed decreases in plant biodiversity explained by the disappearance of several families, favouring the coverage of tolerant species, such as Urtica dioica and Hedera helix. Trace elements were also found in the leaves of several plants, especially in a dominant species that is poorly studied, Alliaria petiolata. Indeed, this species had the highest contents of Zn (1750 mg.kg-1 DW), Ni (13.1 mg.kg-1 DW), and Cd (18 mg.kg-1 DW) found at the site and is a potential Zn bioindicator since its leaf contents were also representative of the Zn extractable contents in soil (R² = 0.94). The hazard quotient and carcinogen risk revealed that most of the site had an identified or possible risk, mainly due to Pb and As. Native species, especially A. petiolata, could be used in phytoextraction to manage and limit these human and environmental risks.

A Pathogen-Inducible Rice NAC Transcription Factor ONAC096 Contributes to Immunity Against Magnaprothe oryzae and Xanthomonas oryzae pv. oryzae by Direct Binding to the Promoters of OsRap2.6, OsWRKY62, and OsPAL1

The rice NAC transcriptional factor family harbors 151 members, and some of them play important roles in rice immunity. Here, we report the function and molecular mechanism of a pathogen-inducible NAC transcription factor, ONAC096, in rice immunity against Magnaprothe oryzae and Xanthomonas oryzae pv. oryzae. Expression of ONAC096 was induced by M. oryzae and by abscisic acid and methyl jasmonate. ONAC096 had the DNA binding ability to NAC recognition sequence and was found to be a nucleus-localized transcriptional activator whose activity depended on its C-terminal. CRISPR/Cas9-mediated knockout of ONAC096 attenuated rice immunity against M. oryzae and X. oryzae pv. oryzae as well as suppressed chitin- and flg22-induced reactive oxygen species burst and expression of PTI marker genes OsWRKY45 and OsPAL4; by contrast, overexpression of ONAC096 enhanced rice immunity against these two pathogens and strengthened chitin- or flg22-induced PTI. RNA-seq transcriptomic profiling and qRT-PCR analysis identified a small set of defense and signaling genes that are putatively regulated by ONAC096, and further biochemical analysis validated that ONAC096 could directly bind to the promoters of OsRap2.6, OsWRKY62, and OsPAL1, three known defense and signaling genes that regulate rice immunity. ONAC096 interacts with ONAC066, which is a positive regulator of rice immunity. These results demonstrate that ONAC096 positively contributes to rice immunity against M. oryzae and X. oryzae pv. oryzae through direct binding to the promoters of downstream target genes including OsRap2.6, OsWRKY62, and OsPAL1.