Artificial light at night (ALAN) alters circadian rhythms in animals and therefore can be a source of environmental stress affecting their physiology and behaviour. The impact of ALAN can be related to the increased light level, but also to the spectral composition of night lighting. Previous research showed that many species can be particularly sensitive to the LED light, but it is unclear if they respond to its broad spectrum or specifically to the blue light wavelength. In this study, we tested whether dim ALAN (2 lx) differing in the spectral quality (warm white LED, blue LED, high-pressure sodium HPS light) modifies behaviour and changes oxidative status in two nocturnal freshwater shredder species: Dikerogammarus villosus and Gammarus jazdzewskii (Gammaroidea, Amphipoda). Our experiment revealed that ALAN, irrespective of its spectral quality, did not affect the oxidative stress markers in cells (the level of reactive oxygen species and lipid peroxidation). However, ALAN changed the gammarid behaviour in a species-specific manner, which can potentially reduce the fitness of the shredders. Dikerogammarus villosus avoided all types of light compared to darkness. Therefore, confined to the shelter, D. villosus may have fewer opportunities to forage and/or mate. Gammarus jazdzewskii was sensitive only to the narrow-spectrum blue light, but did not respond to the HPS and white LED light. Avoidance is a typical response of gammarids to natural light, thus the disruption of this behaviour in the presence of common ALAN sources can increase the predation risk in this species. To summarize, behavioural modifications induced by ALAN seem more pronounced than changes in physiology and can constitute the main driver of disturbances in the processing of organic matter in freshwater ecosystems by invertebrate shredders.

Background/Objectives: Plant metallothioneins (MTs) are low-molecular-weight proteins involved in heavy metal binding and response to stress conditions. This work aimed to analyse canola (Brassica napus L.) MTs (BnMT1-4) response to salinity and plant interaction with bacteria. Methods: (1) We tested germination and canola growth and development in the presence of sodium chloride and bacteria Serratia plymuthica; (2) We analysed phytohormones content using LC-MS/MS; (3) We identified in silico cis-regulatory elements in promoters of BnMT1-4 genes; and (4) we investigated BnMT1-4 genes’ expression in B. napus. Results: Under saline conditions, canola germination and plant growth were notably inhibited, whereas inoculation of seeds with S. plymuthica significantly stimulated the analysed physiological traits of B. napus. The content of auxin, abscisic acid, jasmonates, gibberellins, and salicylic acid in B. napus was significantly affected by salinity and modulated by S. plymuthica presence. The promoter regions of the BnMT1-4 genes contain numerous regulatory elements controlled by light, hormones, and various stresses. Interestingly, the expression of BnMT1-3 genes was down-regulated under salt stress, while BnMT4 transcript levels increased strongly at the highest salt concentrations with and without S. plymuthica present. Conclusions: The results show that BnMT genes are differently affected by salinity and bacteria S. plymuthica and significantly correlate with particular phytohormones content in canola tissues, confirming the diversified functions of MTs in plant responses to changing environment.

Rapeseed oil, constituting 12% of global vegetable oil production, is susceptible to quality degradation due to stress-induced incomplete seed degreening, fatty acid oxidation, or poor nutrient accumulation. We hypothesise that the hyperphosphorylated nucleotide alarmone ppGpp (guanosine tetraphosphate), acts as a pivotal regulator of these processes, given its established roles in nutrient management, degreening, and ROS regulation in leaves. Using qPCR, UHPLC-MS/MS, and biochemical methods, our study delves into the impact of ppGpp on seed nutritional value. We observed a positive correlation between ppGpp levels and desiccation, and a negative correlation with photosynthetic pigment levels. Trends in antioxidant activity suggest that ppGpp may negatively influence peroxidases, which are safeguarding against chlorophyll decomposition. Notably, despite increasing ppGpp levels, sugars, proteins and oils appear unaffected. This newfound role of ppGpp in seed development suggests it regulates the endogenous antioxidant system during degreening and desiccation, preserving nutritional quality. Further validation through mutant-based research is needed.

Progressive climate change increases drought frequency, severely impacting crop growth and yield. New eco-friendly alternatives to chemical protection agents and fertilisers are needed to reduce pollution and enhance plant health. This study evaluated the effects of the plant growth-promoting rhizobacteria (PGPR) and the hydrogel (potassium polyacrylate) on Brassica napus L. during drought conditions. After in vitro and pot experiments, Serratia plymuthica was selected from six PGPR candidates based on its ability to enhance plant biomass, shoot length, and number of internodes. The seed viability test, reactive oxygen species accumulation, and SOD activity showed no adverse effects of applying hydrogel to canola seeds. Moreover, the hydrogel did not show toxicity towards tested bacterial strains. Field trials during the drought demonstrated that inoculation with S. plymuthica significantly increased the number of siliques (16.48%) and yield (19.93%), compared to controls. Plants grown from inoculated seeds were also taller (3.28%) and had more branches (39.99%). We also analysed seedling emergence, number of internodes, thousand seeds’ weight, and seed moisture. The hydrogel applied to the soil delayed seedling emergence and dampened the growth-promoting effect of S. plymuthica, resulting in reduced yield. Compared with plants inoculated with S. plymuthica, there was a decrease in the yield of plants treated solely with hydrogel and in plants treated with hydrogel and the bacterium of 23.61% and 27.79%, respectively. Our results indicate that S. plymuthica has a high potential for use in commercial canola farming, especially as an ingredient added to seed coatings.

Yellow lupine ( Lupinus luteus L.) is a promising protein crop, but domestication has increased flower abscission. Flowers in higher whorls are more likely to abscise, providing a model to study factors influencing flower fate before abscission zone formation. We hypothesise that auxin localisation and miRNA-modulated signal transduction orchestrate flower development and abscission, particularly under drought. We investigated the indole-3-acetic acid (IAA) distribution in ovules and tested the effects of IAA, NPA (auxin transport inhibitor), and PCIB (auxin signalling blocker) on flower retention. Bioinformatic analyses of transcriptome data profiled miRNA-regulated auxin pathway elements (TIR1/AFBs, ARFs), with domain structures analysed for functional divergence. Selected miRNA-mRNA modules were analysed for their role in inflorescence drought response. IAA accumulation exhibited slight differences in upper pre-anthesis flowers. In the field experiment, PCIB treatment led to increased retention of generative organs, suggesting the vital role of auxin nuclear signalling in flower fate. Bioinformatic analyses identified miRNAs (MIR393, MIR160, MIR167, one novel) regulating TIR1/AFB and ARF6 , 8 , 17 , 18 . qPCR revealed the differential expression of AFB3 -, ARF6 -, and ARF18 -encoding transcripts and corresponding miR393, miR167, and miR160 during flower development and drought stress. However, miRNA-target expression lacked a strictly negative correlation, indicating other regulating players.