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.
Rosnące światowe zapotrzebowanie na żywność wymaga wypracowania nowych strategii udoskonalania roślin celem zwiększenia ilości i jakości plonu. Obiecujące możliwości rozwiązania tego problemu oparte są na wykorzystaniu wciąż poszerzającej się wiedzy na temat miRNA, klasy endogennych małych cząsteczek RNA, negatywnie regulujących ekspresję genów na poziomie transkrypcyjnym i potranskrypcyjnym. Opracowywane technologie bazują na zmianie metodami inżynierii genetycznej ekspresji miRNA, zastosowaniu sztucznego miRNA (amiRNA) lub modyfikacji ich genów docelowych, polegającej na pozbawieniu ich wrażliwości na miRNA. Wśród wielu procesów fizjologicznych, poprzez które można wpływać na plonowanie roślin, na szczególną uwagę zasługują: regulacja czasu wejścia w fazę dojrzałą i generatywną, kształtowanie architektury rośliny (krzewienie), dojrzewanie owoców, indukcja partenokarpii, reakcje na stresy biotyczne oraz abiotyczne.
Abstract The degree to which roots elongate is determined by the expression of genes that regulate root growth in each developmental zone of a root. Most studies have, however, focused on the molecular factors that regulate primary root growth in annual plants. In contrast, the relationship between gene expression and a specific pattern of taproot development and growth in trees is poorly understood. However, the presence of a deeply located taproot, with branching lateral roots, can especially mitigate the effect of insufficient water availability in long-lived trees, such as pedunculated oak. In the present article, we integrated the ribonucleic acid (RNA) sequencing data on roots of oak trees into a single comprehensive database, named OakRootRNADB that contains information on both coding and noncoding RNAs. The sequences in the database also enclose information pertaining to transcription factors, transcriptional regulators and chromatin regulators, as well as a prediction of the cellular localization of a transcript. OakRootRNADB has a user-friendly interface and functional tools that increase access to genomic information. Integrated knowledge of molecular patterns of expression, specifically occurring within and between root zones and within root types, can elucidate the molecular mechanisms regulating taproot growth and enhanced root soil exploration. Database URL https://oakrootrnadb.idpan.poznan.pl/
Jasmonates are phytohormones conditioning proper functioning of separate plant development stages. Jasmonates precursor is ?-linolenic acid. Their biosynthesis occurs in three subcellular structures: chloroplasts, peroxisomes and cytosol. This paper summarizes the most recent achievements on participation of jasmonates in the field of reproduction of plants. Jasmonates hinder florescence among the most species of plants. However, researches carried out over rape indicate that the role of these compounds in generative induction is not explicit, i.e. they may speed up the growth of flowers in certain circumstances. Jasmonates are also very important in a process of proper formation of sterile and fertile parts of flower, as well as in opening flower buds. Furthermore, jasmonic acid (JA) nascent in a thread rod synchronizes maturation of pollen grains with the process of opening anthers and flowers. On the basis of gene expression pattern DAD1 analysis (the one that encodes an enzyme involved in the first stage of jasmonates formation), there was created a model of water transport regulation by JA to the stamens and petals of the crown. In addition, it was observed that one of the bioactive forms of jasmonic acid (JA-Ile) acts as an intermediary molecule in the secretion of nectar, regulated by the light. JA-Ile increases in the secretion of nectar in plants cultivated in the light and does not cause its decrease in plants cultivated in the dark. Inhibition of the JA-Ile biosynthesis in the light reduces the secretion of nectar. This result can be inverted by the application of JA-Ile.
In this study, the first ACC oxidase (PnACO1) cDNA from model short-day plant Pharbitis nil was isolated. The expression pattern of PnACO1 was studied under different conditions (photoperiod and auxin), an adequate balance of which determines P. nil flowering. It was shown that the gene was transcribed in all the examined organs of the 5-day-old seedling and was strongly activated by auxin. Our results also revealed that PnACO1 transcript accumulation in the cotyledons showed diurnal oscillations under both LD and SD conditions. On the basis of presented and previously obtained data, we suggest that flowering inhibition evoked by IAA in P. nil results from its stimulatory effect on both ACC synthase and oxidase gene expression and, consequently, enhances ethylene production.
Trees are generally long-lived and are therefore exposed to numerous episodes of external stimuli and adverse environmental conditions. In certain trees e.g., oaks, taproots evolved to increase the tree’s ability to acquire water from deeper soil layers. Despite the significant role of taproots, little is known about the growth regulation through internal factors (genes, phytohormones, and micro-RNAs), regulating taproot formation and growth, or the effect of external factors, e.g., drought. The interaction of internal and external stimuli, involving complex signaling pathways, regulates taproot growth during tip formation and the regulation of cell division in the root apical meristem (RAM). Assuming that the RAM is the primary regulatory center responsible for taproot growth, factors affecting the RAM function provide fundamental information on the mechanisms affecting taproot development.
Interactions between methyl jasmonate (JA-Me) and ethylene in the photoperiodic flower induction of short-day plant Pharbitis nil were investigated. Both JA-Me and gaseous ethylene applied during the inductive long night caused a decrease in the number of flower buds generated by P. nil. Application of ethylene did not affected niether the level of endogenous jasmonates in the cotyledons during the 16 h long inductive night, nor the inhibitory effect of JA-Me on the flowering of P. nil accompanied by variations in ethylene production. The application of acetylsalicylic acid (aspirin)—a jasmonate biosynthesis inhibitor—slightly stimulated flowering. Our results have shown that the mechanisms of P. nil flower inhibition by jasmonates and ethylene are independent.
The ZEITLUPE (ZTL) protein is involved in the control of circadian period, hypocotyl elongation and flowering time in Arabidopsis thaliana. The aim of the present work was the identification of the InZTL gene and localization of its mRNA in the model short-day plant Ipomoea nil. The deduced InZTL protein of 622 amino acid residues contained a LOV domain at the N-terminal part, followed by an F-box domain and six carboxy terminal kelch repeats. Amino acid sequence of InZTL showed 84 % homology with Mesembryanthemum crystallinum ZTL (McZTL) and 83 % with Arabidopsis thaliana ZTL (AtZTL). Fluorescence in situ hybridization (FISH) to InZTL mRNA showed its high accumulation in the vascular bundles as well in the guard cells of the cotyledon. Immunolocalization of ZTL protein indicated a similar distribution pattern of ZTL protein as InZTL mRNAs.
