The interactions between mitochondria and nucleus substantially influence plant development, stress response and morphological features. The prominent example of a mitochondrial-nuclear interaction is cytoplasmic male sterility (CMS), when plants produce aborted anthers or inviable pollen. The genes responsible for CMS are located in mitochondrial genome, but their expression is controlled by nuclear genes, called fertility restorers. Recent explosion of high-throughput sequencing methods enabled to study transcriptomic alterations in the level of non-coding RNAs under CMS biogenesis. We summarize current knowledge of the role of nucleus encoded regulatory non-coding RNAs (long non-coding RNA, microRNA as well as small interfering RNA) in CMS. We also focus on the emerging data of non-coding RNAs encoded by mitochondrial genome and their possible involvement in mitochondrial-nuclear interactions and CMS development.
The phytohormone cytokinin is a regulator of numerous processes in plants. In Arabidopsis (Arabidopsis thaliana), the cytokinin signal is perceived by three membrane-located receptors named ARABIDOPSIS HISTIDINE KINASE2 (AHK2), AHK3, and AHK4/CRE1. How the signal is transmitted across the membrane is an entirely unknown process. The three receptors have been shown to operate mostly in a redundant fashion, and very few specific roles have been attributed to single receptors. Using a forward genetic approach, we isolated constitutively active gain-of-function variants of the AHK2 and AHK3 genes, named repressor of cytokinin deficiency2 (rock2) and rock3, respectively. It is hypothesized that the structural changes caused by these mutations in the sensory and adjacent transmembrane domains emulate the structural changes caused by cytokinin binding, resulting in domain motion propagating the signal across the membrane. Detailed analysis of lines carrying rock2 and rock3 alleles revealed how plants respond to locally enhanced cytokinin signaling. Early flowering time, a prolonged reproductive growth phase, and, thereby, increased seed yield suggest that cytokinin regulates various aspects of reproductive growth. In particular, it counteracts the global proliferative arrest, a correlative inhibition of maternal growth by seeds, an as yet unknown activity of the hormone.
- MeSH
- Arabidopsis anatomy & histology genetics physiology MeSH
- Time Factors MeSH
- Cytokinins metabolism pharmacology MeSH
- Plants, Genetically Modified MeSH
- Histidine Kinase genetics MeSH
- Flowers genetics physiology ultrastructure MeSH
- Meristem genetics physiology ultrastructure MeSH
- Microscopy, Electron, Scanning MeSH
- Mutation * MeSH
- Reverse Transcriptase Polymerase Chain Reaction MeSH
- Arabidopsis Proteins genetics MeSH
- Gene Expression Regulation, Plant MeSH
- Plant Growth Regulators metabolism pharmacology MeSH
- Reproduction genetics physiology MeSH
- Amino Acid Sequence MeSH
- Sequence Homology, Amino Acid MeSH
- Signal Transduction drug effects genetics MeSH
- Publication type
- Journal Article MeSH
Biological invasions can be associated with shifts of the species' climatic niches but the incidence of such shifts is under debate. The reproductive system might be a key factor controlling such shifts because it influences a species' evolutionary flexibility. However, the link between reproductive systems and niche dynamics in plant invasions has been little studied so far. We compiled global occurrence data sets of 13 congeneric sexual and apomictic species pairs, and used principal components analysis (PCA) and kernel smoothers to compare changes in climatic niche optima, breadths and unfilling/expansion between native and alien ranges. Niche change metrics were compared between sexual and apomictic species. All 26 species showed changes in niche optima and/or breadth and 14 species significantly expanded their climatic niches. However, we found no effect of the reproductive system on niche dynamics. Instead, species with narrower native niches showed higher rates of niche expansion in the alien ranges. Our results suggest that niche shifts are frequent in plant invasions but evolutionary potential may not be of major importance for such shifts. Niche dynamics rather appear to be driven by changes of the realized niche without adaptive change of the fundamental climatic niche.
643 s.
The transition from the vegetative to reproductive stage followed by inflorescence is a critical step in plant life; therefore, studies of the genes that influence flowering time have always been of great interest to scientists. Flowering is a process controlled by many genes interacting mutually in a genetic network, and several hypothesis and models of flowering have been suggested so far. Plants in temperate climatic conditions must respond mainly to changes in the day length (photoperiod) and unfavourable winter temperatures. To avoid flowering before winter, some plants exploit a specific mechanism called vernalization. This review summarises current achievements in the study of genes controlling flowering in the dicot model species thale cress (Arabidopsis thaliana), as well as in monocot model species rice (Oryza sativa) and temperate cereals such as barley (Hordeum vulgare L.) and wheat (Triticum aestivum L.). The control of flowering in crops is an attractive target for modern plant breeding efforts aiming to prepare locally well-adapted cultivars. The recent progress in genomics revealed the importance of minor-effect genes (QTLs) and natural allelic variation of genes for fine-tuning flowering and better cultivar adaptation. We briefly describe the up-to-date technologies and approaches that scientists may employ and we also indicate how these modern biotechnological tools and "-omics" can expand our knowledge of flowering in agronomically important crops.
- MeSH
- Biotechnology MeSH
- Breeding MeSH
- Photoperiod * MeSH
- Genetic Engineering MeSH
- Plants, Genetically Modified * genetics physiology MeSH
- Flowers * genetics physiology MeSH
- Crops, Agricultural * genetics physiology MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Review MeSH
MAIN CONCLUSION: Chenopodium ficifoliumflowered under long days despite much lower expression ofFLOWERING LOCUS Thomolog than under short days. Frequent duplications of the FLOWERING LOCUS T (FT) gene across various taxonomic lineages resulted in FT paralogs with floral repressor function, whereas others duplicates maintained their floral-promoting role. The FT gene has been confirmed as the inducer of photoperiodic flowering in most angiosperms analyzed to date. We identified all FT homologs in the transcriptome of Chenopodium ficifolium and in the genome of Chenopodium suecicum, which are closely related to diploid progenitors of the tetraploid crop Chenopodium quinoa, and estimated their expression during photoperiodic floral induction. We found that expression of FLOWERING LOCUS T like 1 (FTL1), the ortholog of the sugar beet floral activator BvFT2, correlated with floral induction in C. suecicum and short-day C. ficifolium, but not with floral induction in C. ficifolium with accelerated flowering under long days. This C. ficifolium accession was induced to flowering without the concomitant upregulation of any FT homolog.
It is known that volatile emissions from some beneficial rhizosphere microorganisms promote plant growth. Here we show that volatile compounds (VCs) emitted by phylogenetically diverse rhizosphere and non-rhizhosphere bacteria and fungi (including plant pathogens and microbes that do not normally interact mutualistically with plants) promote growth and flowering of various plant species, including crops. In Arabidopsis plants exposed to VCs emitted by the phytopathogen Alternaria alternata, changes included enhancement of photosynthesis and accumulation of high levels of cytokinins (CKs) and sugars. Evidence obtained using transgenic Arabidopsis plants with altered CK status show that CKs play essential roles in this phenomenon, because growth and flowering responses to the VCs were reduced in mutants with CK-deficiency (35S:AtCKX1) or low receptor sensitivity (ahk2/3). Further, we demonstrate that the plant responses to fungal VCs are light-dependent. Transcriptomic analyses of Arabidopsis leaves exposed to A. alternata VCs revealed changes in the expression of light- and CK-responsive genes involved in photosynthesis, growth and flowering. Notably, many genes differentially expressed in plants treated with fungal VCs were also differentially expressed in plants exposed to VCs emitted by the plant growth promoting rhizobacterium Bacillus subtilis GB03, suggesting that plants react to microbial VCs through highly conserved regulatory mechanisms.
- MeSH
- Alternaria physiology MeSH
- Arabidopsis microbiology physiology MeSH
- Cytokinins physiology MeSH
- Photosynthesis physiology MeSH
- Real-Time Polymerase Chain Reaction MeSH
- Flowers growth & development physiology MeSH
- Gene Expression Regulation, Plant physiology MeSH
- Rhizosphere MeSH
- Plants microbiology MeSH
- Volatile Organic Compounds metabolism MeSH
- Transcriptome physiology MeSH
- Plant Development physiology MeSH
- Publication type
- Journal Article MeSH
Hydroponicaly cultivated plants were grown on medium containing uranium. The appropriate concentrations of uranium for the experiments were selected on the basis of a standard ecotoxicity test. The most sensitive plant species was determined to be Lactuca sativa with an EC(50) value about 0.1mM. Cucumis sativa represented the most resistant plant to uranium (EC(50)=0.71 mM). Therefore, we used the uranium in a concentration range from 0.1 to 1mM. Twenty different plant species were tested in hydroponic solution supplemented by 0.1mM or 0.5mM uranium concentration. The uranium accumulation of these plants varied from 0.16 mg/g DW to 0.011 mg/g DW. The highest uranium uptake was determined for Zea mays and the lowest for Arabidopsis thaliana. The amount of accumulated uranium was strongly influenced by uranium concentration in the cultivation medium. Autoradiography showed that uranium is mainly localized in the root system of the plants tested. Additional experiments demonstrated the possibility of influencing the uranium uptake from the cultivation medium by amendments. Tartaric acid was able to increase uranium uptake by Brassica oleracea and Sinapis alba up to 2.8 times or 1.9 times, respectively. Phosphate deficiency increased uranium uptake up to 4.5 times or 3.9 times, respectively, by Brassica oleracea and S. alba. In the case of deficiency of iron or presence of cadmium ions we did not find any increase in uranium accumulation.
- MeSH
- Autoradiography MeSH
- Biodegradation, Environmental MeSH
- Species Specificity MeSH
- Hydroponics MeSH
- Plant Roots growth & development metabolism MeSH
- Magnoliopsida growth & development metabolism MeSH
- Soil Pollutants, Radioactive metabolism toxicity MeSH
- Uranium metabolism toxicity MeSH
- Crops, Agricultural growth & development metabolism MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
Práce se zabývá stanovením obsahu kadmia a zinku v bezu černém (Sambucus nigra) a lípě (Tiliaspec.), sbíraných ve čtyřech různých lokalitách České republiky. Z bezu černého byly analyzovány květy (Sambuci flos), pyl a plody (Sambuci fructus), z lípy květy (Tiliae flos). V bezu černém byl stanoven nejvyšší obsah Zn i Cd v pylu ( Zn: 65,0–94,4 mg.kg-1, Cd: 14,1–43,1 µg.kg-1) a nejnižší v plodech (Zn: 4,5–14,7 mg.kg-1 , Cd: max. 8,1 µg.kg-1). V lipovém květu byl zjištěn nižší obsah Zn (13,8–32,5 mg.kg-1) než v květech bezu černého (30,8–49,9 mg.kg-1). Obsah Cd v lipových květech (9,9–58,9 µg.kg-1 ) byl vyšší než v květech bezu černého (3,3–15,3 µg.kg-1). Naměřené koncentrace kadmia v nálevech po louhování (10, 30 a 60 min) se nacházely pod detekčním limitem metody(0,04 µg.l-1). Do nálevů přechází nejvíce Zn z lipových květů (20–36 %), méně z květů bezu černého (17–25 %) a nejméně z plodů bezu černého (12–19 %). Obsah Zn a Cd ve zkoumaných drogách záviselna lokalitách původu rostlin.
The content of cadmium and zinc in the elder (Sambucus nigra) and the lime tree (Tilia spec.) collected from four different localities in the Czech Republic was studied. Fromthe elder, the flowers (Sambuci flos), pollen, and fruits (Sambuci fructus) were collected, from the lime tree, the flowers (Tiliae flos) were used. The highest content of Zn and Cd was found in the pollen of the elder ( Zn65.0–94.4 mg.kg-1 , Cd 14.1–43.1 µg.kg-1), the lowest in its fruits (Zn 4.5–14.7 mg.kg-1, Cd max.8.1 µg.kg-1). The content of Zn was lower in the Tiliae flos (13.8–32.5 mg.kg-1) than in the Sambuciflos (30.8–49.9 mg.kg-1). The Cd content in Tiliae flos (9.9–58.9 µg.kg-1 ) was higher in comparison with the Sambuci flos (3.3–15.3 µg.kg-1). The concentration of Cd in the infusion (10, 30 and 60 min)was found under the detection limit of the used metod (0.04 µg.l-1). The highest content of Zntransported to the infusion came from the Tiliae flos (20-36%), from the Sambuci flos (17–25%), andfrom the Sambuci fruits (12–19%). The content of both zinc and cadmium in the studied drugsdepends on the localities of the original of plants.
The FLOWERING LOCUS T (FT) gene is the essential integrator of flowering regulatory pathways in angiosperms. The paralogs of the FT gene may perform antagonistic functions, as exemplified by BvFT1, that suppresses flowering in Beta vulgaris, unlike the paralogous activator BvFT2. The roles of FT genes in other amaranths were less investigated. Here, we transformed Arabidopsis thaliana with the FLOWERING LOCUS T like (FTL) genes of Chenopodium ficifolium and found that both CfFTL1 and CfFTL2-1 accelerated flowering, despite having been the homologs of the Beta vulgaris floral promoter and suppressor, respectively. The floral promotive effect of CfFTL2-1 was so strong that it caused lethality when overexpressed under the 35S promoter. CfFTL2-1 placed in an inducible cassette accelerated flowering after induction with methoxyphenozide. The spontaneous induction of CfFTL2-1 led to precocious flowering in some primary transformants even without chemical induction. The CqFT2-1 homolog from Chenopodium quinoa had the same impact on viability and flowering as CfFTL2-1 when transferred to A. thaliana. After the FTL gene duplication in Amaranthaceae, the FTL1 copy maintained the role of floral activator. The second copy FTL2 underwent subsequent duplication and functional diversification, which enabled it to control the onset of flowering in amaranths to adapt to variable environments.
- MeSH
- Arabidopsis * genetics metabolism MeSH
- Chenopodium * genetics metabolism MeSH
- Flowers genetics metabolism MeSH
- Arabidopsis Proteins * genetics metabolism MeSH
- Gene Expression Regulation, Plant genetics MeSH
- Seedlings metabolism MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
