Use of Chenopodium murale L. transgenic hairy root in vitro culture system as a new tool for allelopathic assays

Via Air or Rhizosphere: The Phytotoxicity of Nepeta Essential Oils and Malus Dihydrochalcones

Many specialized metabolites found in plants have significant potential for developing environmentally friendly weed management solutions. This review focuses on the phytotoxic effects of volatile terpenes and phenolic compounds, particularly nepetalactone, an iridoid monoterpenoid from Nepeta species, and phloretin, a dihydrochalcone predominantly found in the genus Malus. We highlight current findings on their herbicidal effects, including morphological, physiological, and biochemical responses in target plants. These results underscore their potential for developing sustainable herbicides that could control weeds with minimal environmental impact. We also discuss their soil persistence and methods to enhance their solubility, chemical stability, and bioavailability. Additionally, the possible effects on non-target organisms, such as pollinators, non-pollinating insects, and soil microbiota, are considered. However, further research and a deeper understanding of their long-term ecological impact, along with a resistance development risk assessment, is essential for the potential development of bioherbicides that could be applied in sustainable weed management practices.

Establishment of Dittrichia viscosa L. Hairy Roots and Improvement of Bioactive Compound Production

Dittrichia viscosa is a ruderal plant species growing along roadsides and well adapting to extreme environmental conditions. D. viscosa plant tissues, especially leaves, are known to be a rich source of bioactive metabolites which have antioxidant, cytotoxic, antiproliferative and anticancer properties. Hairy root cultures are a suitable biotechnological system for investigating plant metabolic pathways and producing specialized metabolites in in vitro conditions. In this study, D. viscosa hairy root transformed lines induced by Agrobacterium rhizogenes ATCC15834 were obtained using leaf explants, and the integration of rolB and rolC genes in the genomes of transformed hairy roots were confirmed by PCR analysis. Three hairy root D. viscosa lines (DvHrT1, DvHrT4 and DvHrT5) having different phenotypic features were characterized in terms of total phenolics, flavonoids and antioxidant activity. Correlated with antioxidant activity, phenolic and flavonoid content of DvHrT1 was significantly higher than control roots and the other DvHrT lines. Our results suggest that D. viscosa hairy roots can be a valuable tool for producing various bioactive compounds having antioxidant activity and are to be further investigated to produce other specific molecules that could find application in agricultural or pharmaceutical fields.

Establishment of in vitro culture system for Codonopsis pilosula transgenic hairy roots

The aim of the study was to establish a reliable system of transgenic hairy roots in Codonopsis pilosula through Agrobacterium-mediated genetic transformation. For this, we optimized several steps in the process of A. rhizogenes strain C58C1 mediated hairy root induction, including the most appropriate medium, explant type, time for infection and co-cultivation. We achieved an induction rate of up to 100% when the roots of C. pilosula seedlings were used as explants, infected with A. rhizogenes C58C1 harboring pCAMBIA1305 for 5 min, followed by induction on 1/2MS supplemented with 0.2 mg/L naphthylacetic acid and 200 mg/L cefotaxime sodium. The co-transformed hairy roots were confirmed by PCR amplification of hygromycin phosphotransferase II gene and histochemical GUS assay, and the efficiency of transformation was 70% and 68.3%, respectively, when no hygromycin selection pressure was exerted. To increase biomass production, we excised and self-propagated the transformed hairy roots, which produce saponins. Our successful establishment of an in vitro culture system of transgenic hairy root for this species lays the foundation not only for assessing gene expression and function but also for obtaining high levels of secondary metabolites through genetic engineering technology.

Hairy root culture as a valuable tool for allelopathic studies in apple

Allelopathic plants exploit their chemical 'weapons' to prevail over the competition, suppress neighboring plants and consequently use the available resources more efficiently. However, the investigation of plant allelopathic interactions in rhizosphere is difficult to perform because of its high complexity due to interactions of biotic and abiotic factors. Thus, autonomous, aseptic root cultures of apple (Malus × domestica Borkh.) could facilitate allelopathic studies. We report on the successful genetic transformation of apple cultivars Melrose, Golden Delicious, Čadel and Gloster using Agrobacterium rhizogenes (Riker et al. 1930) Conn 1942 strain 15834 and for the first time the establishment of apple autonomous and permanent in vitro hairy root cultures that could be used as a new tool for apple allelopathic assays. Molecular characterization of transgenic hairy root lines was conducted to elucidate the possible relationship between expression of T-DNA genes and root growth characteristics that include branching. Similar content of phenolic acids (chlorogenic, caffeic, syringic, p-coumaric and ferulic), glycosilated flavonoids (rutin, quercitrin, isoquercitrin, kaempferol-3-glucoside) and flavonoid aglycones (quercetin and naringenin), and dihydrochalcone phloridzin, was detected in untransformed and transgenic apple root tissue by ultra high-performance liquid chromatography with mass spectrometry (UHPLC/(+/-)HESI-MS/MS) analyses, confirming that genetic transformation did not disturb secondary metabolite production in apple. Chlorogenic and caffeic acids and dihydrochalcones phloridzin and phloretin were detected as putative allelochemicals exuded into the growth medium in which transgenic roots were maintained for 4 weeks. Apple hairy root exudates significantly affected shoot and root development and growth of test plant Arabidopsis thaliana (L.) Heynh. seedlings after 5 or 10 days of treatment. Additionally, core cell-cycle genes CDKA1;1, CDKB2;1, CYCA3;1 and CYCB2;4 were down regulated in Arabidopsis shoots suggesting, in part, their role in inhibition of shoot growth. The present work highlighted an autonomous and permanent in vitro hairy root culture system as a valuable tool for studying allelopathic potential of apple, offering new perspective for allelopathy background elucidation in this important fruit species.

A global perspective on the biology, impact and management of Chenopodium album and Chenopodium murale: two troublesome agricultural and environmental weeds

Chenopodium album and C. murale are cosmopolitan, annual weed species of notable economic importance. Their unique biological features, including high reproductive capacity, seed dormancy, high persistence in the soil seed bank, the ability to germinate and grow under a wide range of environmental conditions and abiotic stress tolerance, help these species to infest diverse cropping systems. C. album and C. murale grow tall and absorb nutrients very efficiently. Both these species are allelopathic in nature and, thus, suppress the germination and growth of native vegetation and/or crop plants. These weed species infest many agronomic and horticultural crops and may cause > 90% loss in crop yields. C. album is more problematic than C. murale as the former is more widespread and infests more number of crops, and it also acts as an alternate host of several crop pests. Different cultural and mechanical methods have been used to control these weed species with varying degrees of success depending upon the cropping systems and weed infestation levels. Similarly, allelopathy and biological control have also shown some potential, especially in controlling C. album. Several herbicides have been successfully used to control these species, but the evolution of wide-scale herbicide resistance in C. album has limited the efficacy of chemical control. However, the use of alternative herbicides in rotation and the integration of chemicals and biologically based control methods may provide a sustainable control of C. album and C. murale.

Physiological and cell ultrastructure disturbances in wheat seedlings generated by Chenopodium murale hairy root exudate

Chenopodium murale L. is an invasive weed species significantly interfering with wheat crop. However, the complete nature of its allelopathic influence on crops is not yet fully understood. In the present study, the focus is made on establishing the relation between plant morphophysiological changes and oxidative stress, induced by allelopathic extract. Phytotoxic medium of C. murale hairy root clone R5 reduced the germination rate (24% less than control value) of wheat cv. Nataša seeds, as well as seedling growth, diminishing shoot and root length significantly, decreased total chlorophyll content, and induced abnormal root gravitropism. The R5 treatment caused cellular structural abnormalities, reflecting on the root and leaf cell shape and organization. These abnormalities mostly included the increased number of mitochondria and reorganization of the vacuolar compartment, changes in nucleus shape, and chloroplast organization and distribution. The most significant structural changes were observed in cell wall in the form of amoeboid protrusions and folds leading to its irregular shape. These structural alterations were accompanied by an oxidative stress in tissues of treated wheat seedlings, reflected as increased level of H₂O₂ and other ROS molecules, an increase of radical scavenging capacity and total phenolic content. Accordingly, the retardation of wheat seedling growth by C. murale allelochemicals may represent a consequence of complex activity involving both cell structure alteration and physiological processes.