ABSTRACT
Ocimum basilicum (sweet basil) is an economically important aromatic herb; in Italy, approximately 1000 ha of "Genovese-type" basil are grown annually in greenhouses and open fields and are subjected to Downy Mildew (DM) disease, caused by Peronospora belbahrii, leading to huge crop losses. Mutation of the Susceptibility (S) gene DMR6 (Downy Mildew Resistant 6) has been proven to confer a broad-spectrum resistance to DM. In this work, an effective Genome Editing (GE) approach mediated by CRISPR/Cas9 in O. basilicum 'Italiko', the élite cultivar used to produce "Pesto Genovese D.O.P", was developed. A highly efficient genetic transformation method mediated by A. tumefaciens has been optimized from cotyledonary nodes, obtaining 82.2% of regenerated shoots, 84.6% of which resulted in Cas9+ plants. Eleven T0 lines presented different type of mutations in ObDMR6; 60% were indel frameshift mutations with knock-out of ObDMR6 of 'FT Italiko'. Analysis of six T1 transgene-free seedlings revealed that the mutations of T0 plants were inherited and segregated. Based on infection trials conducted on T0 plants, clone 22B showed a very low percentage of disease incidence after 14 days post infection. The aromatic profile of all in vitro edited plants was also reported; all of them showed oxygenated monoterpenes as the major fraction.
ABSTRACT
The Nemo's Garden® project is an alternative production system for areas with scarce cultivable land but significant presence of water; thus, it is an interesting intervention to address the climate crisis. This work aimed to evaluate the micromorphological, biochemical, and phytochemical characteristics of Stevia rebaudiana (Bertoni) Bertoni grown underwater compared to the terrestrial specimens. The micromorphological analyses, performed on the leaves using light microscopy, fluorescence microscopy, and scanning electron microscopy, evidenced a general uniformity of the trichome morphotype and distribution pattern. The histochemical investigation indicated the simultaneous presence of terpenes and polyphenols in the trichome secreted material from the underwater samples and a prevailing polyphenolic content in the terrestrial specimens; this was also confirmed by biochemical analyses (26.6 mg GAE/g DW). The characterization of non-volatile components, performed using HPLC-MS, showed similar chemical profiles in all the samples, which were characterized by phenolic compounds and steviol glycosides. The volatile compounds, evaluated using HS-SPME coupled with GC-MS, showed sesquiterpene hydrocarbons as the main class in all the analyzed samples (80.1-93.9%). However, the control plants were characterized by a higher content of monoterpene hydrocarbons (12.1%). The underwater biosphere environment did not alter S. rebaudiana micro-morphological characters, although slight qualitative changes were evidenced for the compounds produced as a response to the growth conditions.
Subject(s)
Diterpenes, Kaurane , Stevia , Stevia/chemistry , Diterpenes, Kaurane/analysis , Plant Leaves/chemistry , Polyphenols/chemistry , Chromatography, High Pressure Liquid , AcclimatizationABSTRACT
The Myrtle (Myrtus communis L.) is an evergreen shrub typical of the Mediterranean area; it is an interesting plant with multipurpose use. The ornamental use takes into account the production of green cut branches for indoor decoration and production of pot plants for gardening. In this species, there is a great variability in the natural germplasm around the Mediterranean coasts for type and size of fruit, plant architecture, leaf size and internode length. Selected genotypes have been successfully sterilized and cultured in vitro. The shoots were multiplied on MS (16) salts and vitamins, with 0.5 mg/L BA and 0.2 mg/L IAA. Clones showed variation of multiplication rate and rooting percentage. IAA or IBA at 0.5 mg/L increased the rooting percentage and noticed differences in root number and length. The sucrose concentration can affect rooting, such as light intensity during the in vitro rooting phase can modulate biomass production and chlorophyll content. The combination of these factors enhanced the frequency rate of acclimatization.
