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Vetiver is one of the valued plants in the aromatic world which has been extensively used in fragrances, aromatherapy, and medicines. The essential oils derived from vetiver root portions are mainly responsible for the organoleptic character of the plant. Vetiver essential oil is composed of diverse structural framework biosynthesized by using three isoprene units or sesquitepene leading to a number of bicyclic, tricyclic and tetracylic structures. Sequiterpenoids contribute major proportion to vetiver (Chrysopogon zizanioides) roots. However, the terpene synthases and their role in sesquiterpene biosynthesis in plant have not yet been studied. On the basis of volatile composition, two distinct stable vetiver genotypes viz., 'CIM-Vridhi' and 'CIMAP-Khusinolika' have been identified in 'CSIR-CIMAP' in recent years. Such a unique chemical difference is attributed to the array of structural diversity in sesquiterpenes and their derivatives. The root transcriptome of the two contrasting genotypes 'CIM-Vridhi' and 'CIMAP-Khusinolika' was carried out and three full length terpene synthase (TPS) genes were analyzed. These synthase genes, CZTPS1 , CZTPS2 , and CZTPS3 produce multiple sesquiterpenoids and were functionally characterized. In addition, the gene expression studies leading to metabolite biosynthesis in these genotypes were further confirmed by compound isolation and NMR based structural characterization of compounds from each genotypes. A bicyclic cadinane called khusinol identified as unique identifier in 'CIMAP-Khusinolika' while khusimol, a tricyclic zizaene dominates the 'CIM-Vridhi' oil composition. In conclusion, characterization of unique markers in each genotypes has been well supported by their transcriptomic data. Thus, present study can be utilized to investigate the vetiver terpenoid metabolism and its structure–odor correlations for the production of more potent odor threshold oriented chemicals from this plant. [Display omitted] • Chemically distinct vetiver types 'CIM-Vridhi' and 'CIMAP-Khusinolika' were studied. • Role of terpene synthases in sesquiterpene biosynthesis was investigated. • Terpene synthase genes CZTPS1, CZTPS2, and CZTPS3 produce multiple sesquiterpenoids. • nor -zizaene, zizaene and prezizaane were major odor contributors in vetiver oils. • Structural characterization of sequiterpenoids was carried out using NMR experiments. [ABSTRACT FROM AUTHOR]

• Khus is an important aromatic grass for roots and its valuable oil. • Root's hairs architecture, anatomy, pith size were directly correlated to stability of the genotypes • Six clones were identified stable for the essential oil yield. • Three clones were identified for high photosynthesis rate. Khus/vetiver (Chrysopogon zizanioides (L.) Roberty), family Poaceae, commonly known as khus grass, is important for essential oil used in the perfumery industry as well as in aromatherapy in India, and so is its value world over. The genetic diversity and genotype × environment studies using agronomical traits study in this crop are available. Still, the genotype × environment study using the physiological economic traits is very meager. Therefore, the objectives in the present investigation were to estimate the khus genotypes response over multi-years interaction and the selection of stable high essential oil yielding and carbon sequestration efficient genotypes in the khus. In this study, sixty-five diverse genotypes of khus collected from twenty-five states/places of India and abroad were studied for the seven physiological economic traits in the three consecutive years. The genotypes, environments/years, genotypes × environments/years, years + (genotypes × environments/years), genotype × environments/years (Linn.) related pooled analysis of variance and deviations for the seven characters were found highly significant. This indicates that these genotypes had diverse linear interactions in change environmental conditions. The pooled deviation significances showed that deviation in linear regression contributes towards the genotype's stability. The predictable/linear or unpredictable/non-linear components significantly contributed to the genotype's stability. Both Eberhart and Russell and GGE biplot analyses identified six promising and stable genotypes for essential oil yield and the three highly stable genotypes for the trait photosynthesis rate. The essential oils of the selected genotypes were also found rich for the major compounds: khusilal, preziza-7(15)-en-12-ol, khusol, and khusimol, along with other minor compounds. The preziza-7(15)-en-12-ol, a prezizaen class of compound, is being reported in high proportions for the first time in Chrysopogon zizanioides (L.) Roberty). [ABSTRACT FROM AUTHOR]

[Display omitted] • The intra-specific chemical variations in Ocimum viride are rarely reported. • Chemical variations among seven genotypes of Ocimum viride were studied. • GC-FID analysis revealed high eugenol (37.8−45.7%) and (Z)-β-ocimene (9.3−29.5%). • The (−)-germacrene D was most predominant isomer with 99.1 % enantiomeric excess. • Genotypes, 129 and 132 were the best for essential oil and high eugenol proportions. Ocimum viride is known for its diverse medicinal uses. However, most previous studies have been conducted on phytochemical assessment, but intra-specific chemical variations are rarely reported. Chemical variations among seven genotypes of O. viride were studied over three consecutive years in the experimental farm in CSIR-CIMAP, Lucknow. The essential oils obtained by hydro-distillation from the aerial parts of O. viride genotypes were subjected to GC, enantiomeric GC, and GC/MS analyses for their chemical characterization. GC-FID analysis revealed maximum proportions of eugenol (37.8 %–45.8 %) along with monoterpenes such as (Z)-β-ocimene (9.3 %–29.5 %). The sesquiterpenoids identified were β-caryophyllene (3.1 %–4.6 %), α- trans -bergamotene (5.5 %–7.4 %) and germacrene D (5.9 %–10.6 %). Chiral separation of germacrene D enantiomers [(+)– and (−)–form] were achieved using a cyclodextrin-based capillary column in each genotype. (−)–Germacrene D was found to be the most predominant enantiomer in all genotypes. Genotype 133 was recorded with the highest enantiomeric excess (≥ 99 %) for (−)–germacrene D. Besides, genotype 131 contained high monoterpenoids. Major chemical constituents such as eugenol were isolated through column chromatography, and structure elucidation was carried out using 1D and 2D NMR experiments. The thermo-gravimetric analysis (TGA) showed the stability pattern of extracted essential oils and revealed the complete volatile degradation ranged from 160 °C–200 °C. The statistical analysis was performed to select the best genotypes. The study revealed the best genotypes based on the correlation between constituents × years (C × Y) interaction. These analyses helped better estimate essential oil yield analysis, chemical diversity, and herb yield analysis on a field experiment basis. In conclusion, genotypes 129 and 132 had the highest essential oil output and eugenol content (%). Eugenol, a marker chemical ingredient, was reported with the highest proportions in genotype 132 at the full bloom stage. [ABSTRACT FROM AUTHOR]