Post-Transcriptional Silencing of Flavonol Synthase mRNA in Tobacco Leads to Fruits with Arrested Seed Set

Flavonoids are synthesized by phenylpropanoid pathway. They are known to participate in large number of physiological and biochemical processes in plants. Parthenocarpy and male sterility has earlier been reported by silencing chalcone synthase (CHS) encoding gene. Silencing of CHS has blocked the synthesis of most of useful flavonoids including flavan-3-ols and flavonols. Also, these studies could not identify whether parthenocarpy/male sterility were due to lack of flavan-3-ols or flavonols or both. Flavonol synthase (FLS) is an important enzyme of flavonoid pathway that catalyzes the formation of flavonols. In this article, we propose a novel strategy towards the generation of seedless or less-seeded fruits by downregulation of flavonol biosynthesis in tobacco (Nicotiana tabacum cv Xanthi) through post-transcriptional gene silencing (PTGS) of FLS encoding mRNA. The FLS silenced lines were observed for 20-80% reduction in FLS encoding gene expression and 25–93% reduction in flavonol (quercetin) content. Interestingly, these FLS silenced tobacco lines also showed reduction in their anthocyanidins content. While the content of flavan-3-ols (catechin, epi-catechin and epi-gallocatechin) was found to be increased in FLS silenced lines. The delayed flowering in FLS silenced lines could be due to decrease in level of indole acetic acid (IAA) at apical region of their shoots. Furthermore, the pollen germination was hampered and pollens were unable to produce functional pollen tube in FLS silenced tobacco lines. Pods of FLS silenced lines contained significantly less number of seeds. The in vitro and in vivo studies where 1 µM quercetin was supplied to germination media, documented the restoration of normal pollen germination and pollen tube growth. This finding identified the role of flavonols particularly quercetin in pollen germination as well as in the regulation of plant fertility. Results also suggest a novel approach towards generation of seedless/less-seeded fruits via PTGS of FLS encoding gene in plants

Cloning and differential expression of QM like protein homologue from tea [Camellia sinensis (L.) O. Kuntze]

The QM like protein gene encodes for ribosomal protein L10, which is implicated in tumor suppression, transcription factor regulation, and ribosome stability in yeast and mammals. Present study describes cloning of a full-length QM cDNA (CsQM) from tea leaves using differential display of mRNA followed by rapid amplification of cDNA ends. Expression of CsQM was studied in leaves of different stages of development and under various external cues. CsQM contained an open reading frame of 651 bases, encoding 216 amino acids. CsQM shared 71–87% and 85–91% identity at nucleotide and amino acid sequences, respectively with QM genes isolated from other plant species. During active-growth period of tea, higher expression was observed in apical buds that decreased gradually with increasing age of the leaf. During dormancy season, the expression of CsQM gene was severely down-regulated in all the leaves studied. CsQM transcript was found to be down regulated in response to drought stress and abscisic acid treatment but up-regulated by gibberellic acid treatment. A positive association of CsQM transcript abundance with active cellular growth suggested its role in plant growth and developmen

AN IMPROVED DEVICE FOR ACCLIMATIZATION

An improved device for acclimatization characterized by chamber (1) having an airtight lid (2) for permitting incident light, an adjustable perforated platform (3), a light source (4) being optionally provided above the said lid (2) of the said chamber (1), an inlet (5) alongwith monitor (6) being provided at the side wall of the said chamber (1) for supply of CO2, the said chamber is optionally provided with an inlet (7) connected to reservoir (8) through a pump (9) and a valve (V1) for inter-connecting units, conventional sensors are also provided inside the said chamber for monitoring pH, relative humidity, temperature and light intensity, an outlet (10) being provided at the bottom of the said chamber (1) for draining the liquid

Identification, characterization and utilization of unigene derived microsatellite markers in tea (Camellia sinensis L.)

Background: Despite great advances in genomic technology observed in several crop species, the availability of molecular tools such as microsatellite markers has been limited in tea (Camellia sinensis L.). The development of microsatellite markers will have a major impact on genetic analysis, gene mapping and marker assisted breeding. Unigene derived microsatellite (UGMS) markers identified from publicly available sequence database have the advantage of assaying variation in the expressed component of the genome with unique identity and position. Therefore, they can serve as efficient and cost effective alternative markers in such species. Results: Considering the multiple advantages of UGMS markers, 1,223 unigenes were predicted from 2,181 expressed sequence tags (ESTs) of tea (Camellia sinensis L.). A total of 109 (8.9%) unigenes containing 120 SSRs were identified. SSR abundance was one in every 3.55 kb of EST sequences. The microsatellites mainly comprised of di (50.8%), tri (30.8%), tetra (6.6%), penta (7.5%) and few hexa (4.1%) nucleotide repeats. Among the dinucleotide repeats, (GA)n.(TC)n were most abundant (83.6%). Ninety six primer pairs could be designed form 83.5% of SSR containing unigenes. Of these, 61 (63.5%) primer pairs were experimentally validated and used to investigate the genetic diversity among the 34 accessions of different Camellia spp. Fifty one primer pairs (83.6%) were successfully cross transferred to the related species at various levels. Functional annotation of the unigenes containing SSRs was done through gene ontology (GO) characterization. Thirty six (60%) of them revealed significant sequence similarity with the known/putative proteins of Arabidopsis thaliana. Polymorphism information content (PIC) ranged from 0.018 to 0.972 with a mean value of 0.497. The average heterozygosity expected (HE) and observed (Ho) obtained was 0.654 and 0.413 respectively, thereby suggesting highly heterogeneous nature of tea. Further, test for IAM and SMM models for the UGMS loci showed excess heterozygosity and did not show any bottleneck operating in the tea population. Conclusion: UGMS markers identified and characterized in this study provided insight about the abundance and distribution of SSR in the expressed genome of C. sinensis. The identification and validation of 61 new UGMS markers will not only help in intra and inter specific genetic diversity assessment but also be enriching limited microsatellite markers resource in tea. Further, the use of these markers would reduce the cost and facilitate the gene mapping and marker-aided selection in tea. Since, 36 of these UGMS markers correspond to the Arabidopsis protein sequence data with known functions will offer the opportunity to investigate the consequences of SSR polymorphism on gene function

Characterization of dihydroflavonol 4-reductase cDNA in tea [Camellia sinensis (L.) O. Kuntze]

Tea leaves are major source of catechins-antioxidant flavonoids. Dihydroflavonol 4-reductase (DFR, EC 1.1.1.219) is one of the important enzymes that catalyzes the reduction of dihydroflavonols to leucoanthocyanins, a key "late" step in the biosynthesis of catechins. This manuscript reports characterization of DFR from tea (CsDFR) that comprised 1,413 bp full-length cDNA with ORF of 1,044 bp (115-1,158) and encoding a protein of 347 amino acids. Sequence comparison of CsDFR with earlier reported DFR sequences in a database indicated conservation of 69-87% among amino acid residues. In silico analysis revealed CsDFR to be a membrane-localized protein with a domain (between 16 and 218 amino acids) resembling the NAD-dependent epimerase/dehydratase family. The theoretical molecular weight and isoelectric point of the deduced amino sequence of CsDFR were 38.67 kDa and 6.22, respectively. Upon expression of CsDFR in E. coli, recombinant protein was found to be functional and showed specific activity of 42.85 nmol min(-1) mg protein(-1). Expression of CsDFR was maximum in younger rather than older leaves. Expression was down-regulated in response to drought stress and abscisic acid, unaffected by gibberellic acid treatment, but up-regulated in response to wounding, with concomitant modulation of catechins content. This is the first report of functionality of recombinant CsDFR and its expression in tea

Morphological and molecular analyses of Rosa damascena x R. bourboniana interspecific hybrids

Rosa damascena Mill is the most important scented rose species cultivated for rose oil production. Rosa bourboniana L. (Edward rose), a related species, is popular on account of its longer blooming period and ease of propagation. With an aim to combine the oil quality of R. damascena and recurrent flowering habit of R. bourboniana, two cultivars (Jwala and Himroz) of R. damascena were crossed with R. bourboniana. The F1 hybrids obtained were evaluated using morphological, random amplified polymorphic DNA (RAPD) and microsatellite (SSR) markers. Twenty-two selected RAPD and three SSR primer pairs were utilized for hybrid identification. According to presence or absence of bands RAPD and SSR markers were classified into seven types of markers. The bands specific for the pollen parent and occurring in the hybrids were good markers to confirm the hybridity. The non-parental bands expressing uniquely in hybrids were effective in distinguishing the hybrids from each other. Cluster analysis, based on Jaccard's similarity coefficient using unweighted pair group method based on arithmetic mean (UPGMA), reliably discriminated the hybrids into two main clusters. These results indicate the practical usefulness of RAPID and SSR markers in hybrid identification in scented roses. The approach is advantageous for its rapidity and simplicity, for identification of hybrids at the juvenile stage. One of the studied morphological traits - prickle density, can also complement in the identification of interspecific hybrids between R. damscena (female) and R. bourboniana (male)

A PORTABLE MINI DISTILLATION APPARATUS FOR THE PRODUCTION OF ESSENTIAL OILS AND HYDROSOLS

The present invention relates to a portable mini distillation apparatus for the production of essential oils arid hydrosols. This apparatus is useful to distill essential oils and hydrosols such as rose water, ajowain water from fresh and dried plant material like leaves, flowers, roots and rhizomes by water distillation, water & steam distillations and as an optional, steam distillation can also be performed at atmospheric pressure as well as slightly higher and lower than atmospheric pressure. This unit can be heated on brick-clay furnace with small agro-waste, LPG cooking gas, electrically heated stove or kerosene/diesel burner etc., and requires minimum attention during handling. Since the apparatus is made of stainless steel and glass, the essential oil distilled is of better quality than the oil distilled by glass Clevenger type apparatus used in the laboratory. A laboratory equipment used for distillation of essential oils is called Clevenger type apparatus as shown in Fig. 1 of the drawings accompanying this specification. Reference may be made to Clevenger type, J.F., Apparatus for the determination of volatile oil. J. Amer. Pharm. Assoc., 17, pp. 346(1928), wherein the apparatus (I) is attached to the spherical glass vessel (a) having charged with the plant material along with water in 1:2 ratio through opening (b) which is also used for discharging the mixture after process is complete. The whole system is put on a heating mantle (c), which has an energy regulator (d) for controlling the temperature. After few minutes, the material inside starts boiling. The vapours so formed are passed through a vertical condenser (e) through a long vertical glass tube (f). The cold water around the condenser tube is circulated through inlet (g) and outlet (h). The condensed distillate gets collected in a measuring tube (i) connected to the outlet of the condenser where an air outlet (j) open to atmosphere is placed. The volatile oil separates as an upper layer, from the distillate because of its density difference, as the oil is lighter than the water. A return tube (k), for recycling of aqueous part of the distillate, connects the bottom of the measuring tube (i) and vertical tube (f). The oil is collected at the outlet by opening the stop-cock valve (1). The major drawback of the apparatus is that it was designed to distillate the plant material by water distillation at normal atmospheric pressure only. There are some aromatic plant materials exclusively distilled by steam distillation method rather than water distillation, reason being that some of volatile constituents get hydrolysed due to the presence of excessive water in the vessel. The apparatus works neither on the principle of steam distillation nor on water & steam distillation technique. Clevenger type apparatus is generally restricted to laboratories for the essential oil estimation but cannot be used to produce the essential oil in higher quantities. Since the system is heated up with the help of electric mantle (c) only, with very small batch capacity of material charging vessel (a), long vertical glass tube (f) and condenser (e) are made up of glass which requires careful handling and can not be heated without electricity which is difficult for a marginal farmer with small land holdings in remote areas. The recovery and quality of the essential oil distilled in this glass Clevenger type apparatus is of inferior quality. The colour of the oil is generally lighter than the commercially distilled oil which is not recommended in the market. There are distillation units which are operated by Water & Steam distillation method. Water & Steam distillation method involves a distillation tank with a false bottom and with or without Calendria at the bottom, cohobation column at the top which is connected to the condenser and a distillate receiver. The plant material is charged from the charging hole and closed tightly. Prior to charging of plant material some fresh water is added to the tank and the precautions are to be taken to control the water level which should not touch the false bottom. The water level is maintained by recycling the distillate collected in the receiver to the tank or a continuous or batch-wise fresh water is supplied to the tank. The tank is heated by direct firing of the agro-waste from the hearth bellow. The purpose of this method is to reduce the effect of hydrolysis of essential oil which are get hydrolysed when they came in to continuous contact with excess water. After few minutes the water vapours starts .forming and extracts the essential oil from the plant material and carries it over to condenser where they are condensed to liquid distillate. The distillate is collected in a receiver where it is separated in to two fractions; one as an essential oil and other as a saturated water layer. The essential oil is separated, cleaned and then stored as per the recommended methods. The major drawbacks of the unit are that it can jiqt distill thejpj.ant material by Steam distillation. Some parts of the aromatic herbs such as cedar wood, sandel wood are preferably distilled by Steam distillation method to obtain better recoveries and quality. Also these units can not distill the plant material neither at reduced pressure nor at higher pressure since the system is opened to the atmospheric pressure and can not operated as a closed system. Being an industrial size these units can not be a portable systems and thus difficult to take them to the fields where the plant material is available in remote areas and distilling the fresh raw material is not possible in such a system which is one of the major parameter in affecting the quality of an essential oil. Being commercial scale units they requires more man power, operational costs etc., and the marginal farmers can not afford to purchase these industrial scale distillation units. The widely used hydrodistillation method in the essential oil industry is Steam distillation. The units used to perform the Steam distillation method merely consists of a distillation tank with a false bottom fixed at a certain height from the bottom of the tank. A spurger is provided below the false bottom which is connected to the industrial size boilers. The plant material is placed above the false bottom and then the lid is closed tightly by nut-bolts. Steam generated from the boiler is fed to the tank through the fixed steam spurger to commence the distillation. After few minutes the vapours starts forming which are taken to the vapour inlet of a shell and tube condenser which is connected to the vapour out let of the distillation tank at the top. The condensed liquid is collected in a receiver where the essential oil and distillate are separated. The major drawbacks of the unit are that it can not distill the plant material neither by Water distillation nor by Water & Steam distillation. Some parts of the aromatic herbs are preferably distilled by Water distillation method to obtain better recoveries and quality. Also these units can not distill the plant material neither at reduced pressure nor at higher pressure since the system is opened to the atmospheric pressure and can not operated as a closed system. Being an industrial size these units can not be a portable systems and thus difficult to take them to the fields wnere the plant material is available in remote areas and distilling the fresh raw material is not possible in such a system which is one of the major parameter in affecting the consistency in the quality of an essential oil. Being commercial scale units they requires more man power, operational costs etc., and the marginal farmers can not afford to purchase these industrial scale distillation units. Thus, apparatus, industrial scale units and the process mentioned above has one or the other major drawbacks like inferior oil quality, low oil recovery, low batch capacity, lack of Water distillation, Steam distillation and Water & Steam distillation facility, restricted mode of heating, unable to distill the plant material under vacuum and at higher pressures, difficulty in charging and discharging of plant materials because of narrow mouth and requires more attention during processing, more capital investment, operational cost. The main object of the present invention is to provide a simple, convenient, portable mini distillation apparatus for the production of essential oils and hydrosols, which obviates the drawbacks as detailed above. Another object of the present invention is to provide an apparatus for the distillation of essential oils having capacity little higher than the laboratory scale apparatus to meet the needs of marginal farmers. Still another object of the present invention is to provide an apparatus for the distillation of essential oils, if required, slightly at higher and lower pressures than atmospheric pressure. Yet another object of the present invention is to provide an apparatus for the distillation of essential oil by water distillation, water & steam distillation and steam distillation on small scale. Another object of the present invention is to provide an apparatus for the production of perfumed water from aromatic plant material at small scale. Still another object of the present invention is to provide an apparatus for the production of distilled water from the tap water or natural sources for lab use or for other purpose. Yet another object of the present invention is to provide portable and convenient apparatus for effecting distillation even in the fields or remote farming areas. Another object of the present invention is to provide an apparatus for the production of quality grade essential oils at house hold scale as a cottage industry to suit the marginal farmers/entrepreneurs who can not afford to install bigger capacity units. In fig. 2 of the drawings accompanying this specification, a schematic diagram of an embodiment of the apparatus of the present invention is shown. The present invention essentially consists of main parts such as a distillation vessel (1); a cohobation column (8), condenser (11) and oil retention column (13) with recycle line (16) connected to the cohobation column (8). Accordingly, the present invention provides a A portable mini distillation apparatus for the production of essential oils and hydrosols comprising one or more vessel(s)(l) having conventional means for heating internally/externally, the said vessel characterized in that a threaded rod (6) being fixed concentrically inside bottom of the said vessel(s) so as to allow vertical movement of a sieved false bottom(5,7), one or more steam spurger(s)(24) being provided between the said vessel bottom (2) and the said movable false bottom, the said vessel(s) being provided with removable fixed lid(s)(3) having a safety valve(s)(21), housing(20) for fixing pressure/vacuum/temperature guage and a vapour outlet(s)(9), the said vapour outlet(s) being connected to the inlet of one or more vertical cohobation column(s)(8), the outlet(s) of the said cohobation column(s) being fixed to the inlet(lO) of a conventional condenser(ll) provided with closeable vent(15), outlet(12) of the said condenser being detachably fixed by clamp(14) to a vertical receiver-cum-separator column(13) having a valve(18) controlled outlet(23), the bottom and middle of the said receiver-cum-separator column being provided with a plurality of valve(17,19) controlled recycling pipes (16) connected to the upper portion of the said L nation column (s). In an embodiment of the present invention, the vessel is heated internally by means of known electrical heating system and externally by any conventional/non-conventional beatings means. In another embodiment of the present invention, the vessel has a height to diameter ratio in the range of 0.5 to 1.5. In yet another embodiment of the present invention the vessel, cohobation column, condenser and recycling pipes are made up of metal such as stainless steel, copper, tin. In still another embodiment of the present invention the receiver-cum-separator column is made of glass, coated with transparent plastic or covered with an aluminum casing. In yet another embodiment of the present invention the closeable vent (15) of the condenser is optionally connected through a valve to a vacuum pump. The present portable mini distillation unit provides a simple, convenient, portable apparatus for the distillation of essential oils which comprises charging of aromatic plant material along with water in the ratio in the range of 1:0 to 1:2 in the vessel (1) through the charging hole, as described above and depicted in fig. 2, depending upon the type of the distillation process to be used. Place the gasket properly above the flange of the still, tighten the lid by quickfit joint (4) and attach the cohobation column (8), condenser (11) and glass tube (13) with the lid by tightening the union (9) after ensuring the proper setting of the gasket, place the whole system above the direct fired furnace/LPG burner/Kerosene or Diesel stove for heating the vessel (1). Fill the shell side of the condenser with water and the optimum water flow rate, for the total condensation, was maintained. Fill the oil retention glass tube (13) with water through air vent (15) at rear end of the condenser (11) until water starts flowing in to the cohobation column (8) through recycling line (16). The air vent (15) on the condenser (11) is opened throughout the process, if the plant material is to be distilled at atmospheric pressure and remain closed if the plant material is to be extracted under pressure. The valve (19) on the recycle line is kept opened throughout the process if essential oil only is to be distilled and remain closed if only perfumed distillate required. Now start heating the vessel (1) with any heating means mentioned above. Vapours start forming/ a few minutes later and enter to the condenser (11) through cohobation column (8) where they are condensed and collected in the glass tube. The essential oil in the distillate settles as an upper layer over the lower layer of water as the case may be. The aqueous part of the distillate is recycled, to the cohobation column (8) through the recycling line (16) if the essential oil is lighter than the water otherwise, it is recycled through the other pipe line shown in the fig. 2 as a dotted line. In order to recover the dissolved oil, the process is continued for 3 to 5 hr depending upon the type of plant material and distillation performed. After the completion of process, the essential oil is collected from the outlet (23) of glass tube (13) by opening the valve (18). The collected oil is measured and dried over anhydrous Na2SO4 filtered and then can be stored in aluminium bottles. The constructional features of an embodiment of the apparatusof the present invention are given below : A stainless steal (SS) - 304 vessel (1) having internal diameter (ID) = 325 mm, height = 325 mm with slightly curved bottom (2) and wide mouth ID = 325 mm for easier charging and discharging plant material is to be distilled, above which a conical lid (3) with base diameter =325 mm, vertical height = 150 mm, slant height = 210 mm to which a flange ID = 325 mm, outer diameter (OD) = 350 mm, is welded. The lid is attached to the vessel by a quick-fit joint (4). The material of construction (MOC) of lid (3) is stainless steel (SS) -304. A false bottom (5), 320 Φ, 2 mm thickness (thk.), with 2 Φ holes in Δle pitch and 10 Φ hole in the center to fit in the threaded SS rod (6) with 10 Φ for adjusting up and down according to the plant material charged. A circular strip (7) ID = 315 mm, OD = 325 mm welded to the vessel at a height of 35 mm from the bottom end to hold the false bottom. At the top of conical lid (3), a stainless steel cohobation column (8) is fixed with the help of union (9). The cohobation column (8) ID = 50 mm up to at a height of 780 mm which is reduced to ID = 40 mm upto a length of 215 mm and slant height of the reducer is 40 mm. The outlet of the column, ID = 40 mm, is welded to a bend (10) having same ID. The bend is again welded to a stainless steel horizontal shell and tube 1-1 heat exchanger (condenser) (11) with ten number of SS

De novo sequencing and characterization of Picrorhiza kurrooa transcriptome at two temperatures showed major transcriptome adjustments

<p>Abstract</p> <p>Background</p> <p><it>Picrorhiza kurrooa </it>Royle ex Benth. is an endangered plant species of medicinal importance. The medicinal property is attributed to monoterpenoids picroside I and II, which are modulated by temperature. The transcriptome information of this species is limited with the availability of few hundreds of expressed sequence tags (ESTs) in the public databases. In order to gain insight into temperature mediated molecular changes, high throughput <it>de novo </it>transcriptome sequencing and analyses were carried out at 15°C and 25°C, the temperatures known to modulate picrosides content.</p> <p>Results</p> <p>Using paired-end (PE) Illumina sequencing technology, a total of 20,593,412 and 44,229,272 PE reads were obtained after quality filtering for 15°C and 25°C, respectively. Available (e.g., De-Bruijn/Eulerian graph) and in-house developed bioinformatics tools were used for assembly and annotation of transcriptome. A total of 74,336 assembled transcript sequences were obtained, with an average coverage of 76.6 and average length of 439.5. Guanine-cytosine (GC) content was observed to be 44.6%, while the transcriptome exhibited abundance of trinucleotide simple sequence repeat (SSR; 45.63%) markers.</p> <p>Large scale expression profiling through "read per exon kilobase per million (RPKM)", showed changes in several biological processes and metabolic pathways including <it>cytochrome P450s </it>(<it>CYPs</it>), <it>UDP-glycosyltransferases </it>(<it>UGTs</it>) and those associated with picrosides biosynthesis. RPKM data were validated by reverse transcriptase-polymerase chain reaction using a set of 19 genes, wherein 11 genes behaved in accordance with the two expression methods.</p> <p>Conclusions</p> <p>Study generated transcriptome of <it>P. kurrooa </it>at two different temperatures. Large scale expression profiling through RPKM showed major transcriptome changes in response to temperature reflecting alterations in major biological processes and metabolic pathways, and provided insight of GC content and SSR markers. Analysis also identified putative <it>CYPs </it>and <it>UGTs </it>that could help in discovering the hitherto unknown genes associated with picrosides biosynthesis.</p

A PROCESS FOR EXTRACTION OF ESSENTIAL OIL FROM DRACOCEPHALUM HETEROPHYLLUM BENTH

Complete Specification The present invention relates to a process for the extraction of essential oil from Dracocephalum heterophyllum benth. The present invention relates to an essential oil with citronellol and rose oxides in high yield and other perfumery compounds obtained from a cold desert plant source Dracocephalum heterophyllum benth. The present invention also relates to a process for the extraction of essential oil from the plant source. BACKGROUND ART The generic name Dracocephalum Linn is derived from Greek words Drakon meaning dragon and Kephale meaning head referring to the appearance of the heads of the flowers. The genus Dracocephalum comprises about 50 species distributed in Northern Hemisphere i.e. Southern Europe, North America, North Africa and temperate Asia. Reference may be made to Hooker, J.D. Flora of British India, 1872-97 vol-4, 666, London. Another reference may be made to Bailey, L.H. 1976. Hortus Third (revised edition), MacMillan Co. NY. 398 D. heterophyllum is a native to western Himalaya and Tibet. Reference may be made to Hay, T. 1937. Gard. Chron. 101:203. It is one of the 8 species known so far from Indian subcontinent. D. heterophyllum has been reported from different parts of India including J & K, H.P., Uttaranchal and Sikkim Himalaya between the elevation of 3000-5200m. Reference may be made to Hooker, J.D. Flora of British India, 1872-97 vol-4, 666, London, another reference may be made to Anon., 1952, vol.-III, PID, New Delhi, yet another reference may be made to Hajra, P.K. and Balodi, Vipin 1995, Plant Wealth of Nanda Devi Biosphere Reserve BSI, Dehra Dun. pp.. 277. This plant has not yet been explained for any commercial utility. But on the basis of recent field studies it has been revealed that the crude extract of the plant is used in treating eye ailments like redness of eye, irritation and conjunctivitis of the native people of Spiti valley, HP. The same use has been reported earlier from Ladakh region of J&K reference may be made to Srivastava, T.N. and Gupta, O.P. 1982 in C.K. Atal and B.N. Kapur (eds.): Cultivation and utilization of medicinal plants PP-519. RRL Jammu. A literature survey on Dracocephalum shows that the essential oil of many species have been reported. Reference may be made to Ahmedi, L., Mirza, M. (2001). Volatile constituents of Dracocephallum aucheri Boiss.J. Essent. Oil Res., 13, 202. The result shows that there are remarkable differences in the major constituents. On the basis of major chemical constituents of Dracocephalum species, it can be divided into 5 major chemotypes 1) citral, geraniol type 2) p-mentha-1,8-diene-1 -ol, limonene type 3) 1,8-cineole, limonene, p-cymene type 4) Sabinene, germacene type and 5) Pinocamphone, b-pinene type. Reference may be made to Misra, L.N., Shawl, A.S. Raina, and V.K. (1988) Volatile constituents of Dracocephalum nutans. Planta Med. 53, 165. Keeping in view the significant chemical diversities in essential oil this genus, a detail study of the essential oil of D.heterophyllum is undertaken. However, some of the chemical constituents of the essential oils of this plant have been reported recently. Reference may be made to Lu-Man, Tian-Xuan, Lu-M, Tian-X, (1999), Analysis of essential oil of D. heterophyllum 34, 925. Recently, the plant material (whole plant) of D. heterophyllum has been collected from nature i.e. Shagtal-Gete (4400-4500m) and Kibber (4100-4200m) of Lahul-Spiti region in Himachal Pradesh in the month of August 2001. The study has been carried out to analyze its essential oil constituents and it is revealed that D. heterophyllum has an interesting chemo-rype containing highest content of citronellol and rose oxides. These yields are substantially higher than any other reported species of Dracocephalum and is designated 6th type of chemo-type and named it as citronellol, rose oxide type. Acclimatization process of this plant in ex-situ conditions i.e. in the experimental farm (under controlled condition) of the Institute at Palampur (1300m) has also been carried out to perform comparative studies of the essential oil this plant. In order to collect ethnobotanical, ecological and floristic field data from higher altitudes of western Himalaya, a field survey was conducted in Spiti valley of Lahul- Spiti district of Himachal Pradesh, India in the month of August 2001. While conducting field surveys in the said area, some patches of D. heterophyllum Benth. were located near by Gete (4400-4500m) and Kibber (4100-4200m) Villages in Spiti valley. Population sampling of the same was carried out and simultaneously plant material (whole plant) was collected for chemical examination. The voucher The authenticity of the species was confirmed by way of matching with the specimens documented in the herbarium of Northern Circle, Botanical Survey of India (BSD) Dehra Dun. OBJECTS OF THE PRESENT INVENTION The main object of present invention is to discover a cold desert plant as a new source of essential oil. Another object of present invention is to identify/select D. heterophyllum as a new source of perfumery compounds of commercial significance. Still another object of present invention is the domestication and cultivation of this plant for essential oil production. Further object of present invention is to conduct the comparative studies of the essential oils of both wild and cultivated populations of D. heterophyllum so as to select the elite clones. Still another object of present invention is to discover a high yielding natural source of citronellol and rose oxides. Yet another object of present invention is to harness the potential of this natural plant resource for the economic benefits of the native people living in high mountains. SUMMARY OF THE INVENTION The present invention provides an essential oil with citronellol and rose oxides in high yield and other perfumery compounds obtained from a cold desert plant source Dracocephalum heterophyllum benth. The present invention also relates to a process for the extraction of essential oil from the plant source. DETAILED DESCRIPTION OF THE INVENTION Accordingly, the present invention provides process for the extraction of essential oil from Dracocephalum heterophyllum benth, wherein the said process comprising the steps of: [a] charging the said plant material with water in a preferable ratio of 1:2 in a round bottom flask attached to Clevenger type apparatus; [b] heating the plant material as obtained from step (a) to boiling temperature; [c] condensing the vapor to separate out the volatile oil from the upper layer of distillate to obtain the desired essential oil composition followed by measuring the quantity of the constituents thereof. An embodiment of the present invention, wherein the constituents of said essential oil are identified by Gas Chromatography (GC) and Gas Chromatography Mass Spectra (GCMS). Another embodiment of the present invention, wherein said oil content is a new commercial source for citronellol. Yet another embodiment of the present invention, wherein said oil content is a new commercial source for cis and trans rose oxides. Still another embodiment of the present invention, wherein said oil content is a new commercial source for citronellyl acetate, geranyl acetate and citronellyl iso-butyrate. Yet another embodiment of the present invention, wherein the yields of citronellol and rose oxide thus obtained are substantially higher than from any other Dracocephalum species. Still another embodiment of the present invention, wherein the chemo-type containing highest content of citronellol and rose oxides is designated as 6th type of chemo-type and named as citronellol, rose oxide type. Further embodiment of the present invention, wherein the essential oil yield from D. heterophyllum is about 0.45% on fresh wt. basis. The present invention also provides a process for the extraction of essential from a new plant source, Dracocephalum heterophyllum Benth, said process comprising the steps of: (a) charging plant material with water in a round bottom flask attached to Clevenger type apparatus; (b) heating the plant material to a boiling temperature; (c) condensing the vapor to separate the volatile oil from the upper layer of distillate to obtain the essential oil; An embodiment of the present invention, a process wherein the essential oil yield from D. heterophyllum is about 0.45% on fresh wt. basis. Yet another embodiment of the present invention, a process wherein the plant material is selected from the whole plant. material is selected from the whole plant. Still another embodiment of the present invention, a process wherein the plant material is used obtained both from high altitude natural plants and from low altitude cultivated plants. Further embodiment of the present invention, wherein D. heterophyllum is cultivated in the experimental farm (under controlled condition) of the Institute at Palampur (13300m) and essential oil is distilled on Clevenger apparatus by hydrodistillation yield 0.4% on fresh wt. basis. Yet another embodiment of present invention, wherein the GCMS of the essential oils was carried out on Shimadzu instrument using CP Sil 8CB, non-polar column (5% phenyl polysiloxane), column length 30 mts (i.d. 0.25 mm) carrier gas helium, temperature programmed from 100°C-250°at the rate of 6°C/min. EXAMPLE Method of extraction of essential oil 1kg of fresh plant material was charged along with water in 1:2 ratio in a 5 litre round bottom flash. This flash is attached to a Clevenger type apparatus and the whole system is put on heating mental and heated. After few minutes the material inside start boiling. The vapour so formed is condensed through condenser in Clevenger type apparatus. The condensed distillate get collected in a measuring tube, this process is continued for 3h and the volatile oil is separated from upper layer from the distillate because of its density difference, as oil is lighter than water and the quantity of oil is measured. ADVANTAGES The present invention will open new vistas in R&D leading to harness the potential of D. heterophyllum at commercial level by identifying an alternate promising source of two isomers cis and trans- rose oxides, the highly significant perfumery compounds in addition to rose and geranium oils. This plant contains highest percentage of citronellol among the known sources of Dracocephalum species and can be utilized as an alternate source of this compound. We claim; 1. A process for the extraction of essential oil from Dracocephalum heterophyllum benth, wherein the said process comprising the steps of: [a] charging the said plant material with water in a preferable ratio of 1:2 in a round bottom flask attached to Clevenger type apparatus; [b] heating the plant material as obtained from step (a) to boiling temperature; [c] condensing the vapor to separate out the volatile oil from the upper layer of distillate to obtain the desired essential oil composition followed by measuring the quantity of the constituents thereof. 2. A process as claimed in claim 1, wherein the constituents of the essential oil are identified by Gas Chromatography and Gas Chromatography Mass Spectra. 3. A process as claimed in claim 1, wherein the yield of the essential oil obtained is at least up to 0.45% on fresh weight basis. 4. A process as claimed in claim 1, wherein the plant material used is whole plant and obtained from both high altitude natural plant and low altitude new chemotype named as 6th type of citronellol-rose oxide type chemotype. 5. A process as claimed in claim 1, wherein the mixture of the isolated essential oil comprises in wt%: [a] cis-rose oxide (0.6-1.6 %), [b] trans-rose oxide (0.3-0.5%), [c] citronellal (2.5-6.7%), [d] citronellol (54.3-74.9%), [e] geranial (1.5-2.4%), [fj citronellyl acetate (6.7-21.6%), [g] neryl acetate (0.4-0.7%), [h] geranyl acetate (1.3-11.7%), [i] spathulenol (0.2-1.5%), [j] citronellyl-isobutyrate (0.3-0.8%), [k] citronellol formate (0-0.2%), [1] alpha-bourbonene (0-0.4%), [m] benzaldehyde (0-0.2%), [n] 6-methylheptanone (0-0.2%), [o] neral (0-1.2%), [p] alpha-pinene (0-0.5%), [q] beta-pinene (0-0.2%), [r] linalool (0-0.8%), [s] beta-farnesene (0-0.1%) and [t] delta-elemene (0-0.5%). 6. A process for the extraction of essential oil from Dracocephalum heterophyllum benth substantially as herein described in the specification