Comprehensive identification and expression analysis of GRAS gene family under abiotic stress and phytohormone treatments in Pearl millet.

Pearl millet is an important C4 cereal plant that possesses enormous capacity to survive under extreme climatic conditions. It serves as a major food source for people in arid and semiarid regions of south-east Asia and Africa. GRAS is an important transcription factor gene family of plant that play a critical role in regulating developmental processes, stress responses and phytohormonal signalling. In the present study, we have identified a total number of 57 GRAS members in pearl millet. Phylogenetic analysis clustered all the PgGRAS genes into eight groups (GroupI-GroupVIII). Motif analysis has shown that all the PgGRAS proteins had conserved GRAS domains and gene structure analysis revealed a high structural diversity among PgGRAS genes. Expression patterns of PgGRAS genes in different tissues (leaf, stem and root) and under various abiotic stress (drought, heat and salinity) were determined. Further, expression analysis was also carried out in response to various hormones (SA, MeJA, GA and ABA). The results provide a clear understanding of GRAS transcription factor family in pearl millet, and lay a good foundation for the functional characterisation of GRAS genes in pearl millet.

Synthetic Promoters from Strawberry Vein Banding Virus (SVBV) and Dahlia Mosaic Virus (DaMV).

We have constructed two intra-molecularly shuffled promoters, namely S100 and D100. The S100 recombinant promoter (621 bp) was generated by ligation of 250 bp long upstream activation sequence (UAS) of Strawberry vein banding virus (SV10UAS; - 352 to - 102 relative to TSS) with its 371 bp long TATA containing core promoter domain (SV10CP; - 352 to + 19). Likewise, 726 bp long D100 promoter was constructed by fusion of 170 bp long UAS of Dahlia mosaic virus (DaMV14UAS; - 203 to - 33) with its 556 bp long core promoter domain (DaMV4CP; - 474 to + 82). S100 and D100 promoters showed 1.8 and 2.2 times stronger activities than that of the CaMV35S promoter. The activity of the promoters is comparable to that of the CaMV35S2 promoter. Transcript analysis employing qRT-PCR and histochemical assays supported the above findings. Abscisic acid and salicylic acid induce the activity of the D100 promoter. Leaf protein obtained from Nicotiana tabacum plant expressing NSD2 gene (Nigella sativa L. defensin 2) driven by the D100 promoter showed antifungal activity against Alternaria alternata and Phoma exigua var. exigua and antibacterial activity against Pseudomonas aeruginosa and Staphylococcus aureus. Strong S100 and D100 promoters have potential to become efficient candidates for plant metabolic engineering and molecular pharming.

Phytochemical analysis of flower from Pandanus odorifer (Forssk.) Kuntze for industrial application.

Pandanus odorifer (Forssk.) Kuntze is an economically important aromatic plant. The essential oil from male flowers is widely used in aromatherapy, cosmetics and as food flavouring agent. Phenylethyl methyl ether (PEME), the major constituent of essential oil, gives the chief characteristic fragrance to the oil. In the present study, 180 samples from 12 different regions were collected and hydrodistilled for essential oil isolation. The oil was then subjected to GC and GC-MS analysis to find out the percentage of the constituents. The results revealed PEME as the major constituent ranging from 58.03 to 81.86% and terpinen-4-ol, the second major constituent ranging from 7.81 to 21.46%. Soil nitrogen was found to be the most influential factor for oil yield and PEME content. The flowers containing high essential oil yield and PEME content could be used as elite chemotypes with enough potential for large-scale commercial cultivation to meet the demand of kewda industries.

Differential expression of CURS gene during various growth stages, climatic condition and soil nutrients in turmeric (Curcuma longa): Towards site specific cultivation for high curcumin yield.

Curcuma longa L., accumulates substantial amount of curcumin and essential oil. Little is known about the differential expression of curcumin synthase (CURS) gene and consequent curcumin content variations at different agroclimatic zones. The present study aimed to evaluate the effect of climate, soil and harvesting phase on expression of CURS gene for curcumin yield in two high yielding turmeric cultivars. Expression of CURS gene at different experimental zones as well as at different harvesting phase was studied through transcriptional analysis by qRT-PCR. Curcumin varied from 1.5 to 5% and 1.4-5% in Surama and Roma respectively. The expression of CURS also varied from 0.402 to 5.584 fold in Surama and 0.856-5.217 fold in Roma. Difference in curcumin content at a particular zone varied among different harvesting period from 3.95 to 4.31% in Surama and 3.57-3.83% in Roma. Expression of CURS gene was also effected by harvesting time of the rhizome which varied from 7.389 to 16.882 fold in Surama and 4.41-8.342 fold in Roma. The CURS gene expression was found regardless of variations in curcumin content at different experimental zones. This may be due to the effects of soil and environmental variables. Expression was positively correlated with curcumin content with different harvesting time at a particular zone. This find indicates effect of soil and environment on molecular and biochemical dynamics of curcumin biosynthesis and could be useful in genetic improvement of turmeric.

Characterization of Kewda volatile components by comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry.

Kewda (Pandanus fascicularis Lam.) is a well known medicinal and aromatic plant. The paper aims to precisely characterize volatile constituents present in Kewda flower oil using comprehensive two-dimensional gas chromatography coupled to time of flight mass spectrometry (GCxGC-TOFMS). A total of 159 components were identified due to enhanced chromatographic separation and mass spectral deconvolution of GCxGC-TOFMS. On the basis of its chemical structure, the identified compounds were grouped into hydrocarbons, alcohols, ethers, ketones, esters, nitrogen compounds, aldehydes, acids, lactones, halides and sulfur containing compounds. Ethers were the major components. The predominant compounds identified by GCxGC-TOFMS were kewda ether, ortho-cymene and terpinen-4-ol. A database containing retention indices of compounds was created for the bi-dimensional column, thus proving to be a remarkable step for analysis of constituents using a GCxGC system. GCxGC-TOFMS separated a number of co-eluting components which were unresolved on a single GC column.