Metabolic engineering of plant secondary metabolites: prospects and its technological challenges.

Plants produce a wide range of secondary metabolites that play vital roles for their primary functions such as growth, defence, adaptations or reproduction. Some of the plant secondary metabolites are beneficial to mankind as nutraceuticals and pharmaceuticals. Metabolic pathways and their regulatory mechanism are crucial for targeting metabolite engineering.

Reactive oxygen species turnover, phenolics metabolism, and some key gene expressions modulate postharvest physiological deterioration in cassava tubers.

Rapid postharvest physiological deterioration (PPD) in cassava ( Crantz) tuber is a significant concern during storage. The freshly harvested tubers start spoiling within 24 to 72 h. Accumulation of HO is one of the earliest biochemical events that occurred during PPD, which was detected using the 3,3 diaminobenzidine (DAB) in two contrast cassava genotypes, MNP Local A (29-57 μg g) and Sree Prakash (64-141 μg g).

Phytochemical Composition and Antimicrobial Activity of Essential Oil from the Leaves of L.

is an enormously useful aromatic plant known for its insecticidal, antifungal, parasiticidal, and medicinal values. The main aim of this study is to investigate phytochemical contents and the potential antimicrobial activities of essential oil (AVEO) from the fresh leaves of grown in Manipur. The AVEO isolated by hydro-distillation from were analyzed by gas chromatography/mass spectrometry and solid-phase microextraction-GC/MS to describe their volatile chemical profile.

Internal Transcribed Spacer (ITS) Region of Nuclear Ribosomal DNA as a Suitable DNA Barcode for Identification of Zanthoxylum armatum DC. from Manipur.

Zanthoxylum armatum DC. is a plant with many medicinal values which is extensively used in traditional system of medicine for curing various diseases and ailments, including cancer. The aim of the present study is to identify Zanthoxylum armatum collected from different parts of Manipur, India, at molecular level.

Molecular detection and pathogenicity of a nucleopolyhedrovirus isolated from looper caterpillar (Hyposidra talaca), a tea pest.

Hyposidra talaca is a major defoliating pest of tea plants in north-eastern part of India. In this study, we look for variations (if any) in the attacking virus. Viral samples were collected from different regions of the northern part of West Bengal in India and were analyzed by PCR technique to study the variations across the region.

Enhanced resistance to blister blight in transgenic tea (Camellia sinensis [L.] O. Kuntze) by overexpression of class I chitinase gene from potato (Solanum tuberosum).

Tea is the second most consumed beverage in the world. A crop loss of up to 43 % has been reported due to blister blight disease of tea caused by a fungus, Exobasidium vexans. Thus, it directly affects the tea industry qualitatively and quantitatively.

Biochemical evaluation of triploid progenies of diploid × tetraploid breeding populations of Camellia for genotypes rich in catechin and caffeine.

To verify the quality of triploid varieties of Camellia tea species at the secondary metabolite level, we tested caffeine and catechin profiles of 97 F(1) segregating progenies in two breeding populations with a common tetraploid parent and diploid parents of two geographic and varietal origins. Catechin and caffeine levels of the triploid progenies were quantified and compared against their diploid parent. Some of the progenies showed better performance than their diploid parent.

Identification of drought tolerant progenies in tea by gene expression analysis.

Understanding the genes that govern tea plant (Camellia sinensis) architecture and response to drought stress is urgently needed to enhance breeding in tea with improved water use efficiency. Field drought is a slow mechanism and the plants go through an adaptive process in contrast to the drastic changes of rapid dehydration in case of controlled experiments. We identified a set of drought responsive genes under controlled condition using SSH, and validated the identified genes and their pattern of expression under field drought condition.

Molecular analysis of drought tolerance in tea by cDNA-AFLP based transcript profiling.

A cDNA-AFLP approach was used to identify transcript and/or genes specifically expressed in response to drought in tea. Drought was artificially induced and whole genome transcript profiling was done at three different stages-6 days before wilting, 3 days before wilting and at wilting stage of both tolerant and susceptible cultivars, and genetic differences was thus visualized as polymorphisms in the transcriptome. The cDNA-AFLP technique allowed genes and transcripts to be identified in the tolerant genotype (TV-23) whose expression is responsive to drought stress.

Understanding Darjeeling tea flavour on a molecular basis.

Darjeeling teas are the highest grown teas in the world and preferred for its flavour, aroma and quality. Apart from the genetic makeup of the plant, earlier reports suggest that insect infestation, particularly jassids and thrips triggers the aroma and flavour formation in Darjeeling tea. The present work encompasses the identification of the genes/transcriptomes responsible for the typical flavour of Darjeeling tea, besides understanding the role of jassids and thrips in particular, in producing the best cup character and quality.

New record of nucleopolyhedroviruses in tea looper caterpillars in India.

Tea production in North-East India hit a record loss due to the widespread severe outbreak of a mixed brood of three species of looper caterpillar pests of geometrid moths (Lepidoptera) in 2008-2010. In addition to Buzura suppressaria, two newly recorded geometrids, viz., Hyposidra infixaria and Hyposidra talaca have caused widespread severe damage in recent years.

Transgenic mimicry of pathogen attack stimulates growth and secondary metabolite accumulation.

Plant secondary metabolites, including pharmaceuticals, flavorings and aromas, are often produced in response to stress. We used chemical inducers of the pathogen defense response (jasmonic acid, salicylate, killed fungi, oligosaccharides and the fungal elicitor protein, cryptogein) to increase metabolite and biomass production in transformed root cultures of the medicinal plant, Withania somnifera, and the weed, Convolvulus sepium. In an effort to genetically mimic the observed effects of cryptogein, we employed Agrobacterium rhizogenes to insert a synthetic gene encoding cryptogein into the roots of C.