Ecophysiological traits differentially modulate secondary metabolite accumulation and antioxidant properties of tea plant [Camellia sinensis (L.) O. Kuntze].

Owing to the diverse growing habitats, ecophysiology might have a regulatory impact on characteristic chemical components of tea plant. This study aimed to explore natural variations in the ecophysiological traits within seasons and the corresponding multifaceted biochemical responses given by the gene pool of 22 tea cultivars. Leaf temperature and intercellular carbon concentration (Ci), which varies as a function of transpiration and net photosynthesis respectively, have significant impact on the biochemical traits of the leaf. Occurrence of H2O2, in leaves, was associated to Ci that in turn influenced the lipid peroxidation. With the increment of Ci, total phenolics, epicatechin gallate (ECG), reducing power, and radical scavenging activity is lowered but total catechin and non-gallylated catechin derivatives (e.g. epicatechin or EC, epigallocatechin or EGC) are elevated. Leaf temperature is concomitantly associated (p ≤ 0.01) with phenolics, flavonoids, proanthocyanidin, tannin content, reducing power, iron chelation and free radical scavenging activities. Increased phenolic concentration in leaf cells, conceivably inhibit photosynthesis and moreover, gallic acid, thereafter conjugated to catechin derivatives. This study shed light on the fundamental information regarding ecophysiological impact on the quality determining biochemical characteristics of tea, which on further validation, might ascertain the genotype selection paradigm toward climate smart cultivation.

Temporal depletion of packaged tea antioxidant quality under commercial storage condition.

Shelf life studies play a significant role in determination of time duration for the retention of product quality after packaging. Assessment of tea shelf life in terms of antioxidant quality, a prime health benefit trait of tea would substantiate its marketing and consumption preference to the trade and end users. In shelf life analysis of tea with respect to its antioxidant potentialities, both antioxidant activity and incidences of secondary metabolites are responsible. A temporal analysis with regular intervals since 1 year of said characteristics has been carried out in four types of processed teas. To be precise, the overall initial antioxidant concentrations and activities were almost maintained up to 90-120 days and thereafter declination appeared. Beyond 180 days, rapid declination occurs and beyond 330 days, depletion recorded up to 60-75% of the initial activity. Black tea showed maximum ferrous ion chelating activity initially and white tea commenced with slight lower value but it maintained a similar trend up to 150 days while a rapid declination occurred in such activity of black and green tea after 30 days only. It is observed that total tannins or proanthocyanidins amount highest in white tea among all other three types. The preservation of metal chelating activity of white tea was observed as comparable to its stability in tannin composition (r2 = 0.869, P ≤ 0.01) during the storage period.

MIPS: Functional dynamics in evolutionary pathways of plant kingdom.

The myo-inositol biosynthesis pathway triggering protein MIPS is best known for its necessity, ubiquitous nature and occurrence throughout all living kingdom. However, the functional disparity of MIPS genes in green plant is still viable. The present work considered a comprehensive genome-wide analysis from sequenced plants to identify MIPS homologs in respective organisms and their genomic architecture. Variation of MIPS gene expression in twelve different species in diverse conditions has also been analysed. All MIPS genes share a conserved sequence property in most of its coding region, but its regulatory elements, gene structure and expression network vary significantly. Phylogenetic inference confirms the evolution of MIPS from a single common algal ancestor to seed plants and acquiring functional variation through genomic control. This paper represents MIPS as a model for studying gene duplication, functional divergence and diversification events in plant lineages.

Extrapolative microRNA precursor based SSR mining from tea EST database in respect to agronomic traits.

Tea (Camellia sinensis, (L.) Kuntze) is considered as most popular drink across the world and it is widely consumed beverage for its several health-benefit characteristics. These positive traits primarily rely on its regulatory networks of different metabolic pathways. Development of microsatellite markers from the conserved genomic regions are being worthwhile for reviewing the genetic diversity of closely related species or self-pollinated species. Although several SSR markers have been reported, in tea, the trait-specific Simple Sequence Repeat (SSR) markers, leading to be useful in marker assisted breeding technique, are yet to be identified. Micro RNAs are short, non-coding RNA molecules, involved in post transcriptional mode of gene regulation and thus effects on related phenotype. Present study deals with identification of the microsatellite motifs within the reported and predicted miRNA precursors that are effectively followed by designing of primers from SSR flanking regions in order to PCR validation. In addition to the earlier reports, two new miRNAs are predicting here from tea expressed tag sequence database. Furthermore, 18 SSR motifs are found to be in 13 of all 33 predicted miRNAs. Trinucleotide motifs are most abundant among all followed by dinucleotides. Since, miRNA based SSR markers are evidenced to have significant role on genetic fingerprinting study, these outcomes would pave the way in developing novel markers for tagging tea specific agronomic traits as well as substantiating non-conventional breeding program.

Retraction Note to: Antioxidants and ROS scavenging ability in ten Darjeeling tea clones may serve as markers for selection of potentially adapted clones against abiotic stress.

[This retracts the article DOI: 10.1007/s12298-013-0187-1.].

RAPD and ISSR marker mediated genetic polymorphism of two mangroves Bruguiera gymnorrhiza and Heritiera fomes from Indian Sundarbans in relation to their sustainability.

Increased salinity distresses some key species severely in Indian Sundarbans. Geomorphic characteristics coupled with demographic obligations have proven to be pivotal factor towards the prevalence of elevated salinity in this zone. Better adaptation to rapid changes in microclimate demands wide range of genetic polymorphism as well. RAPD and ISSR molecular markers were used for this genetic diversity study. Degree of polymorphism was found relatively higher in Bruguiera gymnorrhiza (26.43 % in RAPD and 24.36 % in ISSR) than the other taxa, Heritiera fomes (14.43 and 12.76 % respectively) in case of RAPD and ISSR. Dendrogram constructed based on the similarity matrix showed that for H. fomes, least saline and highest saline zones are positioned in the same clade; whereas in B. gymnorrhiza the higher saline areas were clustered together. Nei's gene diversity (h) as revealed from RAPD and ISSR analysis were found to be 0.0821, 0.0785 and 0.0647, 0.0592 in B. gymnorrhiza and H. fomes respectively. The higher degree of polymorphism as revealed from UPGMA Dendrogram and Nei's genetic diversity might be attributed towards the comfortable growth of B. gymnorrhiza all along the Indian Sundarbans. On the other hand the relatively lesser degree of genetic polymorphism of H. fomes might be attributed towards their precarious status in present days elevated salinity in Indian Sundarbans.

Antioxidants and ROS scavenging ability in ten Darjeeling tea clones may serve as markers for selection of potentially adapted clones against abiotic stress.

Ten Darjeeling tea clones (BT15/263, RR17/144, B777, T253, B157, Sundaram, HV39, AV2, K1/1 and TTV1) were collected from the experimental garden of Darjeeling Tea Research and Development Centre, Kurseong. Total phenol, flavonoids and two antioxidating enzymes (peroxidase and superoxide dismutase) were estimated. The total phenol ranged between 241 and 28 GAE mg g(-1) of leaf dry weight. The highest amount obtained in four clones, B15/263 (241.47), RR17/144 (221.2), B777 (154.54) and B157 (140.23 mg g(-1)). Flavonoids were estimated as Catechin equivalent (CE) and ranged between 56.88 and 20.81 CE mg g(-1) leaf dry weight. Higher amounts occurred in BT15/263 (56.88 mg g(-1)), B777 (56.69) and RR17/144 (48.63). Antioxidant activities were measured following DPPH and ABTS free radicle scavenging procedures and the results were well according to total polyphenol content among the clones (in total phenols, ranges of correlation in DPPH assay were r (2) = 0.990-0.989, p ≤ 0.05; in flavonoids r (2) = 0.954, p ≤ 0.01-0.987, p ≤ 0.05). Similarly, ABTS percent scavenging results were quiet significant. The IC50 values were determined for both DPPH and ABTS assay. PAGE expressions of isoforms in two antioxidative enzymes and quantification of them also varied much among the investigated clones. The incidence of total phenols, flavonoids, PRX and SOD and ROS scavenging assay in in-situ condition, might be used as biochemical markers towards the superior adaptability against abiotic stress. In the present work, four clones (B15/263, B777, RR17/144 and B157) would be designated as comparatively better suited to the predicted abiotic stress.

Differential expression of physiological and biochemical characters of some Indian mangroves towards salt tolerance.

Mangroves are physiologically interesting as potential models for stress tolerance and as sources of alternative ideas about physiological strategies relevant at the ecosystem level. Variation in habitat has great impact on the physiological behavior and biochemical expression level of a particular plant species. Five species of mangroves, growing in saline and fresh water conditions were assessed for their ecological fitness in two different habitats. Assessments were based on some physiological and biochemical parameters measured from the fully exposed mature leaves under saline (15-27 PPT) and non-saline (1.2-2 PPT) conditions. Among the five species considered for investigation Bruguiera gymnorrhiza, Excoecaria agallocha and Phoenix paludosa grow luxuriously in the Sundarbans forest, while the rest two (Heritiera fomes, Xylocarpus granatum) are scanty. A comparative account of photosynthetic efficiency, chlorophyll content, mesophyll and stomatal conductance, specific leaf area, photosynthetic nitrogen use efficiency, total foliar free amino acids and differential expression of some antioxidant isoenzymes in leaf were estimated between the saline and non-saline plants. Elevated assimilation rate coupled with increased chlorophyll content, increased conductance and higher specific leaf area in non-saline condition indicates ability of these mangroves to grow even under minimal substrate salinity. The optimum PAR acquisition for photosynthesis in B. gymnorrhiza, E. agallocha and P. paludosa was higher under salt stress, while the maximum assimilation rate was lower in control plants. The opposite trend occurred in H. fomes and X. granatum, where the peak photosynthesis was lower under non-saline conditions even at a higher irradiance than in the saline forest. The isoform patterns of peroxidase, acid phosphatase and esterase indicated considerable difference in regulation of these enzymes due to salt stress and /or reverse adaptation.