Variety Of Mutants Research Articles

Chemical composition of γ-irradiated German chamomile (Matricaria recutita L.) flower essential oils, acetylcholinesterase inhibitory activity and effects on growth inhibition of Staphylococcus aureus and Candida albicans

Radiation-induced mutations have been the most commonly used technique for the development of mutant varieties. The primary aim has been to upgrade the existing plant varieties by varying a few major traits responsible for limiting metabolite productivity. The increasing regulations on protected plant varieties and germplasms have restricted their use. The induced mutants have played a vital role in strengthening the plant breeding program. The medicinal and aromatic plants have been poorly explored for mutation breeding. CSIR-CIMAP has initiated a mutation breeding program on some of the high-value plants, like Matricaria. As a result, we could develop gamma-rays-induced stable accessions. Genus Matricaria is well known for the biosynthesis of diverse bioactive plant secondary metabolites as well as for its traditional and healthcare benefits documented in Ph. Eur. In the present work, gamma-irradiated stable accessions of German chamomile, Matricaria recutita L., have been investigated for their essential oil composition and biological assessment. After a thorough investigation for a two-year cropping period, we have observed that some accessions contain the highest α-bisabolol oxide B proportions (24.3–55.3%), while quite a few showed chamazulene (2.9–5.8%), α-bisabolone oxide A (6.5–38%), and α-bisabolol oxide A (30.1–55.3%). A few accessions were marked by the presence of lavandulol, an irregular monoterpenoid of high fragrance value. The antibacterial, anti-inflammatory, and acetylcholinesterase (AChE) inhibitory properties of these gamma-irradiated accessions were also evaluated. The accessions G6-R5-5 and G2-R1-6 exhibited maximum inhibition against S. aureus whereas G2-R1-1 arrested the growth of C. albicans. Furthermore, G2R1-3 composition is responsible for reducing AChE and inflammation in cell lines. These results may open up ways to develop plant-derived consumer products from Matricaria recutita L.

Gamma-rays induced genome wide stable mutations in cowpea deciphered through whole genome sequencing

Purpose Gamma rays are the most widely exploited physical mutagen in plant mutation breeding. They are known to be involved in the development of more than 60% of global cowpea (Vigna unguiculata (L.) Walp.) mutant varieties. Nevertheless, the nature and type of genome-wide mutations induced by gamma rays have not been studied in cowpea and therefore, the present investigation was undertaken. Materials and Methods Genomic DNAs from three stable gamma rays-induced mutants (large seed size, small seed size and disease resistant mutant) of cowpea cultivar ‘CPD103’ in M6 generation along with its progenitor were used for Illumina-based whole-genome resequencing. Results Gamma rays induced a relatively higher frequency (88.9%) of single base substitutions (SBSs) with an average transition to transversion ratio (Ti/Tv) of 3.51 in M6 generation. A > G transitions, including its complementary T > C transitions, predominated the transition mutations, while all four types of transversion mutations were detected with frequencies over 6.5%. Indels (small insertions and deletions) constituted about 11% of the total induced variations, wherein small insertions (6.3%) were relatively more prominent than small deletions (4.8%). Among the indels, single-base indels and, in particular, those involving A/T bases showed a preponderance, albeit indels of up to three bases were detected in low proportions. Distributed across all 11 chromosomes, only a fraction of SBSs (19.45%) and indels (20.2%) potentially altered the encoded amino acids/peptides. The inherent mutation rate induced by gamma rays in cowpea was observed to be in the order of 1.4 × 10−7 per base pair in M6 generation. Conclusion Gamma-rays with a greater tendency to induce SBSs and, to a lesser extent, indels could be efficiently and effectively exploited in cowpea mutation breeding.

Genetic and pharmacological modulation of lamin Afarnesylation determines its function and turnover.

Hutchinson-Gilford Progeria syndrome (HGPS) is a severe premature ageing disorder caused by a 50 amino acid truncated (Δ50AA) and permanently farnesylated lamin A (LA) mutant called progerin. On a cellular level, progerin expression leads to heterochromatin loss, impaired nucleocytoplasmic transport, telomeric DNA damage and a permanent growth arrest called cellular senescence. Although the genetic basis for HGPS has been elucidated 20 years ago, the question whether the Δ50AA or the permanent farnesylation causes cellular defects has not been addressed. Moreover, we currently lack mechanistic insight into how the only FDA-approved progeria drug Lonafarnib, a farnesyltransferase inhibitor (FTI), ameliorates HGPS phenotypes. By expressing a variety of LA mutants using a doxycycline-inducible system, and in conjunction with FTI, we demonstrate that the permanent farnesylation, and not the Δ50AA, is solely responsible for progerin-induced cellular defects, as well as its rapid accumulation and slow clearance. Importantly, FTI does not affect clearance of progerin post-farnesylation and we demonstrate that early, but not late FTI treatment prevents HGPS phenotypes. Collectively, our study unravels the precise contributions of progerin's permanent farnesylation to its turnover and HGPS cellular phenotypes, and how FTI treatment ameliorates these. These findings are applicable to other diseases associated with permanently farnesylated proteins, such as adult-onset autosomal dominant leukodystrophy.

Morphological Characterization and Fusarium Wilt Resistance of Triploid Banana Mutant Line (Musa acuminata Cola)

Br 23 banana mutant line derived from irradiated gamma-ray from pisang ambon cultivar was triploid (AAA) and sterile. Therefore, application of conventional breeding to improve the agronomic characteristics of bananas requires strenuous effort. Morphological and agronomical characterizations of mutant line were observed during the generative stage on the Fusarium hotspot. Sixteen qualitative characters were observed, and each of which related to color was standardized using RHS color chart. Based on these qualitative characteristics, it was confirmed that pisang Ambon belongs to the acuminata group. Several agronomical characteristics of Br 23 banana mutant line, such as the number of hands/bunch, the weight of fruits/hand, and single fruit weight, were observed. The experimental results on banana production showed that the first harvest could reach 26 t/ha. Unlike from the control plant, the Br 23 mutant line showed tolerant characteristics to Fusarium TR4. The evaluation of susceptibility to Fusarium wilt was analyzed using the Vegetative Compatibility Group (VCG) method with isolate no. 01236/16. These susceptible plants were planted nearby the Br 23 banana mutant line. In early 2019, this Br 23 banana mutant line was registered as a new mutant variety under the name of PIRAMA I.

Agronomical Performances of Gajah Mungkur Mutant Rice Varieties Under Drought Stress

The productivity of the rice plant is commonly influenced by both genotype and environmental factors. One common environmental factor that leads to harvest failure is drought, often caused by low rainfall. Therefore, the development of drought-tolerant varieties should be implemented to obtain optimum productivity under an unfavorable environment. One of the canonical approaches for achieving this is genetic manipulation, such as by gamma radiation-induced mutation. This study aimed to determine the drought tolerance and quantitative characteristics of mutant rice varieties generated from gamma radiation. The methodology used was a split-plot design with two factors, including drought as the first factor consisting of three groups namely control, mid-level, and high-level. The second factor was rice genotypes, which consisted of six genotypes comprising PMG 07/PsJ, PMG 08/ PsJ, and PMG 09/ PsJ (mutant varieties), Gajah Mungkur (parental background), Limboto (drought-tolerant), and IR 20 (drought-susceptible). The data were statistically examined using Analysis of Variance (ANOVA) and further analyzed with Duncan’s Multiple Range Test (DMRT) with a significance level of 5%. The results showed that high-level drought significantly affected plant height during both the vegetative and mature stages. Among the mutants, PMG 08/PsJ exhibited better vegetative growth under dry conditions, retaining a relatively higher height. Drought also had a negative impact on the number of tillers and productive tillers. The PMG 08/PsJ mutant had a slightly higher number of tillers under drought cultivations. On the other hand, PMG 09/PsJ was found to have a relatively more filled grain number per panicle. Leaf rolling and dryness index showed similar trends in all varieties, while drought treatments imposed a delay on the flowering and harvesting age. Although the results demonstrated no substantial improvement over the parental lines, the selected mutant lines provided several beneficial agronomical features such as maintenance of plant height, tiller number, and shorter life cycles under severe drought. These characteristics could serve as valuable genetic resources for breeding programs focused on developing drought-resistant rice varieties for challenging environments.

A comprehensive review on mutation breeding milestones in cereals: Conventional to advanced molecular approaches to achieve sustainable goals in trait improvement

The grass family includes the annual common grasses known as cereals. The 5 main types of cereals are rice, wheat, barley, rye and oats. As a result of their high vitamin (20-80%) and fiber content (90%), these grains can help treat conditions like type II diabetes, complex metabolic syndrome, obesity, gastrointestinal disorders, and high cholesterol. Cereals have inspired a long history of research into their genetics, development, and evolution due to their significance in both economic and scientific terms. They need to be improved because they play a big part in global food production and crop quality is declining. The crop improvement can be done by incorporating desired features from non-adapted landraces/wild resources. That induced mutagenesis has made a significant contribution to crop improvement initiatives by producing mutant varieties with better and desired genetic modifications in the crop plants mainly in agronomically significant features. The mutants produced by the induction of physical and chemical mutagens were highly useful. The notable traits obtained by the induced mutations are semidwarfness and early maturity in rice varieties, disease resistance in barley, salinity, and drought tolerance in wheat, and lodging and disease resistance in oat and rye. In this review, we focused on identifying and developing elite mutants, their genetic function, and their utilization in future breeding programs for various traits in cereal crops.

In Silico Study on Natural Chemical Compounds from Citric Essential Oils as Potential Inhibitors of an Omicron (BA.1) SARS-CoV-2 Mutants' Spike Glycoprotein.

SARS-CoV-2's remarkable capacity for genetic mutation enables it to swiftly adapt to environmental changes, influencing critical attributes, such as antigenicity and transmissibility. Thus, multi-target inhibitors capable of effectively combating various viral mutants concurrently are of great interest. This study aimed to investigate natural compounds that could unitedly inhibit spike glycoproteins of various Omicron mutants. Implementation of various in silico approaches allows us to scan a library of compounds against a variety of mutants in order to find the ones that would inhibit the viral entry disregard of occurred mutations. An extensive analysis of relevant literature was conducted to compile a library of chemical compounds sourced from citrus essential oils. Ten homology models representing mutants of the Omicron variant were generated, including the latest 23F clade (EG.5.1), and the compound library was screened against them. Subsequently, employing comprehensive molecular docking and molecular dynamics simulations, we successfully identified promising compounds that exhibited sufficient binding efficacy towards the receptor binding domains (RBDs) of the mutant viral strains. The scoring of ligands was based on their average potency against all models generated herein, in addition to a reference Omicron RBD structure. Furthermore, the toxicity profile of the highest-scoring compounds was predicted. Out of ten built homology models, seven were successfully validated and showed to be reliable for In Silico studies. Three models of clades 22C, 22D, and 22E had major deviations in their secondary structure and needed further refinement. Notably, through a 100 nanosecond molecular dynamics simulation, terpinen-4-ol emerged as a potent inhibitor of the Omicron SARS-CoV-2 RBD from the 21K clade (BA.1); however, it did not show high stability in complexes with other mutants. This suggests the need for the utilization of a larger library of chemical compounds as potential inhibitors. The outcomes of this investigation hold significant potential for the utilization of a homology modeling approach for the prediction of RBD's secondary structure based on its sequence when the 3D structure of a mutated protein is not available. This opens the opportunities for further advancing the drug discovery process, offering novel avenues for the development of multifunctional, non-toxic natural medications.

Efficiency of navmutant lines in the creation of cotton (g. hirsutum l.) varieties

According to the article, new promising families and lines of cotton that are resistant to unfavorable climatic conditions have been created. The cotton is fruitful, quick-growing, and has high fiber quality. The study was based on the variability and heredity of the main morphoeconomic characters in the hybrid generations obtained between cotton varieties with promising lines of cotton. We investigated the L-203 K line, SML-3882, SML-5531, SML-4042 mutant variety lines, the Bukhara-6 cotton variety, and the connections between the L-203 K line and mutant variety lines in our research. In reciprocal hybrids, the inheritance and variability of features were examined. In the breeding procedure, the maternal form's fully grown flower buds were taken out and the maternal flowers got fertilized the following day after the male pollen grains had reached maturity. The system developed by S. Wright and published in the publications of G. V. Beil and others was employed to determine the degree of character dominance in hybrids of the first syllable. Heritability and variability of traits were studied by comparison with parental samples in the reciprocal hybrids obtained through cross-breeding, including plant height, height of the first harvest branch, time from sowing to flowering, ripening speed, fiber yield, fiber length, cotton weight per boll, number of bolls per plant, etc. Many new families and ridges that were well suited to the soil and climate of the Bukhara region were separated. These families and ridges had high yields, excellent fiber quality, and yields. After extensive breeding over many years, a new cotton variety called "Zhondor Qudrati 1" was produced.

Molecular Mechanism Analysis of STIM1 Thermal Sensation.

STIM1 has been identified as a new warm sensor, but the exact molecular mechanism remains unclear. In this study, a variety of mutants of STIM1, Orai1 and Orai3 were generated. The single-cell calcium imaging and confocal analysis were used to evaluate the thermal sensitivity of the resulting STIM mutants and the interaction between STIM1 and Orai mutants in response to temperature. Our results suggested that the CC1-SOAR of STIM1 was a direct activation domain of temperature, leading to subsequent STIM1 activation, and the transmembrane (TM) region and K domain but not EF-SAM were needed for this process. Furthermore, both the TM and SOAR domains exhibited similarities and differences between STIM1-mediated thermal sensation and store-operated calcium entry (SOCE), and the key sites of Orai1 showed similar roles in these two responses. Additionally, the TM23 (comprising TM2, loop2, and TM3) region of Orai1 was identified as the key domain determining the STIM1/Orai1 thermal response pattern, while the temperature reactive mode of STIM1/Orai3 seemed to result from a combined effect of Orai3. These findings provide important support for the specific molecular mechanism of STIM1-induced thermal response, as well as the interaction mechanism of STIM1 with Orai1 and Orai3 after being activated by temperature.

Direct interaction with the BRD4 carboxyl-terminal motif (CTM) and TopBP1 is required for human papillomavirus 16 E2 association with mitotic chromatin and plasmid segregation function.

Human papillomavirus 16 (HPV16) is a causative agent in around 3%-4% of all human cancers, and currently, there are no anti-viral therapeutics available for combating this disease burden. In order to identify new therapeutic targets, we must increase our understanding of the HPV16 life cycle. Previously, we demonstrated that an interaction between E2 and the cellular protein TopBP1 mediates the plasmid segregation function of E2, allowing distribution of viral genomes into daughter nuclei following cell division. Here, we demonstrate that E2 interaction with an additional host protein, BRD4, is also essential for E2 segregation function, and that BRD4 exists in a complex with TopBP1. Overall, these results enhance our understanding of a critical part of the HPV16 life cycle and presents several therapeutic targets for disruption of the viral life cycle.

The variability of the quantitative traits of flax plants obtained by induced mutagenesis

Induced mutagenesis has proven to be a flexible method, functional and ready to use for any culture, moreover, it is a low-cost technology. With the ability to grow new mutant varieties with very high productive potential. To investigate the mutagenic effect of gamma (γ) irradiation, flax seeds of the three selected varieties (Kaufmann, Dichl 8, Belinka) were treated with four doses 400, 500, 600 and 700 Gy, using the 60Co-γ isotope as an irradiation source. Along the way, the phenological phases of development and evaluation of morphological parameters were miniaturized. From the analysis of multiple parameters, it was observed that the 400 Gy irradiation dose was the most effective and showed the widest phenotypic variability, and the 700 Gy less effective.

Automatic extraction of actin networks in plants.

The actin cytoskeleton is essential in eukaryotes, not least in the plant kingdom where it plays key roles in cell expansion, cell division, environmental responses and pathogen defence. Yet, the precise structure-function relationships of properties of the actin network in plants are still to be unravelled, including details of how the network configuration depends upon cell type, tissue type and developmental stage. Part of the problem lies in the difficulty of extracting high-quality, quantitative measures of actin network features from microscopy data. To address this problem, we have developed DRAGoN, a novel image analysis algorithm that can automatically extract the actin network across a range of cell types, providing seventeen different quantitative measures that describe the network at a local level. Using this algorithm, we then studied a number of cases in Arabidopsis thaliana, including several different tissues, a variety of actin-affected mutants, and cells responding to powdery mildew. In many cases we found statistically-significant differences in actin network properties. In addition to these results, our algorithm is designed to be easily adaptable to other tissues, mutants and plants, and so will be a valuable asset for the study and future biological engineering of the actin cytoskeleton in globally-important crops.

Comparative microbiome analysis reveals the variation in microbial communities between 'Kyoho' grape and its bud mutant variety.

Microbes are an important part of the vineyard ecosystem, which significantly influence the quality of grapes. Previously, we identified a bud mutant variety (named 'Fengzao') from 'Kyoho' grapes. The variation of microbial communities in grape and its bud mutant variety has not been studied yet. So, in this study, with the samples of both 'Fengzao' and 'Kyoho', we conducted high-throughput microbiome sequencing and investigated their microbial communities in different tissues. Obvious differences were observed in the microbial communities between 'Fengzao' and 'Kyoho'. The fruit and the stem are the tissues with relatively higher abundance of microbes, while the leaves contained less microbes. The fruit and the stem of 'Kyoho' and the stem of 'Fengzao' had relatively higher species diversity based on the alpha diversity analysis. Proteobacteria, Enterobacteriaceae and Rhodobacteraceae had significantly high abundance in 'Fengzao'. Firmicutes and Pseudomonas were highly abundant in the stems of 'Kyoho', and family of Spirochaetaceae, Anaplasmataceae, Chlorobiaceae, and Sphingomonadaceae, and genera of Spirochaeta, Sphingomonas, Chlorobaculum and Wolbachia were abundant in the fruits of 'Kyoho'. These identified microbes are main components of the microbial communities, and could be important regulators of grapevine growth and development. This study revealed the differences in the microbial compositions between 'Kyoho' and its bud mutant, and these identified microbes will be significant resources for the future researches on the quality regulation and disease control of grapevines.

Genotypical response of barley to increased cadmium content in soil

The results of a comparative evaluation of spring barley (Hordeum vulgare L.) varieties obtained by different methods on control and provocative soil background for cadmium are presented. A total of 10 varieties were studied: Rodnik Prikamya, Novichok, Dina, Zazersky 85, Triumph, Tallon (hybridization and selection); Forward, Bionic, Vitrum (cell selection); In memory of Dudin (mutagenesis). The studies were carried out in 2021 under the climatic conditions of the Kirov region. Seeds of the plants of each variety were sown in vegetation containers filled with soddy-podzolic soil. Cadmium provocative background (6.4 ± 0.5 mg/kg) was created by adding cadmium acetate to the soil. The average yield of barley varieties in the control (soil background without cadmium) was 279 g/m2; against a provocative background – 216 g/m2. Under the conditions of cadmium stress, the yield of hybrids decreased compared to the control by 12.2 %, regenerants – by 29.6 %, mutant – by 42.4 %. Among the studied varieties, the Bionic variety, which has a regenerated origin, showed a consistently high yield both on the control (334 g/m2) and cadmium background (263 g/m2). Productive bushiness of hybrid barley varieties against the control background varied from 2.8 to 4.1; in regenerants – from 3.4 to 4.8; mutant varieties – 4.3 pieces. Under the conditions of cadmium stress, productive bushiness decreased by an average of 2.7 – in hybrids; for 3.4 – for regenerants, for 2.6 pieces – a mutant. Bionic, regardless of the soil background, compared with other varieties, had the highest productive bushiness. Significant differences in the content of polyphenols in the grain of the studied varieties on the control and provocation soil background for cadmium were not revealed. Under the conditions of cadmium stress, a decrease in the content of flavonoids in grain was noted, as well as the accumulation of cadmium (0.29–0.92 mg/kg). Varieties of hybrid origin showed the ability to accumulate cadmium in grain to a greater extent.

Intense light unleashes male-male courtship behaviour in wild-type Drosophila.

Drosophila courtship studies have elucidated several principles of the neurogenetic organization of complex behaviour. Through an integration across sensory modalities, males perform stereotypic patterns of chasing, courtship song production and copulation attempts. Here we report a serendipitous finding that intense light not only enhances courtship toward female targets but also triggers unexpected courtship behaviours among male flies. Strikingly, in wild-type male-only chambers, we observed extreme behavioural manifestations, such as 'chaining' and 'wheeling', resembling previously reported male-male courtship behaviours in fruitless mutants and in transformants with ectopic mini-white+ overexpression. This male-male courtship was greatly diminished in a variety of visual system mutants, including disrupted phototransduction (norpA), eliminated eye-colour screening pigments (white), or deletion of the R7 photoreceptor cells (sevenless). However, light-induced courtship was unhampered in wing-cut flies, despite their inability to produce courtship song, a major acoustic signal during courtship. Unexpectedly the olfactory mutants orco and sbl displayed unrestrained male-male courtship. Particularly, orco males attained maximum courtship scores under either dim or intense light conditions. Together, our observations support the notion that the innate male courtship behaviour is restrained by olfactory cues under normal conditions but can be unleashed by strong visual stimulation in Drosophila.

Meiotic behavior of two grapevine somatic mutants with ornamental potential

‘Niagara Steck’ and ‘Niagara Variegada’ are two grapevine varieties that arose spontaneously as somatic mutants of ‘Niagara Rosada’. Berries characterize ‘Niagara Steck’ at young stages exhibiting a remarkable brown reticulated structure on the epidermis which develops into a brown-bronze russet-like structure as the berries ripe. The mature berries have strongly acidic flesh. ‘Niagara Variegada’ shows notable variegation in leaves and berries. Meiotic studies were carried out to ascertain if the mutant phenotypes could be related to any change in chromosome number, structure or other irregularity. Floral buds of both varieties at different developmental stages were collected and fixed for cytological analyses. Chromosome counts at diakinesis/metaphase I showed n=19 bivalents for both varieties. Univalent, trivalent, tetravalent chromosomes or chain configuration were not recorded ruling out the possibility of any alteration in the chromosome number or structure in both mutant varieties. However, low percentages of meiotic irregularities were recorded such as chromosome stickiness, laggards, non-oriented chromosomes, precocious chromosome segregation, tetrads with one microcyte, microspore fusion, and tetrad degeneration. The total percentage of abnormalities was higher in ‘Niagara Variegada’ (19.68%) than in ‘Niagara Steck’ (14.40%) which may have contributed to a lower percentage of pollen fertility (79.80%) when compared to ‘Steck’ (90.74%). The aforementioned varieties can be propagated by hardwood cuttings and constitute an interesting option for ornamentation of home backyards, patios, and gardens with the advantage that ‘Niagara Variegada’ bearing sweet edible berries.

The velvet family proteins mediate low resistance to isoprothiolane in Magnaporthe oryzae.

Isoprothiolane (IPT) resistance has emerged in Magnaporthe oryzae, due to the long-term usage of IPT to control rice blast in China, yet the mechanisms of the resistance remain largely unknown. Through IPT adaptation on PDA medium, we obtained a variety of IPT-resistant mutants. Based on their EC50 values to IPT, the resistant mutants were mainly divided into three distinct categories, i.e., low resistance (LR, 6.5 ≤ EC50 < 13.0 μg/mL), moderate resistance 1 (MR-1, 13.0 ≤ EC50 < 25.0 μg/mL), and moderate resistance 2 (MR-2, 25.0 ≤ EC50 < 35.0 μg/mL). Molecular analysis of MoIRR (Magnaporthe oryzae isoprothiolane resistance related) gene demonstrated that it was associated only with the moderate resistance in MR-2 mutants, indicating that other mechanisms were associated with resistance in LR and MR-1 mutants. In this study, we mainly focused on the characterization of low resistance to IPT in M. oryzae. Mycelial growth and conidial germination were significantly reduced, indicating fitness penalties in LR mutants. Based on the differences of whole genome sequences between parental isolate and LR mutants, we identified a conserved MoVelB gene, encoding the velvet family transcription factor, and genetic transformation of wild type isolate verified that MoVelB gene was associated with the low resistance. Based on molecular analysis, we further demonstrated that the velvet family proteins VelB and VeA were indispensable for IPT toxicity and the deformation of the VelB-VeA-LaeA complex played a vital role for the low IPT-resistance in M. oryzae, most likely through the down-regulation of the secondary metabolism-related genes or CYP450 genes to reduce the toxicity of IPT.

On the variability of the leaf relative uptake rate of carbonyl sulfide compared to carbon dioxide: Insights from a paired field study with two soybean varieties

Carbonyl sulfide (COS) has been proposed as a promising tracer for the estimation of the gross primary productivity (GPP) from ecosystem to global scale in recent years. Despite substantial work at spatial scales from leaf to regions, the uncertainty of COS-based GPP estimates are poorly known compared to widely used GPP estimates derived from the net ecosystem CO2 exchange. One key uncertainty in this context is the leaf relative uptake (LRU) of the COS with respect to the GPP, which must be known a priori. To investigate the influence of environmental factors, like drought, on the variability of the LRU, we conducted an experiment using ecosystem flux measurements of COS, CO2 and H2O from two eddy covariance towers above a soybean field, growing a commercial cultivar and a chlorophyll deficient mutant variety, in two separate plots. Our findings suggest that the LRU does not only differ between plant varieties due to differences in the ratio of the internal to ambient CO2 mole fraction and the internal resistance to COS, but also changes in response to drought. We also found the internal resistance to COS uptake to be a significant factor in controlling the total COS flux for both varieties, but more so for the commercial cultivar. Our study indicates that species-specific differences in the LRU need to be investigated further, and that environmental stress might complicate the usage of COS as a tracer for predicting GPP at ecosystem and global scale.

Integrative Analysis of Fruit Quality and Anthocyanin Accumulation of Plum cv. 'Cuihongli' (Prunus salicina Lindl.) and Its Bud Mutation.

Fruit color is one of the quality indicators to judge the freshness of a plum. The coloring process of plum skin is valuable for research due to the high nutritional quality of anthocyanins found in plums. 'Cuihongli' (CHL) and its precocious mutant variety 'Cuihongli Red' (CHR) were used to analyze the changes of fruit quality and anthocyanin biosynthesis during plum development. The results showed that, during the development of the two plums, the total soluble solid and soluble sugar contents were highest at the mature stage, as the titratable acid trended gradually downward as the fruits of the two cultivars matured, and the CHR fruit showed higher sugar content and lower acid content. In addition, the skin of CHR turned red in color earlier than CHL. Compared with CHL, the skin of CHR had higher anthocyanin concentrations, higher activities of phenylalanine ammonia-lyase (PAL), chalcone isomerase (CHI), dihydroflavonol-4-reductase (DFR), and UDPglucose: flavonoid-3-O-glucosyltransferase (UFGT), and higher transcript levels of genes associated with anthocyanin production. In the flesh of the two cultivars, no anthocyanin content was detected. Taken together, these results suggest that the mutation exerted a major effect on anthocyanin accumulation via modification of the level of transcription; thus, CHR advances the ripening period of 'Cuihongli' plum and improves the fruit quality.

Molecular characterization of phototropin signalosome regulating photophysiological processes in green algae.

Phototropin is a blue light-sensing photoreceptor, comprises two LOV domains that non-covalently bind FMN as chromophore and a serine-threonine kinase domain at its C-terminus. Phototropin is well established in higher plants and aquatic algae. However, the photoreceptor biology of the evolutionary important alga has not yet been established. We characterized the phototropin LOV domain from evolutionary important algae and compared the changes with the aquatic green algae, Chlamydomonas reinhardtii phototropin LOV domain. The intraflagellar transport (IFT) machinery responsible for bidirectional movement of proteins inwithin cilia or flagella is involved in trafficking of Chlamydomonas phototropin (CrPhot). Through immunoblotting and immunolocalization experiments with a variety of IFT mutants, we investigated the molecular details of phototropin trafficking. The CrPhot knock-out strains showed reduced photomotility, decrease level of other predicted interacting proteins like ChRs and, 14-3-3 as compared to that of the wild type strain. Various approaches like protein profiling, expression profile (qRT-PCR), and proteomics were applied to delineate its role in light-mediated physiology in C. reinhardtii. We studied the photochemistry, oligomerization, and photodynamic behaviour of LOV1 domain of a novel terrestrial algal phototropin using UV-visible, fluorescence, CD, atomic force microscopy, and time-resolved fluorescence spectroscopy techniques. Our findings highlight the unique characteristics of LOV domain in terms of very long dark recovery time. We identified the key residues responsible for this recovery kinetics in novel LOV1 protein. Different variants of LOV1 protein were produced and photochemistry was compared with the respect to the wild type protein. We proposed optogenetic potential of the engineered LOV domain in modulation of diverse cellular signalling pathways such as ciliogenesis, cell cycle, and apoptosis.