Viraktamath C.A.,University of Agricultural Sciences, Bangalore |
Dietrich C.H.,University of Illinois at Urbana - Champaign
Zootaxa | Year: 2011
Sweta gen. n. is described and illustrated based on type species S. hallucinata sp. n. from northeast India and Thailand and placed in the typhlocybine tribe Dikraneurini. The new genus is unique among known Typhlocybinae in having the pronotum enlarged and extended to the scutellar suture. This feature is characteristic of the related subfamily Signoretii-nae, but among other subfamilies is restricted to a few brachypterous forms. Copyright © 2011 - Magnolia Press.
Ismail S.A.,ETH Zurich |
Ghazoul J.,ETH Zurich |
Ravikanth G.,Ashoka Trust for Research in Ecology and the Environment |
Uma Shaanker R.,University of Agricultural Sciences, Bangalore |
And 2 more authors.
Molecular Ecology | Year: 2012
Tropical trees often display long-distance pollen dispersal, even in highly fragmented landscapes. Understanding how patterns of spatial isolation influence pollen dispersal and interact with background patterns of fine-scale spatial genetic structure (FSGS) is critical for evaluating the genetic consequences of habitat fragmentation. In the endangered tropical timber tree Dysoxylum malabaricum (Meliaceae), we apply eleven microsatellite markers with paternity and parentage analysis to directly estimate historic gene flow and contemporary pollen dispersal across a large area (216 km2) in a highly fragmented agro-forest landscape. A comparison of genetic diversity and genetic structure in adult and juvenile life stages indicates an increase in differentiation and FSGS over time. Paternity analysis and parentage analysis demonstrate high genetic connectivity across the landscape by pollen dispersal. A comparison between mother trees in forest patches with low and high densities of adult trees shows that the frequency of short-distance mating increases, as does average kinship among mates in low-density stands. This indicates that there are potentially negative genetic consequences of low population density associated with forest fragmentation. Single isolated trees, in contrast, frequently receive heterogeneous pollen from distances exceeding 5 km. We discuss the processes leading to the observed patterns of pollen dispersal and the implications of this for conservation management of D. malabaricum and tropical trees more generally. © 2012 Blackwell Publishing Ltd.
Aghera N.,Tata Institute of Fundamental Research |
Earanna N.,University of Agricultural Sciences, Bangalore |
Udgaonkar J.B.,Tata Institute of Fundamental Research
Biochemistry | Year: 2011
To improve our understanding of the contributions of different stabilizing interactions to protein stability, including that of residual structure in the unfolded state, the small sweet protein monellin has been studied in both its two variant forms, the naturally occurring double-chain variant (dcMN) and the artificially created single-chain variant (scMN). Equilibrium guanidine hydrochloride-induced unfolding studies at pH 7 show that the standard free energy of unfolding, ΔG°U, of dcMN to unfolded chains A and B and its dependence on guanidine hydrochloride (GdnHCl) concentration are both independent of protein concentration, while the midpoint of unfolding has an exponential dependence on protein concentration. Hence, the unfolding of dcMN like that of scMN can be described as two-state unfolding. The free energy of dissociation, ΔG°d, of the two free chains, A and B, from dcMN, as measured by equilibrium binding studies, is significantly lower than ΔG°U, apparently because of the presence of residual structure in free chain B. The value of ΔG°U, at the standard concentration of 1 M, is found to be ∼5.5 kcal mol-1 higher for dcMN than for scMN in the range from pH 4 to 9, over which unfolding appears to be two-state. Hence, dcMN appears to be more stable than scMN. It seems that unfolded scMN is stabilized by residual structure that is absent in unfolded dcMN and/or that native scMN is destabilized by strain that is relieved in native dcMN. The value of ΔG°U for both protein variants decreases with an increase in pH from 4 to 9, apparently because of the thermodynamic coupling of unfolding to the protonation of a buried carboxylate side chain whose pKa shifts from 4.5 in the unfolded state to 9 in the native state. Finally, it is shown that although the thermodynamic stabilities of dcMN and scMN are very different, their kinetic stabilities with respect to unfolding in GdnHCl are very similar. © 2011 American Chemical Society.
Kumaraswamy S.,Indian Institute of Science |
Kumaraswamy S.,University of Agricultural Sciences, Bangalore |
Kunte K.,Tata Institute of Fundamental Research
Biodiversity and Conservation | Year: 2013
To achieve food security and meet the demands of the ever-growing human populations, farming systems have assumed unsustainable practices to produce more from a finite land area. This has been cause for concern mainly due to the often-irreversible damage done to the otherwise productive agricultural landscapes. Agro-ecology is proclaimed to be deteriorating due to eroding integrity of connected ecological mosaics and vulnerability to climate change. This has contributed to declining species diversity, loss of buffer vegetation, fragmentation of habitats, and loss of natural pollinators or predators, which eventually leads to decline in ecosystem services. Currently, a hierarchy of conservation initiatives is being considered to restore ecological integrity of agricultural landscapes. However, the challenge of identifying a suitable conservation strategy is a daunting task in view of socio-ecological factors that may constrain the choice of available strategies. One way to mitigate this situation and integrate biodiversity with agricultural landscapes is to implement offset mechanisms, which are compensatory and balancing approaches to restore the ecological health and function of an ecosystem. This needs to be tailored to the history of location specific agricultural practices, and the social, ecological and environmental conditions. The offset mechanisms can complement other initiatives through which farmers are insured against landscape-level risks such as droughts, fire and floods. For countries in the developing world with significant biodiversity and extensive agriculture, we should promote a comprehensive model of sustainable agricultural landscapes and ecosystem services, replicable at landscape to regional scales. Arguably, the model can be a potential option to sustain the integrity of biodiversity mosaic in agricultural landscapes. © 2013 Springer Science+Business Media Dordrecht.
Managave S.R.,Physical Research Laboratory |
Sheshshayee M.S.,University of Agricultural Sciences, Bangalore |
Borgaonkar H.P.,Indian Institute of Tropical Meteorology |
Ramesh R.,Physical Research Laboratory
Geophysical Research Letters | Year: 2010
Intra-annual variations in the cellulose oxygen isotopic composition (δ18O) of several annual growth rings of three teak (Tectona grandis L.F.) trees from central India show a clear seasonal cycle with higher values in the early and late growing seasons and lower values in the middle. This cycle is useful to identify growth occurring during different phases of the growing season. Relative humidity (RH) appears to control the intra-annual δ18O variations rather than rainfall, and therefore past break-monsoon conditions associated with lower RH, could be detected by high resolution sub-sampling of annual rings for δ18O analysis. Copyright © 2010 by the American Geophysical Union.
Murugan R.,University of Kassel |
Kumar S.,University of Agricultural Sciences, Bangalore
Biology and Fertility of Soils | Year: 2013
Amino sugars, as a microbial residue biomarker, are highly involved in microbial-mediated soil organic matter formation. However, accumulation of microbial biomass and responses of bacterial and fungal residues to the management practices are different and poorly characterized in rice soils. The objectives of this study were to evaluate the effects of mineral fertiliser (MIN), farmyard manure (FYM) and groundnut oil cake (GOC) on crop yield and co-accumulation of microbial residues and microbial biomass under rice-monoculture (RRR) and rice-legume-rice (RLR) systems. In the organic fertiliser treatments and RLR, rice grain yield and stocks of soil and microbial nutrients were significantly higher than those of the MIN treatment and RRR, respectively. The increased presence of saprotrophic fungi in the organic fertiliser treatments and RRR was indicated by significantly increased ergosterol/Cmic ratio and extractable sulphur. In both crop rotation systems, the long-term application of FYM and GOC led to increased bacterial residues as indicated by greater accumulation of muramic acid. In contrast, the higher fungal C/bacterial C ratio and lower ergosterol/Cmic ratio in the MIN treatment, is likely caused by a shift within the fungal community structure towards ergosterol-free arbuscular mycorrhizal fungi (AMF). The organic fertiliser treatments contributed 22 % more microbial residual C to soil organic C compared to the MIN treatment. Our results suggest that the negative relationship between the ratios ergosterol/Cmic and fungal C/bacterial C encourages studying responses of both saprotrophic fungi and AMF when assessing management effects on the soil microbial community. © 2013 Springer-Verlag Berlin Heidelberg.
Bhaskaran S.,University of Agricultural Sciences, Bangalore |
Savithramma D.L.,University of Agricultural Sciences, Bangalore
Journal of Experimental Botany | Year: 2011
Salinity is one of the major abiotic stresses affecting plant productivity. Tomato (Solanum lycopersicum L.), an important and widespread crop in the world, is sensitive to moderate levels of salt in the soil. To generate tomato plants that can adapt to saline soil, AVP1, a vacuolar H +- pyrophosphatase gene from Arabidopsis thaliana, and PgNHX1, a vacuolar Na +/H + antiporter gene from Pennisetum glaucum, were co-expressed by Agrobacterium tumefaciens-mediated transformation. A sample of transformants was self-pollinated, and progeny were evaluated for salt tolerance in vitro and in vivo. It is reported here that co-expression of AVP1 and PgNHX1 confers enhanced salt tolerance to the transformed tomato compared with the AVP1 and PgNHX1 single gene transgenic plants and the wild-type. These transgenic plants grew well in the presence of 200mM NaCl while wild-type plants exhibited chlorosis and died within 3 weeks. The transgenic line co-expressing AVP1 and PgNHX1 retained more chlorophyll and accumulated 1.4 times more proline as a response to stress than single gene transformants. Moreover, these transgenic plants accumulated a 1.5 times higher Na + content in their leaf tissue than the single gene transformants. The toxic effect of Na + accumulation in the cytosol is reduced by its sequestration into the vacuole. The physiological analysis of the transgenic lines clearly demonstrates that co-expression of AVP1 and PgNHX1 improved the osmoregulatory capacity of double transgenic lines by enhanced sequestration of ions into the vacuole by increasing the availability of protons and thus alleviating the toxic effect of Na +. © 2011 The Author.
Pruthvi V.,University of Agricultural Sciences, Bangalore |
Narasimhan R.,University of Agricultural Sciences, Bangalore |
Nataraja K.N.,University of Agricultural Sciences, Bangalore
PLoS ONE | Year: 2014
Drought, salinity and extreme temperatures are the most common abiotic stresses, adversely affecting plant growth and productivity. Exposure of plants to stress activates stress signalling pathways that induce biochemical and physiological changes essential for stress acclimation. Stress tolerance is governed by multiple traits, and importance of a few traits in imparting tolerance has been demonstrated. Under drought, traits linked to water mining and water conservation, water use efficiency and cellular tolerance (CT) to desiccation are considered to be relevant. In this study, an attempt has been made to improve CT in drought hardy crop, peanut (Arachis hypogaea L., cv. TMV2) by co-expressing stress-responsive transcription factors (TFs), AtDREB2A, AtHB7 and AtABF3, associated with downstream gene expression. Transgenic plants simultaneously expressing these TFs showed increased tolerance to drought, salinity and oxidative stresses compared to wild type, with an increase in total plant biomass. The transgenic plants exhibited improved membrane and chlorophyll stability due to enhanced reactive oxygen species scavenging and osmotic adjustment by proline synthesis under stress. The improvement in stress tolerance in transgenic lines were associated with induced expression of various CT related genes like AhGlutaredoxin, AhAldehyde reductase, AhSerine threonine kinase like protein, AhRbx1, AhProline amino peptidase, AhHSP70, AhDIP and AhLea4. Taken together the results indicate that co-expression of stress responsive TFs can activate multiple CT pathways, and this strategy can be employed to improve abiotic stress tolerance in crop plants. ©2014 Pruthvi et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Kumaraswamy S.,University of Agricultural Sciences, Bangalore |
Udayakumar M.,University of Agricultural Sciences, Bangalore
Biodiversity and Conservation | Year: 2011
Among the conservation initiatives, biodiversity banking is a strategic new concept that calls for advocacy by the researchers, conservationists, policy planners and business corporate houses to enhance the conservational behaviour of the stakeholders. The concept has dual benefits of restoration of livelihood support systems and conservation of biodiversity that provides ecological services and economic benefits to civil society. Currently, lack of defined guidelines with robust valuation and incentive mechanism for biodiversity banking has resulted in 'business as usual' situation especially in developing and under developed countries. There is need for re-defining the country level biodiversity banking guidelines for the effective private-government-stakeholder participation. Furthermore, the mechanism must consider using robust scientific database of inter-disciplinary nature and suitably adopt the modalities of successful case studies to overcome the flaws/risks. Biodiversity banking is a realizable concept in developing and resource poor countries as additional livelihood support system through the market of accrued ecosystem services linked to conservation behaviour of stakeholders. © 2011 Springer Science+Business Media B.V.
Viraktamath C.A.,University of Agricultural Sciences, Bangalore
Zootaxa | Year: 2011
The tribe Agalliini of the subfamily Megophthalminae is revised for the Oriental and Australian regions. Fifteen genera and 86 species have been recognized including 6 new genera, 40 new species, 7 new synonyms and 9 new combinations. The new genera and species described are Austroagallia balii sp. nov. (Indonesia: Bali Is.), A. distanti sp. nov. (India:Karnataka), A. prachuabensis sp. nov. (India, Thailand), Formallia gen. nov., F. ishiharai sp. nov.(Taiwan), F. longipenis sp. nov. (Taiwan), F. longistyla sp. nov. (Taiwan), F. rugosa sp. nov. (Taiwan), F. truncata sp. nov. (type sepcies) (Taiwan), Hemagallia gen. nov. (type-species: Agallia plotina Distant), Ianagallia gen. nov. (type-species Austroagallia bifurcata Sawai Singh & Gill), Igerna aurora sp. nov. (Sunda Is, Timor Is.), I. darjeelingensis sp. nov. (India: Sikkim, West Bengal), I. delineata sp. nov. (India: Tamil Nadu), I. himalayensis sp. nov. (India: West Bengal), I. keyae sp. nov. (India: Sikkim), I. priyankae sp. nov. (India: Himachal Pradesh, Meghalaya. Nepal), I. quinlani sp. nov. (Nepal), I. sikkima sp. nov. (India: Sikkim), I. wilsoni sp. nov. (India: West Bengal), Japanagallia asymmetrica sp. nov. (China: Fukien), J. curvata sp. nov. (China: Fukien), J. javana sp. nov. (Indonesia: Java), J. longipenis sp. nov. (China: Fukien), J. malaisei sp. nov. (Myanmar), J. mussooriensis sp. nov. (India: Uttar Pradesh), J. neotappana sp. nov. (China: Fukien), J. nepalensis sp. nov. (Nepal), J. peculiaris sp. nov. (Nepal), J. sumatrana sp. nov. (Indonesia: Sumatra), J. yoshimotoi sp. nov. (Taiwan), Nandigallia gen. nov. N. matai sp. nov. (India: West Bengal; China: Fukien), N. nandiensis sp. nov. (type-species) (India: Karnataka, Maharashtra), Paulagallia gen. nov., P. maai sp. nov. (Malaysia: Borneo: Sabah), P. punctata sp. nov. (type-species)( Malaysia: Borneo: Sabah), Sangeeta gen. nov. S. dentata sp. nov. (Indonesia: Pahang), S. dlabolai sp. nov. (Laos), S. fyanensis sp. nov. (Vietnam), S. linnavuorii sp. nov. (Vietnam), S. nigra sp. nov. (Indonesia: Java), S. quadriloba sp. nov. (Indonesia: Sumatra), S. sadongensis sp. nov. (type-species) (Malaysia: Sadong) and S. sarawakensis sp. nov. (Malaysia: Borneo: Sarawak) The following new combinations are proposed: Anaceratagallia srinagarensis (Kameswara Rao & Ramakrishnan) comb. nov. (Agallia), Hemagallia biplagiata (Melichar) comb. nov. (Agallia), Hemagallia plotina (Distant) comb. nov. (Agallia), Ianagallia bifurcata (Sawai Singh & Gill) comb. nov. (Austroagallia), Igerna atrovenosa (Melichar) comb. nov. (Agallia), Igerna fasciata (Osborn) comb. nov. (Agalliopsis), Igerna quadrinotata (Melichar) comb. nov. (Agallia), Igerna nigrita (Melichar) comb. nov. (Oncopsis) and Igerna violacea (Distant) comb. nov. (Nehela). The following species are treated as new synonyms: Agallia pseudorobusta Kameswara Rao & Ramakrishnan syn. nov. of Anaceratagallia cuspidata Dlabola; Anaceratagallia delhiensis Kameswara Rao & Ramakrishnan syn. nov. of Anaceratagallia robusta Pruthi; Agallia campbelli Distant syn. nov. and Agallia janaka Distant syn. nov. of Hemagallia biplagiata (Melichar); Agallia rugosa Distant syn. nov. and Agallia bhuntra Sawai Singh syn. nov. of Hemagallia plotina (Distant), Austroagallia bisinuata Viraktamath & Viraktamath syn. nov. of Igerna quadrinotata (Melichar), and Dryodurgades bifurcatus Cai & Shen syn. nov. of Dryodurgades formosana (Matsumura). Most of these taxa are described and illustrated. Keys to genera and species are also included. Copyright © 2011 . Magnolia Press.