Effect of Some Alien Invasive Plant Species on Soil Microbial Structure and Function

key driver of global environmental change is the invasion of ecosystems by alien species, many of which attain sufficiently high abundance to alter ecosystem structure and function (D‘Antonio and Vitousek, 1992; Ogle et al., 2003; Meffin et al., 2010). Biological invasions affect virtually all ecosystems on earth, but the extent of invasion of different regions and biomes, and the quality of information emanating from them varies greatly (Foxcroft et al., 2010). The invasions by alien species are also known to impact ecosystem services (Charles and Dukes, 2008) and human well-being (Pejchar and Mooney, 2009; Vilà et al., 2011). Invasive alien plants, because of their ability to alter ecological processes, such as carbon and nitrogen cycling (Liao et al., 2008; Ehrenfeld, 2010), hydrological cycles (Calder and Dye, 2001), frequency and/or intensity of fire (Brooks et al., 2004) and alteration of the normal disturbance regimes in the native communities (D‗Antonio and Meyerson, 2002; Werner et al., 2010), have transformed many ecosystems by out competing native species (Lankau, 2010) and thus, are rightly regarded as one of the most substantial threats to biodiversity on earth (Cronk and Fuller, 1995; Chapin et al., 2000; Kowarik, 2003; Werner et al., 2010). Invasive species are known to directly compete for resources with native species (Werner et al., 2010), disrupt inherent co-evolved interactions among long-associated native species (Callaway and Aschehoug, 2000; Callaway et al., 2008; Werner et al., 2010; Zhang et al., 2010), like pollination (Butz Huryn, 1997; Simberloff and Von Holle, 1999; Chittka and Schürkens, 2001; Aizen et al., 2008) and seed dispersal (Knight, 1986; Riera et al., 2002; Traveset and Riera, 2005; Cavallero and Raffaele, 2010) and result in modification of interspecific interactions, community structure, and ecosystem processes in the native communities (Vitousek et al., 1997; Lonsdale, 1999; Richardson et al., 2000; Ehrenfeld et al., 2001; Le Maitre et al., 2002; Karl et al., 2005; Traveset and Richardson, 2006; Emer and Fonseca, 2011). Recent global meta-analysis of 199 A Ph. D Thesis 18 research studies dealing with 1041 field studies involving 135 alien plant taxa revealed that abundance and diversity of resident species decreased in invaded sites, whereas primary production and several other ecosystem processes were enhanced (Vilà et al., 2011). But most of the studies exploring the effects of plant invasions have focused on aboveground flora and fauna (Levine et al., 2003), although soil organisms play important roles in regulating ecosystem-level processes (Wardle et al., 2004), and soils contain much of the biodiversity of terrestrial ecosystems (Torsvik et al., 1990; Vandenkoornhuyse et al., 2002), because aboveground communities are relatively easy to observe and quantify (Belnap and Phillips, 2001) and also because there are methodological limitations in studying belowground diversity. As a result, few studies to date have considered the effects of invasive organisms on the abundance, composition and activity of the soil biota. However, the advent of tools and techniques that exploit presence of signature biomolecules, such as Phospholipid Fatty Acids (PLFA), Denaturing Gradient Gel Electrophoresis (DGGE), Terminal Restriction Fragment Length Polymorphism (T-RFLP) etc. has revolutionized the field of soil microbial ecology. These techniques have been used to monitor changes in microbial communities in many plant invasion studies (Meyer, 1994; Kourtev et al., 2002a, 2003; Angeloni et al., 2006; Batten et al., 2006; Li et al., 2006; Kulmatiski and Beard, 2008; Zhang et al., 2010), and the results have revealed that invasive alien plants may suppress harmful rhizosphere soil microbes (Bais et al., 2004a; Lorenzo et al., 2010) and enrich beneficial ones thereby establishing positive feedback which could contribute to their proliferation (Klironomos, 2002; Batten et al., 2006; Kulmatiski and Beard, 2008; Sanon et al., 2011) to the detriment of native biodiversity (Callaway et al., 2004a; Lorenzo et al., 2010). On the other hand, several studies have also revealed negative effect of invasive plants on soil fungi due to invasion by Bromus tectorum (Belnap et al., 2005), arbuscular mycorrhizal fungi in Ph. D Thesis 19 response to dominance of non-mycorrhizal Alliaria petiolata in North American forests (Roberts and Anderson, 2001; Wolfe and Klironomos, 2005; Stinson et al., 2006; Callaway et al., 2008; Wolfe et al., 2008; Pringle et al., 2009; Vogelsang and Bever, 2009), microbial biomass C and ratio of fungi to bacteria due to Falcataria moluccana (Allison et al., 2006), both soil fungi as well as bacteria due to Acacia dealbata invasion (Lorenzo et al., 2010). Invasive alien plants also significantly influence catabolic diversity of the soil microbial communities through their impact on the activity of soil enzymes, which represent a link between litter decomposition, microbial activity, and nutrient availability (Sinsabaugh et al., 2000; Elk, 2010). The influence of exotic plants on the activity of soil enzymes has been reported by several workers (Kourtev et al., 2002b; Allison et al., 2006; Chapuis-Lardy et al., 2006; Li et al., 2006; Fan et al., 2010). It is clear from the growing number of studies that invasive alien species can alter ecosystem processes through a wide variety of mechanisms, over a variety of spatial and temporal scales (Ehrenfeld, 2010). Indeed, multiple mechanisms have been indentified that interact and reinforce each other in bringing about ecosystem change. Thus, it is necessary to search for mechanisms of impact of invasive alien species through documentation of interacting mechanisms, rather than to focus on single causative pathways as a ―holy grail‘ of universal explanation (Simberloff, 2010). The need for studies that explore the impact of invasive alien species has assumed urgency in India and Kashmir in view of reported occurrence of 1,599 species, belonging to 842 genera in 161 families in India representing 8.5% of the total Indian vascular flora (Khuroo et al., 2011). Likewise, total alien flora of the Kashmir Himalaya is represented by 571 plant species, belonging to 352 genera and 104 families. Of the 787 and 436 species that have either escaped from Ph. D Thesis 20 intentional cultivation, or spread after unintentional introduction in India and Kashmir, respectively, 225 species are invasive in India (Khuroo et al., 2011) and 77 species are invasive in Kashmir (Khuroo et al., 2008). While studies related to demography phenotypic plasticity (Allaie et al., 2005), allelopathy (Allaie et al., 2006), mycorrhizal mutualism (Shah and Reshi, 2007; Shah et al., 2008a and b), herbivore induced over-compensatory growth (Rashid et al., 2006) and seed germination (Rashid et al., 2007) have been carried out on various invasive plant species in Kashmir, very few studies have documented the impact of alien species (Shah et al., 2008a; Khuroo et. al., 2010) in the Kashmir Valley. It is because of these lacunae that broad quantitative syntheses of how impacts vary in response to the attributes of recipient ecosystems and of the invaders themselves (Levine et al., 2003) are not available. This absence of a broad-scale assessment limits the ability to generalize and predict when and where impacts might be most deleterious (Vilà et al., 2011). Besides, there are many studies in which the same invasive alien species causes quite different impacts on ecosystem processes at different sites or at different times. This variability in effect emphasizes the importance of ecological context in understanding and anticipating impact on ecosystems. It is in this context that the present study was carried out to evaluate the impact of three invasive alien plant species, namely Conyza canadensis (L.) Cronq. Sambucus wightiana Wall. ex Wt. and Arn. and Anthemis cotula L. on soil microbial structure and function. While S. wightiana (Adoxaceae) invades the understory of coniferous forests in the Kashmir Valley, A. cotula and C. canadensis (both belonging to Asteraceae) are dominant elements of vegetation in ruderal habitats. The specific questions addressed during the present study were

Systematic studies on genus Nepeta L. (Lamiaceae) in Kashmir Himalaya.

The past century has witnessed compilation of Floras of most of the regions of the World. The taxonomists have documented and communicated a better understanding of the floristic resources, as they are indispensable for the botanical progress of a country or a region. Over the same period, much information on the constituent taxa of Floras has been documented: the information pertaining to their taxonomy, nomenclature, distribution, variation, pollen and seed morphology, economic utility, and many other aspects. Kashmir, naturing beauty on the Earth, has also been a witness to this scenario, the main aim having been to have a thorough insight into and documentation of the overall floristic diversity of the Valley. The floras of several important regions/areas in the Kashmir Himalaya have been worked out. A number of genera in Lamiaceae have been revised/monographed, both on World basis and at regional levels, such as Bentham (1834), Labiatarum Genera Et Species; Bentham (1848), in Candolle, Prodromus ystematis Naturalis Regni Vegetabilis; Hooker (1885), in Flora of British India; Briquet (1896), in Engler and Prantel, Die Naturlichen P flanzenfamilien; Boissier (1879), in Flora Orientalis; Pojarkova (1954), in Flora of USSR; Turner (1972), in Flora Europaea; Hedge and Lamond (1982), in Flora of Turkey; and Rechinger (1982), in Flora Iranica.Digital copy of Thesis.University of Kashmir

Staurosporine augments EGF-mediated EMT in PMC42-LA cells through actin depolymerisation, focal contact size reduction and Snail1 induction – A model for cross-modulation

<p>Abstract</p> <p>Background</p> <p>A feature of epithelial to mesenchymal transition (EMT) relevant to tumour dissemination is the reorganization of actin cytoskeleton/focal contacts, influencing cellular ECM adherence and motility. This is coupled with the transcriptional repression of E-cadherin, often mediated by Snail1, Snail2 and Zeb1/δEF1. These genes, overexpressed in breast carcinomas, are known targets of growth factor-initiated pathways, however it is less clear how alterations in ECM attachment cross-modulate to regulate these pathways. EGF induces EMT in the breast cancer cell line PMC42-LA and the kinase inhibitor staurosporine (ST) induces EMT in embryonic neural epithelial cells, with F-actin de-bundling and disruption of cell-cell adhesion, via inhibition of aPKC.</p> <p>Methods</p> <p>PMC42-LA cells were treated for 72 h with 10 ng/ml EGF, 40 nM ST, or both, and assessed for expression of E-cadherin repressor genes (Snail1, Snail2, Zeb1/δEF1) and EMT-related genes by QRT-PCR, multiplex tandem PCR (MT-PCR) and immunofluorescence +/- cycloheximide. Actin and focal contacts (paxillin) were visualized by confocal microscopy. A public database of human breast cancers was assessed for expression of Snail1 and Snail2 in relation to outcome.</p> <p>Results</p> <p>When PMC42-LA were treated with EGF, Snail2 was the principal E-cadherin repressor induced. With ST or ST+EGF this shifted to Snail1, with more extreme EMT and Zeb1/δEF1 induction seen with ST+EGF. ST reduced stress fibres and focal contact size rapidly and independently of gene transcription. Gene expression analysis by MT-PCR indicated that ST repressed many genes which were induced by EGF (EGFR, CAV1, CTGF, CYR61, CD44, S100A4) and induced genes which alter the actin cytoskeleton (NLF1, NLF2, EPHB4). Examination of the public database of breast cancers revealed tumours exhibiting higher Snail1 expression have an increased risk of disease-recurrence. This was not seen for Snail2, and Zeb1/δEF1 showed a reverse correlation with lower expression values being predictive of increased risk.</p> <p>Conclusion</p> <p>ST in combination with EGF directed a greater EMT via actin depolymerisation and focal contact size reduction, resulting in a loosening of cell-ECM attachment along with Snail1-Zeb1/δEF1 induction. This appeared fundamentally different to the EGF-induced EMT, highlighting the multiple pathways which can regulate EMT. Our findings add support for a functional role for Snail1 in invasive breast cancer.</p

TAXONOMY AND PHYTOGEOGRAPHY OF GENUS CAREX L. (CYPERACEAE) IN THE KASHMIR HIMALAYA

ABSTRACT The genus Carex L., one of the largest genera among angiosperms in the world, is cosmopolitan in distribution, with relatively high species richness in the temperate regions of the Northern Hemisphere. In the Kashmir Himalaya, Carex is one of the most speciose and widely distributed genera, occurring from the sub-tropical Jammu through temperate Kashmir valley to the cold-arid Ladakh region. Owing to its rich diversity and distribution, the present paper provides a taxonomic assessment and distribution status of the Carex in this Himalayan region. In total, 33 species of Carex have been recorded, which are distributed within two sub-genera: Carex and Vignea. Out of the total species recorded, the highest with 23 species are distributed in the Kashmir valley, followed by the Ladakh with 13 species and then Jammu with 8 species

Studies on Reproductive Biology of some Species of the Genus Potamogeton L. in Relation to their Habitat Characteristics

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Screening of apple germplasm of Kashmir Himalayas for scab resistance genes

448-454In India, apple (Malus × domestica) is grown on a large scale in Kashmir province (valley) of the Jammu and Kashmir State. We surveyed several orchards of the valley in order to assess the germplasm. Apple scab was found to be the one of most important diseases, which is caused by the fungal pathogen, <i style="mso-bidi-font-style: normal">Venturia inaequalis. For the present investigation, 80 cultivars were screened for the presence of known genes conferring disease resistance. Different cultivars of apple showed variable response to apple scab. Of the four resistant cultivars identified previously, namely two, Shireen and Firdous were found to harbour Vf (<i style="mso-bidi-font-style: normal">Rvi6) gene as the source of resistance. Other two resistant cultivars were found to lack this gene. Therefore, it appears that these cultivars may have either other known or novel scab resistance gene(s). Using specific primers, PCR technique was used to amplify Vf <span style="mso-bidi-font-style: italic">(Rvi6) specific fragments, which were later cloned, sequenced and further characterized by using bioinformatics tools. These clones showed similarity with different clones of Vf gene isolated from M. floribunda by earlier workers. Bioinformatics analysis showed some similarity of cloned sequences with serine-threonine kinases that help the plant to overcome various stresses. However, further work is needed to confirm this observation. </span