| 1. |
- Kumar, S. Anil, et al.
(författare)
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Beyond just being foot soldiers : osmotin like protein ( OLP ) and chitinase ( Chi11 ) genes act as sentinels to confront salt, drought, and fungal stress tolerance in tomato
- 2016
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Ingår i: Environmental and Experimental Botany. - : Elsevier. - 0098-8472 .- 1873-7307. ; 132, s. 53-65
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Tidskriftsartikel (refereegranskat)abstract
- Osmotin like protein (OLP) and chitinase (Chi11) belong to pathogenesis-related (PR) class of proteins and are induced during both biotic and abiotic stresses. Transgenic tomato was developed with OLP and Chi11 via in vitro and in planta transformation methods. Transgenes integration and transcript levels were confirmed by multiplex PCR, DNA blot, and multiplex reverse transcriptase PCR. Homozygous T2 transgenics when evaluated for salt, drought, and fungal stresses showed enhanced tolerance compared to untransformed controls (UC). Transgenics showed enhanced endochitinase activity and root biomass under normal conditions. Transformants also displayed higher proline content, K+, relative water content, chlorophyll fluorescence, total biomass, vascular conductivity, and fruit yield than the UC under stress conditions. Co-immunoprecipitation revealed that Chi11 co-expresses with phosphofructokinase2 (PFK2), which may play a role in enhanced root biomass. qPCR analysis resulted in higher transcript levels of OLP, Chi11, and PFK2 in transgenics as compared to the untransformed controls. Our findings suggest the use of multiples genes to confer multiple stress tolerance for enhanced crop productivity. This work unveils a new molecular player PFK2, which may play a role in enhanced root biomass.
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| 2. |
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| 3. |
- Koyani, Rina D., et al.
(författare)
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Anatomical Characterisation and In Vitro Laboratory Decay Test of Different Woods Decayed by Xylaria hypoxylon
- 2017
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Ingår i: Wood is Good. - Singapore : Springer. ; , s. 93-103
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Bokkapitel (refereegranskat)abstract
- Different species of Xylaria are often reported as an endophyte in different groups of plants starting from liverworts to angiosperms. In the present study, Xylaria hypoxylon isolated from branch stubs of living trees was utilised for in vitro decay test to investigate the pattern of cell wall alterations in sound wood blocks of Azadirachta indica, Leucaena leucocephala, and Tectona grandis. Naturally infected as well as in vitro decayed wood showed cavities and erosion troughs at the lumen surface. In laboratory decay test, vertical invasion of mycelia occurred through the lateral wall pits of the vessels and vessel-associated parenchyma while ray cells enabled radial movement of mycelia. At the end of 60 days, the progression of degradation in the fibre cell wall was evident by the formation of transverse boreholes in the cell walls, erosion troughs at the lumen surface, and larger cavities in the S2 layer of secondary wall. The erosion channels were angular to round (i.e. V-shaped or U-shaped). Fungus was also tested for polyphenol oxidase (Bavandemm's test) production by on-plate assay and was found to be positive. Confocal microscopy revealed delignification pattern during degradation of cell wall of different cell types in all the three woody species. The SEM analysis of degraded wood showed the ultrastructural changes in the cell wall particularly penetration of hyphae through the S2 layer of the cell walls forming tunnels through it.
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| 4. |
- Koyani, Rina D., et al.
(författare)
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The Delignification Pattern of Ailanthus excelsaWood by Inonotus hispidus (Bull.: Fr.) P. Karst.
- 2015
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Ingår i: Journal of Sustainable Forestry. - : Informa UK Limited. - 1054-9811 .- 1540-756X. ; 34:5, s. 502-515
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Tidskriftsartikel (refereegranskat)abstract
- AbstractIn vitro laboratory decay tests on Ailanthus excelsa Roxb. wood revealed that I. hispidus exhibits a combination of both white-rot and soft-rot patterns of wood decay. Early stages of wood decay showed dissolution of the middle lamella as well as defibration and localized delignification of fiber walls; vessels, axial, and ray parenchyma remained unaltered. Delignification commenced from the middle lamellae at the cell corners without any marked effect on the primary and secondary wall layers. In later stages of growth, the species produces typical soft-rot decay pattern by forming erosion channels through the S2 layers of fiber walls, transverse bore holes in the cell walls, and erosion channels alongside/following the orientation of cellulose microfibrils. The rays showed signs of cell wall alterations only after the extensive damage to the fiber walls. After 120 days of incubation, the vessels also showed localized delignification, the erosion of pits, and separation from associated xylem elements. The extensive weight losses under natural and in vitro decayed wood as well as the very soft nature of severely degraded wood indicate that I. hispidus alters wood strength and stiffness.
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| 5. |
- Kumari, P. Hima, et al.
(författare)
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Overexpression of a Plasma Membrane Bound Na+/H+ Antiporter-Like Protein (SbNHXLP) Confers Salt Tolerance and Improves Fruit Yield in Tomato by Maintaining Ion Homeostasis
- 2017
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Ingår i: Frontiers in Plant Science. - : Frontiers Media S.A.. - 1664-462X. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- A Na+/H+ antiporter-like protein (NHXLP) was isolated from Sorghum bicolor L. (SbNHXLP) and validated by overexpressing in tomato for salt tolerance. Homozygous T2 transgenic lines when evaluated for salt tolerance, accumulated low Na+ and displayed enhanced salt tolerance compared to wild-type plants (WT). This is consistent with the amiloride binding assay of the protein. Transgenics exhibited higher accumulation of proline, K+, Ca2+, improved cambial conductivity, higher PSII, and antioxidative enzyme activities than WT. Fluorescence imaging results revealed lower Na+ and higher Ca2+ levels in transgenic roots. Co-immunoprecipitation experiments demonstrate that SbNHXLP interacts with a Solanum lycopersicum cation proton antiporter protein2 (SlCHX2). qRT-PCR results showed upregulation of SbNHXLP and SlCHX2 upon treatment with 200 mM NaCl and 100 mM potassium nitrate. SlCHX2 is known to be involved in K+ acquisition, and the interaction between these two proteins might help to accumulate more K+ ions, and thus maintain ion homeostasis. These results strongly suggest that plasma membrane bound SbNHXLP involves in Na+ exclusion, maintains ion homeostasis in transgenics in comparison with WT and alleviates NaCl stress.
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| 6. |
- Sivan, Pramod, 1984-, et al.
(författare)
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Histological and ultrastructural alterations in the Ailanthus excelsa wood cell walls by Bjerkandera adusta (Willd.) P. Karst
- 2015
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Ingår i: International Biodeterioration & Biodegradation. - : Elsevier. - 0964-8305 .- 1879-0208. ; 100, s. 124-132
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Tidskriftsartikel (refereegranskat)abstract
- Ailanthus excelsa Roxb. requires less care than other species and thrives in arid and semi-arid regions. Therefore, it becomes an important choice for forestry programs. Young branches of these trees are frequently invaded by the fungus Bjerkandera adusta (Willd.) P. Karst. The main aims of this study were to characterize the wood decay pattern and evaluate the extent of damage caused by the fungus. Infected samples were studied using light microscopy, confocal laser scanning microscopy, transmission electron microscopy, and scanning electron microscopy. Wood of the dead branches became pale white and very soft. In vitro decayed wood showed extensive weight loss of wood blocks (68.6%) at the end of three months. In the xylem, fibres were the most severely affected cell types, whereas wall structure of the axial parenchyma remained virtually unaltered. Unlike axial parenchyma, walls of the ray cells formed several boreholes and finally collapsed in the advanced stage of decay. By contrast, the middle lamella of all the xylem elements remained intact even at the end of three months. In the early stages of infection, vessels appeared to be resistant to the fungal action but they also became eroded at the advanced stage. The degradation pattern showed anatomical characteristics of both the white-rot and soft-rot type of decay. Thinning of walls from the lumen side and appearance of U-notches resembles white-rot decay, while tunnels through the S2 layer of the fibre wall added the characteristics of the soft-rot decay pattern. Extensive weight loss of wood blocks following infection suggests B. adusta is an aggressive wood-degrading fungus.
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| 7. |
- Sivan, Pramod, 1984-, et al.
(författare)
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Immunofluorescence Localization of β-(1-4)-d-Galactan and Xylans in Tension Wood and Normal Wood Fibres of Leucaena leucocephala
- 2017
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Ingår i: Wood is Good. - Singapore : Springer. ; , s. 63-71
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Bokkapitel (refereegranskat)abstract
- The distribution pattern of β-(1-4)-D-galactan and xylans in the fibres of tension wood and normal wood of Leucaena leucocephala was investigated using immunofluorescence microscopy. Light microscopic observation of tension wood fibres revealed that they are characterized by the presence of typical non-lignified, tertiary wall layer. LM-5 labelling of normal fibres showed weak labelling from the cell wall, indicating less concentration of β-(1-4)-D-galactans or masking effect due to co-polymerization of other polymers. Both less substituted (LM-10) and highly substituted (LM-11) xylans found to be distributed more in the secondary wall region, while compound middle lamella showed weak labelling. In tension wood fibres, LM-5 labelling revealed strong signals from tertiary wall layer, indicating that gelatinous layer contains more amount of β-(1-4)-D-galactans. The lignified secondary wall and compound middle lamellae showed weak labelling with LM-5. Labelling of xylans with LM-10 showed intense fluorescence signals from the lignified secondary wall, while gelatinous layer showed weak labelling, indicating less concentration of xylans in the gelatinous layer. In conclusion, in addition to the generalized concept that the G-layer in tension wood fibre is rich in cellulose, our results showed that constitution of pectins and xylans is also different compared to the secondary wall of normal wood fibres.
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| 8. |
- Sivan, Pramod, 1984-, et al.
(författare)
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Immunolocalization of β-(1–4)-D-galactan, xyloglucans and xylans in the reaction xylem fibres of Leucaena leucocephala (Lam.) de Wit
- 2019
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Ingår i: Plant physiology and biochemistry (Paris). - : Elsevier. - 0981-9428 .- 1873-2690. ; 142, s. 217-223
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Tidskriftsartikel (refereegranskat)abstract
- Cell wall architecture of tension wood fibres represents a suitable biological system to study the mechanism of growth and maintenance of posture of trees growing under various physical and physiological growth constraints. In the present study, we investigated the spatial distributions of β-(1–4)-D-galactan, xyloglucan and xylans (both less and highly substituted) in the opposite and tension wood fibres of bent Leucaena leucocephala by immunolabelling with monoclonal antibodies LM5, CCRCM1, LM10 and LM11 specific to these carbohydrate epitopes. The presence of non-lignified, tertiary wall layer is the typical tension wood characteristic associated with the reaction xylem fibres in Leucaena. LM5 labelling of opposite fibres showed weak labelling in the cell walls indicating less concentration of β-(1–4)-D-galactans while tension wood showed strong labelling in the tertiary wall layer suggesting the gelatinous layer (G-layer) has a strong cross linking with β-(1–4)-D-galactans. Xyloglucan distribution was more in the compound middle lamellae and the primary wall-S1 layer boundary of tension wood fibres as compared to that of opposite wood. A weak labelling was also evident near the boundary between the G-layer and the secondary wall of tension wood fibres. The secondary wall of opposite and tension wood fibres showed a strong distribution of both ls ACG Xs (LM10) and hs ACG Xs (LM11) while a weak labelling was noticed in the compound middle lamella. Tension wood fibres also showed strong xylan labelling mainly confined to the lignified secondary walls while the G-layer showed weak xylan labelling. In conclusion, our results suggest that β-(1–4)-D-galactans and xyloglucans could be implicated in the tensile stress generation within the G-layer of tension wood fibres of Leucaena leucocephala.
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| 9. |
- Bhatt, Isha M, et al.
(författare)
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Anatomical changes in the cell-wall structure of Leucaena leucocephala(Lam.) de Wit as caused by the decay fungi Trametes versicolorandTrametes hirsuta
- 2015
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Ingår i: Southern Forests, a journal of forest science. - : National Inquiry Services Center (NISC). - 2070-2620 .- 2070-2639. ; 77:4, s. 297-303
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Tidskriftsartikel (refereegranskat)abstract
- The structural changes in the cell wall and delignification pattern caused by Trametes versicolor and Trametes hirsuta in the sap wood of Leucaena leucocephala were examined by light and confocal laser scanning microscopy. The in vitro decay test was conducted for 12 weeks. Both species of Trametes used in this study caused anatomical characteristics specific to simultaneous white rot. Formation of boreholes, erosion troughs, erosion channels with U-shaped notches in tangential sections and thinning of cell walls were evident in the wood inoculated with each of the fungal species. Cell separation due to removal of middle lamellae occurred at the early stages of infection (30 d) with T. versicolor. In contrast, middle lamellae remained intact in wood inoculated with T. hirsuta and showed cell separation due to degradation of the outer layer of the secondary wall and degradation of the middle lamellae observed only in severely decayed wood at late stages. Confocal microscopy revealed the delignification pattern particularly from cell corners and vessel walls at an advanced stage of decay, indicating strong ligninolytic activity of both species in the sapwood of L. leucocephala.
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| 10. |
- Bhatt, I.M., et al.
(författare)
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Anatomical characterization of Eucalyptus globulus wood decay by two white rot species of Trametes
- 2016
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Ingår i: Journal of plant pathology. - : Springer. - 1125-4653 .- 2239-7264. ; 98:2, s. 227-234
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Tidskriftsartikel (refereegranskat)abstract
- Application of ligninolytic enzymes in paper and pulp industry has opened a new avenue to overcome the problems associated with mechanical and chemical pulping. The present study was therefore aimed to investigate the anatomical alterations in the cell wall of eucalyptus sap wood inoculated with Trametes hirsuta (Fr.) Pilat and T. versicolor (Fr.) Pilat. T. hirsuta caused cell separation, formation of oval shaped cavities rich in cellulosic polysaccharides and pit erosion during early stages of decay, suggesting selective delignification pattern. However, degradation of carbohydrate components resulting in large void areas was detected during advanced stages of decay. Thinning of cell wall was detected in the fibres of wood blocks colonized by T. versicolor, indicating simultaneous white rot decay. The degradation occurred preferentially to the middle layers of secondary wall, while compound middle lamellae and S₃ layer resisted degradation during early stages of decay. Confocal microscopy revealed strong delignification from vessel wall and separation of fibres following delignification of compound middle lamellae. The degradation of lignin rich vessel wall during advanced stages of decay by both species suggests their strong ligninolytic properties suitable for its use in paper and pulp industry.
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