Leptolyngbya
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publication ID |
https://doi.org/ 10.11646/phytotaxa.316.2.1 |
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persistent identifier |
https://treatment.plazi.org/id/03EE825E-FFE0-FFD1-FEC7-79579B46E3F0 |
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treatment provided by |
Felipe |
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scientific name |
Leptolyngbya |
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Genus: Leptolyngbya View in CoL View at ENA
Diagnosis for Leptolyngbya indica Debnath and Bhadury sp. nov. ( Fig. 2 View FIGURE 2 )
Diagnosis:— Morphologically and ecologically quite distrinct than other validly described soil-borne species of the genus Leptolyngbya with very thin trichomes with constriction; cells cylindrical, longer than broad; cell division transverse, daughter cells divided and attained full length before next division; absence of false branch and necridic cell; apical cells subobtuse to obtuse when older. The 16S rRNA sequence is different from other known species.
Leptolyngbya indica (in.di.ca. n. indica of india named after the origin country name India).
In nature, LBK isolate grown in alluvial rice field soil (affected by arsenic) in LGP of West Bengal, India. The trichomes are light blue green, microscopic; in solid culture plate blue green spreading colonies ( Fig. 2A View FIGURE 2 ) and in liquid medium they appeared as blue green biomass with glass wall attachment later free, when older becoming yellowish green. Filaments are flexuous and entangled. Cells are less constricted with translucent cross walls ( Fig. 2B View FIGURE 2 ). Sheath facultative, colourless, transparent, firm and attached to the trichome ( Figs. 2B, C View FIGURE 2 ). Cells are cylindrical, 1.5–2.56 μm long and 0.7 to 0.97 (≤1) μm wide ( Figs. 2D, E View FIGURE 2 ). Terminal cells subobtuse to obtuse ( Figs. 2D, E View FIGURE 2 ). Centroplasma and chromatoplasma clearly distinguishable in centre and periphery towards the cell wall ( Fig. 2F View FIGURE 2 ).
When we compared the LBK isolate with other validly described taxa and strains, morphological differences have been noted along habitat ecology ( Table 2).
available=NA; Present= +, rarely present= (+), absent= -; Constricted= +, distinctly constricted= ++, rarely constricted=
(+)]
Holotype: — Voucher specimen VSP 006 preserved in 3% formaldehyde, prepared from cultured material, deposited in Marine Algal Culture Laboratory, IISER Kolkata , Mohanpur, Nadia, India.
Reference strain: — LBK, deposited in Marine Algal Culture Laboratory under no. MDPB 005, IISER Kolkata, Mohanpur, Nadia, India.
Type locality: — Grew as soil crust on arsenic affected alluvial rice field collected from Karimpur II block, Nadia district of the lower Gangetic plain, West Bengal, India.
Habitat: — Grown as early soil crust in arsenic affected alluvial rice field.
Etymology: — Specific nomenclature derived after the name of country of origin- India.
Molecular phylogeny of Leptolyngbya indica sp. nov.:—The isolate LBK identified by morphological attributes was subjected to molecular phylogenetic study to get a clear understanding of its taxonomic affiliation.A total of 54 partial16S rRNA sequences (above 1000 nt only considered) of representative taxa from available sequences of Leptolyngbyaceae deposited in published sequence databases were analyzed, along with the 16S rRNA sequence of LBK isolate. The NJ and ML phylogeny produced similar clustering and therefore only the ML tree topology with boot strap support values obtained from both the approach are detailed in each node as part of Fig. 7 View FIGURE 7 . The identity matrix of the LBK isolate 16S rRNA sequence (1342 nt) showed ~90–96% identity with published 16S rRNA sequences (GenBank/EMBL/DDBJ) representing filamentous cyanobacterial genus Leptolyngbya spp. ( Table 3). In the phylogenetic tree 54 sequences distributed among 13 genera of Leptolyngbyaceae and 2 from Oscillatoriaceae . The phylogenetic reconstruction based on the 16S rRNA resolved into 9 clades (Clade I–IX) representing the family Leptolyngbyaceae with strong bootstrap support ( Fig. 7 View FIGURE 7 ). In the tree topology 13 previously described genera corresponded to the Limnolyngbya Li & Li (clade I), Pantanalinema Vaz et al. (clade III), Scytolyngbya Song et al. (clade IV), Phormidesmis Turicchia et al. (clade VII), Alkalinema Vaz et al. (clade VII), Halomicronema Abed et al. , Nodosilinea Perkerson & Casamatta (clade IX) and Leptolyngbya Anagnostidis & Komárek. The genera Plectolyngbya Taton et al. , (clade VII), Planktolyngbya Anagnostidis & Komárek (clade VII), Thermoleptolyngbya Sciuto & Moro (clade VIII), Oculatella Zammit et al. (clade VIII), Trichocoleus Anagnostidis (clade IX) and Haloleptolyngbya Dadheech et al. (clade IX) were represented by single sequence. Interestingly 25 sequences of the type genus Leptolyngbya were distributed in different clades (II, V, VI) and sister clades (of clade III, IV, VII, VIII, IX) across the tree topology indicating interspecific heterogenecity within this genus. Based on NJ/ML phylogeny of LBK 16S rRNA sequences (Acc. no. KY421911), showed strong taxonomic affiliation with the genus Leptolyngbya ( Fig. 7 View FIGURE 7 ) and formed a distinct clade (clade-VI) containing two sequences of Leptolyngbya sp. (Acc. no. KC182752 and FJ933259). To get a further clearer understanding of the taxonomic affiliation of the LBK isolate, another phylogenetic tree based on ML approach and containing bootstrap support values obtained from this approach as well as NJ approach was reconstructed along with 37 published 16S rRNA reference sequences of the genus Leptolyngbya representing five clades A–E ( Fig. 8 View FIGURE 8 ). Topology of the ML tree showed that the Leptolyngbya assemblages in clade A were segregated into two subclades supported by moderate bootstrap values. The earliest diverging subclade included Leptolyngbya sensu stricto group ( Fig. 8 View FIGURE 8 ) representing specific biotopes of aquatic, subaerial and edaphic habitat. The second subclade has 6 strains of genus Leptolyngbya , from soil biotope of extreme habitat like desert crust in USA and South Africa ( Fig. 8 View FIGURE 8 ). In clade B, Leptolyngbya indica sp. nov. is strongly supported by bootstrap values in NJ/ML topology forming a distinct sister clade along with Leptolynbgya sp. C1 and Leptolyngbya sp. FYG, sequences originated from the thermal spring of Yellowstone National Park. However, the 16S rRNA sequence of LBK isolate diverged from the rest confirming that the isolate is novel as evident from the phylogeny ( Figs. 7 View FIGURE 7 & 8 View FIGURE 8 ) and identity matrix ( Table 3).
Physiology of Leptolyngbya indica sp. nov.:—The new taxon is a slow growing cyanobacterium (generation time: 178.5 hours) with low nitrogenase (ARA) activity (0.70±0.04 C 2 H 4 μg Chl a -1 h-1). Auto fluorescence (red) intensity was high towards the periphery of cells indicating location of thylakoids ( Fig. 2F View FIGURE 2 ). In vivo, four distinct pigments were detected from vegetative cell derived fluorescence emission spectra. Three PBPs namely phycoerythrin (PE), phycocyanin (PC) and allophycocyanin (APC) were present. Each of them exhibited characteristic wavelengths of fluorescence emission maximum (λemax): PE, λemax ~ 575 nm; PC, λemax ~ 635–645 nm; and APC, λemax ~ 656 nm. The Chl a autofluorescence has λemax ~ 675–685 nm, may overlap with PC and APC (λemax ~630–685).
Description of other morphotypes determined only by morphotaxonomic criteria.
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.