Arun K. Pandey

Molecular systematics of Indian Crotalaria (Fabaceae) based on analyses of nuclear ribosomal ITS DNA sequences

Crotalaria L. (Fabaceae) comprises approximately 700 species that are distributed in tropical and subtropical regions of the world. In India, it is the largest legume genus with 92 species. Sequences of the nuclear internal transcribed spacer from species representing all the six recognized sections of Indian Crotalaria were subjected to phylogenetic analyses. Ancestral state reconstructions were done for two morphological characters, corolla keel beak, and leaf form. Analyses reveal five major well-supported clades within a monophyletic Crotalaria. Clade 1 has members with rostrate-spirally twisted keel beaks while the remaining four clades comprise members with keel beaks rostrate-not spirally twisted. Clade 1 further bifurcates into two clades characterized by differences in leaf morphology: (1a) contains species with simple leaves belonging to section Calycinae, section Crotalaria subsection Crotalaria and subsection Bractetae and multifoliolate leaves belonging to section Crotalaria subsection Polyphyllae (1b) contains species with trifoliate leaves belonging to section Dispermae, section Crotalaria subsection Longirostres. Sub-clade iii in Clade 1a contains four species complexes, each forming a monophyletic group. Of these one comprising C. madurensis, C. subperfoliata, C. shevaroyensis, and C. longipes is endemic to a region in southern India. Each of the others contains one endemic species and one widespread species that is sympatric with the endemic one (C. hirta and C.mysorensis; C. epunctata and C. albida; C. clarkei and C. triquetra). The present study suggests that: (1) all members of section Calycinae and most members of section Crotalaria form a clade, (2) members of section Crotalaria subsection Longirostres and section Dispermae form a distinct clade, (3) twisting of the keel beak is an apomorphy within the genus, (4) there is a reversal to keel beak rostrate-not spirally twisted in C. shevaroyensis and an independent origin of a rostrate-spirally twisted keel beak in C. humilis, and (5) the trifoliolate condition is a plesiomorphy in the genus and the simple leaf condition an apomorphy; there is a single reversal to the trifoliolate condition in C. orixensis. The current morphological classification system of Indian Crotalaria species includes six sections, but these circumscriptions are not supported by the molecular data.

Molecular phylogeny of Nassauvia (Asteraceae, Mutisieae) based on nrDNA ITS sequences

The phylogeny of the genus Nassauvia and closely related genera was reconstructed using sequences from the internal transcribed spacer regions (ITS) of nuclear ribosomal DNA. The genus Triptilion is nested within Nassauvia, making the latter genus paraphyletic. Neither of the two subgenera Nassauvia and Strongyloma is resolved as monophyletic, and none of the sections of subgenus Nassauvia is recovered as monophyletic. The evolution of the compound secondary inflorescences has been complex in Nassauvia, with the highly aggregated forms representing the original condition in the genus. However, the ancestral condition is equivocal in several clades, and there are alternative reconstructions for the gains–losses of the variously aggregated conditions. There has been at least one gain of solitary capitula in Nassauvia. The evolution of flavonoid chemistry has been complex in Nassauvia, and flavonoids are of limited phylogenetic-taxonomic utility in the genus. Gains–losses of flavonols occur only on terminals whereas changes in flavones and C-glycosyl flavones occur at various levels in the tree. Gains–losses of methylation of flavones and flavonols occur only on terminals.

Genetic Homogeneity Revealed Using SCoT, ISSR and RAPD Markers in Micropropagated Pittosporum eriocarpum Royle- An Endemic and Endangered Medicinal Plant

Pittosporum eriocarpum Royle, a medicinally important taxon, is endemic to Uttarakhand region of Himalaya. It has become endangered due to over-collection and the loss of habitats. As raising plants through seeds in this plant is problematic, a reliable protocol for micropropagation using nodal explants has been developed. High shoot regeneration (95%) occurred in MS medium augmented with BA 0.4mg/l in combination IBA 0.6mg/l. In vitro regenerated shoots were rooted in MS medium supplemented with three auxins, of which 0.6 mg/l indole butyric acid proved to be the best for rooting (90%) with maximum number of roots per shoot. Thereafter, rooted plants were hardened and nearly 73% of rooted shoots were successfully acclimatized and established in the field. Start codon targeted (SCoT), inter simple sequence repeats (ISSR) and random amplified polymorphic DNA (RAPD) markers were used to validate the genetic homogeneity amongst nine in vitro raised plantlets with mother plant. DNA fingerprints of in vitro regenerated plantlets displayed monomorphic bands similar to mother plant, indicating homogeneity among the micropropagated plants with donor mother plant. The similarity values were calculated based on SCoT, ISSR and RAPD profiles which ranged from 0.89 to 1.00, 0.91 to 1.00 and 0.95 to 1.00 respectively. The dendrograms generated through Unweighted Pair Group Method with arithmetic mean (UPGMA) analysis revealed 97% similarity amongst micropropagated plants with donor mother plant, thus confirming genetic homogeneity of micropropagated clones. This is the first report on micropropagation and genetic homogeneity assessment of P. eriocarpum. The protocol would be useful for the conservation and large scale production of P. eriocarpum to meet the demand for medicinal formulations and also for the re-introduction of in vitro grown plants in the suitable natural habitats to restore the populations.

A revised circumscription of the species in Bracteatae complex (section Calycinae) in the genus Crotalaria L.: evidence from nuclear and chloroplast markers

The existing sectional classification of the genus Crotalaria has merged the Indian sections Calycinae and Crotalaria under the section Calycinae Wight & Arn. emend. M.M.Le Roux & B.-E.van Wyk. Crotalaria subsection Bracteatae is re-evaluated to ascertain its position in the Calycinae clade. Evidences from morphological and molecular sequence data (ITS and trnL-F regions) are used to assess the subsectional position of Bracteatae. Within the recognized 12 species in the subsection, the morphological characters currently used to distinguish these species, are insignificant and overlapping and do not merit diagnostic characters of the species. Examination of the types and vouchers at different herbaria and specimens collected during field trips enabled us for a new interpretation of the existing circumscription of the species. Further, pod anatomical and molecular sequence data were also used for the delimitation of the species. Based on the results of the above studies, a new circumscription has been formalized here and contains five recognized species in the Bracteatae clade, viz., C. berteroana DC., C. longipes Wight & Arn., C. paniculata Willd., C. pulchra DC. and C. pellita DC. of the section Calycinae emend. M.M.Le Roux & B.-E.van Wyk. Crotalaria subsection Bracteatae appeared to be a well supported monophyletic group, but nested within the Calycinae clade. In order to maintain the monophyly of Crotalaria section Calycinae, Bracteatae is synonymized with the former.

A New Species of Crotalaria (Fabaceae, Crotalarieae) from Meghalaya, India

Abstract A new species of Crotalaria from Meghalaya (Northeast India) is described and illustrated. The new species is assigned to Crotalaria section Calycinae based on affinities to C. sessiliflora and C. occulta. The distribution, ecology, and conservation status of C. meghalayensis are briefly discussed. We also provide evidence from molecular data and statistical analyses to authenticate the distinctiveness of the new species.

Discovery of two new species of Crotalaria (Leguminosae, Crotalarieae) from Western Ghats, India

Two new species of Fabaceae-Papilionoideae are described and illustrated. Crotalaria suffruticosa from Karul Ghat region of Maharashtra is morphologically close to C. albida and C. epunctata. C. multibracteata from Panhala region of Maharashtra resembles C. vestita. C. suffruticosa differs from C. albida and C. epunctata in its habit, leaf, inflorescence, callosity, keel type, stigma, style morphology and number of seeds/pod. To test if the new species differ from their morphologically most similar species, we measured various traits and performed a Principal Component Analysis (PCA). This analysis shows that the new species differs from similar species in gross morphology for several diagnostic traits and showed correlations between the variables or distance among groups and estimated the contribution of each character. Phylogenetic analyses were also conducted based on nuclear (ITS) and plastid (matK) markers. The analyses revealed nucleotide differences between the new species and their close allies attributing to their distinctiveness. A map and key including all species of Crotalaria from Maharashtra state are provided. Conservation status of the two new species have also been assessed.

Repeated domestication of melon (Cucumis melo) in Africa and Asia and a new close relative from India

PREMISE OF THE STUDY The domestication history of melon is still unclear. An African or Asian origin has been suggested, but its closest wild relative was recently revealed to be an Australian species. The complicated taxonomic history of melon has resulted in additional confusion, with a high number of misidentified germplasm collections currently used by breeders and in genomics research. METHODS Using seven DNA regions sequenced for 90% of the genus and the major cultivar groups, we sort out described names and infer evolutionary origins and domestication centers. KEY RESULTS We found that modern melon cultivars go back to two lineages, which diverged ca. 2 million years ago. One is restricted to Asia (Cucumis melo subsp. melo), and the second, here described as C. melo subsp. meloides, is restricted to Africa. The Asian lineage has given rise to the widely commercialized cultivar groups and their market types, while the African lineage gave rise to cultivars still grown in the Sudanian region. We show that C. trigonus, an overlooked perennial and drought-tolerant species from India is among the closest living relatives of C. melo. CONCLUSIONS Melon was domesticated at least twice: in Africa and Asia. The African lineage and the Indian C. trigonus are exciting new resources for breeding of melons tolerant to climate change.

The Namib-Thar Desert Disjunction in Dactyliandra (Cucurbitaceae) is the Result of a Recent Introduction to India

Abstract Depending on taxonomic concept, the genus Dactyliandra (Cucurbitaceae) comprises up to four species: two from Southwest Africa, D. luederitziana (Namibia) and D. welwitschii (Angola), and two very locally distributed and poorly known taxa from Northeast Africa, D. nigrescens and D. stefaninii. In addition to these African populations, D. welwitschii was also reported as a possibly native species from the Thar desert of Northwestern India and Pakistan ca. 8,000 km away from the Namib range. A phylogenetic analysis of plastid and nuclear ribosomal ITS DNA sequences including all Dactyliandra species and D. welwitschii from the Thar desert revealed that this striking disjunction is of very recent origin. Dactyliandra is monophyletic only after exclusion of the East African taxa, which are best placed in Trochomeria. The species Dactyliandra welwitschii is monophyletic and includes the Indian plants, which group with a sample from an Angolan population. We hypothesize that this unexpected connection is a result of man-mediated introduction to India from Africa perhaps in the times of the slave trade. The new combinations Blastania lucorum and Trochomeria nigrescens are published here.

Metabolomic homeostasis shifts after callus formation and shoot regeneration in tomato

Plants can regenerate from a variety of tissues on culturing in appropriate media. However, the metabolic shifts involved in callus formation and shoot regeneration are largely unknown. The metabolic profiles of callus generated from tomato (Solanum lycopersicum) cotyledons and that of shoot regenerated from callus were compared with the pct1-2 mutant that exhibits enhanced polar auxin transport and the shr mutant that exhibits elevated nitric oxide levels. The transformation from cotyledon to callus involved a major shift in metabolite profiles with denser metabolic networks in the callus. In contrast, the transformation from callus to shoot involved minor changes in the networks. The metabolic networks in pct1-2 and shr mutants were distinct from wild type and were rewired with shifts in endogenous hormones and metabolite interactions. The callus formation was accompanied by a reduction in the levels of metabolites involved in cell wall lignification and cellular immunity. On the contrary, the levels of monoamines were upregulated in the callus and regenerated shoot. The callus formation and shoot regeneration were accompanied by an increase in salicylic acid in wild type and mutants. The transformation to the callus and also to the shoot downregulated LST8 and upregulated TOR transcript levels indicating a putative linkage between metabolic shift and TOR signalling pathway. The network analysis indicates that shift in metabolite profiles during callus formation and shoot regeneration is governed by a complex interaction between metabolites and endogenous hormones.

Molecular systematics of Indian Alysicarpus (Fabaceae) based on analyses of nuclear ribosomal DNA sequences

Alysicarpus Necker ex Desvaux (Fabaceae, Desmodieae) consists of