Debjyoti Bhattacharyya

Genetic structure of wild pea (Pisum sativum subsp. elatius) populations in the northern part of the Fertile Crescent reflects moderate cross-pollination and strong effect of geographic but not environmental distance

Knowledge of current genetic diversity and mating systems of crop wild relatives (CWR) in the Fertile Crescent is important in crop genetic improvement, because western agriculture began in the area after the cold-dry period known as Younger Dryas about 12,000 years ago and these species are also wild genepools of the world’s most important food crops. Wild pea (Pisum sativum subsp. elatius) is an important source of genetic diversity for further pea crop improvement harbouring traits useful in climate change context. The genetic structure was assessed on 187 individuals of Pisum sativum subsp. elatius from fourteen populations collected in the northern part of the Fertile Crescent using 18,397 genome wide single nucleotide polymorphism DARTseq markers. AMOVA showed that 63% of the allelic variation was distributed between populations and 19% between individuals within populations. Four populations were found to contain admixed individuals. The observed heterozygosity ranged between 0.99 to 6.26% with estimated self-pollination rate between 47 to 90%. Genetic distances of wild pea populations were correlated with geographic but not environmental (climatic) distances and support a mixed mating system with predominant self-pollination. Niche modelling with future climatic projections showed a local decline in habitats suitable for wild pea, making a strong case for further collection and ex situ conservation.

Genomic diversity and macroecology of the crop wild relatives of domesticated pea

There is growing interest in the conservation and utilization of crop wild relatives (CWR) in international food security policy and research. Legumes play an important role in human health, sustainable food production, global food security, and the resilience of current agricultural systems. Pea belongs to the ancient set of cultivated plants of the Near East domestication center and remains an important crop today. Based on genome-wide analysis, P. fulvum was identified as a well-supported species, while the diversity of wild P. sativum subsp. elatius was structured into 5 partly geographically positioned clusters. We explored the spatial and environmental patterns of two progenitor species of domesticated pea in the Mediterranean Basin and in the Fertile Crescent in relation to the past and current climate. This study revealed that isolation by distance does not explain the genetic structure of P. sativum subsp. elatius in its westward expansion from its center of origin. The genetic diversity of wild pea may be driven by Miocene-Pliocene events, while the phylogenetic diversity centers may reflect Pleisto-Holocene climatic changes. These findings help set research and discussion priorities and provide geographical and ecological information for germplasm-collecting missions, as well as for the preservation of extant diversity in ex-situ collections.

Phanera jampuiensis (Leguminosae: Caesalpinioideae: Cercideae), a new species from Tripura, India

SummaryPhanera jampuiensis (Leguminosae: Caesalpinioideae: Cercideae), a new species from Tripura, India, is described and illustrated. P. jampuiensis resembles P. chalcophylla, but differs in having chartaceous leaves, lamina with strigose hairs mainly on abaxial midveins, fawn tomentose floral buds and shorter filament and style.

Transcript free energy positively correlates with codon usage bias in mitochondrial genes of Calypogeia species (Calypogeiaceae, Marchantiophyta)

Abstract The present study attempts to focus on the pattern of codon usage bias (CUB) in mitochondrial genes among four species of Calypogeia viz. C. arguta, C. integristipula, C. neogaea and C. suecica along with the factors influencing their CUB as no work was reported yet. The four taxa exhibit noticeable difference in their morphological features, habitat preference and growth forms. To understand the patterns of codon usage in Calypogeia mitochondrial genomes, we used bioinformatic tools to analyze the mitochondrial protein-coding sequences of four Calypogeia. In our current study, the mean nucleobase T was the highest while G was the lowest in all four species. The overall GC content was higher than AT content i.e. genes were AT rich. The CUB was low in mitochondrial genes of C. arguta, C. integristipula, C. neogaea and C. suecica, respectively as revealed from low synonymous codon usage order (SCUO) values. Heat map study revealed that most of the GC and AT ending codons showed positive correlations between codon usage and GC3. From the neutrality plot, the slope of the regression line indicated that natural selection might have played a major role over mutation pressure in shaping the CUB of mitochondrial genes in these four taxa. Highly significant (p < .01) correlation was found between mRNA free energy (mFE) and SCUO for entire mRNA which suggested that the release of higher energy by entire mRNA is associated with higher degree of codon usage bias. Further, highly significant (p < .01) negative correlation of mFE for entire mRNA was found with GC, GC1, GC2 and GC3 in all the four taxa. This indicated that higher GC content might have induced the release of lesser energy by mRNA molecules.

Grasses and bamboos of Barail Wildlife Sanctuary in Assam, India

A total of 66 species (53 species of grasses and 13 species of bamboos) of Gramineae (Poaceae) are enumerated here from Barail Wildlife Sanctuary in Assam, India. These are distributed under 41 genera and 11 tribes. The study was based on fresh collection of specimens from the sanctuary during 2012 – 2014, consultation of herbarium specimens and scrutiny of literature. A list of species is provided with updated nomenclature, vernacular name(s), phenology, occurrences in the study area and habit. Field photographs of some selected members are also provided for ease of identification.

A Remarkable Taxon Jackiella javanica Schiffner Variety cordifolia Schiffner Proclaims its First Occurrence in North-eastern India

Jackiella Schiffner is highly interesting and remarkable genus belonging to the monogeneric family Jackiellaceae. Globally, the genus is represented by eight species and two varieties and in India by two species and two varieties. The present communication records the first report of Jackiella javanica Schiffner variety cordifolia Schiffner, a rare taxon from north-eastern India which is a part of the Indo-Burma Biodiversity Hotspot. Earlier it was confined to southern peninsular India and Indonesia only. The phytogeographical distribution of all the globally recognized taxa of the genus Jackiella has also been tabulated in this paper.