Swapan K. Datta

Agricultural biotechnology for crop improvement in a variable climate: Hope or hype?

Developing crops that are better adapted to abiotic stresses is important for food production in many parts of the world today. Anticipated changes in climate and its variability, particularly extreme temperatures and changes in rainfall, are expected to make crop improvement even more crucial for food production. Here, we review two key biotechnology approaches, molecular breeding and genetic engineering, and their integration with conventional breeding to develop crops that are more tolerant of abiotic stresses. In addition to a multidisciplinary approach, we also examine some constraints that need to be overcome to realize the full potential of agricultural biotechnology for sustainable crop production to meet the demands of a projected world population of nine billion in 2050.

Overexpression of Rab16A gene in indica rice variety for generating enhanced salt tolerance

We report here the overexpression of Rab16A full length gene (promoter + ORF), from the salt-tolerant indica rice Pokkali, in the salt-susceptible indica rice variety Khitish, via particle bombardment. Molecular analysis of the transgenics revealed stable integration of the transgene upto T2 generation. High level of expression of the transgene (driven by its own stress-inducible promoter), as well as the protein, was detectable in the leaves under simulated salinity stress (250 mM NaCl, 24 h); the expression level being higher than wild type (WT) plants. The Rab16A transcript also increased gradually with seed maturity, with its maximal accumulation at 30 d after pollination (DAP) i.e., fully matured seeds, explaining the protective role of Rab16A gene during seed maturation. Enhanced tolerance to salinity was observed in the plants transformed with Rab16A. The superior physiological performances of the transgenics under salt treatment were also reflected in lesser shoot or root length inhibition, reduced chlorophyll damages, lesser accumulation of Na+ and reduced loss of K+, increased proline content as compared with the WT plants. All these results indicated that the overproduction of RAB16A protein in the transgenics enable them to display enhanced tolerance to salinity stress with improved physiological traits. Our work demonstrates the profound potential of Group 2 LEA proteins (to which RAB16A belongs to) in conferring stress tolerance in crop plants through their genetic manipulation.

Molecular breeding of Osfer2 gene to increase iron nutrition in rice grain

Rice being a staple food, contains little iron in the edible grain. To increase the iron nutrition in rice grains, our present study highlights the first time development of high iron rice grain by exploring the endosperm specific overexpression of endogenous ferritin gene. The gene has been cloned from rice and overexpressed under the control of endosperm specific GlutelinA2 (OsGluA 2) promoter. After genetic transformation of aromatic indica rice cultivar, Pusa-sugandhi II, the milled seeds of resulting T 3 transgenics exhibited 7.8-fold of ferritin overexpression, which contributed to 2.09- and 1.37-fold of iron and zinc accumulation respectively. T 3 seeds demonstrated endosperm specific localization of iron that confirms the tissue specific activity of GluA2 promoter. Transgenic and non-transgenic plants showed no difference in their agronomic traits. Our study suggested that overexpression of rice endogenous ferritin gene is a step ahead toward cisgenic approach and can act as an effective tool for iron biofortification.

Pearl millet genome sequence provides a resource to improve agronomic traits in arid environments

Pearl millet [Cenchrus americanus (L.) Morrone] is a staple food for more than 90 million farmers in arid and semi-arid regions of sub-Saharan Africa, India and South Asia. We report the ∼1.79 Gb draft whole genome sequence of reference genotype Tift 23D2B1-P1-P5, which contains an estimated 38,579 genes. We highlight the substantial enrichment for wax biosynthesis genes, which may contribute to heat and drought tolerance in this crop. We resequenced and analyzed 994 pearl millet lines, enabling insights into population structure, genetic diversity and domestication. We use these resequencing data to establish marker trait associations for genomic selection, to define heterotic pools, and to predict hybrid performance. We believe that these resources should empower researchers and breeders to improve this important staple crop.

Standing Up for GMOs

On 8 August 2013, vandals destroyed a Philippine “Golden Rice” Field Trial. Officials and staff of the Philippine Department of Agriculture that conduct rice tests for the International Rice Research Institute (IRRI) and the Philippine Rice Research Institute (PhilRice) had gathered for a peaceful dialogue. They were taken by surprise when protesters invaded the compound, overwhelmed police and village security, and trampled the rice. Billed as an uprising of farmers, the destruction was actually carried out by protesters trucked in overnight in a dozen jeepneys.

Global Wild Annual Lens Collection: A Potential Resource for Lentil Genetic Base Broadening and Yield Enhancement

Crop wild relatives (CWRs) are invaluable gene sources for various traits of interest, yet these potential resources are themselves increasingly threatened by the impact of climate change as well as other anthropogenic and socio-economic factors. The prime goal of our research was to cover all aspects of wild Lens genetic resource management like species characterization, agro-morphological evaluation, diversity assessment, and development of representative sets for its enhanced utilization in lentil base broadening and yield improvement initiatives. We characterized and evaluated extensively, the global wild annual Lens taxa, originating from twenty seven counties under two agro-climatic conditions of India consecutively for three cropping seasons. Results on various qualitative and quantitative characters including two foliar diseases showed wide variations for almost all yield attributing traits including multiple disease resistance in the wild species, L. nigricans and L. ervoides accessions. The core set developed from the entire Lens taxa had maximum representation from Turkey and Syria, indicating rich diversity in accessions originating from these regions. Diversity analysis also indicated wide geographical variations across genepool as was reflected in the core set. Potential use of core set, as an initial starting material, for genetic base broadening of cultivated lentil was also suggested.

Biotechnology Research in Rice for Asia: Priorities, Focus and Directions

Over the last four decades, substantial genetic improvements have been made in rice through conventional breeding. The adoption of modern rice varieties by farmers in irrigated ecosystems has contributed to food production increases that were greater than the growth in population. The “green revolution” in rice cultivation, however, has bypassed unfavorable rice-growing environments that still account for over half of the rice land. These areas are subject to droughts, floods and problem soils that have been difficult to handle through conventional breeding. Biotechnology research has opened up new opportunities to address agricultural problems in unfavorable environments, where the majority of Asia’s poor now live. Current research on rice biotechnology, however, focuses more on insect and disease resistance than on stresses faced by farmers in less favored lands. For biotechnology to benefit the poor, research directions must be changed and their output widely shared.

Chemodifferentiation of diosgenin in Dioscorea composita

Abstract Diosgenin was isolated from different parts of a three-year-old plant of Dioscorea composite . The amounts (% on a dry wt basis) present were: tubers, 3.6; vine internodes and nodes with their leaves from first 20 nodes from the tubers, 1.6; similarly from intermediate 20 nodes, 0.039 and from upper 20 nodes, 0.03. The amounts (% on a dry wt basis) from tissue culture of nodal explants were: 30-day-old callus, 0.89; 90-day-old callus, 1.61; emergent shoots, 2.5; regenerated roots, 0.08.

Data on draft genome sequence of chickpea (Cicer arietinum)

The dataset contains genome sequence of the ~738 Mb chickpea genome from CDC Frontier, a kabuli variety, which contains an estimated 28,269 genes. Re-sequencing and analysis of 90 cultivated and wild genotypes from 10 different countries identifies both targets of breeding-associated genetic sweeps and targets of breeding-associated balancing selection. Candidate genes for disease resistance and agronomic traits are highlighted, including traits that distinguish the two main classes of cultivated chickpea- desi and kabuli. These data comprise a resource for chickpea improvement through molecular breeding, and provide insights into both genome diversity and domestication. GBrowse Visualization Links: Chickpea genome at LIS Research Article

Rapid clonal multiplication of Angelonia salicariefolia through tissue culture

Nodal explants of Angelonia salicariefolia were cultured on MS basal medium and induced to form shoots when supplemented with either Kn (1.0 mg/l) or BAP (1.0 mg/l). Rooted shoots were formed in response to Kn+NAA (1.0 mg/l+0.5 mg/l). Subcultures of the shoots of these cultures grown on the same medium supplemented with 0.5 mg/l of NAA, IAA or IBA, together with lowered concentrations of inorganic salts, induced root formation in 20–30 days. Up to 18×103 plants were produced from one plant in less than a month. Successful transfer of regenerants into soil has been accomplished.