Digital divide and access to online education: new evidence from Tamil Nadu, India.

The pandemic and the long closure of educational institutions have changed the learning and teaching practices across the globe. A massive and unplanned shift towards online education with unequal access to digital infrastructure deepens the existing digital divide and socio-economic inequalities. Tamil Nadu Covid Pulse Survey shows the state's commitment to strengthening evidence-based policymaking and continuing its welfare tradition including its efforts to provide uninterrupted education during the crisis. Based on the three recent rounds of the panel survey conducted in October 2020 and August 2021, this article discusses Tamil Nadu's experience in continuing education during the pandemic. The result highlights the existing digital divide and challenges faced by students in accessing online education. Some of the government initiatives like Kalvi TV telecasting classes for school students have been effective in addressing the digital divide between rural and urban areas in the state and making its education system more inclusive.

Stimulation or Inhibition: Conflicting evidence for (+/-)-catechin's role as a chemical facilitator and disease protecting agent.

The occurrence of plant hormesis is a poorly understood phenomenon, wherein low doses of phytotoxins unusually promote growth responses in higher plants. In contrast, negative plant-plant interactions mediated through secreted small molecular weight compounds initiate growth inhibitory responses. Studies related to (+/-)-catechin mediated allelopathy have transpired both novel information and generated significant controversy. Specifically, studies related to the phytotoxicity responses mediated by (+/-)-catechins have been seriously debated. The pronged opinion that (+/-)-catechin is phytotoxic versus non-phytotoxic relies more on the target plant systems and the conditions used to test phytotoxic responses. It is reported that lower than MIC dosage supplementation of (+/-)-catechin could promote growth responses in the model plant Arabidopsis thaliana. Furthermore, it was shown that sub-MIC levels of (+/-)-catechin supplementation leads to elicitation of disease resistance against Pseudomonas syringae DC3000 (hereafter DC3000). Intrigued by the unique hormesis response observed, we tested whether (+/-)-catechin indeed promotes growth responses in A. thaliana. In our hands, we observed no growth promotion responses of (+/-)-catechin against A. thaliana under in vitro or in soil conditions. We also evaluated the previously reported disease protecting properties of (+/-)-catechin in A. thaliana against DC3000. The systematic observations to evaluate disease protecting properties entailing colony counts, disease incidences and loss of chlorophyll studies showed no disease protecting properties of (+/-)-catechin. The transcriptional response for a marker pathogenesis related PR1 defense gene showed no induction post (+/-)-catechin supplementation. The cell death genes (ACD2 and CAD1) associated with programmed cell death revealed unchanged expression levels in plants treated with sub-MIC levels of (+/-)-catechin. Further, we report supplementation of sub-MIC levels of (+/-)-catechin negates any change in the expression of an auxin responsive gene. Our results refute the previous claims of growth and defense inducing effects of (+/-)-catechin, thus suggesting that a thorough reexamination is required to evaluate the hormetic effect of (+/-)-catechin under both controlled and natural conditions.

Physicochemical and genetic analysis of an endemic rice variety, Njavara (Oryza sativa L.), in comparison to two popular South Indian cultivars, Jyothi (PTB 39) and IR 64.

Njavara is a medicinal rice strain, endemic to Kerala, South India, bestowed with medicinal qualities. Genetic variations and some of the physicochemical properties were studied using standard molecular protocols and compared with those of nonmedicinal rice varieties: Jyothi and IR 64. Njavara showed 11 unique positive and 36 unique negative markers to differentiate it from Jyothi and IR 64. Genetic similarity coefficient studies showed two well-defined clusters separating Njavara from Jyothi and IR 64. All the three varieties had waxy gene Wx(a) allele. Njavara had (CT)(n) repeats at (CT)(10), while Jyothi and IR 64 had repeats at (CT)(11) in the 5'-untranslated region of waxy gene. Njavara showed a CGTG sequence, while Jyothi and IR 64 had a CGCG sequence at the 14th exon of Sbe 1 gene. Njavara, Jyothi, and IR 64 have similar amylose equivalent (AE), which was confirmed by microsatellite markers. The SSR primers for protein content and setback viscosity primer (RM 4608) were observed to be polymorphic in case of Njavara. Njavara rice, with a distinct gene pool and medicinal properties, can be exploited as a nutraceutical rice.

Spermine-induced morphogenesis and effect of partial immersion system on the shoot cultures of banana.

Contribution of exogenous polyamines (PAs) and polyamine-inhibitors on plantlet regeneration patterns of banana (cv. Nanjanagudu Rasabale-AAB) was studied and the performance of regenerated shoots in temporary immersion system was evaluated. The rhizome explants (without shoot bud) of in vitro shoots produced a mixture of embryogenic and nonembryogenic calli on modified MS medium. The analyses of endogenous pools of polyamines showed higher levels of PAs in embryogenic than in nonembryogenic calli. Supplementation of various levels of (10-50 microM) spermine (Spm), spermidine (Spd), and putrescine (Put) to cultures with secondary embryogenesis showed that about 50% of embryogenic calli rapidly produced secondary embryos only in the presence 40 microM Spm but not in other treatments. The crucial role of Spm was further confirmed by the use of 0.1 mM each of alpha-DL-Difluromethylornithine and alpha-DL-Difluromethylarginine along with Spm where the presence of inhibitors concomitantly inhibited the secondary embryogenesis. The shoots obtained from the embryogenic cultures were checked for their performance on solid medium (SM) and partial immersion system (PIS). The rate of shoot multiplication was higher in PIS than in SM throughout 6 weeks culture period. Uniformity in elongation of all the shoot buds was observed in PIS but not in SM. Evaluation for the acclimatization, survival under greenhouse conditions revealed the better performance of PIS-derived plants than those from SM.

The use of genetic markers for detecting DNA polymorphism, genotype identification and phylogenetic relationships among banana cultivars.

Genetic variations and relationships among 21 commercially important banana cultivars of South India were evaluated using 50 decamer RAPD primers and 12 ISSR primers. The primers were selected after a preliminary screening of several such primers for their ability to produce clear and reproducible patterns of multiple bands. The analyses resulted in the amplification of totally 641 bands of 200-3100bp, of which 382 bands were polymorphic, corresponding to nearly 60% genetic diversity. The RAPD and ISSR surveys between pairs of 21 cultivars revealed 60.15% and 56.73% of polymorphic bands, respectively. A strong linear relationship was observed between the Resolving power (Rp) of the primer and its ability to distinguish genotypes. Based on these data, a genetic similarity matrix was established and a dendrogram for each set of primers was developed by UPGMA. The genetic similarity coefficients in RAPD analysis ranged from 0.3177 to 0.7818 and in ISSR analysis from 0.1800 to 0.8462. A fingerprinting key was generated where the presence/absence of specific RAPD/ISSR bands were recorded for each cultivar. The presence of a specific RAPD (OPC-5(800)) band was observed for an endemic cultivar--Nanjanagudu Rasabale (NR). The study resulted in the identification and molecular classification of South Indian banana cultivars of which Robusta and Williams are global and others have either limited geographical distribution or purely endemic to South India. A group of eight cultivars was identified that are highly distinct from one another. The members of this group may be useful for generating 2X and 4X breeding populations for further use in breeding secondary triploid hybrids.

Morphometric and biochemical characterization of red beet (Beta vulgaris L.) hairy roots obtained after single and double transformations.

It is known that T-DNA of Agrobacterium rhizogenes affects processes of plant development and activates the synthesis of secondary metabolites in transformed plant cells. In the present investigation, we provide evidence that different strains of A. rhizogenes significantly affect morphometric, morphological and functional characteristics of hairy roots of red beet (Beta vulgaris L.). Infection with four strains of A. rhizogenes (A4, A 2/83, A 20/83 and LMG-150) resulted in ten clones of hairy roots, which were named accordingly as A4(1), A4(2), A4(3), A 2/83(1), A 2/83(2), A 2/83(3), A 20/83(1), A 20/83(2), A 20/83(3) and LMG-150. Their growth characteristics, pigment content, levels of endogenous auxin and T-DNA copy number showed significant differences probably due to the physiological status of the host cell rather than the T-DNA copy number. Although A 2/83 showed highest hairy root induction capacity, the best hairy root clone was obtained with strain LMG-150 that produced highest biomass and pigments. In this root clone, the enzyme peroxidase was found involved in altering the endogenous auxin pool. When root clone LMG-150 was re-transformed to insert additional individual rol genes, two double transformed clones were obtained, one for rolABC and the other for rolC gene where the former produced higher biomass and betalaine than the latter. Despite the established fact that rol genes of T-DNA influence endogenous phytohormones, no direct correlation among the single transformants and the double transformants was found. This is the first report, in our knowledge, where a hairy root clone has been used to obtain double transformants.

Specific pretreatments reduce curing period of vanilla (Vanilla planifolia) beans.

With the aiming of reducing the curing period, effects of pretreatments on flavor formation in vanilla beans during accelerated curing at 38 degrees C for 40 days were studied. Moisture loss, change in texture, levels of flavoring compounds, and activities of relevant enzymes were compared among various pretreatments as well as the commercial sample. Use of naphthalene acetic acid (NAA; 5 mg/L) or Ethrel (1%) with blanching pretreatment resulted in 3-fold higher vanillin on the 10th day. Other flavoring compounds-vanillic acid, p-hydroxybenzoic acid, and p-hydroxybenzaldehyde-fluctuated greatly, showing no correlation with the pretreatments. Scarification of beans resulted in nearly 4- and 3.6-fold higher vanillin formations on the 10th day in NAA- and Ethrel-treated beans, respectively, as compared to control with a significant change in texture. When activities of major relevant enzymes were followed, addition of NAA or Ethrel helped to retain higher levels of cellulase throughout the curing period and higher levels of beta-glucosidase on the 20th day that correlated with higher vanillin content during curing and subsequent periods. Peroxidase, being highest throughout, did not correlate with the change in levels of major flavoring compounds. The pretreatment methods of the present study may find importance for realizing higher flavor formation in a shorter period because the major quality parameters were found to be comparable to those of a commercial sample.

Nutraceutical applications of garlic and the intervention of biotechnology.

Garlic (Allium sativum L.) is an important and widely cultivated plant with both culinary and medicinal uses stemming from its biological activities, which include antibiotic, anticancer, anti-thrombotic, and lipid-lowering cardiovascular effects. Though such medicinal use of garlic existed for centuries, there was little scientific support for its therapeutic and pharmacological properties. However, there has been a recent upsurge of research on garlic aiming to understand its exact mechanism of action in each case so that garlic and its products may have more judicious future applications. Since garlic is vegetatively propagated, its improvement for desired traits through conventional means is difficult. The intervention of biotechnological methods such as tissue culture and gene transfer protocols developed recently hold great promise for improving this crop. Due to new innovations in instrumentation and processing technologies coupled with more judicious experimental models, better products are foreseen in the market. The objective of this article was to review the recent developments made towards understanding the mechanism by which garlic imparts different therapeutic effects as well as to review what biotechnology can offer to improve this crop and its products.