Genotyping SNPs in lignin biosynthesis gene (CAD1) and transcription factors (MYB1 and MYB2) exhibits association with wood density in teak (Tectona grandis L.f.).

BACKGROUND: Teak (Tectona grandis L.f.), an important source of tropical timber with immense economic value, is a highly outcrossing forest tree species. 150 unrelated accessions of teak (Tectona grandis L.f.) plus trees assembled as clones at National Teak Germplasm Bank, Chandrapur, Maharashtra, India was investigated for association mapping of candidate lignin biosynthesis gene (CAD1) and transcription factors (MYB1 and MYB2). METHODS AND RESULTS: The CAD1, MYB1 and MYB2 were amplified using specifically designed primers. The amplified sequences were then sequenced and genotyped for 112 SNPs/11 indels. We evaluated the association between SNPs and wood density in teak accessions using GLM and MLM statistical models, with Bonferroni correction applied. The teak accessions recorded an average wood density of 416.69 kg.m-3 (CV 4.97%) and comprised of three loosely structured admixed sub-populations (K = 3), containing 72.05% genetic variation within sub-populations with low intragenic LD (0-21% SNP pairs) at P < 0.05 and high LD decay (33-934 bp) at R2 = 0.1. GLM and MLM models discounting systematic biases (Q and K matrices) to avoid false discovery revealed five loci at rare variants (MAF 0.003) and three loci at common variants (MAF 0.05) to be significantly (P < 0.05) associated with the wood density. However, the stringent Bonferroni correction (4.06-7.04 × 10-4) yielded only a single associated locus (B1485C/A) from exon of MYB1 transcription factor, contributing to about 10.35% phenotypic variation in wood density trait. CONCLUSION: Scored SNP locus (B1485C/A) can be developed as a molecular probe for selection of improved planting stock with proven wood density trait for a large-scale teak plantation.

Tuberculosis notification in a private tertiary care teaching hospital in South India: a mixed-methods study.

OBJECTIVES: India contributes approximately 25% of the 'missing' cases of tuberculosis (TB) globally. Even though ~50% of patients with TB are diagnosed and treated within India's private sector, few are notified to the public healthcare system. India's TB notification policy mandates that all patients with TB are notified through Nikshay (TB notification portal). We undertook this study in a private hospital to assess the proportion notified and factors affecting TB notifications. We explored barriers and probable solutions to TB notification qualitatively from health provider's perspective. STUDY SETTING: Private, tertiary care, teaching hospital in Bengaluru, South India. METHODOLOGY: This was a mixed-methods study. Quantitative component comprised a retrospective review of hospital records between 1 January 2015 and 31 December 2017 to determine TB notifications. The qualitative component comprised key informant interviews and focus groups to elicit the barriers and facilitators of TB notification. RESULTS: Of 3820 patients diagnosed and treated, 885 (23.2%) were notified. Notifications of sputum smear-positive patients were significantly more likely, while notifications of children were less likely. Qualitative analysis yielded themes reflecting the barriers to TB notification and their solutions. Themes related to barriers were: (1) basic diagnostic procedures and treatment promote notification; (2) misconceptions regarding notification and its process are common among healthcare providers; (3) despite a national notification system other factors have prevented notification of all patients; and (4) establishing hospital systems for notification will go a long way in improving notifications. CONCLUSIONS: The proportion of patients with TB notified by the hospital was low. A comprehensive approach both by the hospital management and the national TB programme is necessary for improving notification. This includes improving awareness among healthcare providers about the requirement for TB notifications, establishing a single notification portal in hospital, digitally linking hospital records to Nikshay and designating one person to be responsible for notification.

Genetic diversity and population structure of Litsea glutinosa (Lour.) in Central India.

Litsea glutinosa (Lour.), one of the most dwindling forest species in central India, is represented by highly fragmented populations that have been drastically reduced for the last 40 years, promulgating government ban on its extraction. For the first time with the help of ISSR markers, we investigated genetic variation and population structure of L. glutinosa in central Indian states. A total of 84 genotypes from 10 populations covering the entire potential pockets of the species in central India were collected. The percentage of polymorphic loci ranged from 44.79% (Rewa) to 94.79% (Marvahi) with a mean value of 70.10%. The sampled populations harbored high level of genetic diversity (mean h = 0.294 and I = 0.424) that was partitioned more within populations (73%) than between populations (27%). Bayesian structure analysis revealed the existence of four admixed genetic pools in L. glutinosa. The unsustainable extraction rather than genetic factor seems to be responsible for population fragmentation and dwindling status of this species. The dioecious nature of the species advocates an in-situ conservation to be the most suited approach for which Chhindwara, Jagdalpur, Balaghat and Jabalpur populations are appropriate.

Effect of discrete (individual) and mixed (bulk) genomic DNA on genetic diversity estimates and population structure in Teak (Tectona grandis L. f.).

Teak (Tectona grandis L.f.), a paragon timber tree of tropical deciduous forests of Central and Peninsular India, is highly prized for its wood colour, decorative grains, durability and lightness. An experiment was carried out to compare the genetic variation detected and genetic relationships inferred in five teak populations via 10 genomic DNA samples per population each of either single seed or bulk of 3- or 5- seeds with the help of ISSR markers. The genomic DNA of single seed exhibited higher number of polymorphic loci, per cent polymorphism, nei's genetic diversity and shannon Information Index than the bulk genomic DNA of 3- or 5- seeds. The bulking of genomic DNA of 3- and 5- seeds using Nei's genetic distance coefficient revealed similar genetic relationships, which were at variance with those in single seed treatment. Mantel's correlation test among the genetic distance matrices of single seed sampling, 3-seed bulk and 5-seed bulk sampling also confirmed the trend. Since the bulking of genomic DNA did not generate compatible estimates of diversity parameters and genetic relationship of five populations from its single seed sampling, we recommend strict guarding of identities of genotypes within the collected samples for obtaining precise estimates and drawing accurate conclusions about the genetic diversity and clustering of populations.