Genome-wide analysis of cellulose synthase gene superfamily in Tectona grandis L.f.

This study aimed to explore Cellulose synthase gene superfamily of teak, and its evolutionary relationship with homologous genes of other woody species. The incidence of evolutionary events like gene duplication and gene loss, influence of the selection pressure, and consequent adaptive functional divergence of the duplicated TgCes gene were assessed alongside it's role in wood coloration. This study identified 39 full-length non-redundant proteins belonging to CesA and Csl gene families. TgCesA and TgCsl proteins with Cellulose synthase domain repeats indicated tandem gene duplication and probable genetic variability, enabling local adaptation. Further, multi-domain protein (MYB-like DNA-binding domain and CesA domain) with maximum introns was also identified indicating gene fusion and formation of complex protein with novel functions. Phylogenetic analysis grouped the genes into seven subfamilies (CesA, CslA, CslC, CslD, CslE, CslG, and CslM) with each undergoing gene duplication and loss along their evolutionary history. Post-species gene duplications and probable neofunctionalization were identified in TgCesA and TgCsl gene families. Each subfamily was found to be under strong purifying selection with a few or no sites under positive selection. Functional divergence analysis further revealed site-specific selective constraints in CesA and Csl genes of the teak Cellulose synthase gene family. Furthermore, protein-protein interaction network analysis identified co-expression of Cellulose synthase gene with flavonoid 3',5'-hydroxylase (F3'5'H, CYP75A), involved in the biosynthesis of xylem anthocyanin compounds, probably responsible for wood coloration. This study thus offers a foundation for future research in wood formation and wood property traits specific to teak and its provenances. Supplementary Information: The online version contains supplementary material available at 10.1007/s13205-024-03927-6.

Gender specific SNP markers in Coscinium fenestratum (Gaertn.) Colebr. for resource augmentation.

BACKGROUND: Unregulated extraction of highly traded medicinal plant species results in drastic decline of the natural resources and alters viable sex ratio of populations. Conservation and long-term survival of such species, require gender specific restoration programs to ensure reproductive success. However, it is often difficult to differentiate sex of individuals before reaching reproductive maturity. C. fenestratum is one of the medicinally important and overexploited dioecious woody liana, with a reproductive maturity of 15 years. Currently, no information is available to identify sex of C. fenestratum in seedling stage while augmenting the resources. Thus, the current study envisages to utilize transcriptomics approach for gender differentiation which is imperative for undertaking viable resource augmentation programmes. METHODS AND RESULTS: Gender specific SNPs with probable role in sexual reproduction/sex determination was located using comparative transcriptomics approach (sampling male and female individuals), alongside gene ontology and annotation. Nine sets of primers were synthesized from 7 transcripts (involved in sexual reproduction/other biological process) containing multiple SNP variants. Out of the nine primer pairs, only one SNP locus with no available information of its role in reproduction, showed consistent and accurate results (males-heterozygous and females-homozygous), in the analyzed 40 matured individuals of known sexes. Thus validated the efficiency of this SNP marker in differentiating male and female individuals. CONCLUSIONS: The study could identify SNPs linked to the loci with apparent role in gender differentiation. This SNP marker can be used for early sexing of seedlings for in-situ conservation and resource augmentation of C. fenestratum in Kerala, India.

Narrow gene pool can threaten the survival of Calamus nagbettai R. R. Fernald & Dey: a highly, endemic dioecious rattan species in the Western Ghats of India.

Rattans, the spiny climbing palms of Arecaceae (Palmae) family exhibit high endemism to the biodiversity hot spots in India. Of the five rattan genera, Calamus is the only genus found in peninsular India with 15 of 21 species, endemic to the Western Ghats. The extensive utilization of rattans owing to their strength, durability and huge demand has resulted in depletion of their natural resources. Of the 15 endemic species, C. nagbettai is the most affected species on account of endemism, low population size and restricted distribution with fragmented populations. The present study revealed high amount of genetic diversity in the surviving scattered populations of the species using microsatellite markers. High gene flow (Nm = 1.498) observed across the populations resulted in low genetic differentiation (14%). A clear genetic admixture could be seen in Kerala as well as one of the Karnataka's populations while the remaining two populations were genetically distinct. UPGMA, PCoA and STRUCTURE analyses showed significantly different genetic composition in Kerala population compared to other populations. Kerala and Karnataka populations of C. nagbettai were also unique in their genetic structure and allelic composition. Therefore, effective management and conservation strategies have to be implemented to preserve the rarealleles with adaptive potential to protect this economically valuable Calamus species from endangerment. Over exploitation, low seed set and poor regeneration, as well as habitat fragmentation can further threaten the survival of this endemic, narrowly distributed dioecious rattan species in the Western Ghats region.

Draft genome of a high value tropical timber tree, Teak (Tectona grandis L. f): insights into SSR diversity, phylogeny and conservation.

Teak (Tectona grandis L. f.) is one of the precious bench mark tropical hardwood having qualities of durability, strength and visual pleasantries. Natural teak populations harbour a variety of characteristics that determine their economic, ecological and environmental importance. Sequencing of whole nuclear genome of teak provides a platform for functional analyses and development of genomic tools in applied tree improvement. A draft genome of 317 Mb was assembled at 151× coverage and annotated 36, 172 protein-coding genes. Approximately about 11.18% of the genome was repetitive. Microsatellites or simple sequence repeats (SSRs) are undoubtedly the most informative markers in genotyping, genetics and applied breeding applications. We generated 182,712 SSRs at the whole genome level, of which, 170,574 perfect SSRs were found; 16,252 perfect SSRs showed in silico polymorphisms across six genotypes suggesting their promising use in genetic conservation and tree improvement programmes. Genomic SSR markers developed in this study have high potential in advancing conservation and management of teak genetic resources. Phylogenetic studies confirmed the taxonomic position of the genus Tectona within the family Lamiaceae. Interestingly, estimation of divergence time inferred that the Miocene origin of the Tectona genus to be around 21.4508 million years ago.