Species complex delimitations in the genus Hedychium: A machine learning approach for cluster discovery

Characterization of SSR markers from draft genome assembly and genotypic data in Hedychium spicatum (Zingiberaceae)

The plant family Zingiberaceae consists of many medicinally important tropical herbs. Here, we provide a contig level genome assembly for Hedychium spicatum, one of the medicinally utilized species in this family. We used genome assembly to identify candidate Simple Sequence Repeat (SSR) markers in the nuclear, chloroplast and mitochondrial compartments. We identified a total of 60,695 SSRs, which consisted of di-, tri-, tetra-, penta- and complex repeat types, and primers were designed for 14,851 SSR loci from both coding and non-coding parts of the genome. A total of 62 sets of candidate SSR primers were tested, out of which a final set of 20 SSR markers were characterized and they met the criteria of amplification success and retention of the repeat motif and homology. Out of these 20 markers, we genotyped 11 markers by amplifying and sizing 99 accessions of H. spicatum from 13 different geographic locations. The 11 markers were also characterised for four congeneric species, H. ellipticum, H. gomezianum, H. venustum, and H. yunnanense. All 11 SSR markers were found to be polymorphic and showed cross-species amplification. The total number of alleles per locus varied from 5 to 25. SSR markers continue to be a valuable tool for researchers because of their cost-effectiveness and simplicity. The cross-species amplification and variability of the SSR markers generated here further extend the utility of the markers to other Hedychium spp. The markers presented in this dataset can be used for a variety of studies, such as population genetics of invasive Hedychium species, QTL mapping, DNA fingerprinting, parentage analysis and genetic diversity assessments.

Evolutionary patterns of variations in chromosome counts and genome sizes show positive correlations with taxonomic diversity in tropical gingers

PREMISE

Cytogenetic traits such as an organism's chromosome number and genome size are taxonomically critical as they are instrumental in defining angiosperm diversity. Variations in these traits can be traced to evolutionary processes such as polyploidization, although geographic variations across cytogenetic traits remain underexplored. In the pantropical monocot family Zingiberaceae (~1500 species), cytogenetic traits have been well documented; however, the role of these traits in shaping taxonomic diversity and biogeographic patterns of gingers is not known.

METHODS

A time-calibrated Bayesian phylogenetic tree was constructed for 290 taxa covering three of the four subfamilies in Zingiberaceae. We tested models of chromosome number and genome size evolution within the family and whether lineage age, taxonomic diversity, and distributional range explain the variations in the cytogenetic traits. Tests were carried out at two taxonomic ranks: within Zingiberaceae and within genus Hedychium using correlations, generalized linear models and phylogenetic least square models.

RESULTS

The most frequent changes in chromosome number within Zingiberaceae were noted to be demi-polyploidization and polyploidization (~57% of the time), followed by ascending dysploidy (~27%). The subfamily Zingiberoideae showed descending dysploidy at its base, while Alpinioideae showed polyploidization at its internal nodes. Although chromosome counts and genome sizes did not corroborate with each other, suggesting that they are not equivalent; higher chromosome number variations and higher genome size variations were associated with higher taxonomic diversity and wider biogeographic distribution.

CONCLUSIONS

Within Zingiberaceae, multiple incidences of polyploidization were discovered, and cytogenetic events appear to have reduced the genome sizes and increased taxonomic diversity, distributional ranges and invasiveness.

Floral evolution and pollinator diversification in Hedychium: Revisiting Darwin's predictions using an integrative taxonomic approach

PREMISE

Hedychium J. Koenig (Zingiberaceae) is endemic to the Indo-Malayan Realm and is known for its colorful and fragrant flowers. Historically, two different pollination syndromes characterize Hedychium: diurnal or bird pollination, and nocturnal or moth pollination. In this study, we aim to understand the evolution of nocturnal and diurnal flowers, and to test its putative association with lineage diversification in Hedychium.

METHODS

A molecular tree of Hedychium was used as a scaffold upon which we estimated ancestral character states, phylogenetic signals, and correlations for certain categorical and continuous floral traits. Furthermore, we used phylomorphospace and trait-dependent diversification rate estimation analyses to understand phenotypic evolution and associated lineage diversification in Hedychium.

RESULTS

Although floral color and size lacked any association with specific pollinators, white or pale flowers were most common in the early branching clades when compared to bright-colored flowers, which were more widely represented in the most-derived clade IV. Five categorical and two continuous characters were identified to have informative evolutionary patterns, which also emphasized that ecology may have played a critical role in the diversification of Hedychium.

CONCLUSIONS

From our phylogenetic analyses and ecological observations, we conclude that specializations in pollinator interactions are rare in the hyperdiverse clade IV, thus challenging the role of both moth-specialization and bird-specialization as central factors in the diversification of Hedychium. However, our results also suggest that clade III (predominantly island clade) may show specializations, and future studies should investigate ecological and pollinator interactions, along with inclusion of new traits such as floral fragrance and anthesis time.

Proteomic Changes of Osteoclast Differentiation in Rheumatoid and Psoriatic Arthritis Reveal Functional Differences

Background

Osteoclasts play a crucial role in the maintenance, repair, and remodeling of bones of the adult vertebral skeleton due to their bone resorption capability. Rheumatoid arthritis (RA) and psoriatic arthritis (PsA) are associated with increased activity of osteoclasts.

Objectives

Our study aimed to investigate the dynamic proteomic changes during osteoclast differentiation in healthy donors, in RA, and PsA.

Methods

Blood samples of healthy donors, RA, and PsA patients were collected, and monocytes were isolated and differentiated into osteoclasts in vitro using macrophage colony-stimulating factor (M-CSF) and receptor activator of nuclear factor κB ligand (RANK-L). Mass spectrometry-based proteomics was used to analyze proteins from cell lysates. The expression changes were analyzed with Gene Set Enrichment Analysis (GSEA).

Results

The analysis of the proteomic changes revealed that during the differentiation of the human osteoclasts, expression of the proteins involved in metabolic activity, secretory function, and cell polarity is increased; by contrast, signaling pathways involved in the immune functions are downregulated. Interestingly, the differences between cells of healthy donors and RA/PsA patients are most pronounced after the final steps of differentiation to osteoclasts. In addition, both in RA and PsA the differentiation is characterized by decreased metabolic activity, associated with various immune pathway activities; furthermore by accelerated cytokine production in RA.

Conclusions

Our results shed light on the characteristic proteomic changes during human osteoclast differentiation and expression differences in RA and PsA, which reveal important pathophysiological insights in both diseases.

Himalayan orogeny and monsoon intensification explain species diversification in an endemic ginger (Hedychium: Zingiberaceae) from the Indo-Malayan Realm

The Indo-Malayan Realm is a biogeographic realm that extends from the Indian Subcontinent to the islands of Southeast Asia (Malay Archipelago). Despite being megadiverse, evolutionary hypotheses explaining taxonomic diversity in this region have been rare. Here, we investigate the role of geoclimatic events such as Himalayan orogeny and monsoon intensification in the diversification of the ginger-lilies (Hedychium J.Koenig: Zingiberaceae). We first built a comprehensive, time-calibrated phylogeny of Hedychium with 75% taxonomic and geographic sampling. We found that Hedychium is a very young lineage that originated in Northern Indo-Burma, in the Late Miocene (c. 10.6 Ma). This was followed by a late Neogene and early Quaternary diversification, with multiple dispersal events to Southern Indo-Burma, Himalayas, Peninsular India, and the Malay Archipelago. The most speciose clade IV i.e., the predominantly Indo-Burmese clade also showed a higher diversification rate, suggesting its recent rapid radiation. Our divergence dating and GeoHiSSE results demonstrate that the diversification of Hedychium was shaped by both the intensifications in the Himalayan uplift as well as the Asian monsoon. Ancestral character-state reconstructions identified the occurrence of vegetative dormancy in both clades I and II, whereas the strictly epiphytic growth behavior, island dwarfism, lack of dormancy, and a distinct environmental niche were observed only in the predominantly island clade i.e., clade III. Finally, we show that the occurrence of epiphytism in clade III corresponds with submergence due to sea-level changes, suggesting it to be an adaptive trait. Our study highlights the role of recent geoclimatic events and environmental factors in the diversification of plants within the Indo-Malayan Realm and the need for collaborative work to understand biogeographic patterns within this understudied region. This study opens new perspectives for future biogeographic studies in this region and provides a framework to explain the taxonomic hyperdiversity of the Indo-Malayan Realm.

Instance segmentation for the fine detection of crop and weed plants by precision agricultural robots

PREMISE

Weed removal in agriculture is typically achieved using herbicides. The use of autonomous robots to reduce weeds is a promising alternative solution, although their implementation requires the precise detection and identification of crops and weeds to allow an efficient action.

METHODS

We trained and evaluated an instance segmentation convolutional neural network aimed at segmenting and identifying each plant specimen visible in images produced by agricultural robots. The resulting data set comprised field images on which the outlines of 2489 specimens from two crop species and four weed species were manually drawn. We adjusted the hyperparameters of a mask region-based convolutional neural network (R-CNN) to this specific task and evaluated the resulting trained model.

RESULTS

The probability of detection using the model was quite good but varied significantly depending on the species and size of the plants. In practice, between 10% and 60% of weeds could be removed without too high of a risk of confusion with crop plants. Furthermore, we show that the segmentation of each plant enabled the determination of precise action points such as the barycenter of the plant surface.

DISCUSSION

Instance segmentation opens many possibilities for optimized weed removal actions. Weed electrification, for instance, could benefit from the targeted adjustment of the voltage, frequency, and location of the electrode to the plant. The results of this work will enable the evaluation of this type of weeding approach in the coming months.