Begonia, one of the most diverse plant taxa and the fifth or sixth largest angiosperm genus, consists of over 1800 accepted species. The number of species recognized within this genus has greatly increased over the past 20 years, rising from 80 to 200 species in China alone. Based on recent field surveys, the number of begonia species in China is predicted to be between 250 and 300. Given the large number of begonia species that still remain to be described, further taxonomical work is urgently required. This is especially true for Chinese Begonia, in which there is a huge diversity of habitat, habit, plant size, leaf type, flower and fruit morphology, and most species are narrowly distributed in isolated habitats that are subject to negative disturbances from climate change, as well as agricultural and industrial activities. Although the conservation status for the majority of species has been evaluated using the standards of the International Union for Conservation of Nature, the results don't represent the truth in many species, and also about 11.5% of which are data-absent. In addition, illegal collection and over-harvesting of wild begonias for ornamental or medicinal use has increased due to the rapid development of internet commerce. Far more often than predicted, these species should be categorized as rare and endangered and require immediate protection. Ex situ conservation of Chinese begonias started in 1995 and over 60% of the total species have been so far introduced into cultivation by several major botanical gardens in China. However, only few research institutions, limited funds and human resources have been involved in Begonia conservation; moreover, no project has conducted reintroduction. Therefore, more conservation-based work remains to be done. Improved conservation of Chinese begonias in the future depends on further field survey, an improved understanding of population diversity, and integrative approaches, including in situ and ex situ conservation, seed banking, and plant reintroduction. Species-targeted conservation zones should be established for endangered species excluded from the existing nature reserves. Additionally, laws pertaining to plant protection should be extended to prevent the illegal collection and transaction of wild plants, particularly for those species with unique habitats and small populations.

Begonia pseudoedulis, a new species in Begonia sect. Platycentrum (Klotzsch) A.DC. (Begoniaceae) from southern Guangxi of China, is here described and illustrated. It morphologically resembles B. edulis H.Lév. and B. dielsiana E.Pritz. ex Diels but differs easily by its hairy petioles and inflorescences, and red hispidulous flower tepals, ovary and capsules. The molecular phylogenetic analysis based on ITS supported that the new species was a monophyletic lineage, separating from both B. dielsiana and B. edulis. Due to its isolated distribution with several small populations, which are possibly disturbed by human activities, the species is considered as “Near Threatened” (NT) according to the IUCN Red List Categories and Criteria.

Asian lotus (Nelumbo nucifera Gaertn.) is the national flower of India, Vietnam, and one of the top ten traditional Chinese flowers. Although lotus is highly valued for its ornamental, economic and cultural uses, genomic information, particularly the expressed sequence based (genic) markers is limited. High-throughput transcriptome sequencing provides large amounts of transcriptome data for promoting gene discovery and development of molecular markers. In this study, 68,593 unigenes were assembled from 1.34 million 454 GS-FLX sequence reads of a mixed flower-bud cDNA pool derived from three accessions of N. nucifera. A total of 5,226 SSR loci were identified, and 3,059 primer pairs were designed for marker development. Di-nucleotide repeat motifs were the most abundant type identified with a frequency of 65.2%, followed by tri- (31.7%), tetra- (2.1%), penta- (0.5%) and hexa-nucleotide repeats (0.5%). A total of 575 primer pairs were synthesized, of which 514 (89.4%) yielded PCR amplification products. In eight Nelumbo accessions, 109 markers were polymorphic. They were used to genotype a sample of 44 accessions representing diverse wild and cultivated genotypes of Nelumbo. The number of alleles per locus varied from 2 to 9 alleles and the polymorphism information content values ranged from 0.6 to 0.9. We performed genetic diversity analysis using 109 polymorphic markers. A UPGMA dendrogram was constructed based on Jaccard’s similarity coefficients revealing distinct clusters among the 44 accessions. Deep transcriptome sequencing of lotus flower buds developed 3,059 genic SSRs, making a significant addition to the existing SSR markers in lotus. Among them, 109 polymorphic markers were successfully validated in 44 accessions of Nelumbo. This comprehensive set of genic SSR markers developed in our study will facilitate analyses of genetic diversity, construction of linkage maps, gene mapping, and marker-assisted selection breeding for lotus.

The lotus (Nelumbo Adans.) is a perennial aquatic plant with important value in horticulture, medicine, food, religion, and culture. It is rich in germplasm and more than 2000 cultivars have been cultivated through hybridization and natural selection. Microsporogenesis and male gametogenesis in the anther are important for hybridization in flowering plants. However, little is known about the cytological events, especially related to the stamen, during the reproduction of the lotus. To better understand the mechanism controlling the male reproductive development of the lotus, we investigated the flower structure of the Asian lotus (N. nucifera). The cytological analysis of anther morphogenesis showed both the common and specialized cytological events as well as the formation of mature pollen grains via meiosis and mitosis during lotus anther development. Intriguingly, an anatomical difference in anther appendage structures was observed between the Asian lotus and the American lotus (N. lutea). To facilitate future study on lotus male reproduction, we categorized pollen development into 11 stages according to the characterized cytological events. This discovery expands our knowledge on the pollen and appendage development of the lotus as well as improving the understanding of the species differentiation of N. nucifera and N. lutea.

Introduction: Begonia L., one of the 10 largest plant genera, contains over 2,100 species, most of which have a very limited distribution range. Understanding the spatial genetic structure and distribution dynamics of a widespread species in this genus will contribute to clarifying the mechanism responsible for Begonia speciation.Methods: In this study, we used three chloroplast DNA markers (ndhF-rpl32, atpI-atpH, and ndhA intron), coupled with species distribution modeling (SDM), to investigate the population genetic structure and distribution dynamics of Begonia grandis Dryand., the species of Begonia with the widest distribution in China.Results: Thirty-five haplotypes from 44 populations clustered into two groups, and haplotype divergence began in the Pleistocene (1.75 Mya). High genetic diversity (H_d = 0.894, H_T = 0.910), strong genetic differentiation (F_ST = 0.835), and significant phylogeographical structure (G_ST/N_ST = 0.848/0.917, P < 0.05) were observed. The distribution range of B. grandis migrated northwards after the last glacial maximum, but its core distribution area remained stable.Discussion: Combined, the observed spatial genetic patterns and SDM results identified the Yunnan-Guizhou Plateau, the Three Gorges region, and the Daba Mountains as potential refugia of B. grandis. BEAST-derived chronogram and haplotype network analysis do not support the Flora Reipublicae Popularis Sinicae and Flora of China for subspecies classification based on morphological characteristics. Our results support the hypothesis that population-level allopatric differentiation may be an important speciation process for the Begonia genus and a key contributor to its rich diversity.

Tropical lotus (Nelumbo) is an important and unique ecological type of lotus germplasm. Understanding the genetic relationship and diversity of the tropical lotus is necessary for its sustainable conservation and utilization. Using 42 EST-SSR (expressed sequence tag-simple sequence repeats) and 30 SRAP (sequence-related amplified polymorphism) markers, we assessed the genetic diversity and inferred the ancestry of representative tropical lotus from Thailand and Vietnam. In total, 164 and 41 polymorphic bands were detected in 69 accessions by 36 EST-SSR and seven SRAP makers, respectively. Higher genetic diversity was revealed in Thai lotus than in Vietnamese lotus. A Neighbor-Joining tree of five main clusters was constructed using combined EST-SSR and SRAP markers. Cluster I included 17 accessions of Thai lotus; cluster II contained three Thai accessions and 11 accessions from southern Vietnam; and cluster III was constituted by 13 accessions of seed lotus. Consistent with the results from the Neighbor-Joining tree, the genetic structure analysis showed that the genetic background of most Thai and Vietnamese lotus was pure, as artificial breeding has been rare in both countries. Furthermore, these analyses indicate that Thai and Vietnamese lotus germplasms belong to two different gene pools or populations. Most lotus accessions are genetically related to geographical distribution patterns in Thailand or Vietnam. Our findings showed that the origin or genetic relationships of some unidentified lotus sources can be evaluated by comparing morphological characteristics and the data of molecular markers. In addition, these findings provide reliable information for the targeted conservation of tropical lotus and parent selection in breeding novel cultivars of lotus.