Acquisition of green algal photobionts enables both chlorolichens and chloro-cyanolichens to activate photosynthesis at low humidity without liquid water.

Cyanobacteria require liquid water for photosynthesis, whereas green algae can photosynthesise with water vapour alone. We discovered that several Lobaria spp. which normally have cyanobacteria as the sole photobiont, in some regions of the trans-Himalayas also harboured green algae. We tested whether green algal acquisition was: limited to high elevations; obtained from neighbouring chloro-Lobaria species; enabled photosynthesis at low humidity. Lobaria spp. were collected from 2000 to 4000 m elevation. Spectrophotometry quantified green algal abundance by measuring chlorophyll b (absent in cyanobacteria). Thalli cross-sections visually confirmed green algal presence. We sequenced gene regions: Lobaria (ITS-EF-1α-RPB2), green algae (18S-RBC-L) and Nostoc (16S). Phylogenetic analysis determined myco-photobiont associations. We used a custom closed-circuit gas exchange system with an infrared gas analyser to measure CO2 exchange rates for desiccated specimens at 33%, 76%, 86% and 98% humidity. Cross-sections revealed that the photobiont layers in putative cyano-Lobaria contained both cyanobacteria and green algae, indicating that they should be considered chloro-cyanolichens. Chloro-Lobaria had no visible cephalodia nor cyanobacteria in the photobiont layer. Chloro-Lobaria and chloro-cyano-Lobaria had comparable levels of chlorophyll b. Chloro-Lobaria usually contained Symbiochloris. Chloro-cyano-Lobaria mainly associated with Parachloroidium and Nostoc; infrequently with Symbiochloris, Apatococcus, Chloroidium, Pseudochlorella, Trebouxia. Sequences from two green algal genera were obtained from within some thalli. Desiccated specimens of every Lobaria species could attain net photosynthesis with light exposure and 33% humidity. CO2 exchange dynamics over a five-day period differed between species. At all elevations, chloro-cyano-Lobaria spp. had abundant green algae in the photobiont layer, but green algal strains mostly differed to those of chloro-Lobaria spp. Both chloro-Lobaria and chloro-cyano-Lobaria were capable of conducting photosynthesis without liquid water. The data strongly suggest that they attained positive net photosynthesis.

Morphological and Phylogenetic Characterisations Reveal Four New Species in Leptosphaeriaceae (Pleosporales, Dothideomycetes).

Leptosphaeriaceae is a widely distributed fungal family with diverse lifestyles. The family includes several genera that can be distinguished by morphology and molecular phylogenetic analysis. During our investigation of saprobic fungi on grasslands in Yunnan Province, China, four fungal taxa belonging to Leptosphaeriaceae associated with grasses were collected. Morphological observations and phylogenetic analyses of the combined SSU, LSU, ITS, tub2, and rpb2 loci based on maximum likelihood and Bayesian inference were used to reveal the taxonomic placement of these fungal taxa. This study introduces four new taxa, viz. Leptosphaeria yunnanensis, L. zhaotongensis, Paraleptosphaeria kunmingensis, and Plenodomus zhaotongensis. Colour photo plates, full descriptions, and a phylogenetic tree to show the placement of the new taxa are provided.

The legacy effects of rubber defoliation period on the refoliation phenology, leaf disease, and latex yield.

The leaf phenology of trees has received particular attention for its crucial role in the global water and carbon balances, ecosystem, and species distribution. However, current studies on leaf phenology have mainly focused on temperate trees, while few studies including tropical trees. Little attention has been paid to globally extensive industrial plantations. Rubber plantations are important to both the local and global economies. In this study, we investigated the legacy effects of defoliation phenology on the following year's leaf flushing, leaf disease, and also latex yield of rubber trees, an economically important tree to local people and the world. Results show that extended duration of defoliation increased the subsequent duration of refoliation and rates of infection by powdery mildew disease, but led to reduced latex yield in March. This legacy effect of rubber defoliation may relate to the carbohydrate reserved in the trees. A longer duration of defoliation would consume more reserved carbohydrates, reducing available reserves for disease defense and latex production. Extended duration of defoliation period was associated with either a lower temperature before the cessation of latex tapping in October-November and/or a higher temperature after the cessation of latex tapping in December-January. Leaf falling signals the end of photosynthetic activities in deciduous trees. Thus, the leaf falling phenology will impact ecological processes involving rubber trees. Our findings indicated that the inclusion of defoliation periods in future rubber trees' research, will be crucial to furthering our understanding of leaf flushing, powdery mildew disease, and latex yield.

Two New Species and a New Record of Microdochium from Grasses in Yunnan Province, South-West China.

Microdochium species are frequently reported as phytopathogens on various plants and also as saprobic and soil-inhabiting organisms. As a pathogen, they mainly affect grasses and cereals, causing severe disease in economically valuable crops, resulting in reduced yield and, thus, economic loss. Numerous asexual Microdochium species have been described and reported as hyphomycetous. However, the sexual morph is not often found. The main purpose of this study was to describe and illustrate two new species and a new record of Microdochium based on morphological characterization and multi-locus phylogenetic analyses. Surveys of both asexual and sexual morph specimens were conducted from March to June 2021 in Yunnan Province, China. Here, we introduce Microdochium graminearum and M. shilinense, from dead herbaceous stems of grasses and report M. bolleyi as an endophyte of Setaria parviflora leaves. This study improves the understanding of Microdochium species on monocotyledonous flowering plants in East Asia. A summary of the morphological characteristics of the genus and detailed references are provided for use in future research.

Seedling survival after simulating grazing and drought for two species from the Pamirs, northwestern China.

For plant populations to persist, seedling recruitment is essential, requiring seed germination, seedling survival and growth. Drought and grazing potentially reduce seedling recruitment via increased mortality and reduced growth. We studied these seed-related processes for two species indigenous to the Pamir Mountains of Xinjiang in northwestern China: Saussurea glacialis and Plantago lessingii. Seeds collected from Taxkorgan, Xinjiang, had a viability rate of 15.8% for S. glacialis but 100% for P. lessingii. Of the viable seeds, the highest germination rates were 62.9% for S. glacialis and 45.6% for P. lessingii. In a greenhouse experiment, we imposed a series of stressful conditions, involving a combination of simulated grazing and drought events. These had the most severe impact on younger seedlings. Modelling showed that 89% of S. glacialis mortality was due to early simulated grazing, whereas 80% of P. lessingii mortality was due to early simulated drought. Physiological differences could contribute to their differing resilience. S. glacialis may rely on water storage in leaves to survive drought events, but showed no shifts in biomass allocation that would improve grazing tolerance. P. lessingii appears more reliant on its root system to survive grazing, but the root reserves of younger plants could be insufficient to grow deeper in response to drought. After applying all mortality factors, 17.7 seedlings/parent of P. lessingii survived, while only <0.1 seedlings/parent of S. glacialis survived, raising concerns for its capacity to persist in the Pamirs. Inherent genetic differences may underlie the two species' contrasting grazing and drought responses. Thus, differing conservation strategies are required for their utilization and protection.

Endophytic Fungi Associated with Aquilaria sinensis (Agarwood) from China Show Antagonism against Bacterial and Fungal Pathogens.

Agarwood is the most expensive non-construction wood product in the world. As a therapeutic agent, agarwood can cure some diseases, but few studies have been carried out on the antagonistic abilities of endophytic fungi associated with agarwood. Agarwood is mainly found in the genus Aquiaria. The objectives of this study are to understand the antimicrobial activities and their potential as biocontrol agents of the endophytic fungi of Aquilaria sinensis. First, fresh samples of A. sinensis were collected from Yunnan and Guangdong Provinces in 2020-2021, and the endophytic fungi were isolated and identified to genus level based on the phylogenetic analyses of the Internal Transcribed Spacer (ITS) region. In this bioassay, 47 endophytic strains were selected to check their bioactivities against three bacterial pathogens viz. Erwinia amylovora, Pseudomonas syringae, and Salmonella enterica; and three fungal pathogens viz. Alternaria alternata, Botrytis cinerea, and Penicillium digitatum. The antibiosis test was carried out by the dual culture assay (10 days), and among the 47 strains selected, 40 strains belong to 18 genera viz. Alternaria, Annulohypoxylon, Aspergillus, Botryosphaeria, Colletotrichum, Corynespora, Curvularia, Daldinia, Diaporthe, Fusarium, Lasiodiplodia, Neofusicoccum, Neopestalotiopsis, Nigrospora, Paracamarosporium, Pseudopithomyces, Trichoderma, Trichosporon and one strain belongs to Xylariaceae had antimicrobial activities. In particular, Lasiodiplodia sp. (YNA-D3) showed the inhibition of all the bacterial and fungal pathogens with a significant inhibition rate. In addition, the strains viz; Curvularia sp. (GDA-3A9), Diaporthe sp. (GDA-2A1), Lasiodiplodia sp. (YNA-D3), Neofusicoccum sp. (YNA-1C3), Nigrospora sp. (GDA-4C1), and Trichoderma sp. (YNA-1C1) showed significant antimicrobial activities and are considered worthy of further studies to identify individual fungal species and their bioactive compounds. This study enriches the diversity of endophytic fungi associated with agarwood, and their potential antagonistic effects against bacterial and fungal pathogens.

Insight into the Taxonomic Resolution of the Pleosporalean Species Associated with Dead Woody Litter in Natural Forests from Yunnan, China.

In the course of investigating the systematics of woody litter micromycete associates in Yunnan Province, China, we found one new species in Phaeoseptaceae, one new genus and three new species in Sulcatisporaceae from 16 specimens collected (ten collections of ascomycetous teleomorphs, four collections of hyphomycetous and two collections of coelomycetes anamorphs) from Ailaoshan, Chuxiong, Diqing, Honghe, Kunming, Lancang, Mengla and Yuxi in Yunnan Province. These taxonomic novelties were recognized with the aid of morphological comparisons and phylogenetic analyses of multiple gene sequences (non-translated loci and protein-coding regions). Pleopunctum menglaense sp. nov. is accommodated in Phaeoseptaceae (Pleosporales) based on its hyphomycetous anamorph, which is characterized by superficial sporodochia on the host surface, macronematous, mononematous, cylindrical, unbranched, aseptate, hyaline and smooth-walled conidiophores, monoblastic, terminal, hyaline conidiogenous cells, hyaline, muriform α conidia, and brown, muriform ß conidia with tri-lobed wing like basal cells. Kazuakitanaka gen. nov. (type: K. yuxiensis) is introduced in Sulcatisporaceae (Massarineae, Pleosporales) for a saprobic ascomycete with teleomorphic and anamorphic (coelomycetous) features. The teleomorph possesses globose to subglobose ascomata with acentric ostiole, a peridial wall of textura angularis to textura prismatica, cylindric-clavate, pedicellate asci with an ocular chamber, and 1-2-septate, hyaline, fusiform, guttulate ascospores with a distinct mucilaginous sheath. The anamorph features pycnidial conidiomata, phialidic, ampulliform to cylindrical, hyaline conidiogenous cells and ampulliform to cylindrical, one-to-three-septate, hyaline, guttulate conidia. Loculosulcatispora was known only from its anamorph of L. thailandica. We observed the teleomorph of Loculosulcatispora hongheensis sp. nov. and amended the generic description of Loculosulcatispora accordingly. Loculosulcatispora hongheensis is characterized by globose to subglobose ascomata with a central ostiole, a peridial wall of textura angularis to globosa, branched, septate, pseudoparaphyses, clavate asci with a short pedicel and a minute ocular chamber and hyaline, fusiform, 1-septate ascospores with a thick irregular mucilaginous sheath. This study provides some insights into the diversity of fungi on dead woody litter in terrestrial habitats.

Taxonomic Reappraisal of Periconiaceae with the Description of Three New Periconia Species from China.

As a result of an ongoing research survey of microfungi in Yunnan, China, several saprobic ascomycetes were collected from various host substrates. Preliminary morphological analyses identified a few of these taxa as Periconia species. We obtained DNA sequence data of the Periconia species from pure cultures and investigated their phylogenetic affinities. Phylogenetic analyses of a combined LSU, ITS, SSU and tef1-α sequence dataset demonstrated that five isolates of Periconia formed well-resolved subclades within Periconiaceae. Accordingly, three new Periconia species are introduced viz. P. artemisiae, P. chimonanthi and P. thysanolaenae, and new host and geographical records of P. byssoides and P. pseudobyssoides, are also reported from dead branches of Prunus armeniaca and Scrophularia ningpoensis. Periconia celtidis formed a monophyletic clade with P. byssoides in the present phylogenetic analyses. Results of the pairwise homoplasy index (PHI) test indicated significant recombination between P. byssoides and P. celtidis. Therefore, P. celtidis has been synonymized under P. byssoides. In addition, we re-illustrated and studied the type specimen of the sexual genus Bambusistroma. As a type species of Bambusistroma, B. didymosporum features similar morphology to the sexual morph of Periconia homothallica and P. pseudodigitata. We therefore synonymize Bambusistroma under Periconia based on morphological and phylogenetic evidence. Furthermore, our new isolates produced brown conidia of asexual morph in agar media typical of the genus Noosia. Based on morphological comparison with Periconia in vitro and phylogenetic status of Noosia, we also treat Noosia as a synonym of Periconia. Detailed descriptions and illustrations of three novel taxa and two new records of Periconia byssoides and P. pseudobyssoides as well as the illustration of P. didymosporum comb. nov. are provided. An updated phylogenetic tree of Periconiaceae using maximum likelihood and Bayesian inference analyses is constructed. Generic circumscription of Periconia is amended.

Taxonomy and Phylogeny of Novel and Extant Taxa in Pleosporales Associated with Mangifera indica from Yunnan, China (Series I).

Pleosporales is the largest fungal order with a worldwide distribution in terrestrial and aquatic environments. During investigations of saprobic fungi associated with mango (Mangifera indica) in Baoshan and Honghe, Yunnan, China, fungal taxa belonging to pleosporales were collected. Morphological examinations and phylogenetic analyses of ITS, LSU, SSU, rpb2 and tef1-α loci were used to identify the fungal taxa. A new genus, Mangifericomes; four new species, namely Mangifericomes hongheensis, Neomassaria hongheensis, Paramonodictys hongheensis, and Paramonodictys yunnanensis; and six new host and country records, namely Byssosphaeria siamensis, Crassiparies quadrisporus, Paradictyoarthrinium aquatica, Phaeoseptum mali, Torula fici, and Vaginatispora amygdali, are introduced. Photoplates, full descriptions, and phylogenetic trees to show the placement of new and known taxa are provided.

Taxonomy and phylogeny of the novel rhytidhysteron-like collections in the Greater Mekong Subregion.

During our survey into the diversity of woody litter fungi across the Greater Mekong Subregion, three rhytidhysteron-like taxa were collected from dead woody twigs in China and Thailand. These were further investigated based on morphological observations and multi-gene phylogenetic analyses of a combined DNA data matrix containing SSU, LSU, ITS, and tef1-α sequence data. A new species of Rhytidhysteron, R.xiaokongense sp. nov. is introduced with its asexual morph, and it is characterized by semi-immersed, subglobose to ampulliform conidiomata, dark brown, oblong to ellipsoidal, 1-septate, conidia, which are granular in appearance when mature. In addition to the new species, two new records from Thailand are reported viz. Rhytidhysterontectonae on woody litter of Betula sp. (Betulaceae) and Fabaceae sp. and Rhytidhysteronneorufulum on woody litter of Tectonagrandis (Lamiaceae). Morphological descriptions, illustrations, taxonomic notes and phylogenetic analyses are provided for all entries.

A Taxonomic Appraisal of Bambusicolous Fungi in Occultibambusaceae (Pleosporales, Dothideomycetes) with New Collections from Yunnan Province, China.

During our ongoing studies of bambusicolous fungi in southwest China and Thailand, three saprobic pleosporalean taxa were discovered on bamboos in Yunnan Province of China. Occultibambusa hongheensis and Seriascoma bambusae spp. nov. are introduced based on morphological characteristics coupled with multi-locus phylogenetic analyses of combined LSU, SSU, TEF1-α, RPB2 and ITS sequence data. Occultibambusa kunmingensis is also reported from a terrestrial habitat for the first time. Comprehensive descriptions, color photo plates of micromorphology, and a phylogenetic tree showing the placements of these three taxa are provided. In addition, synopsis tables of Occultibambusa and Seriascoma with morphological features are also provided.

Novel saprobic Hermatomyces species (Hermatomycetaceae, Pleosporales) from China (Yunnan Province) and Thailand.

During our survey of the diversity of woody litter fungi in China and Thailand, three Hermatomyces species were collected from dead woody twigs of Dipterocarpus sp. (Dipterocarpaceae) and Ehretiaacuminata (Boraginaceae). Both morphology and multigene analyses revealed two taxa as new species (Hermatomycesturbinatus and H.jinghaensis) and the remaining collections as new records of H.sphaericus. Hermatomycesturbinatus is characterized by 1) dimorphic conidia, having circular to oval lenticular conidia and 2) turbinate conidia consisting of two columns with two septa composed of 2-3 cells in each column. Hermatomycesjinghaensis is characterized by dimorphic conidia, having circular to oval lenticular conidia and clavate or subcylindrical to cylindrical conidia and consisting of one or two columns with 6-8 cells in each column. Phylogenetic analyses of combined LSU, ITS, tub2, tef1-α and rpb2 sequence data supports the placement of these new taxa within Hermatomycetaceae with high statistical support.

Morpho-Phylo Taxonomy of Novel Dothideomycetous Fungi Associated With Dead Woody Twigs in Yunnan Province, China.

Within the field of mycology, macrofungi have been relatively well-studied when compared to microfungi. However, the diversity and distribution of microfungi inhabiting woody material have not received the same degree of research attention, especially in relatively unexplored regions, such as Yunnan Province, China. To help address this knowledge gap, we collected and examined fungal specimens from different plants at various locations across Yunnan Province. Our investigation led to the discovery of four species that are clearly distinct from extant ones. These taxonomic novelties were recognized based on morphological comparisons coupled with phylogenetic analyses of multiple gene sequences (non-translated loci and protein-coding regions). The monotypic genus Neoheleiosa gen. nov. (type: N. lincangensis) is introduced in Monoblastiaceae (Monoblastiales) for a woody-based saprobic ascomycete that possesses globose to subglobose or obpyriform ascomata with centric or eccentric, papillate ostioles, an ascomatal wall with thin-walled cells of textura globulosa, cylindric, pedicellate asci with an ocular chamber, and 1-septate, brown, guttulate, longitudinally striated, bicellular ascospores. Neoheleiosa has a close phylogenetic affinity to Heleiosa, nevertheless, it is morphologically dissimilar by its peridium cells and ornamented ascospores. Acrocalymma hongheense and A. yuxiense are described and illustrated as new species in Acrocalymmaceae. Acrocalymma hongheense is introduced with sexual and asexual (coelomycetous) features. The sexual morph is characterized by globose to subglobose, ostiolate ascomata, a peridium with textura angularis cells, cylindric-clavate asci with a furcate to truncate pedicel and an ocular chamber, hyaline, fusiform, 1-septate ascospores which are surrounded by a thick, distinct sheath, and the asexual morph is featured by pycnidial conidiomata, subcylindrical, hyaline, smooth, annelledic, conidiogenous cells, hyaline, guttulate, subcylindrical, aseptate conidia with mucoid ooze at the apex and with a rounded hilum at the base. Acrocalymma yuxiense is phylogenetically distinct from other extant species of Acrocalymma and differs from other taxa in Acrocalymma in having conidia with three vertical eusepta. Magnibotryascoma kunmingense sp. nov. is accommodated in Teichosporaceae based on its coelomycetous asexual morph which is characterized by pycnidial, globose to subglobose, papillate conidiomata, enteroblastic, annelledic, discrete, cylindrical to oblong, hyaline conidiogenous cells arising from the inner layer of pycnidium wall, subglobose, oval, guttulate, pale brown and unicelled conidia.

Screening of Phosphate-Solubilizing Fungi From Air and Soil in Yunnan, China: Four Novel Species in Aspergillus, Gongronella, Penicillium, and Talaromyces.

Phosphate-solubilizing fungi (PSF) play an important role in increasing the bioavailability of phosphorus in soils for plants. Thirteen fungal strains, one collected from air and 12 from soil, were screened and described here in detail. These fungal strains were tested for their ability to solubilize tricalcium phosphate (TCP) on both solid and liquid Pikovskaya (PVK) media in vitro. The airborne fungal strain KUMCC 18-0196 (Aspergillus hydei sp. nov.) showed the most significant phosphate solubilizing activity on a solid PVK medium with the solubilization index (SI) (2.58 ± 0.04 cm) and the highest solubilized phosphates (1523.33 ± 47.87 µg/mL) on a liquid PVK medium. To the best of our knowledge, A. hydei sp. nov. is the first phosphate-solubilizing fungus reported from air. We also provide the identification especially for Aspergillus, Penicillium and Talaromyces, generally reported as PSF. It is important to not only screen for PSF but also identify species properly so that researchers have a clearer taxonomic picture for identifying potential taxa for future plant growth-promoting applications. Herein, A. hydei (section Nigri), Gongronella hydei, Penicillium soli (section Lanata-Divaricata) and Talaromyces yunnanensis (section Talaromyces) are fully described and introduced as new to science. These four new species are identified based on both morphological characteristics and multigene phylogenetic analyses, including the genealogical concordance phylogenetic species recognition method where necessary. Penicillium austrosinense is considered to be a synonym of P. guaibinense.

Taxonomy and phylogenetic appraisal of Spegazzinia musae sp. nov. and S. deightonii (Didymosphaeriaceae, Pleosporales) on Musaceae from Thailand.

Tropical plants host a range of fungal niches including endophytes, pathogens, epiphytes and saprobes. A study undertaken to discover the saprobic fungal species associated with Musa sp. (banana) from northern Thailand found two hyphomycetous taxa of Spegazzinia (Didymosphaeriaceae, Pleosporales). These were collected during the dry season and their morpho-molecular taxonomic relationships were investigated. Based on phylogenetic analysis of combined SSU, LSU, ITS and TEF1-α sequence data (77% ML, 0.99 BYPP) and contrasting morphological features to the sister taxon, we introduce Spegazzinia musae as a novel species from a decaying leaf of Musa sp. Details on the taxonomy, ecology and geographical distribution of Spegazzinia species are provided. In addition, we report S. deightonii as a new host record from Musa sp. Our data further validate the taxonomic placement of Spegazzinia in Didymosphaeriaceae.

Three Novel Entomopathogenic Fungi From China and Thailand.

Entomopathogenic fungi are ubiquitous in tropical rainforests and feature a high level of diversity. This group of fungi not only has important ecological value but also medicinal value. Nevertheless, they are often ignored, and many unknown species have yet to be discovered and described. The present study aims to contribute to the taxonomical and phylogenetic understanding of the genus Paraisaria by describing three new species collected from Guizhou and Yunnan Provinces in China and Krabi Province in Thailand. The three novel species named Paraisaria alba, P. arcta, and P. rosea share similar morphologies as those in the genus Paraisaria, containing solitary, simple, fleshy stroma, completely immersed perithecia and cylindrical asci with thickened caps and filiform ascospores that often disarticulate at maturity. Phylogenetic analyses of combined LSU, SSU, TEF1-α, RPB1, RPB2, and ITS sequence data confirm their placement in the genus Paraisaria. In this study, the three entomopathogenic taxa are comprehensively described with color photographs and phylogenetic analyses. A synopsis table and a key to all treated species of Paraisaria are also included.

Two novel species of Neoaquastroma (Parabambusicolaceae, Pleosporales) with their phoma-like asexual morphs.

The monotypic genus Neoaquastroma (Parabambusicolaceae, Pleosporales) was introduced for a microfungus isolated from a collection of dried stems of a dicotyledonous plant in Thailand. In this paper, we introduce two novel species, N. bauhiniae and N. krabiense, in this genus. Their asexual morphs comprise conidiomata with aseptate and hyaline conidia. Neoaquastroma bauhiniae has ascomata, asci and ascospores that are smaller than those of N. krabiense. Descriptions and illustrations of N. bauhiniae and N. krabiense are provided and the two species compared with the type species of the genus, N. guttulatum. Evidence for the introduction of the new taxa is also provided from phylogenetic analysis of a combined dataset of partial LSU, SSU, ITS and tef1 sequence data. The phylogenetic analysis revealed a distinct lineage for N. bauhiniae and N. krabiense within the family Parabambusicolaceae.

Multiple origins and a narrow genepool characterise the African tea germplasm: concordant patterns revealed by nuclear and plastid DNA markers.

Despite the highly economic value of tea in Africa, its genetic and geographic origins remain largely unexplored. Here we address this by collecting 439 samples across 11 countries in Africa and Asia to investigate the origin and genepool composition of African tea based on 23 nuclear microsatellites loci (nSSRs) and three cpDNA intergenic spacer regions. Our results indicated that the African tea represents a potpourri originating from multiple introductions over time. The nSSR analysis revealed that the majority (79%) of tea accessions collected in Africa belong to Indian Assam tea which have likely originated from India and/or Sri Lanka. The patterns of nSSR variation also showed that Chinese Assam tea is genetically distinct from Indian Assam tea, and has rarely been used in African tea breeding efforts since only 4% of the African tea accessions possessed this genotype. We found a total of 22 cpDNA haplotypes, which grouped into three main geographic clades that were concordant with the distribution of microsatellite genotypes. Several private cpDNA haplotypes were identified in Chinese Assam tea in Southern Yunnan province of China. Therefore Chinese Assam tea will be important for the enrichment of African tea gene pools. Our results is a useful guide in future tea breeding programmes in Africa.

Domestication Origin and Breeding History of the Tea Plant (Camellia sinensis) in China and India Based on Nuclear Microsatellites and cpDNA Sequence Data.

Although China and India are the two largest tea-producing countries, the domestication origin and breeding history of the tea plant in these two countries remain unclear. Our previous study suggested that the tea plant includes three distinct lineages (China type tea, Chinese Assam type tea and Indian Assam type tea), which were independently domesticated in China and India, respectively. To determine the origin and historical timeline of tea domestication in these two countries we used a combination of 23 nSSRs (402 samples) and three cpDNA regions (101 samples) to genotype domesticated tea plants and its wild relative. Based on a combination of demographic modeling, NewHybrids and Neighbour joining tree analyses, three independent domestication centers were found. In addition, two origins of Chinese Assam type tea were detected: Southern and Western Yunnan of China. Results from demographic modeling suggested that China type tea and Assam type tea first diverged 22,000 year ago during the last glacial maximum and subsequently split into the Chinese Assam type tea and Indian Assam type tea lineages 2770 year ago, corresponding well with the early record of tea usage in Yunnan, China. Furthermore, we found that the three tea types underwent different breeding histories where hybridization appears to have been the most important approach for tea cultivar breeding and improvements: a high proportion of the hybrid lineages were found to be F2 and BCs. Collectively, our results underscore the necessity for the conservation of Chinese Assam type tea germplasm and landraces as a valuable resource for future tea breeding.

Insights into the Genetic Relationships and Breeding Patterns of the African Tea Germplasm Based on nSSR Markers and cpDNA Sequences.

Africa is one of the key centers of global tea production. Understanding the genetic diversity and relationships of cultivars of African tea is important for future targeted breeding efforts for new crop cultivars, specialty tea processing, and to guide germplasm conservation efforts. Despite the economic importance of tea in Africa, no research work has been done so far on its genetic diversity at a continental scale. Twenty-three nSSRs and three plastid DNA regions were used to investigate the genetic diversity, relationships, and breeding patterns of tea accessions collected from eight countries of Africa. A total of 280 African tea accessions generated 297 alleles with a mean of 12.91 alleles per locus and a genetic diversity (H S) estimate of 0.652. A STRUCTURE analysis suggested two main genetic groups of African tea accessions which corresponded well with the two tea types Camellia sinensis var. sinensis and C. sinensis var. assamica, respectively, as well as an admixed "mosaic" group whose individuals were defined as hybrids of F2 and BC generation with a high proportion of C. sinensis var. assamica being maternal parents. Accessions known to be C. sinensis var. assamica further separated into two groups representing the two major tea breeding centers corresponding to southern Africa (Tea Research Foundation of Central Africa, TRFCA), and East Africa (Tea Research Foundation of Kenya, TRFK). Tea accessions were shared among countries. African tea has relatively lower genetic diversity. C. sinensis var. assamica is the main tea type under cultivation and contributes more in tea breeding improvements in Africa. International germplasm exchange and movement among countries within Africa was confirmed. The clustering into two main breeding centers, TRFCA, and TRFK, suggested that some traits of C. sinensis var. assamica and their associated genes possibly underwent selection during geographic differentiation or local breeding preferences. This study represents the first step toward effective utilization of differently inherited molecular markers for exploring the breeding status of African tea. The findings here will be important for planning the exploration, utilization, and conservation of tea germplasm for future breeding efforts in Africa.