Colletotrichum horii and Colletotrichum fioriniae Causing Anthracnose on Star Anise (Illicium verum) in China.

Star anise (Illicium verum) is an important economic and medical plant widely cultivated in Guangxi province, China. Its fruit can be used as spice and medicine (Wang et al. 2011). In recent years, anthracnose led to a serious decline in the production of star anise in Guangxi. In 2021, a survey conducted in CenwangLaoshan Reserve of Guangxi (24°21'N; 106°27'E) showed that the 2500 ha planting area had disease incidence greater than 80%. The leaf symptoms initially appeared as small spots, then expanded to round spots, finally becoming withered with grayish-white centers, surrounded by dark brown margins. Sometimes, small black acervuli were observed in the later stage. To explore the pathogen, infected leaves were collected and cut into small pieces (about 5 mm2) from the edge of the lesion, disinfected with 75% ethanol for 10 s, 1% NaClO for 1 min, washed with sterilized water and incubated on potato dextrose agar (PDA) plates at 28 °C in the dark. Ten single-spore isolates were obtained from the cultures. After 7 days on PDA at 28 °C, the colonies of 7 isolates were white with abundant aerial hyphae, gray-black with white-gray margins, and the other 3 isolates were light gray on the upper surface, and pink or orange on the underside. Representative isolates BS3-4 and BS3-1 were selected from 3 isolates and 7 isolates, respectively. Conidia of BS3-4 and BS3-1 were both hyaline, cylindrical, aseptate, smooth, apex obtuse, base truncate, and no significant differences (P > 0.05) in size between BS3-1 (13.22 to 5.38 × 3.89 to 1.99 µm) (n = 50) and BS3-4 (12.04 to 4.34 × 3.48 to 1.64 µm) (n = 50). These morphological characteristics were consistent with the Colletotrichum ssp. (Damm et al. 2012). The species identification of BS3-4 and BS3-1 was performed based on DNA sequence analysis. Genomic DNA was extracted as a template. Partial sequences of the rDNA internal transcribed spacer (ITS), actin gene (ACT), ß-tubulin2 (TUB2) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) were amplified and sequenced (Weir et al. 2012). The sequences were deposited in GenBank (ITS:OQ062642-43; ACT:OQ067614-15; GAPDH:OQ067616-17;TUB2：OQ067618-19). Based on the concatenated sequences of the 4 genes (ITS-ACT- GAPDH -TUB2) of BS3-4 and BS3-1 as well as sequences of other Colletotrichum spp. obtained from GenBank, the Maximum likelihood (ML) tree which produced with IQ-TREE (Minh et al. 2020) revealed that the isolate BS3-1 was Colletotrichum horii, and BS3-4 was Colletotrichum fioriniae. Pathogenicity was confirmed on healthy leaves of 1-year-old star anise seedlings (cultivar Dahong), and the leaves were wounded by sterilized toothpicks, and were inoculated with 10 µl of conidial suspensions of BS3-1 and BS3-4 (106 conidia/ml). Control seedlings were inoculated with sterilized distilled water. Five leaves per plant and 3 plants per treatment were selected. All inoculated seedlings were maintained in the greenhouse (12/12h light/dark, 25 ± 2℃, 90% relative humidity). Wound sites inoculated with BS3-1 and BS3-4 both turned greenish-brown after 2 days and then turned light brown with water-soaked spots. Black (BS3-1) or orange (BS3-4) dots of acervuli developed after 6 days. The lesion diameter of BS3-1 (14.4 mm) was larger than that of BS3-4 (8.1 mm). No symptoms were observed on controls. BS3-1 and BS3-4 were re-isolated from inoculated leaves, fulfilling Koch's postulates. Anthracnose of star anise caused by C.horii has been reported in China (Liao et al. 2017). However, to our knowledge, this is the first report of C.fioriniae infecting star anise in China. Accurate pathogen identification in this study could provide a reference for the control of anthracnose on star anise.

First Survey of the Pathogenic Fungus Batrachochytrium dendrobatidis in Wild Populations of the Yunnan Caecilian (Ichthyophis bannanicus) in Guangxi, China.

Batrachochytrium dendrobatidis (Bd), which causes chytridiomycosis, mainly infects Anura and Caudata but is poorly known in Gymnophiona. We conducted a survey of Bd in the Yunnan caecilian (Ichthyophis bannanicus) and found that 6 of 71 samples (8.4%) tested positive for Bd. To our knowledge, this is the first detection of Bd in wild I. bannanicus.

Latitudinal and Temperature-Dependent Variation in Embryonic Development Rate and Offspring Performance in a Freshwater Turtle.

The thermal environment of embryos differs significantly along a latitudinal cline, and the mechanism by which embryos respond to this geographic temperature variation has attracted increasing attention recently. Here, we carried out a common-garden experiment of egg incubation at two fluctuating temperature regimes to elucidate the latitudinal pattern and thermal dependence of the embryonic development rate and offspring performance in the Chinese soft-shelled turtle (Pelodiscus sinensis). Our results demonstrated significant temperature-by-population interactions on variations in the incubation period and hatchling righting response. The incubation period was shorter and the daily number of heart beats was higher in the medium- and high-latitude populations than in the low-latitude population at low incubation temperatures but not at high temperatures. Offspring from the medium- and high-latitude populations showed a faster righting response than those from the low-latitude population when incubated at low temperatures, whereas offspring from the high-latitude population showed a faster righting response than those from the medium-latitude population when incubated at high temperatures. This indicates that turtle embryos from different latitudinal locations may have evolved divergent thermal sensitivities of embryonic development in response to their respective nest environments.

Extremely low genetic diversity of mtDNA control region and remarkable population differentiation of Ichthyophis bannanicus (Amphibia: Gymnophiona).

It is widely accepted that the mitochondrial DNA (mtDNA) control region (CR) gene evolves more quickly than protein-encoding genes, such as ND2 and Cyt b, with few exceptions. However, some species have a different evolution pattern. In the present study, we sequenced the mtDNA CR partial sequences (454 base pairs) of 142 individuals from five sampling sites of Ichthyophis bannanicus and compared the genetic diversity and structure with the information from the NADH dehydrogenase subunit 2 (ND2) and Cytochrome b (Cyt b) genes within this species. Extremely low genetic diversity was found in the mtDNA CR compared with those of the ND2 and Cyt b genes. These results showed that the relatively mean clock rate of the CR was broadly lower than those of the ND2 (about 2.55 times) and Cyt b (about 3.14 times) genes. Despite the extremely low genetic diversity of CR, the population structure analysis identified two groups, Xishuangbanna and Northern Vietnam-Yulin-Yangchun-Deqing, which indicated that the Red River systems may have acted as gene-flow barriers for I. bannanicus.

External morphological features of the gills of Ichthyophis bannanicus embryo (Amphibia, Gymnophiona) / Características morfológicas externas de las branquias del embrión de Ichthyophis bannanicus (Amphibia, Gymnophiona)

The gills of Ichthyophis bannanicus have yet to be investigated. This paper describes the external morphological features of the gills of mature I. bannanicus embryos exhibiting three pairs of gills on their neck region. Each gill is composed of an axis and filaments. In newly released embryos, the filaments and the axis form at approximately 90° relative to each other; eventually, this angle decreases and the color of the gill fades. The filaments on the axis are arranged alternately, and their spacing varies. The mid-pair of gills is significantly longer by nearly twofold than the front and rear pairs. Likewise, the lengths of the front and rear pairs of gills are not significantly different (P >0.05); for the same pair of gills, the lengths of the left and right parts are not significantly different (P >0.05). The number of filaments is greater in the mid-pair of gills than in the front and rear pairs (P <0.05); the number of filaments in the front pair is not significantly different from that of the rear pair (P >0.05); the number of filaments in the left part does not significantly differ from that of the right parts (P >0.05). Results showed that the gills of I. bannanicus embryo are more similar to those of other species in Ichthyophiidae than to those of species in other families.

Las branquias del Ichthyophis bannanicus aún no se han investigado. En este trabajo se describen las características morfológicas externas de las branquias de embriones maduros de I. bannanicus, que exhiben tres pares de branquias en la región del cuello. Cada branquia está compuesta de un eje y filamentos. En embriones recién liberados los filamentos y la forma del eje es de aproximadamente 90° respecto a la otra; finalmente, este ángulo disminuye y el color de las branquias se desvanece. Los filamentos en el eje están dispuestos en forma alternada y su separación varía. La media de par de branquias es significativamente más larga, por casi el doble que los pares anterior y posterior. Del mismo modo, las longitudes de la parte delantera y posterior de pares de branquias no son significativamente diferentes (p >0,05); para el mismo par de branquias, las longitudes de las partes izquierda y derecha no son significativamente diferentes (p >0,05). El número de filamentos es mayor en el par medio de branquias, que en la parte delantera y posterior de pares (p <0,05); el número de filamentos en el par frontal no es significativamente diferente de la del par trasero (p >0,05); el número de filamentos en la parte izquierda no varía significativamente del de las partes derechas (p >0,05). Los resultados mostraron que las branquias del embrión de I. bannanicus son más similares a los de otras especies en Ichthyophiidae que de otras especies.

Mitochondrial genome of the Aix galericula (Anatidae: Aix).

Aix galericula has very wide geographical range in eastern Asia. Here, the complete mitochondrial genome of A. galericula (16,605 bp in length) been analyzed for building the database. Similar to the typical mtDNA of vertebrates, it contained 37 genes (13 protein-coding genes, 2 rRNA genes and 22 tRNA genes) and a non-coding region (D-loop). All the genes in A. galericula were distributed on the H-strand, except for the ND6 subunit gene and 10 tRNA genes which were encoded on the L-strand.

The Phylogeography and Population Demography of the Yunnan Caecilian (Ichthyophis bannanicus): Massive Rivers as Barriers to Gene Flow.

Ichthyophis bannanicus is the only caecilian species in China. In this study, the phylogeography and population demography of I. bannanicus were explored, based on the mitochondrial DNA genes (cyt b and ND2) and 15 polymorphic microsatellite loci. Altogether 158 individuals were collected from five populations in Yunnan province, Guangxi province, Guangdong province, and Northern Vietnam. Phylogeographical and population structure analysis identified either two groups (Xishuangbanna, Northern Vietnam-Yulin-Yangchun-Deqing) or three groups (Xishuangbanna, Northern Vietnam-Yulin-Yangchun, and Deqing), indicating that the Red River and Pearl River systems may have acted as gene-flow barriers for I. bannanicus. Historical population expansion that happened 15-17 Ka ago was detected for mtDNA data and was possibly triggered by warmer weather after the Last Glacial Maximum. However, the Bayesian simulations of population history based on microsatellite data pinpointed population decline in all populations since 19,123 to 1,029 years ago, demonstrating a significant influence of anthropogenic habitat alteration on I. bannanicus.

Genetic variation of the major histocompatibility complex (MHC class II B gene) in the threatened Hume's pheasant, Syrmaticus humiae.

Major histocompatibility complex (MHC) genes are the most polymorphic genes in vertebrates and encode molecules that play a crucial role in pathogen resistance. As a result of their diversity, they have received much attention in the fields of evolutionary and conservation biology. Here, we described the genetic variation of MHC class II B (MHCIIB) exon 2 in a wild population of Hume's pheasant (Syrmaticus humiae), which has suffered a dramatic decline in population over the last three decades across its ranges in the face of heavy exploitation and habitat loss. Twenty-four distinct alleles were found in 73 S. humiae specimens. We found seven shared alleles among four geographical groups as well as six rare MHCIIB alleles. Most individuals displayed between one to five alleles, suggesting that there are at least three MHCIIB loci of the Hume's pheasant. The dN / dS ratio at putative antigen-binding sites (ABS) was significantly greater than one, indicating balancing selection is acting on MHCIIB exon 2. Additionally, recombination and gene conversion contributed to generating MHCIIB diversity in the Hume's pheasant. One to three recombination events and seventy-five significant gene conversion events were observed within the Hume's pheasant MHCIIB loci. The phylogenetic tree and network analysis revealed that the Hume's pheasant alleles do not cluster together, but are scattered through the tree or network indicating a trans-species evolutionary mode. These findings revealed the evolution of the Hume's pheasant MHC after suffering extreme habitat fragmentation.