Association of ectomycorrhizal fungi with Picea crassifolia (Pinaceae, Piceoidae) from high-altitude stands in Mount Helan Nature Reserve, China.

We investigated the diversity of ectomycorrhiza associated with the endemic Picea crassifolia in Mount Helan National Nature Reserve in Inner Mongolia, China. Toward this objective, we conducted morphological and molecular identification of ectomycorrhizae in soil cubes taken from pure P. crassifolia stands. Eleven types of ectomycorrhizal (ECM) organisms were separated, briefly described, and identified. Nine morphotypes belonged to the phylum Basidiomycotina [Amphinema byssoides, Cortinarius sp (cf. limonius), Cortinarius vernus, Inocybe cf. nitidiscula, Inocybe sp 1, Sebacina incrustans, Sebacina sp, Suillus luteus, and Piceirhiza tuberculata x Picea crassifolia (comb. Nov.)], and two morphotypes to the phylum Ascomycotina (Cenococcum geophilum and Helvella sp). The diversity of ECM organisms in P. crassifolia was lower than that reported by other studies on spruce or pine forests, or on sporocarp diversity in the high-mountain forests of China. Most of the fungi in the rhizosphere did not correspond to species previously recorded as sporocarps above ground. Here, several new ectomycorrhiza morphotypes are proposed and described. We also confirmed the ectomycorrhizal status of the genus Sebacina (order Sebacinales).

Effect of karst rocky desertification on soil fungal communities in Southwest China.

Karst mountainous ecosystems are associated with karst rocky desertification (KRD), which can greatly impact soil structure and function. Despite the importance of soil microbes as a major factor maintaining ecosystem stability, we know little about the effect on soil fungal communities of KRD in karst regions. We investigated this relationship across a gradient of KRD soils from Guizhou, China by polymerase chain reaction and denaturing gradient gel electrophoresis (PCR-DGGE). Fungal diversity indices (Shannon-Wiener, richness, and evenness) significantly differed (P < 0.05) based on KRD severity, being lowest in moderately affected areas. Cluster analysis showed that the five sites examined clustered into two main groups according to KRD grade (high and low). Moreover, a homology search using sequences recovered from PCR-DGGE bands showed that the dominant fungi in each community varied remarkably, and included Aspergillus, Aphanoascus, Blastomyces, Fusarium, Glomus, Geomyces, Gibberella, Mortierella, Tetracladium, and Tumularia species, and an unclassified group. In conclusion, these findings demonstrate that KRD has a significant impact on soil fungal communities.

Genetic diversity of Ceratoides arborescens, a species endemic to China, detected by inter-simple sequence repeat (ISSR).

In order to investigate genetic diversity and population structure of Ceratoides arborescens, six populations were selected from different steppe types in Inner Mongolia grasslands of China. Inter-simple sequence repeat (ISSR) markers were used to assess the genetic diversity within and among natural populations of C. arborescens. Thirteen ISSR primers generated 154 discernible DNA bands, of which 151 (98.05%) were polymorphic. High genetic diversity was detected at the species level [percentage of polymorphic loci (PPB) = 98.05%; H = 0.2984; I = 0.4557], whereas, relatively low genetic diversity existed within populations (PPB = 80.62%; H = 0.2675; I = 0.4031). Analysis of molecular variance showed that variation existed mainly within populations (73.25%) rather than among populations (26.75%), which was in line with the high level of gene flow (Nm = 4.3332). The Mantel test found no significant correlation between genetic distance and geographic distance (r = 0.7522, P < 0.05). Six populations were clustered into two main groups, a desert steppe group and a typical steppe group.

Novel and recurrent COL2A1 mutations in Chinese patients with spondyloepiphyseal dysplasia.

Spondyloepiphyseal dysplasia (SED) is an autosomal dominant skeletal dysplasia characterized by short stature, abnormal epiphyses and flattened vertebral bodies. SED is mainly caused by mutations in the gene encoding the type II procollagen α-1 chain (COL2A1). We looked for mutations in COL2A1 in three unrelated Chinese families with SED. Putative mutations were confirmed by RFLP analysis. We identified three missense mutations (p.G504S, p.G801S and p.G1176V) located in the triple-helical domain; p.G801S and p.G1176V are novel mutations. The p.G504S mutation has been associated with diverse phenotypes in previous studies. Our study extends the mutation spectrum of SED and confirms a relationship between mutations in the COL2A1 gene and clinical findings of SED.

Identification of novel and recurrent mutations in the calcium binding type III repeats of cartilage oligomeric matrix protein in patients with pseudoachondroplasia.

Pseudoachondroplasia is an autosomal dominant osteochondrodysplasia characterized by disproportionate short stature, joint laxity, and early onset osteoarthrosis. Pseudoachondroplasia is caused by mutations in the gene encoding cartilage oligomeric matrix protein (COMP). We looked for mutations in the COMP gene in three sporadic Chinese pseudoachondroplasia patients and identified two novel mutations, c.1189G>T (p.D397Y) and c.1220G>A (p.C407Y), and one recurrent mutation, c.1318G>C (p.G440R), in the calcium binding type III repeats of COMP. This study confirms the relationship between mutations of the COMP gene and clinical findings of pseudoachondroplasia; it also provides evidence for the importance of the calcium binding domains to the functioning of COMP.