Pterygiella, a genus endemic to southwestern China, belongs to hemiparasitic rhinanthoid Orobanchaceae. Since P.bartschioides was segregated as an independent genus of its own, i.e. Xizangia, the genus was treated to include four species, P.duclouxii, P.nigrescens, P.cylindrica, and P.suffruticosa. However, the discriminative characters are obscure among these species, and the delimitation of the two varieties in P.duclouxii remains problematic. To revise the taxonomy of the genus, thirteen populations from the four species were collected for both morphometric and molecular systematic analyses. Principal component analysis (PCA) and cluster analysis via unweighted pairgroup method with an arithmetic average (UPGMA) were used. In addition, four chloroplast sequences (i.e., atpBrbcL, psbAtrnH, trnDtrnT and trnStrnG) and nuclear ITS region were studied. The results showed that Pterygiella includes only three species, namely P.nigrescens, P.duclouxii, and P.cylindrica, while P.suffruticosa should be merged into P.cylindrica as a variety. The previous delimitation of the two varieties within P.duclouxii was probably caused by imperfect analysis of morphological characters. Thus, a lectotype was designated for P.duclouxii and the plants formerly treated as P.duclouxii that bear eglandular stem hairs should be put into P.nigrescens, while the individuals with glabrous stem should remain in P.duclouxii. A new key to the three species in the genus reflecting the results of this study was presented, and a taxonomic revision was given.
Leaf traits can reflect the adaptation of plants to environments. Understanding leaf traits of orchids and their adaptive implications in karst area of southwestern China is contributive to the conservation for those endangered orchids. Leaf traits of 19 orchids and their correlations in Guangxi Yachang Orchids Nature Reserve were studied in both dry season and rainy season. Only Oberonia myosurus was CAM plant and its stomata distribution was amphistomaty. Other orchids were C3 plants and their stomata distributions were hypostomaty. Compared with deciduous orchids，evergreen orchids had higher leaf mass per area (LMA) and ratio of leaf carbon to leaf N (C/N), lower leaf N and P content. For the evergreen orchids, lithophytic orchids showed higher leaf Ca content and leaf δ13C than did terrestrial orchids. Leaf P content of evergreen lithophytic orchids in rainy season was higher than in dry season. Leaf δ13C of terrestrial orchids in dry season was higher than in rainy season. The value of N/P in evergreen orchids showed that these orchids in karst area might suffer the limitation of phosphorus.
In this study, we examined the nuclear ribosomal DNA internal transcribed spacer (ITS) sequence variation of Eriophyton wallichii, a perennial endemic to alpine scree of the QinghaiTibetan Plateau. Nineteen haplotypes were detected by analyzing 187 individuals from 20 populations of E.wallichii. Most populations hold the unique haplotype, which showed different population with different haplotype. An analysis of molecular variance (AMOVA) for populations showed that the genetic variation mainly resided among populations (89.54%), the level of differentiation among populations was very high (GST=0.863; NST=0.957) but didn’t show a significant phylogeographical structure. It is different from foregoing other species reported in QinghaiTibetan Plateau that the haplotypes of E.wallichii showed a distribution pattern that almost one population hold one unique haplotype, hardly share same halotype among populations.We hypothesized the unique genetic structure of E.wallichii might result from allopatric fragmentation in the “islands of alpine” due to the extremely isolated alpine scree and rough topography of the region, through the Quaternary climate oscillation dramatically caused population expanding or shrinking.
Large scale permanent plots (LSPP) work as important platform for longterm research on biodiversity, community phylogenetics and evolution, and ecosystem function in forests. The paper selected four Chinese forest dynamics plots representing four climatic types of Chinese vegetation (Xishuangbanna in tropics, Dinghushan in southern subtropics, Gutianshan in middle subtropics, and Changbaishan in temperate zone) to analyze the arealtypes of seed plants at the level of family, genus, and species, according to the approach of Wu et al. The results showed that Xishuangbanna was characteristic of the margin of tropical flora, Dinghushan was characteristic of the transition from tropical flora to subtropical flora, Gutianshan being characteristic of typical subtropical flora, and Changbaishan being characteristic of temperate zone. These results were consistent with previous findings in Chinese forests, exhibiting distinctly geographic distribution of Chinese genera along altitude gradient, which indicated that the comparatively floristic analysis of multiregion, benefiting from the LSPP platform sharing original data, was testified to be feasible and effective.
Truffles are fungi belonging to the genus Tuber (Ascomycota), which form belowground ascocarps or fruiting bodies (hypogeous fungi). Some truffles are highly prized culinary commodities in the world. Although China has rich mushroom cultures and a quite few edible or medicinal fungal species were described in ancient texts but no truffle (Tuber) was recorded. A false truffle, the species of basidiomycetes Rhizopogon rubescens, was described in Renyu Chen’s “JunPu” in 1245 and called “Maixun”. This name was also found in some ancient Japanese mushroom books with the species also referred to as “Songlu”. Recently there has been a trend in China to call truffles “Songlu” in many publications and websites. However, the use of this name should be discouraged as it specifically refers to R.rubescens and is not appropriate to use for true truffles. Since the 1990s, increasing amounts of Chinese black truffles have been sold in international markets and harvesting and trading of Chinese black truffles is now a multimillion dollar industry. Unfortunately, one of consequences of largescale commercial harvesting of Chinese black truffles is that their forest environments have been severely damaged by unrestricted plundering of these natural resources. Local production has declined to the extent that truffle resources may face extinction if destructive harvesting methods are not stopped. Management and legislation on the commercial harvesting and conservation of truffles in China are urgently needed. The main edible black truffle species in China are Tuber indicum, Tuber sinese, Tuber aestivum, and Tuber pseudohimalayense (=T.pseudoexcavatum). The species known as Tuber himalayense has not been found in China up to now. Attempts to obtain DNA sequences from the type specimen of T.indicum were unsuccessful so it was subsequently impossible to analyse the phylogenetic relationship between T.indicum and T.sinense. There seems to be no sound evidence that collections previously identified as T.indicum from SW China actually represent this species which was originally described from India. Future collections of T.indicum from the type locality or nearby areas may clarify this issue. Several collections of white truffle species were obtained from SW China in 2010. Although their exact taxonomic positions have not yet been established, their large ascocarps and strong truffle aroma suggest significant commercial potential. These recent findings indicate that China has much richer truffle diversity than previously expected. A brief introduction to some important edible European truffle species including Tuber magnatum, Tuber melanosporum, T.aestivum (=T.uncinatum), Tuber brumale and Tuber borchii is given. The ecological and economic importance of truffles and aspects of their cultivation are also discussed.
Lesliea, a newly recorded genus of Orcihdaceae from Yunnan, China, is reported. This is monotypic genus, differing from its relatives by having saccate spur, long and bifid rostellum and the obconical stipe.
The WRKY gene superfamily is one of the largest transcriptional regulators which mainly exists in plants. Arabidopsis WRKY25 is one of the group I WRKY proteins and responds to both biotic and abiotic stresses. GUS staining and qRTPCR analysis show that the expression of WRKY25 mainly focuses on roots, rosette leaves and cauline leaves. Transgenic plants overexpressing WRKY25 show early flowering under longday conditions when compared with wildtype plants. RTPCR analysis demonstrates that the expression of AP1 is upregulated in 21dold and 27dold transgenic plants. Thus, it is possible that WRKY25 affects flowering through upregulation of AP1 directly or indirectly.
Glandular trichomes are special organs involved in plant defense response and synthesis of volatile secondary metabolites, analyzing trichome specific expressed sequence tags will help us further understand the specific function of plant trichomes. In this paper, suppression subtractive hybridization（SSH） based on magnetic beads technology was used to isolate differential expressed genes of the glandular trichomes in Lycopersicon esculentum. The differential expressing cDNA library was constructed using the glandular trichomes cDNA as tester and the cDNA from the stem without glandular trichomes as driver. After randomly sequencing 108 differential ESTs, Blast2go program was used to do blastx, functional annotation and metabolism analysis. The results show that most ESTs are related to substance metabolism, response to stress, biotic or abiotic stimulus, and have binding and catalytic function. These differential genes lay the foundation for further research on defense mechanism of the tomato trichomes.
Functional molecular markers M7 and M2 have been developed based on the DNA sequence differences of badh2 between fragrant rice varieties and nonfragrant varieties in intron2, intron 4, exon7 and exon 2 respectively. PCR analyses on genome DNA of exon7mutated fragrant rice Wxiang 99075, exon2mutated fragrant rice Wuxiang14,nonfragrant rice 261S and the F1 plants by M7 and M2 showed that M7 and M2 could be absolutely used to the molecular markerassisted rice breeding experiments when exon7mutated and exon2mutated fragrant rice varieties are used as parents. The design of M7 primers took mutations both in exons and intrones into account. Moreover, taking 261S,Wxiang 99075 and Wuxiang14 as controls, the mutation sites of badh2 in 22 fragrant rice varieties were analyzed, it was showed that fragrant rice varieties could be classified into 3 types: exon 2mutated fragrant rice, exon 7mutated fragrant rice and nonexonmutated fragrant rice. At the same time, the mutation sites of badh2 in the main fragrant rice varieties which are grown in Shanghai and the surrounding areas have been verified. This research laid an important foundation for molecular markerassisted selection for novel fragrant rice.
Tacca (Dioscoreaceae) is a small genus which is taxonomically difficult because of a lack of obvious morphologically differences among species. DNA barcoding is a new method of rapid species identification and discovery using short, standardized genes or DNA regions. In this study, four candidate DNA barcoding regions that three (rbcL, matK, trnHpsbA) from chloroplast genome and one (ITS) from the nuclear genome, were evaluated among 36 accessions representing 6 species of Tacca. The capability of those regions were evaluated by intra and interspecific divergence and barcode gap analyses, and the identification efficiency was assessed using Treebased and BBA methods. The results indicated that both ITS and the core barcode rbcL+matK proposed by CBOL exhibited the highest resolution as a single and combined data respectively. Based on overall performance: matK+rbcL can be considered as a potential barcode for identifying the species of Tacca, ITS can be used as a supplementary barcode. DNA barcoding revealed two distinct lineages of T.integrifolia distributed allopatrically in Tibet and Malaysia. And these two lineages with morphological variations may potentially represent new species.
Natural hybridization is very common in plants, and plays an important role in plant evolution. Besides the traditional methods including morphological analysis and hand crossing, molecular evidence is needed for studying natural hybridization.In order to analyze natural hybridization in Roscoea,HAT-RAPD technique was used to identify putative hybrids from parental species by principal coordinate analysis and hybrid index. The results indicated that the bands amplified by HAT-RAPD technique were more stable and reliable than that of RAPD. The result of principal coordinate analysis and hybrid index showed that intermediate individuals were the hybrids of R.humeana and R.cautleoides, and showed closer relationships to R.humeana. These results suggested that HAT-RAPD could be used to study natural hybridization. As it is simple and easy to manipulate, HATRAPD may prove to be a very effective technique in hybrid identification in the studies of plant evolution.
