Mechanistic analysis for the origin of diverse diterpenes in Tripterygium wilfordii

Tripterygium wilfordii is a valuable medicinal plant rich in biologically active diterpenoids, but there are few studies on the origins of these diterpenoids in its secondary metabolism. Here, we identified three regions containing tandemly duplicated diterpene synthase genes on chromosomes (Chr) 17 and 21 of T. wilfordii and obtained 11 diterpene synthases with different functions. We further revealed that these diterpene synthases underwent duplication and rearrangement at approximately 2.3-23.7 million years ago (MYA) by whole-genome triplication (WGT), transposon mediation, and tandem duplication, followed by functional divergence. We first demonstrated that four key amino acids in the sequences of TwCPS3, TwCPS5, and TwCPS6 were altered during evolution, leading to their functional divergence and the formation of diterpene secondary metabolites. Then, we demonstrated that the functional divergence of three TwKSLs was driven by mutations in two key amino acids. Finally, we discovered the mechanisms of evolution and pseudogenization of miltiradiene synthases in T. wilfordii and elucidated that the new function in TwMS1/2 from the terpene synthase (TPS)-b subfamily was caused by progressive changes in multiple amino acids after the WGT event. Our results provide key evidence for the formation of diverse diterpenoids during the evolution of secondary metabolites in T. wilfordii.

Influences of enhanced UV-B radiation and drought stress on biomass accumulation and allocation of Fagopyrum dibotrys / 中国中药杂志

<p><b>OBJECTIVE</b>To study the influences of enhanced UV-B radiation and drought stress on the biomass accumulation and allocation of Fagopyrum dibotrys, and so as to provide a theoretical basis for the cultivation, the protection and use of F. dibotrys.</p><p><b>METHOD</b>By experiment of potted plant, the biomass accumulation and allocation of F. dibotrys were measured under different drought stresses and UV-B radiations.</p><p><b>RESULT</b>In conditions of adequate water, enhanced UV-B radiation significantly reduced biomass accumulation to root, biomass accumulation to leaves, total biomass accumulation and biomass allocation to root in F. dibotrys, while it could increase biomass allocation to stem. In conditions of moderate drought stress, enhanced UV-B radiation increased biomass accumulation to root, biomass accumulation to stem and biomass accumulation to root. In the conditions of severe drought stress, enhanced UV-B radiation increased biomass accumulation to root, it also could lead in a certain increase to biomass accumulation to stem. Biomass allocation to root, stem and leaves was not sensitive to enhanced UV-B radiation.</p><p><b>CONCLUSION</b>The influences of enhanced UV-B radiation in simulation and drought stress on the biomass accumulation and allocation of F. dibotrys were determined by water conditions and different apparatus. Overall, we verified that enhanced UV-B radiation would reduce the influences of biomass accumulation of F. dibotrys by drought.</p>

RAPD analysis for genetic diversity of medicinal plant Coptis omeiensis / 中国中药杂志

<p><b>OBJECTIVE</b>To discuss the genetic diversity of Coptis omeiensis.</p><p><b>METHOD</b>The genetic diversity of 110 individuals from 10 populations was analyzed by RAPD.</p><p><b>RESULT</b>14 primers were selected to produce highly reproducible RAPD bands. Among 132 amplified bands, 98 showed polymorphism, the percentage of polymorphic bands reached to 74.24%. Nei's gene diversity index (H) was 0.2863, Shannon's information index (I) was 0.3624, G(st) was 0.2305. The genetic distance coefficient and the similarity were 0.1931-0.5245 and 0.5016-0.8843, respectively.</p><p><b>CONCLUSION</b>There exists a held high genetic diversity in C. omeiensis and the majority of genetic variation occurs in the populations. By cluster analysis, the geographical distribution is very obvious. The RAPD marker can be used for the analysis of the genetic diversity and genetic variation of C. omeiensis.</p>

RAPD analysis for genetic diversity of Fagopyrum cymosum / 中国中药杂志

<p><b>OBJECTIVE</b>To study the genetic diversity of Fagopyrum cymosum.</p><p><b>METHOD</b>The genetic diversity of 87 individuals from 10 populations was analyzed by random amplified polymorphic DNA (RAPD).</p><p><b>RESULT</b>Twelve primers were selected to produce highly reproducible RAPD bands. Among 85 amplified bands, seventy-five showed polymorphism, the percentage of polymorphic bands reached to 88.24%. Nei's gene diversity index (H) was 0. 3103, Shannon information index (I) was 0.5632, Gst was 0.1924. The genetic similarity coefficient and the genetic distance were 0.6720-0.9678 and 0.0328-0.3975, respectively.</p><p><b>CONCLUSION</b>F. cymosum shows high genetic diversity and the majority of genetic variation occurs in populations. By cluster analysis, the geographical distribution is very obvious. The RAPD marker can be used for the analysis of the genetic diversity and genetic variation of F. cymosum.</p>

Leaf epidermal features of 21 medicinal plants of Euonymus in China / 中国中药杂志

<p><b>OBJECTIVE</b>To accumulate taxonomic data of the leaf epidermal features of the medicinal species of Euonymus.</p><p><b>METHOD</b>Twenty-nine materials of 21 taxa (including 16 species, 4 varieties and 1 form) representing 5 sections of Euonymus are examined by using both of light microscopy and scanning electron microscopy.</p><p><b>RESULT</b>The form of epidermal cells in Euonymus is usually polygonal or irregular. The stomata were anomocytic in all the species examined except E. maackii and E. bungeanus var. semipersistens. Stomatal types of all species studied may be anomocytic, anisocytic, cycolocytic or the transitional types among them.</p><p><b>CONCLUSION</b>The results show that some characteristics (including cuticular membrane, shape of guard cells, inner margin of outer stomatal rim, outer stomatal rim and stomata type) of the leaf epidermis can provide some anatomical evidence for the classification. The characteristics of leaf epidermis support following treatments: E. acanthocarpus var. longipes, E. acanthocarpus var. scandens and E. acanthocarpus var. sutchuanensis should be merged into E. acanthocarpus; E. bungeanus var. semipersistens should be merged into E. maackii; E. hamiltonianus f. lanceifolius should be merged into E. hamiltonianus.</p>