Sequence-related amplified polymorphism primer screening on Chinese fir(Cunninghamia lanceolata(Lamb.) Hook)

Chinese fir（Cunninghamia lanceolata（Lamb.）Hook） is one of the most important coniferous tree species used for timber production in China. Here, we conducted a sequence-related amplified polymorphism（SRAP） primer screening assay with a total of 594 primer combinations,using 22 forward and 27 reverse primers on four representative Chinese fir genotypes. The obtained results indicated that Chinese fir genomic DNA has a notable amplification bias on the employed forward or reverse primer nucleotides（30selection bases）. Out of the tested primer sets, 35 primer combinations with clearly distinguished bands, stable amplification, and rich polymorphism were selected and identified as optimal primer sets. These optimal primer pairs gave a total of 379 scorable bands,including 265 polymorphic bands, with an average of 10.8bands and 7.6 polymorphic bands per primer combination.The produced band number for each optimal primer set ranged from 7 to 14 with a percentage of polymorphic bands spanning from 33.3 to 100.0 %. These primer combinations could facilitate the next SRAP analysis assays in Chinese fir.

Screening of Primers for DNA Barcoding of Sedum Plants

[ Objective] This study aimed to screen primers for DNA barcoding of Sedum plants. [ Method] Sedum lineare Thunb., S. spectabile Boreau, S. ta- tarinowii Maxim, S. aizoon L. and S. sarmentosum Bunge were used as experimental materials. Nuclear DNA and chloroplast DNA were extracted from these five Sedum plants with CTAB method for primer screening by PCR amplification. PCR products were detected by agarose gel electrophoresis. [ Result] Four sequences suitable for DNA barcoding of Sedum plants were preliminarily screened from six candidate sequences （psbA-trnH, ropB, rbcL, rpoC1, ITS 2, marK）, including psbA-trnH, ropB, rpoC1 and ITS 2. The amplification rate of these four sequences reached 100%. [ Conclusion] This study provided basis for DNA barcoding of Sedum plants.

Evaluation of SRAP markers efficiency in genetic diversity of Aspergillus flavus from peanut-cropped soils in China

In order to evaluation the efficiency of SRAP markers on genetic diversity of Aspergillus flavus,we screened out 17sets of primer pairs which could produce clear and reproducible SRAP bands from 150 SRAP primer pairs.The size of SRAP fragments ranged from 120 to 2100 bp.Primer pair Me10/Em9 produced the maximum number of polymorphic bands(12 bands),while Me8/Em13 produced the fewest number of polymorphic bands(only 1).Through analysis genetic diversity ability of different sets of primer pairs,the set of 12 primer pairs was selected for SRAP genetic marker of A.flavus.Cluster analysis was performed based on the genetic similarity coefficients,which ranged from 0.53 to 0.89.A dendrogram assembled using the unweighted pair-group method with arithmetic averages grouped A.flavus samples into 5 main clusters.The results suggested that SRAP marker is a useful molecular technology for the diversity of A.flavus from peanut soils in China.