果糖激酶是果糖磷酸化过程中主要的催化酶,在植物的生长发育过程中起着非常关键的调节作用。为了深入研究果糖激酶在甜瓜属作物中的结构及理化性质、鉴定出更多潜在的果糖激酶基因,本研究从两个拟南芥（Arabidopsis thaliana）果糖激酶基因（AT-FRK）入手,在葫芦科数据库（http://cucurbitgenomics.org/）中鉴定出甜瓜（Cucumis melo L.）果糖激酶基因3条、黄瓜（Cucumis sativus L.）果糖激酶基因2条,并利用生物信息学的分析方法对甜瓜属FRK基因的结构特征、编码蛋白质的理化性质和结构进行分析,还进行了系统进化树的构建。结果显示,甜瓜属FRK基因在染色体上的分布无规律,编码区序列有996 bp和1 047 bp 2种大小,亚细胞定位预测有胞外基质和细胞质2种情况。FRK蛋白绝大数为亲水性蛋白,稳定性较好,等电点在酸性范围内,α螺旋和无规则卷曲为蛋白二级结构的主要构成形式,高级结构则大部分相似。本研究为甜瓜属作物FRK基因结构及功能的进一步发掘提供参考。

In this research,the genetic linkage map and size related traits of watermelon seeds were constructed and accurately located by using the F2 population derived from the hybridization and selfing of Egusi watermelon (Citrullus lanatus ssp.mucosospermus) PI186490 and cultivated watermelon (Citrullus lanatus ssp.vulgaris) W1-1.The results showed that (1) Two QTL locis associated with seed length and width were obtained with the contribution rates of 24.57％ and 24.79％,respectively.(2) The CAPS markers (CAPS13,CAPS14) which were closely linked with the length and width of the seeds were used to verify the conformance of 72 different natural populations with different seed sizes.The detection rate of CAPS13 in large seed group was 36.11％,and in small seed group was 80.56％;And the counterpart of CAPS14 in large group was 30.56％,and in small group was 83.33％.

In this study,salicylic acid (SA),methyl jasmonate (MeJA),Ca2+,and sterile water as a control were used as exogenous inducers to pretreat the melons for resistance and susceptibility to fusarium wilt.Two days after the induction of pretreatment,they were inoculated with F.melilocarpa,and the incidence was observed on the 5,7 and 9 d after inoculation.The disease status was investigated,and melon leaves were taken at 1,3,5,7 and 9 d after inoculation.Expression changes of Fom-2 and CHT in resistant melon (MR-1) and susceptible melon (M1-15) leaves were evaluated in order to check the wilt in control wilt with the technical way of dyeing.The results showed that:(1) the disease indexes of the two varieties after inoculation with exogenous MeJA and SA were significantly lower than that of the control and there was no significant difference between the condition index after Ca2+ treatment and the control.(2) After inoculated with exogenously induced pretreatment,the expression of Fom-2 and CHT genes in leaves of MR-1 and M1-15 cultivars was different but the effect of Ca2+ on upregulation was not strong.(3) After inoculated with SA and MeJA,the expression of Fom-2 and CHT genes in the leaves of the two cultivars were significantly higher than those of the control,but the expression level of Fom-2 for resistant melon MR-1,the peaks were reached at 5 d and 7 d and all susceptible melon M1-15 were peaked at 9 d after inoculation.The expression of CHT gene for resistant melon MR-1 peaked at 7 d after inoculation.M1-15 showed peak at 7 and 9 days after inoculation,respectively.(4) There was no significant effect of Ca2+ treatment on the expression of Fom-2 and CHT genes in muskmelon leaves.(5) The correlation analysis showed that the disease index of Fusarium wilt was correlated with the expression levels of Fom-2 and CHT genes after SA and MeJA induced pretreatment inoculation.The effect of Ca2+ treatment is not significant.

Phenylalanine ammonia-lyase is the first entry enzyme in the metabolism of phenylpropanoid, which plays a key role in plant development, stress resistance and signal transduction. In order to further study the structure and physicochemical properties of phenylalanine ammonia-lyase in Cucurbitaceae, and explore more potential phenylalanine ammonia lyase genes, this study started from four L-phenylalanine ammonia-lyase genes in Arabidopsis thaliana, and the homologous genes of melon (Cucumis melo L.), watermelon (Citrullus lanatus) and cucumber (Cucumis sativus L.) were identified by BLAST comparison in Cucurbitaceae database (), and their bioinformatics prediction and analysis were carried out. The results showed that 4, 6 and 5 homologous genes were identified in melon, watermelon and cucumber, respectively, which were named as MELO-PAL 1～4, Cla-PAL 1～6, and Csa-PAL 1～5. Its structure and physicochemical properties at different levels were all relatively similar to those of Arabidopsis thaliana. Phylogenetic tree analysis indicated that phenylalanine ammonia-lyasegenes from each species shared highly homology. In addition, MELO-PAL4 was cloned using molecular biology, which was subsequently ligated to T vector for sequencing. The sequencing results implied that the total similarity between cloned gene sequences and BLAST one was 92.54％. This study provided important help for the further excavation of the functions of PAL gene in Cucurbitaceae.

Two-hundred-twenty-five BC1 generations were obtained from backcrossing F1 of the shallow green rind, red flesh, no bitterness cultivated watermelon inbred line W1-1 and the dark green rind, white flesh, bitter wild species PI186490 hybrid as well as their female parents. CAPS makers spanning the whole genome were used to genotype every individual based on whole-genome resequencing data. Watermelon genetic linkage maps of 186 CAPS markers corresponding to 11 chromosomes were constructed, spanning a total distance of 1468.09 cM. Genetic analysis and gene mapping were performed using the flesh color, rind pattern and flesh bitterness as 3 qualitative traits. The results showed that wide rind stripes and flesh bitterness were controlled by a dominant gene, with red flesh recessive to white flesh, and 3 loci were identified related to the 3 fruit traits mentioned above. This study provides a theoretical basis for molecular marker-assisted selection of desirable watermelon fruit traits.

苯丙氨酸解氨酶是苯丙烷代谢途径的第一个酶,对植物发育、抗逆及信号传导起着尤为重要的作用.为了在葫芦(Lagenaria siceraria cv.USVL1VR-Ls)中更为深入地研究苯丙氨酸解氨酶的结构及理化性质,发掘更多潜在的苯丙氨酸解氨酶基因,本研究从一个拟南芥(Arabidopsis thaliana)苯丙氨酸解氨酶基因(AT3G53260)入手,通过BLAST比对方法在葫芦科数据库中鉴定葫芦苯丙氨酸解氨酶同源基因,并进行生物信息学预测分析.结果表明,在葫芦中比对出5条同源基因,其各级结构及理化性质与拟南芥苯丙氨酸解氨酶基因均较为相似.本研究为进一步发掘葫芦PAL基因功能提供了新的思路.

甜叶菊(Stevia rebaudian)是富含甜菊苷类物质的多年生菊科草本植物,其叶片中含一类天然甜味剂——甜菊醇糖苷(steviol glycosides,SGs).在其合成的过程中,尿嘧啶二磷酸-糖基转移酶(UDP-glycosyl transferase,UGT)催化糖基从供体分子转移到受体分子上,参与糖苷转运代谢,达到提高甜叶菊甜度的目的.为了在甜叶菊中更为深入地研究尿嘧啶二磷酸-糖基转移酶的结构和理化性质,改良甜叶菊品质,以甜叶菊3个主要UGT基因UGT76G1(AY345974)、UGT85C2(AY345978)、UGT91D1(AY345980)为研究对象,对其蛋白质进行生物信息学预测分析和进化树的构建.结果表明,3个UGT蛋白质初级结构理化性质较为相似,均为亲水性蛋白,且结构中含较多的α螺旋和无规则卷曲,但三级结构具有一定的差异.进化树及多序列比对结果表明,甜叶菊3个UGT基因同源性不高,但与康乃馨等其他作物中UGT基因有一定的进化关系.研究为进一步探究甜叶菊UGT基因及蛋白质的功能奠定了基础.