摘要：
Tubers are vegetative reproduction organs formed from underground extensions of the plant stem. Potato tubers are harvested and stored for months. Storage under cold temperatures of 2-4 degrees C is advantageous for supressing sprouting and diseases. However, development of reducing sugars can occur with cold storage through a process called cold-induced sweetening (CIS). CIS is undesirable as it leads to darkened color with fry processing. The purpose of the current study was to find differences in biological responses in eight cultivars with variation in CIS resistance. Transcriptome sequencing was done on tubers before and after cold storage and three approaches were taken for gene expression analysis: 1. Gene expression correlated with end-point glucose after cold storage, 2. Gene expression correlated with increased glucose after cold storage (after-before), and 3. Differential gene expression before and after cold storage. Cultivars with high CIS resistance (low glucose after cold) were found to increase expression of an invertase inhibitor gene and genes involved in DNA replication and repair after cold storage. The cultivars with low CIS resistance (high glucose after cold) showed increased expression of genes involved in abiotic stress response, gene expression, protein turnover and the mitochondria. There was a small number of genes with similar expression patterns for all cultivars including genes involved in cell wall strengthening and phospholipases. It is proposed that the pattern of gene expression is related to chilling-induced DNA damage repair and cold acclimation and that genetic variation in these processes are related to CIS.
摘要：
Fumarylacetoacetate hydrolase (FAH) catalyses the final step of the tyrosine degradation pathway, which is essential to animals but was of unknown importance in plants until we found that mutation of Short-day Sensitive Cell Death1 (SSCD1), encoding Arabidopsis FAH, results in cell death under short-day conditions. The sscd1 mutant accumulates succinylacetone (SUAC), an abnormal metabolite caused by loss of FAH. Succinylacetone is an inhibitor of delta-aminolevulinic acid (ALA) dehydratase (ALAD), which is involved in chlorophyll (Chl) biosynthesis. In this study, we investigated whether sscd1 cell death is mediated by Chl biosynthesis and found that ALAD activity is repressed in sscd1 and that protochlorophyllide (Pchlide), an intermediate of Chl biosynthesis, accumulates at lower levels in etiolated sscd1 seedlings. However, it was interesting that Pchlide in sscd1 might increase after transfer from light to dark and that HEMA1 and CHLH are upregulated in the light-dark transition before Pchlide levels increased. Upon re-illumination after Pchlide levels had increased, reactive oxygen species marker genes, including singlet oxygen-induced genes, are upregulated, and the sscd1 cell death phenotype appears. In addition, Arabidopsis WT seedlings treated with SUAC mimic sscd1 in decline of ALAD activity and accumulation of Pchlide as well as cell death. These results demonstrate that increase in Pchlide causes cell death in sscd1 upon re-illumination and suggest that a decline in the Pchlide pool due to inhibition of ALAD activity by SUAC impairs the repression of ALA synthesis from the light-dark transition by feedback control, resulting in activation of the Chl biosynthesis pathway and accumulation of Pchlide in the dark.
摘要：
WRKY是一类广泛参与高等植物各种抗逆调控活动的转录因子,可以通过激活下游相关信号转导途径调节自身的应激反应,进而增强植物抗逆性。本研究通过RNA-Seq从马铃薯(Solanum tuberosum)中筛选出一个晚疫病菌诱导WRKY转录因子基因StWRKY。采用RT-PCR技术获得该基因CDS全长,并对其进行序列分析及结构功能预测。根据StWRKY蛋白序列进行同源性搜索,得到与其蛋白序列相似度较高的其他物种的蛋白序列,使用MEGA7软件对StWRKY蛋白序列及其同源序列进行多序列比对分析并构建了系统进化树。利用在线工具ProtParam对StWRKY进行氨基酸理化性质分析;利用SMART在线工具进行蛋白序列分析;利用SWISS-MODEL在线工具和PredictProtein在线平台分别对StWRKY蛋白二级结构和三级结构进行分析。结果表明,StWRKY核苷酸序列CDS全长为957 bp,编码含318个氨基酸的蛋白质,预测蛋白分子量为36.17 kD,等电点为6.49。既不是分泌蛋白也不是膜蛋白,未发现跨膜区、信号肽和复合螺旋区。 StWRKY三维空间结构主要由无规卷曲以及β-折叠组成。通过XcmⅠ酶切、连接将StWRKY装载到pCXSN载体上,构建了该基因的超表达载体pCXSN-StWRKY。StWRKY基因的克隆,为进一步从分子水平上验证其抗晚疫病的生物学功能以及揭示马铃薯生物胁迫抗逆机制奠定基础,并为马铃薯抗病育种提供新的基因资源。 <&wdkj&>WRKY is a kind of transcriptional factor that widely participates in the regulation of various stress resistant activities of higher plants, which can regulate its own stress response by activating downstream related signal transduction pathway to enhance plant stress resistance. In this study, a WRKY transcription factor gene StWRKY induced by Phytophthora infestans was screened from Solanum tuberosum by RNA-seq. The full-length CDS of the gene was obtained by RT-PCR, and the sequence analysis and structural function prediction were carried out. Homology search was performed according to StWRKY protein sequence, and protein sequences of other species with high similarity to its protein sequences were obtained. A multiple sequence alignment was analyzed and phylogenetic tree was constructed on StWRKY protein sequence and its homologous sequences by MEGA7. The physical and chemical properties of StWRKY were analyzed by online tool ProtParam. StWRKY protein sequence was analyzed by SMART online tools. The secondary structure and tertiary structure of StWRKY protein were analyzed by SWISS-MODEL online tool and PreidictProtein online platform, respectively. The results showed that the full-length CDS of StWRKY nucleotide sequence was 957 bp, encoding 318 amino acids, with the predicted molecular mass of 36.17 kD and the isoelectric point of 6.49. Neither a secreted protein nor a membrane protein, and no transmembrane region, signal peptide and complex helix region were found. The StWRKY three-dimensional space structure was mainly composed of random coils and β-sheets. The overexpression vector pCXSN-StWRKY was constructed by loading StWRKY on plasmid pCXSN through XcmⅠenzyme digestion and linkage. The cloning of StWRKY gene could provide a basis for further identification of the biological function of anti-late blight on the molecular level, to reveal the resistance mechanism of potato biotic stress and offer new genetic resources for the resistance breeding of potato.
作者机构：
[秦玉芝; Zeng L.; 胡新喜] College of Horticulture and Landscape, Hunan Agricultural University, Hunan Provincial Key Laboratory of Crop Germplasm Innovation and Utilization, Hunan Provincial Engineering Research Center for Potatoes, Changsha, 410128, China;[索海翠; 李小波] Research Institute of Crops, Provincial Key Laboratory of Crops Genetic Improvement, Guangdong Academy of Agricultural Sciences, Guangzhou, 510640, China;[王万兴] Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Root and Tuber Crops, Ministry of Agriculture, Beijing, 100081, China;[王丽] College of Horticulture and Landscape, Hunan Agricultural University, Hunan Provincial Key Laboratory of Crop Germplasm Innovation and Utilization, Hunan Provincial Engineering Research Center for Potatoes, Changsha, 410128, China, Research Institute of Crops, Provincial Key Laboratory of Crops Genetic Improvement, Guangdong Academy of Agricultural Sciences, Guangzhou, 510640, China;[熊兴耀] College of Horticulture and Landscape, Hunan Agricultural University, Hunan Provincial Key Laboratory of Crop Germplasm Innovation and Utilization, Hunan Provincial Engineering Research Center for Potatoes, Changsha, 410128, China, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Root and Tuber Crops, Ministry of Agriculture, Beijing, 100081, China
通讯机构：
[Li, X.] R;Research Institute of Crops, China
摘要：
In order to further understand the thermal performance of the double phase change material (PCM) layer wallboard, the wallboard model was established and a comprehensively numerical parametric investigation was carried out. The variation laws of inner wall temperature rise and the heat flux transferred under different phase transition temperatures and thermal conductivities are presented in detail. The main results show that the temperature of the inside wall for case 2 can be reduced by about 1.5 K further compared to that for case 1. About 83% of the heat transferred from the outside is absorbed by the PCM layer in case 2. Reducing the phase transition temperature of the PCM layer can decrease the inside wall temperature to a certain extent in the period of high temperature. The utilization of double PCM layers shows much more performance compared to that of the single PCM layer case, and the temperature of the inside wall can be reduced by 2 K further.
作者机构：
[Tai, Helen H.; Gardner, Kyle; Lague, Martin; Davidson, Charlotte; Nolan, Lana; Murphy, Agnes; Paudel, Jamuna Risal; Goyer, Claudia; Bizimungu, Benoit; Neilson, Jonathan; De Koeyer, David] Agr & Agri Food Canada, Fredericton Res & Dev Ctr, POB 20280, Fredericton, NB E3B 4Z7, Canada.;[Sonderkaer, Mads; Hedegaard, Sanne; Nielsen, Kare Lehmann] Aalborg Univ, Dept Chem & Biosci, Fredrik Bajers Vej 7, DK-9220 Aalborg, Denmark.;[Wang, Hui Ying; Xiong, Xingyao] Hunan Agr Univ, Coll Hort & Landscape, Changsha 410128, Hunan, Peoples R China.;[Halterman, Dennis] USDA ARS, Vegetable Crops Res Unit, Madison, WI 53706 USA.;[De Koeyer, David] Int Inst Trop Agr, PMB 5320,Oyo Rd, Ibadan 200001, Oyo State, Nigeria.
通讯机构：
[Tai, Helen H.] A;Agr & Agri Food Canada, Fredericton Res & Dev Ctr, POB 20280, Fredericton, NB E3B 4Z7, Canada.
摘要：
Verticillium dahliae Kleb. is a pathogenic fungus causing wilting, chlorosis, and early dying in potato (Solanum tuberosum L.). Genetic mapping of resistance to V. dahliae was done using a diploid population of potato. The major quantitative trait locus (QTL) for Verticillium resistance was found on chromosome 5. The StCDF1 gene, controlling earliness of maturity and tuberization, was mapped within the interval. Another QTL on chromosome 9 co-localized with the Ve2 Verticillium wilt resistance gene marker. Epistasis analysis indicated that the loci on chromosomes 5 and 9 had a highly significant interaction, and that StCDF1 functioned downstream of Ve2. The StCDF1 alleles were sequenced and found to encode StCDF1.1 and StCDF1.3. Interaction between the Ve2 resistance allele and the StCDF1.3 was demonstrated, but not for StCDF1.1. Genome-wide expression QTL (eQTL) analysis was performed and genes with eQTL at the StCDF1 and Ve2 loci were both found to have similar functions involving the chloroplast, including photosynthesis, which declines in both maturity and Verticillium wilt. Among the gene ontology (GO) terms that were specific to genes with eQTL at the Ve2, but not the StCDF1 locus, were those associated with fungal defense. These results suggest that Ve2 controls fungal defense and reduces early dying in Verticillium wilt through affecting genetic pathway controlling tuberization timing.
