Sequences of the 3′ Halves of the Genomes of Barley Yellow Dwarf Virus-PAV cpA Isolates that Vary in Symptom Severity

Barley yellow dwarf virus (BYDV)-PAV isolates from USA have been separated into two distinct clusters (Chay et al. (1996) Virology 219: 57–65; Chay et al. (1996) Phytopathology 86: 370–377). Following this finding we have shown that BYDV-PAV is divided into two groups cpA and cpB based on their coat protein gene sequence, and distinct host preferences (Mastari et al. (1998) Phytopathology 88: 818–821). We have sequenced the complete 3 half of the genomes of two lethal and two mild cpA isolates and compared them with those of several known PAV cpA isolates to assess variability and locate potential determinants of severity. Open reading frames (ORFs) 3, 4, 5, 6 and the 3 untranslated regions had different percent homologies between isolates: ORF5 (92–97%), ORF3 (88–98%) 3-translational enhancer (87–100%) ORF4 (85–99%), 3 untranslated region (72–97%) and ORF6 (61–99%). In contrast to the mild isolates, the field-lethal isolates (FHv1 and FHv2) fell into the same cluster, regardless of the genomic region analysed. The isolates FHv1 and FHv2 differed from mild isolates by eight amino acid substitutions in ORFs 3 and 4, and insertions in ORF5. Four amino acid substitutions in the 17-kDa protein encoded by ORF4 caused a change in local net charge in the field-lethal isolates. Two insertions of four amino acids were identified in the C-terminal half of ORF5 of the field-lethal isolates, but were not present systematically in all lethal isolates analysed. The potential relationships of these differences in predicted amino acid sequences to disease severity are discussed.     

Selection of Homozygous Cotton Lines Transformed with Two Insect-Resistant Genes

A plant expression vector containing a chimeric Bt29K gene coding for the activated Cry1Ac protein and the arrowhead proteinase inhibitior gene API-B were introduced into the cotton cultivar Jihe321 mediated by Agrobactertium tumefaciens. Based on the results of kanamycin resistant testing, PCR detection for both foreign genes and insect bioassay using Heliethis armigera, nine transgenic homozygous cotton lines with insect-resistance of more than 90% and better agronomic traits were bred through six generations from the original transgenic plants. Results from insect bioassay and sequence analysis of the PCR products of plants from some homozygous lines indicated that the chimeric Bt29K gene was stably inherited in these transgenic cotton lines. The main agronomic characters of these homozygous cotton lines, such as boll productivity and fibre strength, were better than that of the original cotton cv. Jihe321.     

美洲棉铃虫CYP321A1基因启动子区萤火虫荧光素酶报告基因载体的构建及活性测定

【目的】构建美洲棉铃虫细胞色素P450基因CYP321 A1启动子区萤火虫荧光素酶报告基因载体,为探索CYP321 A1基因的转录调控机制奠定基础。【方法】设计合成PCR引物,从美洲棉铃虫基因组DNA中扩增并克隆CYP321 A1基因的启动子区;将克隆的启动子片段插入载体pGL3-basic构建萤火虫荧光素酶报告基因载体p(-1 470/+64);用p(-1 470/+64)转染美洲棉铃虫脂肪体细胞系BCIRL-HzFB33,并用双荧光素酶报告基因检测系统分析该启动子活性。【结果】p(-1 470/+64)经双酶切、PCR鉴定及DNA测序分析鉴定准确无误;通过转染细胞和荧光素酶活性分析,证实所构建的重组载体p(-1 470/+64)可以反映CYP321 A1启动子活性;黄酮、花椒毒素处理极显著地增强了重组载体p(-1 470/+64)的荧光活性。【结论】成功构建了美洲棉铃虫细胞色素P450基因CYP321 A1启动子区萤火虫荧光素酶报告基因载体,CYP321A1启动子活性可以被植物次生物质黄酮、花椒毒素高度诱导。     

“321＂移栽法效益评价及应用推广研究——基于重庆巫山的实证分析

通过重庆巫山等区县田间试验论证,得出“321”移栽法在烟叶生产减工降本、降低病害发生比率、实现烟苗早生快发、提升烟叶产量质量、提高烟农经济效益等方面的优越性,并就“321”移栽法在山地烟区的应用推广进行了分析.结果表明：相比于常规移栽,通过推行“321”移栽法,移栽用工节约2/3;团棵期、旺长期病害发生比率和病情指数明显低于常规移栽;移栽后几乎无还苗期,促进了烟苗早生快发;中上等烟比例达91.56％,相比常规移栽提升4.97个百分点,产值平均增加3 516.0元/hm2.     

红麻新品种闽红321的选育

闽红321系从红麻722×闽红82-59有性杂交后代中选育而成的红麻新品种。该品种2003～2004年参加福建红麻新品种联合区域试验,平均原麻产量为6235．0kg·hm^-2,比红引135增产21．7％,差异达极显著水平;1999-2000年参加全国红麻新品种联合区域试验,平均纤维产量为3491．25kg·hm^-2,比对照红引135增产15．48％,差异达极显著水平。闽红321表现株高、茎粗、有效株数多、抗病力强、高产稳产、适应性广,其纤维品质和抗病性亦均优于对照,具有较好的推广应用前景。