蚕豆萎蔫病毒2号山西分离株的全基因组序列测定与分析

本试验在生物学接种的基础上,利用非序列依赖性PCR扩增（sequence-independent amplification,SIA）对感病青椒（Capsicum annuum）进行了分子鉴定. 序列测定及分析发现,侵染青椒的病毒为蚕豆萎蔫病毒2号（Broad bean wilt virus 2, BBWV2）. 为明确BBWV2青椒分离物（BBWV2 Ca）的分类地位,对BBWV2 Ca的全基因组序列进行了分段克隆、序列测定和分析. BBWV2-Ca RNA1全长5 929 bp,含有1个ORF. BBWV2 Ca RNA2全长3 559 bp,含有1个ORF,编码3种蛋白：VP53/VP37、外壳蛋白大亚基（large coat protein, LCP）和外壳蛋白小亚基(small coat protein, SCP). 全序列核苷酸同源性分析显示,BBWV2-Ca RNA1与BBWV2其它分离物核苷酸同源性在77.9%～93.7%之间|RNA2与BBWV2其它分离物核苷酸同源性在80.2%～93.8%之间. 全序列系统进化分析显示,BBWV2-Ca RNA1与BBWV2-XJ14-3以及BBWV2-RP3株系聚为一簇,亲缘关系最近|RNA2与BBWV2-Am形成一个独立分支,亲缘关系最近.     

Temperature linked degenerative tissue rots in Capsicum annuum (L.) varieties diseased with Phytophthora capsici

Five-week-old seedlings of Capsicum annuum variety SAMPEP 4, Californian Wonder and Ex Dandamasa drenched with 15,000 infectious units per ml of Phytophthora capsici were incubated at 5°C, 20°C, 30°C and 35°C in alternating light–dark cool cycle Gallenkamp incubators and monitored for root rot development. Each host–pathogen system was replicated five times. Successful disease development was contingent on been incubated at ambient temperature for not less than 3.5 ± 0.5 h. Depending on variety, degenerate tissue rots were aggravated ≤2–3 days after a preconditioning temperature treatment for 24 h possibly linked to cell wall constitution, composition and permeability. Lesion development on stem heightened (27.8%) when incubated at temperatures above 20°C. Ten days after treatment, plant mortality and disease severity were not affected significantly by post-inoculation temperature.     

4种(变种)辣椒的核型研究

本文研究了辣椒属4种(变种)的核型,各个种的核型可简式为小米辣2n=24=23m+1sm:簇生辣2n=24=20m+2sm+2st:樱桃辣2n=24=20m+4sm(2SAT):“印度辣”2n=24=22m+2st。按照Stebbins的核型分类,小米辣为2A型;簇生辣和樱桃辣为2A型,印度辣为2B型。     

Feeding‐induced phenol production in Capsicum annuum L. influences Spodoptera litura F. larval growth and physiology

We studied the role of induced plant phenols as a defense response to insect herbivory. Phenolic compounds were induced in Capsicum annuum L., the source of many culinary peppers, after feeding by different stages of the insect pest, Spodoptera litura F. The phenols were identified and quantified using high performance liquid chromatography (HPLC) and effects produced by these phenols on larval development were studied. Vanillic acid was identified in plants challenged by second, fourth, and fifth instar larvae, but not in plants challenged by third instar nor unchallenged plants. Syringic acid production was induced in chili plants infested with second (0.429 ± 0.003 μg/g fresh weight, fourth (0.396 ± 0.01 μg/g fresh weight), and fifth instar (5.5 ± 0.06 μg/g fresh weight) larvae, compared to untreated plants (0.303 ± 0.01 μg/g fresh weight) plants. Leaves surface treated with the rutin deterred oviposition. Dietary exposure to chlorogenic acid, vanillic acid, syringic acid, sinapic acid, and rutin led to enhanced activities of detoxifying enzymes, β‐glucosidase, carboxyl esterase, glutathione S‐transferase, and glutathione reductase in the midgut tissues of all the larval instars, indicating the toxic nature of these compounds. Protein carbonyl content and acetylcholinesterase activity was analyzed to appreciate the role of induced plant phenols in insect protein oxidation and terminating nerve impulses.     

过量表达辣椒CaNPR1提高烟草对青枯菌的抗性

对水稻和拟南芥等模式植物的研究表明,NPR1(nonexpressor of pathogenesis-related genes 1)是依赖于SA通路的防御反应调节基因,但在辣椒和烟草等茄科作物中该蛋白的功能还鲜有报道.研究从辣椒cDNA文库中分离获得一个NPR1的类似物全长cDNA(CaNPR1),并获得了其超表达的转基因烟草T1代株系.研究结果表明,这些株系与其野生型植株没有明显表型差异,但却表现出较野生型植株更高的抗青枯菌侵染活性.同时,研究还发现CaNPR1的超表达还显著提高了防御相关基因的表达,表明NPR1在不同植物间具有较强的功能保守性.     

Role of salicylic acid in regulating ultraviolet radiation-induced oxidative stress in pepper leaves

The effect of salicylic acid (SA) counteracting the UV-A, UV-B, and UV-C-induced action on pepper (Capsicum annuum L.) plants was studied. For this purpose, the activities of antioxidant enzymes (peroxidase, polyphenol oxidase, ascorbate peroxidase, catalase, and glutathione reductase) were measured. Plants were sprayed with SA and treated with UV-A (320–390 nm), UV-B (312 nm), and UV-C (254 nm) radiation with a density of 6.1, 5.8, and 5.7 W/m². The activities of antioxidant enzymes were enhanced in leaves in response to UV-B and UV-C radiation. SA treatment moderated an increase in the activities of some antioxidant enzymes (peroxidase, ascorbate peroxidase, catalase, and glutathione reductase) in plants that were treated with UV radiation. The activity of antioxidant enzyme polyphenol oxidase in plants that were treated with UV-B, UV-C, and SA was significantly increased. The aim of the present study was to investigate the possible protective effect of SA treatment on UV-A, UV-B, and UV-C stress.     

Inhibition of electron transport activities in mitochondria from avocado and pepper fruit by naturally occurring polyamines

The effects of the naturally occurring polyamines, spermine, putrescine, and spermidine were explored on mitochondrial state 3. state 4, and uncoupled respiration activities, ADP/O ratio, respiratory control ratio of pepper ( Capsicum annuum L. cv. Early Cal Wonder) and avocado ( Persea americana Mill. cv. Booth-8 or Simmonds) mitochondria oxidizing either succinate, external NADH, malate, α-ketoglutarate or tetramethyl- p -phenylenediamine. Abnormally high concentrations of spermine and spermidine such as might occur during chilling stress of these chilling-sensitive fruits were detrimental to several oxidase activities, especially to external NADH oxidase. State 3 respiration for NADH oxidase was inhibited more than 70% by 10 m M spermine. The spermine inhibition of uncoupled NADH oxidase was not reversed by the presence of divalent cations including Ca²⁺, Mg²⁺, Mn²⁺, and Sr²⁺ at concentrations up to 10 m M or by 100 m M KCl. The inhibition primarily affected the V_max. Other possible sites of polyamine interactions are discussed.     

辣椒R2R3-MYB转录因子家族的全基因组鉴定与比较进化分析

MYB转录因子作为植物中最大的转录因子家族之一,参与植物的生长、代谢、抵御生物和非生物胁迫等多种生理生化过程。R2R3-MYB是MYB转录因子家族的主要存在形式。辣椒是具有重要经济价值的蔬菜作物,其R2R3-MYB转录因子缺乏系统的研究。从一年生辣椒(Capsicum annuum)、浆果状辣椒(C. baccatum...     

Effects of prolonged drought stress and nitrogen deficiency on the respiratory O2 uptake of bean and pepper leaves

We analyzed the combined effects of mild drought stress and severe nitrogen (N) deprivation on respiration of acclimated mature leaves of beans (Phaseolus vulgaris L. cv. Garrofal) and peppers (Capsicum annuum L., pure line B6). Rates of oxygen uptake were measured polarographically, and inhibitors were added to the closed cuvette to compare the effects of environmental stress on the cytochrome (cyt) and alternative pathways of mitochondrial respiration. Dark oxygen uptake was decreased by the water deficit treatment in both plants, and in the case of N limitation leaf respiration rates (R_D) of peppers were also reduced. R_D of leaves of beans and peppers grown under N-limiting conditions did not follow the decrease in leaf N concentration, since R_D expressed per unit of tissue N was considerably higher in the N-stressed leaves. Values obtained with specific inhibitors of the two terminal oxidases of mitochondrial respirations suggested that the cyt pathway of respiration was affected by mild drought and severe N stress. When plants were exposed to both environmental stresses, leaf respiration response was similar to that under N limitation, in this case the most severe stress. This revised version was published online in June 2006 with corrections to the Cover Date.     

Biochemical changes associated with the ripening of hot pepper fruit

Hot pepper ( Capsicum annuum L. cv. Chooraehong) fruit underwent a respiratory climacteric during ripening. However, the rate of ethylene production was low, reaching a maximum of approximately 0.7 μl kg⁻¹ h⁻¹ at the climacteric peak when the surface color was 30 to 40% red. Ripening was accompanied by a loss of galactose and arabinose residues from the cell wall. The content of uronic acid and cellulose in the wall changed only slightly during ripening. The average molecular weight of a cell wall hemicellulosic fraction shifted progressively toward a lower molecular weight during ripening. Total β-galactosidase (EC 3.2.1.23) activity increased 50-fold from the immature green to the red ripe stage. No polygalacturonase (EC 3.2.1.15) activity was detected at any stage of ripeness. Thus, the loss of galactose and arabinose residues from the cell wall, as well as the observed modification of hemicelluloses during ripening, seem to be unrelated to active polygalacturonase. Soluble polyuronide content remained relatively constant at approximately 60 μg (g fresh weight)⁻¹ as fruit ripended.