Hyperhydricity in pepper plants regenerated in vitro: involvement of BiP (Binding Protein) and ultrastructural aspects

 Hyperhydricity in regenerated pepper plants was monitored by the induction of the ER-luminal resident protein, as observed by immunoblotting. Immunoblotting of total protein using an anti-soybean BiP serum indicated that the induction and accumulation of an 80-kDa protein was related to BiP (Binding protein), a 78-kDa ER-resident molecular chaperone. The anti-BiP serum cross-reacted with an 80-kDa protein which was significantly induced by hyperhydricity. Based on similar molecular weight and immunological reactivity we concluded that the 80-kDa protein induced in hyperhydric plants is a BiP homologue. The ultrastructural organisation of leaves in non-hyperhydric and hyperhydric pepper (Capsicum annuum L.) plants was investigated with the aim of identifying the subcellular changes associated with this phenomenon. In non-hyperhydric leaves the chloroplasts of the palisade cells had normally developed thylakoids and grana and a low accumulation or absence of starch grains and plastoglobules. In the hyperhydric plants, however, the chloroplasts exhibited thylakoid disorganisation, low grana number, an accumulation of large starch grains and a low accumulation or absence of plastoglobules. Although the structure of mitochondria and peroxisomes did not change in hyperhydric plants, the number of peroxisomes did increase. Received: 23 July 1998 / Revision received: 26 February 1999 / Accepted: 17 March 1999     

In vitro stem elongation of sweet pepper in media containing 24-epi-brassinolide

In vitro regeneration of sweet pepper (Capsicum annuum L. cvs Jupiter and Pimiento Perfection) has been performed via direct organogenesis. The resulting shoot-buds were placed on media containing 24-epi-brassinolide (EBR) 0.1 μM, a plant steroid lactone, in the presence or absence of zeatin 9.1 μM plus GA3 5.2 μM for further stem elongation. Different responses to these treatments were recorded depending upon the protocols used and the genotypes tested. It appears that EBR does not always act directly on stem elongation but may be an elicitor and/or an enhancer of elongation in concert with endogenous and other exogenously added growth regulators. Elongated shoots were easily rooted with alpha-naphtalenacetic acid 0.5 μM (0.1 mgl-1) and transfered to soil, and following acclimation were taken to maturity in the greenhouse. This revised version was published online in June 2006 with corrections to the Cover Date.     

辣椒果色相关研究进展

辣椒是全球广泛种植的高经济价值茄科作物之一。在辣椒的各个经济性状中果色是最直观的重要性状之一。由于辣椒果色丰富多彩,目前已经成为研究果色遗传的一种模式植物。辣椒青熟果色与老熟果色存在差异且遗传、分子调控机制不同,本文将就辣椒这两个时期果色的遗传及分子调控机制研究做一个综述。     

Impact of moderate and extreme climate change scenarios on growth,morphological features,photosynthesis, and fruit production of hot pepper

Horticultural crop production and changes in physiological aspects during the growing season may be affected by climate change factors (CC), which include increased temperature and the associated doubling or tripling of atmospheric CO₂ concentrations. However, the potential effects are complex and many parameters might impact on the observed effects. To evaluate the effects of CC, the growth, yield, fruit characteristics, photosynthetic traits, and morphological characteristics of hot peppers were investigated. The hot peppers were grown under two CC scenarios, with the Representative Concentration Pathway (RCP) of 4.5 (Temp.; +3.4°C, CO₂ conc.; 540 μmol/mol, Precipitation +17.3%) and RCP 8.5 (Temp.; +6.0°C and CO₂ conc.; 940 μmol/mol, Precipitation +20.3%), respectively, using extreme weather simulators. This was compared with existing weather conditions occurring in Jeonju, South Korea in terms of air temperature, relative humidity, radiation, and precipitation. Overall, the plant height showed the highest under moderate CC conditions (RCP 4.5) among all the treatments tested. The number of leaves in the RCP 8.5 condition showed 7,739/plants, which was 2.2 times higher than that of the control. In addition, fruit shape was shortened and percentage dry matter was also the highest. The yield of hot pepper in the CC RCP 4.5 and 8.5 conditions were decreased by 21.5% and 89.2% when compared with that of the control, respectively. The days to harvest in the condition of CC scenarios were shortened from 5 to 13 compared with that of control, predominantly due to the increased air temperature. The results indicated that the severe RCP CC scenarios made reduction in the yields and negative affection on the fruit qualities. Overall, hot pepper was tolerant of mild CC scenarios of temperature × CO₂ but was significantly affected by more extreme CC interacting parameter concentrations (or similar).     

辣椒雄性不育系SDH4基因的表达特性分析

为了探究线粒体电子传递复合体Ⅱ的关键酶基因(SDH4)与辣椒细胞质雄性不育的关系,该试验通过GenBank报道的辣椒线粒体基因组序列,特异引物扩增SDH4基因,并通过分析SDH4基因的时空表达及转录本编辑位点,以期找到辣椒细胞质雄性不育系9704A和保持系9704B的差异。结果表明:(1)从辣椒细胞质雄性不育系9704A和保持系9704B中获得的目的基因编码区片段长度一致,全长均为378bp,编码125个氨基酸残基。(2)辣椒保持系不同组织中SDH4基因表达存在差异,种子中表达最高,茎中表达最低。(3)在不同材料花蕾发育的同一时期,SDH4基因表达也不一致,在花粉母细胞减数分裂时期,不育系SDH4基因表达量明显低于保持系;而在造孢细胞增殖期、小孢子单核期和小孢子成熟期的表达量均高于保持系。(4)不育材料中SDH4基因在29位点出现RNA编辑,导致氨基酸由丝氨酸变为亮氨酸,增强了蛋白结构的疏水性能。研究认为,辣椒细胞质雄性不育系9704A和保持系9704B中SDH4基因的表达差异可能引起植物的能量代谢供应出现异常,从而导致雄性不育的产生。     

Cellulase elicitor induced accumulation of capsidiol in Capsicum annumm L. suspension cultures

When growth-phase cell suspension cultures of Capsicum annuum were treated with cellulase-elicitor preparation at 3 μg/ml, the level of capsidiol was transiently increased in the culture media rather than in the cells reaching its maximum approx 24 h after treatment. With methyl jasmonate it took 18 h. Elicitor treatment doubled phospholiphase A₂ (PLA₂) activity but simultaneous treatment with aristolochic acid, a PLA₂ inhibitor, inhibited sesquiterpenoid accumulation as well as PLA₂ activity. Mastoparan, a G protein activator, treatment also increased PLA₂ activity and capsidiol production. Taken together, the present study shows that induction of capsidiol production in the C. annuum is mediated by PLA₂ activation.     

Capsicum ethanol extracts and capsaicin enhance interleukin-2 and interferon-gamma production in cultured murine Peyer's patch cells ex vivo

We investigated the effects of red pepper (Capsicum annuum Lin.) extracts (capsicum extract) and its main pungent capsaicin on T helper 1 (Th1) and 2 (Th2) cytokine production in cultured murine Peyer's patch (PP) cells in vitro and ex vivo. Direct administration of capsicum extract (1 and 10 mug/ml) and capsaicin (3 and 30 muM) resulted in suppression of interleukin (IL)-2, interferon (IFN)-gamma, IL-4 and IL-5 production. In an ex vivo experiment using PP cells removed from the mice after oral administration of capsicum extract (10 mg/kg/day for 4 consecutive days), IL-2, IFN-gamma and IL-5 increased in response to concanavalin A (Con A). Oral administration of 3 mg/kg/day capsaicin, one active constituent of the extract, also enhanced IL-2, INF-gamma and IL-4 production in response to Con A stimulation but did not influence the production of IL-5. Orally administered capsazepine (3 mg/kg/day), a selective transient receptor potential vanilloid 1 (TRPV1) antagonist, slightly enhanced IL-2 production also irrespective of Con A stimulation. The capsaicin-induced enhancement of both IL-2 and IFN-gamma production was not reduced by oral administration of capsazepine (3 mg/kg/day), suggesting a TRPV1 receptor-independent mechanism. Flow cytometric analysis revealed that the population of CD3(+) cells in the PP cells was significantly reduced while CD19(+) cells increased after oral administration of capsicum extract (1 and 10 mg/kg/day) and capsaicin (0.3 and 3 mg/kg/day). Capsazepine (3 mg/kg/day) weakly but significantly reversed these effects. Orally administered capsicum extract and capsaicin did not change the T cell subset (CD4(+) and CD8(+)), Th1 (IFN-gamma(+)) and T2 (IL-4(+)) ratio. These findings indicate that capsicum extract and capsaicin modulate T cell-immune responses, and their immunomodulatory effects on murine PP cells are partly due to both TRPV1-dependent and -independent pathway.     

Efficient transient expression and transformation of PEG-mediated gene uptake into mesophyll protoplasts of pepper (<Emphasis Type="Italic">Capsicum annuum</Emphasis> L.)

PEG-mediated transformation was used for gene delivery and evaluation of various parameters affecting the transient expression of a gene for ß-glucuronidase (gus) in mesophyll protoplasts of Capsicum annuum. Transient expression was found to be dependent on PEG concentration and exposure time of plasmid DNA to protoplasts as well as the amount of plasmid DNA. Maximum GUS activity was obtained when protoplasts were applied to 40% concentration and molecular weight was 6,000 of PEG solution with 30 min of exposure time. Protoplasts of pepper were transformed with a vector, pCAMBIA::Ac, which contained a pCAMBIA1302 T-DNA vector carrying a maize transposable element, Ac (activator), a selection marker HPT (hygromycin phosphotransferase), and a GFP-coding region driven by the 35S promoter in the presence of PEG. Approximately 30% of the protoplasts expressed GFP. Visibly transformed colonies were obtained from protoplasts after 2 months of culture and GFP was expressed. Southern hybridization confirmed the presence of Ac in the pepper genome.     

Virus adaptation to quantitative plant resistance: erosion or breakdown?

Adaptation of populations to new environments is frequently costly due to trade‐offs between life history traits, and consequently, parasites are expected to be locally adapted to sympatric hosts. Also, during adaptation to the host, an increase in parasite fitness could have direct consequences on its aggressiveness (i.e. the quantity of damages caused to the host by the virus). These two phenomena have been observed in the context of pathogen adaptation to host's qualitative and monogenic resistances. However, the ability of pathogens to adapt to quantitative polygenic plant resistances and the consequences of these potential adaptations on other pathogen life history traits remain to be evaluated. Potato virus Y and two pepper genotypes (one susceptible and one with quantitative resistance) were used, and experimental evolutions showed that adaptation to a quantitative resistance was possible and resulted in resistance breakdown. This adaptation was associated to a fitness cost on the susceptible cultivar, but had no consequence either in terms of aggressiveness, which could be explained by a high tolerance level, or in terms of aphid transmission efficiency. We concluded that quantitative resistances are not necessarily durable but management strategies mixing susceptible and resistant cultivars in space and/or in time should be useful to preserve their efficiency.     

辣椒OSCA基因家族的全基因组鉴定及不同胁迫条件下表达分析

钙通透性阳离子通道蛋白(OSCA)在渗透胁迫感应中发挥重要的作用.本研究利用辣椒(Capsicum an-nuum L.)全基因组信息,鉴定出14个OSCA基因(CaOSCA),染色体定位及同源性分析表明,它们分别位于1、2、4、6、7、8、9、12号染色体上,亚细胞定位预测表明其编码产物均位于质膜上.系统进化树分析这...