Characterization of Geminivirus resistance in an accession of Capsicum chinense Jacq

Pepper golden mosaic virus (PepGMV) and Pepper huasteco yellow vein virus (PHYVV), members of the Geminiviridae family, are important pathogens of pepper (Capsicum annuum L.) and other solanaceous crops. Accession BG-3821 of C. chinense Jacq. was reported earlier as resistant to mixed infection with PepGMV and PHYVV. In this work, we characterized the Geminivirus resistance trait present in BG-3821. Segregation analysis suggested that resistance depends on two genes. Our data showed that PepGMV replication in protoplast of resistant plants is approximately 70% lower when compared with the levels observed in protoplasts from susceptible plants. Additionally, viral movement is less efficient in resistant plants. We also evaluated several characteristics commonly associated with systemic acquired resistance (SAR), which is a conserved defensive mechanism. The concentration of salicylic acid was higher in resistant plants inoculated with PepGMV than in susceptible plants. Marker genes for SAR were induced after inoculation with PepGMV in resistant leaves. Similarly, we found a higher accumulation of reactive oxygen species on resistant leaves compared with susceptible ones. A model for the mechanism acting in the Geminivirus resistance detected in BG-3821 is proposed. Finally, the importance of BG-3821 in Geminivirus resistance breeding programs is discussed.     

中国辣椒热激蛋白HSP70基因家族分析

以中国辣椒(Capsicum chinense Jacq.)基因组数据为基础, 采用生物信息学方法对中国辣椒HSP70基因家族进行全基因组鉴定分析.结果显示, 中国辣椒全基因共鉴定得到20个HSP70基因, 编码蛋白序列长度为516～854 aa, 分子量大小为56.21～94.26 kD.系统进化分析结果表明, 中国...     

Cadaverine: a common polyamine in zygotic embryos and somatic embryos of the species Capsicum chinense Jacq.

The behavior of endogenous polyamines was studied in somatic embryos and zygotic embryos of Habanero pepper (Capsicum chinense). In the first part of the work, the polyamine content was evaluated in both types of embryos (somatic and zygotic). As a result, in addition to the common polyamines (putrescine, spermidine and spermine), it was also possible to detect cadaverine, a polyamine rarely found in plants. In general, all the polyamines were found to be more abundant in somatic embryos than in zygotic embryos, with significantly higher contents of putrescine and cadaverine. Subsequently, the content of putrescine, spermidine, spermine and cadaverine, in their different forms (free, bound and conjugated) was determined in somatic embryos which were cultured in non-ventilated and ventilated containers. Detection of polyamines was carried out at 28 and 42 days of culture by the HPLC method. The ethylene content was monitored during the process in both culture conditions (ventilated and non-ventilated). As a result of the analysis, cadaverine was always found present, indicating that it is a common polyamine in the species. Ethylene was detected in containers without ventilation throughout the culture, except during replenishment of the culture medium (R1, R2 and R3). The behavior pattern of each polyamine, analyzed under different culture conditions (ventilated and non-ventilated) and at different moments of culture (28 and 42 days of culture), show that the polyamines are not only involved in morphogenic processes in plants; polyamines are also significantly affected by the surrounding environment. However, the most novel result, presented for the first time in this paper, is that cadaverine is found to be a common polyamine in C. chinense since it is present in both zygotic embryos and somatic embryos.

     

Occurrence of Cotton leaf curl Multan virus and associated betasatellites with leaf curl disease of Bhut-Jolokia chillies (Capsicum chinense Jacq.) in India

Molecular Biology Reports - Geminiviridae comprises the largest family of plant viruses which causes severe crop losses in India. The highest pungency chilli Bhut-Jolokia or ghost pepper (Capsicum...     

Isolation, Characterization and Antifungal Activity of Proteinase Inhibitors from Capsicum chinense Jacq. Seeds

Capsicum species belong to the Solanaceae family and have great social, economic and agronomical significance. The present research presents data on the isolation and characterization of Capsicum chinense Jacq. peptides which were scrutinized in relation to their toxicity towards a diverse set of yeast species. The protein extract was separated with C18 reverse-phase chromatography in high performance liquid chromatography, resulting in three different peptide enriched fractions (PEFs) termed PEF1, PEF2 and PEF3. Tricine-SDS-PAGE of the PEF2 revealed peptides with molecular masses of approximately 5.0 and 8.5 kDa. These PEFs also exhibited strong antifungal activity against different yeasts. In the presence of the PEF2, Candida tropicalis exhibited morphological changes, including cellular agglomeration and formation of pseudohyphae. Determined N-terminal sequences of PEF2 and PEF3 were proven to be highly homologous to serine proteinase inhibitors, when analysed by comparative database sequence tools. For this reason were performed protease inhibitory activity assay. The PEFs displayed high inhibitory activity against trypsin and low inhibitory activity against chymotrypsin. PEF2 and PEF3 were considerably unsusceptible to a broad interval of pH and temperatures. Due to the myriad of application of Proteinase inhibitors (PIs) in fields ranging from plant protection against pathogens and pests to medicine such as in cancer and virus replication inhibition, the discovery of new PIs with new properties are of great interest.     

Induction of capsaicinoid accumulation in placental tissues of Capsicum chinense Jacq. requires primary ammonia assimilation

The activities of primary ammonia assimilation enzymes were analyzed in isolated placentas of habanero peppers (Capsicum chinense Jacq.). The placentas were cultured in vitro and exposed to conditions promoting capsaicinoid accumulation, such as treatments with salicylic acid (SA) and methyl jasmonate (MeJa). Although exposure to both inducers resulted in increased accumulation of capsaicinoids, the induction by SA was more pronounced. Glutamine synthetase (GS) activity, which incorporates ammonia into glutamine, increased more than six fold under such conditions, suggesting GS participation in fulfilling the demand for amino acids required to support the increase in capsaicinoid synthesis. Glutamate dehydrogenase (GDH), which has been involved in nitrogen assimilation in non-photosynthetic tissues such as placentas, was apparently not involved; its activity decreased in tissues exposed to the inducers. Thus, under the conditions tested, the activation of secondary metabolism required activation of basal nitrogen metabolism.     

Morpho-histological and ultrastructural study on direct somatic embryogenesis of Capsicum chinense Jacq. in liquid medium

Somatic embryo-like structures were produced from the hypocotyls of aseptic plants of Capsicum chinense. Different concentrations of 2,4-dichlorophenoxyacetic acid (0, 4.5, 9.05 μM), several exposure times of the explant to this auxin (15, 30, 45, 60 days) and the development of somatic embryos cultured in a solid and/or liquid medium were evaluated. As a result, a novel system of regeneration via direct somatic embryogenesis in liquid medium was established, with an efficiency of 1.77 × 10⁴ somatic embryos per liter of medium. Critical stages of embryogenesis, including cellular acquisition of morphogenetic competence, suspensor formation, and development and maturation of somatic embryos, were identified by histological analysis and scanning electron microscopy. Our results show a promising new outlook on the in vitro regeneration of this species. Contrary to what has been reported to date for the Capsicum genus, it is a species of plants with higher embryogenic potential in vitro.     

水稻花药对高温胁迫的生理响应

为了探明水稻花药在高温胁迫下的生理反应及适应机理,以耐热水稻品系996和热敏感水稻品系4628为材料,在人工气候室进行高温（9：00-17：00,37℃;17：00-9：00,30℃）和适温处理（9：00-17：00,30℃;17：00～9：00,25℃）,研究高温胁迫对水稻花药可溶性糖、可溶性蛋白质、热稳定蛋白、维生素C含量、膜透性及内源激素含量等生理特性的影响。结果表明,高温使水稻花药中可溶性糖含量、可溶性蛋白质含量和维生素C含量下降,热稳定蛋白含量上升;热敏感品系4628花药中丙二醛含量和相对电导率在高温胁迫下增幅大于耐热品系996;高温胁迫下,水稻花药中GA3和IAA含量降低,ABA含量上升,耐热品系996花药中GA3、IAA含量降低幅度小于热敏感品系4628,ABA含量增加幅度小于热敏感品系4628。     

Influence of hydrogen peroxide foliar applications on in vitro antimicrobial activity in Capsicum chinense Jacq.

The aim of this study was to evaluate the effect of foliar applications of hydrogen peroxide on the antimicrobial activity of Capsicum chinense Jacq. methanolic extracts. The effects of hydrogen peroxide application on metabolites accumulation of C. chinense var. Jaguar and var. Chichen Itza were evaluated. Total flavonoid and phenolic contents, as well as HPLC quantification of capsaicin and dihidrocapsaicin were carried out. Methanolic extracts were microbiologically tested against Staphylococcus aureus, Escherichia coli, Streptococcus mutants, Salmonella thompson, Listeria monocytogenes, Streptococcus faecalis, and Candida albicans. Total phenolics, flavonoids, and capsaicinoids contents in both varieties treated with hydrogen peroxide were found significantly higher as compared to control. The antibacterial activity of chili extracts was observed against Gram-positive and Gram-negative bacteria as well as anti-yeast. The results of in vitro antibacterial activity showed that hydrogen peroxide application increases the inhibitory effect against the pathogenic micro-organisms. Methanolic extracts of var. Jaguar, were the most active against S. aureus, S. Thompson, and C. albicans, while var. Chichen Itza was most potent against E. faecalis and E. coli. Thus, this study confirmed that metabolite-induced factors (MIFs) as hydrogen peroxide, increased secondary metabolites accumulation in C. chinense methanolic extracts and augmented their antimicrobial activity.     

Dynamics of changes in bioactive molecules and antioxidant potential of Capsicum chinense Jacq. cv. Habanero at nine maturity stages

The changes in bioactive molecules (capsaicin, total phenol, total flavonoid, ascorbic acid and β-carotene) and antioxidant potential in Capsicum chinense Jacq. cv. Habanero were examined during nine maturity stages (at 7-day interval from fruit set). The rate of in vivo synthesis of these antioxidants increased progressively with advancing maturity. Capsaicin, ascorbic acid, and β-carotene contents increased about 3, 10, and 9 times, respectively, at 63 days after fruit set (DAFS) while the highest value for total phenol (~330 mg CE/100 g), flavonoid (~138 mg RE/100 g), DPPH radical scavenging activity (~82 %), and metal chelating activity (~75 %) recorded in 42–49 DAFS. Bioactive molecules were positively correlated with radical scavenging and metal chelating activities. The results underline the effect of maturity on the bioactive molecules and antioxidant potential suggesting that fruits at the red stage (42–49 DAFS) are optimal from the nutritional point of view.     

Osmotic stress induced-capsaicin production in suspension cultures of Capsicum chinense Jacq.cv. Naga King Chili

The influence of osmotic stress on capsaicin production was investigated in cell suspension cultures of Capsicum chinense Jacq.cv. Naga King Chili, a chili species native to Northeastern India. The sterilized seeds were germinated in Murashige and Skoog medium. Two-week-old hypocotyls were excised from in vitro germinated seedlings and implanted in MS medium containing 2, 4-dichlorophenoxyacetic acid (2?mg/l), and Kinetin (0.5?mg/l) for callus induction. Capsaicin production in the suspension cultures was significantly affected using sucrose, mannitol, and NaCl in the medium. Stoichiometric analysis with different combinations of sucrose and non-sugar osmotic agent (NaCl) showed that osmotic stress was an important factor for enhancing capsaicin production in cell suspension cultures of C. chinense. The capsaicin content of 1,644.1???g?g^?1 f.wt was recorded on day 15 in cultures grown in MS medium containing 87.64?mM sucrose in combination with 40?mM NaCl. However, osmotic stress treatment at 160?mM NaCl with sucrose resulted in lowering capsaicin accumulation and separation of cell wall from their cytoplasm, under microscopic observation.     

Physiological Changes in Portulacaria afra (L.) Jacq. during a Summer Drought and Rewatering

The changes of titratable acidity, enzyme activity, water status, and pigment composition were studied in Portulacaria afra (L.) Jacq. during a normal summer drought and rewatering. Two groups of plants were grown outside under a clear plastic canopy with water stress initiated at 2-week intervals in May 1986. Drought resulted in a linear decrease of fresh weight for 80 days and there was no further fresh weight change for the next 65 days. Nocturnal CO₂ uptake remained measurable for 83 days. Cessation of exogenous CO₂ uptake corresponded to the point where the pressure potential (Ψ_p) became zero. Ribulose-1, 5-bisphosphate (RuBP) and phosphoenolpyruvate carboxylase were reduced to 50% of this activity by the end of the drought period. Phosphoenolpyruvate carboxykinase activity was undetectable after 120 to 140 days of drought. Chlorophyll (Chl) levels decreased with a preferential loss of Chl a over Chl b. Carotenoid content was relatively constant over the course of the drought period. After 145 days of drought, plants responded to rewatering within 24 hours; Ψ_p became positive and daytime CO₂ uptake resumed after 24 hours. After 3 days, RuBP carboxylase activity reached control levels. Activity of the CAM pathway recovered after 5 days, as noted by increased diurnal acid fluctuations. Phosphoenolpyruvate carboxylase and phosphoenolpyruvate carboxykinase activity fully recovered within 6 days. Chl levels were greater than control levels within 5 days. Chl a/b ratios took 27 days to return to control levels. The results indicated that P. afra can withstand a normal summer drought by utilizing the CAM and CAM-idling pathway for 130 to 140 days. The plants respond rapidly to rewatering because of the conservation of enzyme activity and the quick recovery of Ψ_p.     

中国辣椒热胁迫转录因子的全基因组鉴定及热胁迫响应的初步分析

采用生物信息学方法,从中国辣椒(Capsicum chinense Jacq.)全基因组序列中鉴定得到28个热胁迫转录因子(HSF)候选基因,并对这些候选基因的染色体分布、基因结构及编码蛋白的3D结构特征进行了分析。结果显示:28个候选基因的编码蛋白长度为128~526 aa;系统发育分析结果表明,HSF可分为A、B、C 3个亚家族。进一步对热胁迫处理后的中国辣椒种质进行转录组分析,共检测到27个HSF转录本,与对照组相比,实验组中有25个基因对热胁迫有不同程度的响应。     

圈养普氏野马对夏季高温生理应答的非损伤性研究

为研究圈养普氏野马Equus przewalskii对夏季高温刺激的生理应答,采用非损伤性取样法和放射性免疫法,随机选取5个圈养家族群中的成年雄马、成年雌马和成年带驹雌马各5匹,对其夏季高温期粪便内糖皮质激素和三碘甲腺原氨酸(T3)代谢产物的水平进行了测定。结果表明:(1)普氏野马在夏季高温期间一直维持在较高的激素水平;(2)不同类群的糖皮质激素代谢产物水平之间的差异有统计学意义(F_2,_(60)=22.885,P0.001),成年雄马成年雌马成年带驹雌马;(3)不同类群的T3代谢产物水平之间的差异有统计学意义(F_2,_(60)=37.780,P0.001),成年雌马成年雄马成年带驹雌马;(4)3组组内不同应激程度(THI28.9 vs.THI≤28.9)下的激素水平差异无统计学意义,且组别与应激程度不存在交互作用。鉴于圈养普氏野马在夏季高温期不同类群的生理应答水平不同,建议对野马分组、分圈进行管护,防止高温造成意外损失;同时,建议利用非损伤性取样法对圈养普氏野马生理状况进行监测,为管理者进行有效的生存管理提供基础资料。     

Assessment of Gene Flow from Genetically Modified Anthracnose-Resistant Chili Pepper (Capsicum annuum L.) to a Conventional Crop

We conducted a 2-year field assessment of the gene flow from genetically modified (GM) chili pepper (Capsicum annuum L.), containing the PepEST (pepper esterase) gene, to a non-GM control line “WT512” and two commercial hybrid cultivars, “Manidda” and “Cheongpung Myeongwol (CM).” After seeds were collected from the pollen-recipient non-GM plants, hybrids between them and the GM peppers were screened by a hygromycin assay. PCR with the targeting hpt gene was performed to confirm the presence of transgenes in hygromycin-resistant seedlings. Out of 7,071 “WT512” seeds and 6,854 “Manidda” seeds collected in 2006, eight and 12 hybrids, respectively, were detected. In 2007, 33 hybrids from 3,456 “WT512” seeds and 50 hybrids from 3,457 “CM” seeds were found. The highest frequency of gene flow, 6.19%, was observed in that 2007 trial. These results suggest that a limited isolation distance would be sufficient to prevent gene flow from GM to conventionally bred chili peppers.     

施硒对人参菜生长及生理特性的影响

为研究施硒对人参菜生长的影响并培育富硒人参菜,采用盆栽试验,测定了施硒(0、2.5、5、10、20 mg/kg)对人参菜生长、叶片光合色素含量、生理特性以及硒积累的变化情况。结果显示:(1)施硒对人参菜生长有"低促高抑"的影响,人参菜的株高、茎粗、根长、分支数、生物量均呈先升高后降低的趋势。(2)施硒能增加人参菜叶片中光合色素的含量,其中高浓度硒(≥10 mg/kg)对人参菜叶片中光合色素含量影响显著。(3)人参菜叶片SOD、POD活性在硒浓度为2.5 mg/kg时最高(P0.05),CAT活性在硒浓度为5 mg/kg时最高(P0.05);随着硒浓度的增加,人参菜叶片中维生素C含量逐渐升高,可溶性蛋白含量先升后降,可溶性糖含量下降。(4)人参菜中硒含量的分布表现为:根叶茎,且随硒浓度升高而升高,表明人参菜根系是硒积累的主要部位。研究认为,硒浓度为5 mg/kg是培育富硒人参菜的最佳浓度。     

Effects of pepper (Capsicum chinense) genotypic diversity on insect herbivores

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