梨花芽休眠相关miRNA的鉴定和差异表达分析

为了探究梨花芽休眠进程中miRNA的表达模式和靶基因,利用Solexa测序技术、生物信息学分析和实时荧光定量PCR（qPCR）技术,对内休眠、内休眠解除和生态休眠解除3个时期梨花芽的miRNA进行高通量测序、筛选和鉴定。结果表明,内休眠、内休眠解除和生态休眠解除时期3个样本文库中分别有12 276 226、10 135 952、11 453 981条Unique序列。miRNA主要分布在21 ~ 24 nt之间,其中长度为24 nt的数量最多。共检测到151个已知的miRNA,属于39个不同的家族,并利用生物信息学软件预测到了209个新的miRNAs。比较分析从内休眠进入到生态休眠解除的整个休眠转换时期差异表达的miRNA,筛选出8个miRNA（ahy-miR156b-5p、cpa-miR319、aly-miR172c-3p、aau-miR396、mdm-miR858、aly-miR171b-3p、bdi-miR160f和hbr-miR166a）,其靶基因主要参与转录调控、信号传导等过程。利用qPCR验证了8个miRNA及其8个靶基因的表达。     

GMS杂交辣椒新品种星秀的选育

星秀是以R0971AB细胞核雄性不育系(GMS)为母本,R0997为父本配制而成的杂交一代小米辣类型辣椒品种,果实小指形,果长7.5 cm左右,果宽1.4 cm左右,青熟果白色,老熟果红色,单生朝天,果尖较尖,单果质量4.9 g左右,果实辣味浓,单株挂果多,丰产潜力大,抗性强,适合作干椒或泡辣椒。     

辣椒育性恢复的遗传及恢复系和保持系的鉴定

对稳定的辣椒雄性不育系(cms)CCA-4261与恢复系Pantc-1的杂交组合的育性恢复遗传进行了研究.结果认为Pantc-1的育性恢复遗传属于单基因控制性状.对全部属于C.annuum的48个辣椒品种(系)和5个甜椒品种(系)进行筛选,以查明它们是否存在育性恢复基因或雄性不育保持基因,并根据雄性不育细胞质是否转移到比较理想的辣椒品系讨论了这些品种(系)究竟属于保持系还是恢复系.     

辣椒育性恢复的遗传及恢复系和保持系的鉴定

对稳定的辣椒雄性不育系(cms)CCA-4261与恢复系Pantc—1的杂交组合的育性恢复遗传进行了研究。结果认为Pantc—1的育性恢复遗传属于单基因控制性状。对全部属于C.annuum的48个辣椒品种(系)和5个甜椒品种(系)进行筛选,以查明它们是否存在育性恢复基因或雄性不育保持基因,并根据雄性不育细胞质是否转移到比较理想的辣椒品系讨论了这些品种(系)究竟属于保持系还是恢复系。     

辣椒(Capsicum annuum L.)果实发育及品质相关新microRNA的鉴定与分析

MicroRNA(miRNA)是一种非编码的小RNA,在各种生物过程中起着重要的调节作用。前人研究表明,模式植物中miRNA与果实发育相关。然而,人们对辣椒(Capsicum annuum L.)果实品质及发育相关的miRNA了解尚不清楚。本研究利用二代测序技术(Next-generation sequencing technology)比较了不同品种辣椒果实在不同发育时期的小RNA。利用miRDeep2软件从4个样本中共鉴定出了59个已知miRNA和310个新miRNA。预测了新miRNA的靶基因,共656个,并对其中402个靶基因进行了注释。GO分析和KEGG途径表明,某些靶基因与淀粉糖、氨基糖以及核糖代谢相关。qPCR表明一些miRNA的表达模式与其靶向基因相反,该结果为今后研究miRNA调控果实发育和品质形成提供了重要基础。     

辣椒细胞质雄性不育相关基因的克隆与表达分析

以辣椒细胞质雄性不育系21A及其相应保持系21B为试材,根据辣椒细胞质雄性不育相关基因orf456序列设计特异引物,对21A及21B的基因组DNA进行特异性扩增,获得了不育系特有的目的条带,克隆测序表明其大小为292bp,命名为CMS292。采用QRT-PCR方法,研究了CMS292分别在蕾期、盛花期对根、茎、叶和花蕾中的表达水平的影响,以期探索雄性不育相关基因的表达机制。结果表明:该基因只在不育系中表达,并且在所检测的组织中都有表达;蕾期根和花蕾中的表达量明显高于茎和叶,盛花期根和叶中的表达量高于茎和花蕾;从蕾期到盛花期根、茎和花蕾中的表达量呈下降趋势,而叶中的表达量呈上升趋势,推测CMS292控制辣椒花药中蛋白的表达,引起小孢子败育,进而导致雄性不育。     

利用抑制消减杂交技术分离辣椒细胞质雄性不育育性恢复相关EST

 以辣椒(Capsicum annuum L. ) 细胞质雄性不育系23A、121A, 和其相应的近等基因恢复系23C、121C为试验材料, 利用抑制消减杂交( SSH) 技术成功构建了CMS恢复基因诱导表达的消减cDNA文库。结合高密度点阵膜杂交差异筛选, 获得了282个阳性克隆。通过测序, 除去重复序列共得到175个Unique ESTs。在GenBank上进行BLAST分析, 55个EST片段未找到对应的同源序列, 可能代表了新基因;120个EST片段找到了对应的同源序列, 包括103个已知功能基因和17个未知功能基因。按照MIPS功能分类法, 将其分为14个功能组, 涉及代谢、胁迫应答、蛋白活性、转录因子、信号转导等多方面的功能。     

辣椒杂种优势利用途径分析

辣椒为常异花授粉植物,其不同品种或类型之间存在着明显的杂种优势。通常辣椒一代杂交品种比常规品种增产30％以上,且抗病性、抗逆性等优势明显。辣椒具有繁殖系数大的特点,其杂种优势能在生产上大面积利用。目前,我国鲜食辣椒品种已经实现了杂种化。辣椒杂种优势利用的途径通常有4种：常规途径、细胞核雄性不育、细胞质雄性不育和功能性雄性不育。     

辣椒新品种湘研812的选育

湘研812是以任两AB细胞核雄性不育系为母本、R07360为父本配制而成的三系配套杂交一代,极早熟,果实长灯笼形,果实由绿色转红色,果纵径17~18cm,果横径4.8cm左右,果肉厚0.3cm,平均单果质量90g。味微辣,连续坐果性强,产量高,平均鲜椒产量3000kg/667m~2。高抗炭疽病、疫病及青枯病,抗病毒病,该品种适合在辽宁、江苏、安徽、山东、重庆及新疆等地区栽培。     

Abortion of reproductive organs in sweet pepper (Capsicum annuum L.): a review

Summary

Levels of abortion of reproductive organs (i.e., buds, flowers, and young fruits) in sweet pepper plants (Capsicum annuum L.) are high, and cyclical fluctuations occur in fruit set. Stages susceptible to abortion are very young buds (< 2.5 mm), buds close to anthesis, and flowers and fruits up to 14 d after anthesis. An overview of factors and processes involved in flower and fruit abortion in sweet peppers is presented. More light, higher CO₂ concentrations, and lower planting density, increase the availability of assimilates per plant, and decrease fruit abortion. The cyclical pattern in fruit set is caused by changes in demand for assimilates. High flower abortion occurs when fast growing fruit (at approx. 3 weeks after anthesis) are present, due to competition for assimilates. Fruit set increases when fast growing fruit are almost mature and have a low assimilate demand. Prior to abortion, auxin export from the reproductive organ diminishes, ethylene production increases, and lower levels of activity of sucrose-cleaving enzymes are found. Severe water stress and low nutrient supply also increase abortion levels. Low night- and high day-time temperatures hamper pollen development, causing low seed set, which can result in fruit abortion. Two theories have been used to explain abortion: unbalanced demand for and supply of assimilates, and hormonal dominance of developing fruit over young fruit. Attempts to prevent abortion or to diminish the cyclical pattern of fruit set have not yet been successful, but new suggestions are presented.     

Apoplastic anti-oxidants in pepper (Capsicum annuum L.) fruit and their relationship to blossom-end rot

Summary

The aim of the present research was to study changes in the major anti-oxidative enzyme activities known to be associated with the apoplast, during the induction of blossom-end rot (BER) in bell pepper (Capsicum annuum L.) fruits grown under saline conditions. Pepper plants of the BER-sensitive cv. ‘Mazurka’ and less-sensitive cv. ‘Selica’ were grown under control, low- and high-salinity irrigation regimes. Fruits were harvested continuously and, after approx. 7 months under these conditions, BER symptoms started to appear (in the Spring season) and fruits were sampled for biochemical measurements. The intercellular washing fluid (IWF; apoplast fraction) of the fruit pericarp was prepared and enzyme activities in that fraction were determined. The results showed that production of reactive oxygen species (ROS) in the fruit apoplast was higher in ‘Mazurka’ than in ‘Selica’. Apoplastic peroxidase and superoxide dismutase (SOD) activities, and the concentration of ascorbic acid, increased during ‘Selica’ fruit development, whereas the concentration of H₂O₂ decreased. During the stage of rapid growth, when fruits are most susceptible to BER, apoplastic peroxidase activity was greatly enhanced in the healthy pericarp of BER-affected fruits compared to healthy fruits. Under saline conditions, apoplastic peroxidase and SOD activities, as well as ascorbic acid and H₂O₂ levels, increased in healthy fruits of the resistant cultivar ‘Selica’; whereas, in healthy fruit of the BER-sensitive cultivar ‘Mazurka’, apoplastic peroxidase activity decreased while the level of ascorbic acid increased, but to a much lesser extent than in ‘Selica’. SOD activity and H₂O₂ levels increased similarly in both cultivars with increasing levels of salinity. It is proposed that apoplast-associated peroxidase activity and ascorbic acid concentration are increased coordinately in response to salt stress and may be part of a protective anti-oxidation mechanism that determines cultivar sensitivity to BER.     

Heterosis studies in chilli (Capsicum annuum L.)

By top-crossing 12 different homozygous chilli varieties with a genetic male sterile (MS), 12 hybrids were produced. Heterosis over mid-parent (MP) and superior parent (SP) was studied for days to flower, plant height, number of primary branches, length of fruit, number of fruits per plant and fruit yield per plant. Degree and direction of heterosis varied greatly for different characteristics and crosses studied. The hybrid MS × K-2 exhibited significant positive heterosis for fruit yield over its SP (157%), followed by MS × Pant-C-1, MS × Japanese bunch variety and MS × Bhiwapur local, indicating that male sterility can be utilised for commercial exploitation of hybrid vigour. Heterosis was observed for days to flower, plant height, number of primary branches, fruit length and number of fruits per plant.     

Evaluation of new rootstocks for resistance to soil-borne pathogens and productive behaviour of pepper (Capsicum annuum L.)

Summary

An evaluation of five rootstocks for pepper (Capsicum annuum L.) was carried out over a 3-year period on three farms in Campania (Italy). Pepper is very susceptible to soil-borne pathogens, especially Phytophthora capsici, Verticillium dahliae and Meloidogyne spp. (root-knot nematode). The lack of resistant hybrids and of crop rotation, and the longterm survival of propagules of the pathogen, have increased the risk of damage that so far has been controlled by pre-planting soil treatment with methyl bromide. The use of pepper grafted onto rootstocks resistant to the main soil-borne pathogens is not undertaken commercially in Italy because the available rootstocks are unsatisfactory. P. capsici, V. dahliae, Fusarium oxysporum, F. solani and M. incognita have been detected on farms where the new rootstocks were tested. Trials were performed on the same sites for 2 or 3 years in order to provide favourable conditions for parasites. Two rootstocks, ‘Graffito’ and ‘Gc 1002’, were found to be resistant to P. capsici. In the presence of an early, high population density of M. incognita, ‘Graffito’ showed good tolerance, while ‘Gc 1002’ was susceptible to the root-knot nematode. In addition, both rootstocks showed good compatibility with the different scions tested and did not decrease vegetative growth, fruit yield or the size of the scions. In contrast, in the presence of V. dahliae, F. oxysporum and F. solani, none of the rootstocks tested was sufficiently resistant to vascular or crown and root rot damage.     

辣椒种质资源抗旱性鉴定与筛选

为了筛选到优良的辣椒抗旱资源,选用111个辣椒品系(种)为试验材料,在漂浮育苗条件下,采用反复干旱存活率对辣椒品系(种)苗期和成株期的抗旱性进行了鉴定。结果表明,苗期反复干旱存活率RDSR(Repeated drought survival rate)≥70.00%的品系(种)有9个,占供试品系(种)的8.11%;成株期RDSR≥70.00%的品系(种)有6个,占供试品系(种)的5.41%;苗期和成株期平均RDSR≥70.00%的品系(种)有5个,占供试品系(种)的4.50%。综合考虑苗期、成株期及这2个阶段平均反复干旱存活率的分析结果,筛选出‘gx2016-25’‘gc2016-33’和‘gc2016-69’共3个在苗期和成株期抗旱性均较强的品系(种)。     

The effect of root restriction on the incidence of blossom-end rot in bell pepper (Capsicum annuum L.)

Summary

Water and calcium uptake are important factors affecting the incidence of fruit blossom-end rot (BER) in tomato and pepper. In the present study an attempt was made to manipulate these factors by severe root pruning and to examine the effect on BER in greenhouse-grown bell pepper (Capsicum annuum L., cv. Mazurka). Pepper plants were transplanted, with the root system split into four separated compartments, each containing a single root quarter. Removal of half, or three quarters, of the root from fruit-bearing plants significantly reduced fruit BER incidence compared with plants with intact roots, especially in fruits which were at the rapid expansion stage at the beginning of the treatments. Removal of three quarters of the root reduced midday leaf water potential, stomatal conductance, and plant height. The number and weight of fruits were not affected by these treatments. Root pruning caused only a slight reduction in stem sap flow, as measured by the heat pulse technique. Calcium concentrations in the distal part of fruits from quarter-root-plants were higher than in fruits from non-pruned plants, whereas magnesium and potassium concentrations were not affected. On the other hand, in the leaves, calcium, magnesium and potassium concentrations were all reduced by root pruning. The K/Ca ratio decreased in the blossom-end of the fruits and increased in the leaves of root-pruned compared with control plants. The results suggest that root pruning did not affect the total uptake of calcium, apparently driven by transpiration, but did enhance calcium partitioning to the developing fruit. Root pruning also affected calcium distribution within the fruit and therefore attenuated BER incidence.     

辣椒始花节位遗传研究

 应用植物数量性状主基因+多基因混合遗传模型和经典遗传学方法对特早熟辣椒‘B₉₄₃₁ ’与‘吉林长椒’杂交组合多个世代群体始花节位进行了联合分析, 结果表明: ‘B₉₄₃₁ ’始花节位受1对隐性等位主基因控制, B₉₄₃₁ ×吉林长椒始花节位遗传符合1对主基因+多基因混合遗传模型。该杂交组合的B₁、B₂ 和F₂ 群体主基因遗传率分别为83.72%、76.56%和86.63% , 多基因遗传率分别为10.96%、18.58%和7.94%。     

Blossom-end rot is associated with impairment of sugar metabolism and growth of pepper (Capsicum annuum L.) fruits

Summary

Blossom-end rot (BER) in pepper fruits is known as a “physiological” disease which is evoked by climatic and osmotic stresses (e.g., high temperatures and salinity) and by deficit irrigation management. The physiological and biochemical mechanisms involved in the stimulation of BER are still a matter of dispute. It has been proposed that BER occurs under cultivation conditions that accelerate fruit growth beyond calcium supply to the growing tissue. In the present study, we investigated this hypothesis by recording fruit growth and sugar metabolism under normal and BER-inducing conditions.The results showed that pepper fruits grown in a ventilated-cooled greenhouse, which ameliorated BER, had a higher initial growth rate than those grown in a non-cooled greenhouse, but had lower calcium concentrations in the fruit pericarp. Fruits that grew without ventilation-cooling had higher concentrations of apoplastic and symplastic sucrose and reducing sugars, and higher levels of symplastic starch than those that developed in a cooled greenhouse. Concomitantly, fruits that developed in a non-cooled greenhouse had lower acid invertase, sucrose synthase and fructokinase activities than those that developed in a cooled greenhouse. Accordingly, the non-necrotic part of BER-affected fruits had higher concentrations of symplastic starch, reducing sugars and sucrose than healthy fruits. These findings indicate that the occurrence of BER in pepper fruits was associated with impaired sucrose metabolism in fruit tissues, which led to reductions in growth rate and final size. Thus, the present findings negate the notion that BER occurs when fruit growth rate is stimulated, and favour the idea that direct impairment of fruit sugar metabolism and of normal fruit growth are involved.     

辣椒种质资源鉴定、评价及利用研究进展

本文综述了国内外辣椒在种质资源鉴定、评价及利用方面的研究进展情况。     

Effects of an evaporative cooling system on greenhouse climate,fruit disorders and yield in bell pepper (Capsicum annuum L.)

Summary

The main goal of this research was to investigate the effects of a wet pad-and-fan evaporative cooling system (ECS) on the incidence of blossom-end rot (BER) and fruit cracking in greenhouse-grown bell pepper (Capsicum annuum L.). The specific objectives were: (i) to study the efficiency of the wet pad-and-fan ECS in improving plant water status and reducing transpiration; and (ii) to explore the impact of these conditions on fruit yield, fruit Ca content and the incidence of BER and fruit cracking. For 3 years, peppers were grown in the Lachish Region, Israel, in a greenhouse divided into two compartments, one with and one without (control) a pad-and-fan ECS. The results showed that the ECS increased total fruit yield and the incidence of cracked fruits, but reduced the incidence of BER. The efficiency of the ECS in reducing temperature and vapour pressure deficit (VPD) decreased as the distance from the wet pad increased. Consequently, the incidence of cracked fruits decreased with distance from the wet pad, whereas the incidence of BER increased.