柠檬合子胚自交实生苗的鉴定及其对柑橘溃疡病的抗性初步评价

枸橼C-05是抗溃疡病的柑橘种质资源,柠檬是枸橼的后代,其自交后代可能继承枸橼的抗性基因。为分析柠檬自交群体对柑橘溃疡病的抗感性规律,本研究建立了433株的‘尤力克’柠檬自交后代群体,并利用SSR分子标记对合子胚实生苗进行了鉴定,观察合子胚实生苗和珠心胚实生苗叶片形态学的差异,对所有自交后代离体注射接种柑橘溃疡病菌,初步评价了实生后代对柑橘溃疡病的抗病性差异。结果表明‘尤力克’柠檬存在多胚性,从300对SSR引物中筛选到8对可用于‘尤力克’柠檬合子胚鉴定的引物,共鉴定出合子胚实生苗57株,确定珠心胚实生苗4株。叶形指数、叶尖指数、翼叶长、翼叶宽和叶柄长均不能作为区分‘尤力克’柠檬合子胚实生苗与珠心胚实生苗的形态学标记,但合子胚实生苗的翼叶长度变异幅度大于珠心胚。57株合子胚实生苗离体接种柑橘溃疡病菌后,5株表现为抗病,52株表现为感病;4株珠心胚实生苗均表现为感病;在372株未鉴定清楚的自交后代中,8株表现为抗病,364株表现为感病。本研究表明利用SSR分子标记还不能完全鉴定出‘尤力克’柠檬合子胚植株,可能需要更多的引物或更灵敏的分子标记才能把全部实生后代鉴定出来。利用合子胚自交后代接种鉴定,更有利于分析‘尤力克’柠檬对柑橘溃疡病的抗感性遗传规律,挖掘抗性基因,为柠檬的抗病育种提供种质资源。     

激光--检测柑橘溃疡病的新武器

巴西圣保罗大学与巴西柑橘基金会目前正合作研究一项新的检测方法,即使用激光来检测柑橘病害,尤其是柑橘溃疡病。圣保罗大学的研究人员发现,用绿色激光照射甜橙树或以甜橙作砧木的其他柑橘树时,会因树体健康状况不同而发出不同颜色的光。目前研究人员已研究出了怎样用此方法鉴别柑橘及实验室苗木上的溃疡病,该技术有望在1年后推广到生产中。在此之前,检测柑橘溃疡病的惟一方法就是目测。当人们目测出溃疡病时,该病可能已大面积传播开了。巴西圣保罗州法律明确规定,当柑橘园内有0.5%的植株感染了柑橘溃疡病时,种植园周边的柑橘树就都要移除;…     

30％氢氧化铜悬浮剂防治柑橘溃疡病效果研究

柑橘溃疡病是柑橘的危险性病害之一，是一种影响全球柑橘产业发展的重大顽固病害。柑橘感染溃疡病后，在叶、枝、果上形成火山口状的病斑，后期落叶、落果，严重影响着柑橘产量和果实品质的提高。由于该病传染性很强，一旦暴发，将会给发病区带来极大的损失。为了寻求防治柑橘溃疡病的最佳药剂，搞清30％氢氧化铜悬浮剂的最佳使用浓度，特设置本试验示范。     

陈善春研究员团队在柑橘抗病分子育种获得突破

<正>笔者从中国农业科学院柑橘研究所获悉,近段时间,该所所长陈善春研究员团队在柑橘溃疡病和黄龙病抗病分子育种研究领域取得突破性进展,建立并利用基于CRISPR/Cas9的柑橘基因组编辑技术对柑橘感病基因CsL OB1启动子区进行定点编辑获得抗溃疡病柑橘材料,通过韧皮部特异表达抗菌肽基因Cecropin B获得对黄龙病耐性显著提高的转基因柑橘材料。有     

柑橘溃疡病解决方案

<正>柑橘溃疡病是国内外的植物检疫对象。近年来,由于苗木的盲目调运引种和生产上的疏忽,各地柑橘产区的溃疡病有上升蔓延趋势,果实受害重者落果,轻者带有病疤不耐贮藏,发生腐烂,大大降低果实商品价值,使果农增加病虫防治成本,经济效益受损。一、农业防治1.严格实行检疫制度。严禁病区苗木及砧木、接穗外调,     

噻唑类有机铜杀菌剂嘉~?,已瞄准了细菌性病害防控市场的历史机遇!

<正>喜好高温、高湿环境的柑橘溃疡病,近年来随着沃柑等感病品种的北上,发病面积也随之扩展。但由于多数橘农的粗犷管理和防治技术不到位等原因,溃疡病近年来已发展成了仅次于黄龙病的第二大柑橘病害,日益制约柑橘产业的快速发展。浙江龙湾化工有限公司(下称龙湾化工)4月27在五十多位经销合作伙伴见证下,成功首发上市的噻菌铜新品嘉~?,不仅成为了防控溃疡病的新星,同时也成为了种植者心中应对多种细菌性病害时"杀菌治病和增产创收"的新利器。     

夏秋季要注意防治柑橘潜叶蛾

<正>柑橘潜叶蛾,又名绘图虫、鬼画符、潜叶虫,属鳞翅目、潜叶蛾科,其发生遍布全国柑橘产区,是为害柑橘树夏、秋梢的主要害虫。如防治不及时,就会导致卷叶、新梢生长差,削弱光合作用,影响树势和次年开花结果,同时也为溃疡病的入侵和红蜘蛛等害虫的聚居、越冬提供了有利条件。下面将其发生特点与防治技术作一介绍,以帮助果农科学防治。一、发生特点1.形态特征其成虫为银白色小蛾,体长2毫米,翅     

柑橘完熟栽培技术（下）

正六、病虫害防治在常规防治的基础上,要加强对影响果实外观品质的病虫害,如柑橘疮痂病、柑橘溃疡病、柑橘树脂病、柑橘黑斑病、柑橘煤烟病、柑橘黄斑病及介壳虫、柑橘锈壁虱、柑橘黑刺粉虱、柑橘吸果夜蛾等的防治,以提高果面光洁度。生产上以预防为主,实行综合防治。采收后或早春萌芽前结合修剪,将树上剪下的病虫枝、枯枝、交叉枝、     

柑橘R2R3-MYB类转录因子CitMYB20的克隆与表达分析

为解析柑橘R2R3-MYB转录因子家族成员CitMYB20基因的分子生物学特征及受柑橘黄龙病病菌和溃疡病病菌的诱导表达情况。本研究同源克隆了不同柑橘品种中CitMYB20基因的开放阅读框序列,利用生物信息学方法预测其生物学功能并分析比较该基因在不同品种间的序列差异。在洋葱表皮细胞中瞬时表达观察CitMYB20的亚细胞定位。利用qRT-PCR技术分析黄龙病病菌胁迫和溃疡病病菌胁迫时CitMYB20的表达量变化。研究结果显示柑橘CitMYB20基因在晚锦橙、酸柚、纽荷尔脐橙和四季橘中的相似度达到99.01%,高度保守。晚锦橙中该基因含有3个外显子和2个内含子,其开放阅读框为804 bp,编码267个氨基酸残基。CitMYB20蛋白的N端高度保守,具有两个R结构域,属于典型的R2R3类型的MYB转录因子家族的成员。洋葱表皮细胞亚细胞定位分析结果表明该基因定位于细胞核中。CitMYB20基因受黄龙病病菌胁迫时,在黄龙病敏感品种晚锦橙和耐性品种酸柚中均显著上调表达,其中在耐病品种酸柚中上调表达24倍,在感病品种晚锦橙中上调表达34倍;而在溃疡病病菌胁迫时,CitMYB20基因仅在溃疡病抗性品种四季橘中显著差异表达,感病后上调表达3倍。推测该基因对黄龙病和溃疡病的应答差异可能是因为不同的调控机制造成的,构建CitMYB20基因过表达载体拟对不同病原的应答情况进行深入研究。     

九个中华类红肉猕猴桃品种的亲缘关系及其溃疡病抗性分析

为明确中华类红肉猕猴桃品种的亲缘关系并从中筛选溃疡病抗性种质,本研究使用SCo T分子标记对九个红肉猕猴桃品种的亲缘关系进行鉴定,同时使用离体枝条鉴定的方法对各品种的溃疡病抗性进行评价。结果表明:除红阳系品种‘红阳’、‘红昇’、‘红实1号’、‘红实2号’、‘东红’、‘脐红’等明显聚为一类外,野外实生选育品种‘湘吉红’也与红阳系有较近的亲缘关系,甚至比东红更优先聚类,说明其可能具有‘红阳’的遗传背景。而‘楚红’和‘桂红’与红阳系品种具有明显较远的遗传距离,甚至远于对照品种‘Hort16A’和‘Hayward’,说明其与红阳系有着明显不同的遗传背景。红阳系除‘红实2号’表现为感病外,其余均表现为高感。‘楚红’和‘桂红’被证明对溃疡病的抗性较强,甚至强于耐病对照品种‘Hayward’。研究明确了九个中华类红肉猕猴桃品种的亲缘关系及其对溃疡病的抗性,筛出了两个对溃疡病具有显著抗性的红肉猕猴桃资源,为进一步培育具有溃疡病抗性的红肉猕猴桃新品种提供了重要的物质基础。     

叶片结构与柑橘溃疡病抗性的初步研究

摘要: 对5个柑橘品种（稻叶温州蜜柑[Citrus unshiu (L.) var. Inaba]、春见[(C. reticulata × C. sinensis) var. Okitsu No. 44]、卡拉卡拉红肉脐橙[C. sinensis (O.) var. Cara Cara]、玫瑰橙[C. Sinensis var. Meiguicheng]和HB柚[C. grandis (L.) var. HB]） 的夏梢老熟叶片气孔及其显微结构进行解剖构造的观察和测定。结果表明：不同品种间叶片的气孔密度差异显著,并且与品种抗病性成正相关,其相关系数为0.888;可以把叶片气孔的密度作为抗柑橘溃疡病的形态结构的初步鉴定指标。不同品种间叶片的显微结构特征差异不显著,与品种抗病性相关性不显著,品种间变化规律性不强。     

Regeneration and characterization of somatic hybrid plants of Citrus sinensis (sweet orange) and Citrus micrantha, a progenitor species of lime

Most commercial citrus fruit species and cultivars are inter- and intra-specific hybrids. Conventional hybridization in citrus is largely handicapped by apomixis and long juvenility. As an alternative, somatic hybridization via protoplast fusion has been employed to create novel citrus germplasm. Witches' broom disease of lime (WBDL) emerged in Oman during the 1970s, which has been spreading to the neighboring countries. The disease is extremely destructive. A possible solution to the WBDL problem is to develop resistant hybrids. Resistance is available among the citrus relatives of lime i.e., sweet orange. Somatic hybrids combining sweet orange with lime have been produced but the fruit characteristics are different from lime. Herein, we report the development of somatic hybrids between a progenitor of lime (Citrus micrantha) and sweet orange (Citrus sinensis) in efforts to recreate a lime-like fruit using sweet orange as a donor of disease resistance gene(s). Successful somatic hybridization was verified by ploidy analyses using flow cytometry and RAPD analyses. This is the first report of using a progenitor species in somatic hybridization experiments in efforts to resynthesize an improved lime.     

不同烤烟品种种子萌发的低温耐受性比较

烤烟育苗期间,低温冻害常有发生,不同烤烟品种在抵抗低温胁迫时存在差异,但缺乏相应的数据验证。以烤烟主栽品种‘云烟85’、‘云烟87’、‘K326’、‘红花大金元’（‘红大’）和‘云烟97’的种子为研究材料,比较不同品种烟草种子萌发期的低温耐受性,为烤烟品种选择和布局提供参考。结果表明,常温（25℃）下5个烤烟品种均能在5天后开始萌发,但达到最大发芽率的时间相差1~2天,以‘云烟97’最迟;随着培养温度的降低,5个烤烟品种种子的发芽势、标准发芽率和发芽指数均有不同程度的下降;综合比较各发芽参数,不同品种萌发期的低温耐受性以‘云烟97’最差,其他4个品种之间的综合表现差异不明显;低温会明显抑制烤烟种子萌发、延长育苗时间,但温度在10℃~25℃范围内,各品种最大发芽率仍能在30天内达到95%以上。     

基于SSR标记的肇庆地区柑橘品种分类地位研究

评价广东省肇庆地区地方柑橘品种与其它部分柑橘属和近缘属植物的亲缘关系,为其分类和育种提供理论依据。从34对柑橘SSR引物中筛选到13对多态性较好的SSR引物,对8份肇庆地方柑橘品种和22份柑橘属、枳属、酒饼簕属植物材料进行PCR扩增,并采用1.5%琼脂糖凝胶电泳检测,用遗传相似性和聚类分析等方法分析检测结果。13对引物共扩增出83条谱带,多态检出率为100%,通过聚类分析能够有效的区分柑橘属、枳属和酒饼簕属,以及柑橘属内的种、品种甚至品系。结果表明SSR分子标记技术能够用于肇庆柑橘种质资源分类地位研究,并且供试的肇庆地方柑橘品种亲缘关系较近。     

Citrus breeding,genetics and genomics in Japan

Citrus is one of the most cultivated fruits in the world, and satsuma mandarin (Citrus unshiu Marc.) is a major cultivated citrus in Japan. Many excellent cultivars derived from satsuma mandarin have been released through the improvement of mandarins using a conventional breeding method. The citrus breeding program is a lengthy process owing to the long juvenility, and it is predicted that marker-assisted selection (MAS) will overcome the obstacle and improve the efficiency of conventional breeding methods. To promote citrus molecular breeding in Japan, a genetic mapping was initiated in 1987, and the experimental tools and resources necessary for citrus functional genomics have been developed in relation to the physiological analysis of satsuma mandarin. In this paper, we review the progress of citrus breeding and genome researches in Japan and report the studies on genetic mapping, expression sequence tag cataloguing, and molecular characterization of breeding characteristics, mainly in terms of the metabolism of bio-functional substances as well as factors relating to, for example, fruit quality, disease resistance, polyembryony, and flowering.     

Disease resistance in protected crops and mushrooms

Summary Cultivars of tomatoes, cucumbers, lettuce and peppers have been bred for resistance to one or more pathogens. Some tomato and cucumber cultivars have resistance to a wide range of diseases. Resistance has been transient in many cases and a succession of cultivars with new genes or new combinations of resistance genes has been necessary to maintain control. There has been a number of notable exceptions and these have included durable resistance to such pathogens asFulvia fulva and tomato mosaic virus. With lettuce the resistance situation is complicated by the occurrence of fungicide resistant pathotypes. There are no strains ofAgaricus bisporus purposely bred for disease resistance.In protected flower crops only resistance to Fusarium wilt in carnations has been purposely bred but differences in disease resistance are apparent in cultivars of many ornamental crops. This is particularly so in chrysanthemums where there are cultivars with resistance to many of the major pathogens. Similar situations occur with other flower crops and pot plants. Cultivars of some species have not been systematically investigated for resistance.The need for genetic resistance will increase with the further reduction, in the limits on pesticide use and an increasing public awareness and importance of pesticide pollution.ADAS is an executive agency of the Ministry of Agiculture, Fisheries and Food and the Welsh Office.     

Potential application of simple easy-to-use insertion-deletion (InDel) markers in citrus cultivar identification

We previously developed insertion-deletion (InDel) markers that distinguish three genotypes (two homozygous and one heterozygous) of diverse citrus cultivars. These InDel markers were codominant and could be clearly detected by using simple agarose gel electrophoresis. We sought to establish a method for cultivar identification using these 28 InDel markers to genotype 31 citrus cultivars. The results revealed that a minimum of 6 markers were required to identify individuals using the three-genotype classification method. Furthermore, we found that a simple method for distinguishing between two genotypes (homozygous and heterozygous) could be used to identify individuals using a minimum of 7 markers. Our findings provide a basis for the development of simple and rapid citrus cultivar identification methods.     

Identification of origin and analysis of population structure of field-selected imidazolinone-herbicide resistant red rice (<Emphasis Type="Italic">Oryza sativa</Emphasis>)

Several red rice biotypes have evolved resistance to imidazolinone herbicides. The origin of resistance has been attributed to gene flow from the herbicide-resistant rice cultivars, but independent evolution of spontaneous mutation can also contribute to the herbicide resistance. The objective of this study was to quantify the occurrence of gene flow and independent selection as the mechanisms of origin of imidazolinone-resistance in red rice to correctly define the management practices for red rice control. Three single nucleotide polymorphism markers were used to identify acetolactate synthase (ALS) gene mutations, and four simple sequence repeat markers were used to identify hybrids of imidazolinone-resistant rice cultivars and red rice. In addition, genetic diversity and population structure analyses were performed. Artificial hybrids were used as controls. Gene flow was the main origin of imidazolinone herbicide resistance, but independent selection occurred in 1.1 % of the evaluated red rice plants. Two red rice plants that independently evolved herbicide resistance had the ALS gene mutation, Gly₆₅₄Glu. Population structure analysis also indicated intense gene flow from rice cultivars to red rice, but some populations maintained a high genetic identity based on a small amount of gene introgression from the rice cultivars. These results indicate the importance of adopting controls of red rice escapees to avoid gene flow from the imidazolinone-resistant rice, and the necessity of biotechnological approaches to mitigating gene flow in the development of new herbicide-resistant rice cultivars.     

Different types of resistance against greenbug, Schizaphis graminum Rond, and the Russian wheat aphid, Diuraphis noxia Mordvilko, in wheat

A collection of 26 cultivars of wheat Triticum aestivum were screened for resistance against the two main aphid pests of cereals, the greenbug Schizaphis graminum Rond. and the Russian wheat aphid (RWA) Diuraphis noxia Mordvilko. Since genetic variability has been found in Argentinean populations of both aphid species, this work was aimed at determining the response of different types of resistance in wheat cultivars when infested with aphids. Antixenosis, antibiosis and tolerance were evaluated with traditional tests in controlled environmental conditions using a clone of greenbug biotype C and a clone of RWA collected on wheat. Genetic resistance was found against one or both aphid species in several wheats. Most of the highest levels of antixenosis, antibiosis and tolerance against the two aphids occurred in different cultivars; as a consequence the resistance mechanisms for both pests appear to be partly independent. Antibiosis against greenbug or RWA appears to be determined by two different sets of genes, one affecting development time and the other reducing fecundity and longevity. The antibiosis against both aphid species in terms of their development time and the intrinsic rate of population increase resulted in a partial cross effect of these aphid traits against the alternative insect species. Nonetheless, the same cultivars affected the total fertility and the longevity of both aphids. Since the highest plant performance levels and the least plant damage were recorded in different wheats, different patterns of tolerance were displayed against the greenbug and the RWA. Consequently, different genes appear to be involved in several traits of the resistance mechanisms against the two aphids. The genes that independently conferred resistance to aphids could be combined in new cultivars of wheat to broaden their genetic base of resistance against the greenbug and the RWA.     

Resistance of almond cultivars to Plum pox virus (sharka)

Sharka, a disease caused by Plum pox virus (PPV), mainly affects some Prunus species, including apricot, peach and plum, and to a lesser degree, sweet cherry and sour cherry. In almond, different PPV isolates have been transmitted experimentally to the ‘Aï’ cultivar. In this study, the resistance of 10 almond cultivars to a Dideron PPV isolate was evaluated in controlled conditions by grafting the cultivars on to inoculated GF305 peach rootstocks. The results demonstrated a high level of resistance to PPV in all the almond cultivars assayed. They did not show any symptoms and were ELISA and RT‐PCR negative, despite the strong symptoms observed in their GF305 rootstocks. The implications of these results for the dispersion of PPV, and the potential role of almond as a source of resistance to PPV in other Prunus species such as peach, are also discussed.