棉花抗黄萎病生理生化机制研究进展

棉花是我国的重要经济作物,是关系我国国计民生的支柱性产业,是影响世界大宗农产品及下游纺织品贸易格局的战略性产业。由大丽轮枝菌Verticillium dahliae引起的棉花黄萎病是棉花生产上的头号病害,严重影响棉花产量与质量。黄萎病菌侵染过程中会激发棉花植株产生一系列防御反应,如组织结构抗性变化、植物激素信号通路响应及抗病相关基因表达等。目前,已从棉花中挖掘出大量响应黄萎病菌的基因,阐明了这些抗性相关基因通过调控生理生化反应而发挥抗病功能的机制。本文从活性氧、防御酶、次生代谢产物和植物激素4个方面综述了棉花抗性相关生理生化作用机制,总结了棉花抗性相关生理生化反应的调控网络,为深入了解棉花抗黄萎病机制、选育抗病品种提供理论依据。     

蜡蚧轮枝菌对西花蓟马成虫和若虫的毒力测定

利用蜡蚧轮枝菌MZ041024菌株的不同浓度孢子液对西花蓟马成虫和若虫进行室内毒力测定。结果表明:在3.6×10~8个/mL浓度下,蜡蚧轮枝菌MZ041024菌株对成虫的最高死亡率为(76.87±4.38)%,致死中浓度(4.140±0.10)×10~6个/mL,致死中时间为(5.54±0.22)d;若虫的最高死亡率为(80.95±1.71)%,致死中浓度(1.598±0.064)×10~5个/mL,致死中时间为(5.13±0.25)d,随浓度增加其杀虫速度加快,随处理时间延长其毒力增强。     

不同嫁接方法对甜瓜枯萎病抗性的影响及其生理响应

本文研究了插接、断根嫁接和靠接3种嫁接方法对甜瓜枯萎病抗性的影响。结果显示,3种嫁接方法均能显著提高甜瓜的抗枯萎病能力．但3种嫁接方法之间无显著差异。接种枯萎病菌后,嫁接苗根系活力、叶绿素含量、根系中SOD、POD、PAL活性显著高于自根苗,而MDA含量、相对电导率显著低于自根苗。以上结果表明,嫁接是提高甜瓜对枯萎病抗性的有效措施,但不同嫁接方法对甜瓜枯萎病抗性无显著影响;嫁接苗通过抗氧化系统和PAL活性的提高抵御了枯萎病菌侵染后所致的膜脂过氧化伤害,维持了根系和叶片的正常生理功能,从而提高了嫁接苗对甜瓜枯萎病的抗性。     

Virulence of Verticillium lecanii (Z.) against cereal aphids; does timing of infection affect the performance of parasitoids and predators?

BACKGROUND: Entomopathogenic fungi such as Verticillium lecanii (Z.) (Mycotal^®) are used for pest control as an alternative to chemical control. In this study, the effect of V. lecanii on cereal aphids is assessed. In addition, an investigation is carried out to determine whether the use of V. lecanii affects the performance of two natural enemies of aphids, the predator Harmonia axyridis (P.) and the parasitoid Aphidius colemani (V.), in no‐choice experiments under laboratory conditions. RESULTS: The number of Rhopalosiphum padi (L.) and Sitobion avenae (F.) killed was increased by increasing the concentration of V. lecanii. The timing of application of fungus to aphids affected the efficacy of other biocontrol agents, a parasitoid and a predator. Parasitation by A. colemani (V.) in both cereal aphids (S. avenae and R. padi) was not affected by V. lecanii when aphids were first treated with V. lecanii and then exposed to A. colemani. The emergence of adults from parasitised mummies was, however, lower in infected aphids than in uninfected aphids when the aphids were first exposed to the parasitoids and then treated with fungus. The female sex ratio in the emerging adults was lower in V. lecanii‐treated aphids in both species. When aphids were first treated with V. lecanii, 72 h before predation, fewer aphids of both species were consumed by H. axyridis (P.). CONCLUSION: Use of entomopathogenic fungus as a biological control agent could be a complementary strategy in an integrated pest management programme against cereal aphids, but it can reduce the efficiency of other biocontrol agents (parasitoids and predators) when applied simultaneously. © 2012 Society of Chemical Industry     

转抗菌肽基因辣椒株系的青枯病抗性鉴定及系统选育

利用通过农杆菌介导技术获得的T0代转抗菌肽基因辣椒植株为试材,对其自交株系世代群体连续进行抗青枯病鉴定筛选、分子生物学检测和系统选育,首次获得了具有抗青枯病能力的转抗菌肽基因辣椒稳定株系。同时,对其主要果实性状、青枯病抗性进行的对比试验结果表明,转抗菌肽辣椒株系除抗青枯病能力明显提高外,果实性状基本不变。上述结果显示,外源目的基因主要特性的遗传是稳定的、表达是忠实的,从实践上验证了转抗菌肽基因工程操作的实用性。     

Cloning of Proteinase Inhibitor Gene StPI in Diploid Potato and Its Expression Analysis

A full-length cDNA of proteinase inhibitor gene with completed open reading frame of 116 amino acids was cloned from Ralstonia solanacearum (Rs) resistant potato leaves using the rapid amplification of cDNA ends (RACE) method and designated as StPI. BLAST search against NCBI showed that the StPI gene shared 89% identity with potato proteinase inhibitor Ⅰ precursor in nucleotide and 74% in amino acid. Analysis of semi-quantitative RT-PCR indicated that this gene was induced by Rs as well as up-regulated by jasmonic acid (JA). The StPI gene expression reached the highest level during 6-12 h post Rs-inoculation or JA-treatment, and then leveled off. Moreover, this gene was strongly induced by JA and its mRNA accumulation increased more quickly than that of Rs-inoculation. The StPI gene may play a role in potato resistance against Rs. The induction of StPI by Rs invasion may have a similar signal transduction pathway with JA treatment.     

作物青枯病研究进展

茄科雷尔氏菌侵染引起的青枯病是世界性、毁灭性的作物细菌病害，该病害是典型的土传病害。茄科雷尔氏菌属薄壁菌门β- 变形菌纲雷尔氏菌属，为革兰氏阴性、好氧棒状杆菌，可侵染50 多科200 余种植物。该病原菌在无寄主植物存在时可在土壤、水体中存活5 年以上，一旦有合适的寄主植物，即可通过寄主植物的根部侵染维管束系统，引起寄主植物整株性、不可逆的萎蔫枯死。茄科雷尔氏菌是一个复合种，具有明显的生理分化与遗传多样性，已发现有5 个生理小种、5 个生化变种、4 个演化型和57 个序列变种。作物青枯病在广东省多种作物上发生十分严重，是广东省重要的植物细菌病害之一。目前，至少发现有35 种植物受到茄科雷尔氏菌的侵染与为害，其中桑、桉树、甘薯、沙姜、南瓜、空心菜、菊花、向日葵、广藿香、胜红蓟和人参果等作物青枯病被首次发现与报道，每年均造成巨大的经济损失。对国内外茄科雷尔氏菌及青枯病主要研究进展进行综述，并总结了本团队近20 年来在青枯病研究方面取得的主要成效。     

露地栽培番茄斑萎病毒病发生流行规律调查及TSWV重要寄主植物监测

为明确云南省昆明市露地栽培条件下番茄斑萎病毒病的发生流行特征,于2014—2015年采用病害系统调查法结合病毒ELISA及RT-PCR检测方法研究露地栽培条件下由番茄斑萎病毒(tomato spotted wilt virus,TSWV)引起的病毒病发生规律及其重要寄主种类,并研究利用防虫网隔离蓟马对番茄斑萎病毒病的防控效果。结果表明:番茄斑萎病毒病在露地番茄主要种植期3—10月普遍发生,番茄苗期和移栽初期是该病毒病防控的关键期,带毒种苗调运是该病毒病的主要传播途径;田间多种茄科和菊科植物是TSWV的重要中间寄主。在田间,菊科寄主植物油麦菜、莴苣、鬼针草、牛膝菊上TSWV的检出率均较高,在42.53%～81.63%之间;茄科寄主植物中辣椒上TSWV的检出率最高,为41.99%,其次为马铃薯,TSWV检出率为27.78%,在番茄上TSWV的检出率为19.02%,因此生产中应对这些TSWV重要中间寄主给予更多关注和防控。应用防虫网能有效隔离蓟马,使番茄斑萎病毒病发病率和病情指数较对照分别降低了6.44个百分点和5.31,可有效降低番茄苗期及定植期斑萎病毒病的发生。     

Soil Potassium Indices and Clay‐Sized Particles affecting Banana‐Wilt Expression Caused by Soil Fungus in Banana Plantation Development on Transported Volcanic Soils

Abstract

Relations among the expression of banana disease symptoms caused by the soil fungus Fusarium oxysporum f. sp. cubense, soil potassium (K)–sodium (Na) properties [soluble K‐Na ratios (SK/SS), potential buffering capacity for K (KBC), potassium adsorption ratio (KAR)], and clay‐sized particles were evaluated in Sorribas plots from the Canary Islands. Soils were sampled in areas of Sorribas where banana plants show positive or negative wilting symptoms characteristic of Panama disease. The Bartoli method was used for soil dispersion (Na resin). This method was able to show a clear separation between diseased and disease‐free areas by the amount of clay‐sized particles. Results also show that the greatest SK/SS ratios and clay‐sized particles in soils from diseased areas could explain the increase of water‐stable aggregate mass in these soils and the release of available iron (Fe) to soil solution in diseased areas, at least in Sorribas cultivated soils under the arid climate conditions of the Canary Islands.     

木霉菌对甜瓜枯萎病的防治

研究木霉菌T23、Ta22菌株对甜瓜枯萎病菌的拮抗作用和T23、Ta22二者复合处理对甜瓜枯萎病的室内及田间防治效果，结果表明：T23与Ta22对枯萎病菌拮抗系数都很高，二者复合处理对甜瓜枯萎病的田间相对防效可达79．00％。