Postharvest Treatment with β-Aminobutyric Acid Induces Resistance Against Dry Rot Caused by Fusarium sulphureum in Potato Tuber

The effectiveness ofpostharvest β-aminobutyric acid （BABA） treatment was studied for inducing resistance against dry rot caused by Fusarium sulphureum in tubers and slices of two potato cultivars （resistant cultivar Shepody and susceptible cultivar Xindaping）. The results showed that BABA at 100 mmol L-1 significantly reduced lesion diameter in inoculated both tubers and slices. The chemical at 100 mmol L-1 showed an effective reduction in infection ability ofF. sulphureum inoculated 48 and 72 h after treatment in slices of resistant cultivar, and 72 and 96 h in susceptible ones. BABA increased the activitives of peroxidase （POD）, polyphenoloxidase （PPO） and phenylalanine ammonialyase （PAL）, and accumulated the contents of lignin, flavonoids and phenolics in slices. The resistant cultivar had a stronger resistant response than the susceptible one. These findings suggest that the BABA treatment can induce the resistance in potato tubers, however, the inducing degree depends on the original level of resistance present in each cultivar.     

Progresses in the Mechanism of Resistance to Fusarium Wilt in Cucumber （Cucumis sativus L.）

Fusarium wilt caused by Fusarium oxysporum f.sp. cucumerinum （Owen） is one of the most devastating diseases in cucumber production worldwide. Recent progresses in the mechanism of resistance to Fusarium wilt in cucumber were reviewed in this paper, including pathogenic mechanism of Fusarium oxysporum, the resistance mechanism of cucumber, the heredity of resistance, and the location of resistance genes. Following works should be the location and cloning of resistance genes with molecular biologic methods.     

Identification of Molecular Markers Linked to the Wilt Resistance Gene FuJ7（t） in Flax

A cross between wilt resistant flax variety Jinya7 and susceptible variety Jinyal was made for mapping wilt resistance gene(s). The inoculation test of F1 and F2 progeny proved that the resistance of Jinya7 to wilt is controlled by two dominant genes. With 48 EcoRⅠ /MseⅠ primer combinations, amplified fragment length polymorphisms (AFLP) analysis was performed on two parents and their F2 resistance and susceptibility bulks. A total of about 3 300 distinguishable bands were amplified, of which three bands had stable differences. The genetic linkage analysis of the three polymorphic DNA fragments with the resistance gene(s) was made in the F2 segregating population derived from the cross between Jinya7 and Jinyal. The DNA fragment AG/CAG was found closely linked to one of the wilt-resistant genes, which with a genetic distance of 5.2cm, was tentatively named FuJ7(t). The cloned fragment AG/CAG was sequenced and then converted successfully to a sequence characterized amplified region (SCAR) marker, which can be used more conveniently in the identification and marker-assisted selection for the wilt resistance gene FuJ7(t) to flax wilt.     

Induction of Tolerance to Fusarium Wilt and Defense-Related Mechanisms in the Plantlets of Susceptible Berangan Banana Pre-lnoculated with Pseudomonas sp. （UPMP3） and Burkholderia sp. （UPMB3）

This study is aimed at assessing the ability of two endophytic bacteria originally isolated from healthy oil palm roots, Pseudomonas sp. （UPMP3） and Burkholderia sp. （UPMB3） to induce resistance in susceptible Berangan banana against Fusarium oxysporum race 4 （FocR4）. Increased accumulation of resistance-related enzymes such as peroxidase （PO）, phenylalanine ammonia lyase （PAL）, lignithioglycolic acid （LTGA）, and pathogenesis-related （PR） proteins （ehitinase and β-1,3-glucanase） has been observed in plantlets treated with endophytic bacteria UPMP3 and UPMB3 singly or as mixture under glasshouse conditions. Pre-inoculation of banana plantlets with UPMP3 showed a significant reduction in Fusarium wilt incidence 72 d after challenged inoculation with FocR4. UPMB3 was less effective in suppressing Fusarium wilt compared to UPMP3, whereas, the mixture of both endophytes showed an intermediate effect. Based on these results, it is concluded that UPMP3 could be a promising biological control agent that can trigger resistance against Fusarium wilt in susceptible Berangan banana.     

Enhancement of Phenylalanine Ammonia Lyase,Polyphenoloxidase, and Peroxidase in Cucumber Seedlings by Bemisia tabaci（Gennadius） （Hemiptera： Aleyrodidae） Infestation

In this study, the activities of phenylalanine ammonia lyase （PAL）, polyphenoloxidase （PPO）, and peroxidase （POD） were assayed in cucumber seedlings （Cucumis sativus L.） at 0, 6, 12, 24, 48, 72, and 96 h after they were infested by Bemisia tabaci （Gennadius） using spectrophotometric analysis. The results indicated that herbivore infestation increased the activities of PAL, PPO, and POD. The enzymes showed different activity levels at different times after the infestation. The PAL activity reached the first high peak by 23.1% at 6 h and the highest peak by 29.1% at 48 h compared to the control. The PPO activity reached the first high peak by 22.7% at 6 h and the highest peak by 52.6% at 24 h, and the POD activity reached the highest peak by 213.2% at 6 h and another higher peak value by 135.2% at 96 h. The results suggest that the enhanced activities of the enzymes may contribute to bioprotection of cucumber plants against B. tabaci infestation.     

北苍术枝枯病病原菌（Fusarium equiseti）的鉴定及其生物学特性研究

近年来,随着北苍术栽培面积的扩大,病害发生日趋严重。为了明确引起北苍术枝枯病病原菌及其生物学特性,利用柯赫氏法则、形态学特征及分子生物学技术对菌株进行了鉴定,并测定了菌丝生长最佳条件。结果表明,气生菌丝初期呈绒毛状至棉絮状、白色至粉红色、后期发展成驼色,分生孢子镰刀型、弯曲、中部细胞显著膨大、顶孢延长呈锥形、多数为3~7个分隔,厚垣孢子呈球形、成链状或单生于菌丝或孢子中。该致病菌的ITS序列与GenBank中木贼镰刀菌Fusarium equiseti（MK621018）的相似性为 100%,结合形态特征与分子鉴定最终将其确定为木贼镰刀菌,GenBank登录号(MH290363)。该菌菌丝生长最适温度范围为25~30 ℃;菌丝在pH 4~11时均能正常生长,pH 8~11时生长最快;燕麦及玉米面培养基最适合该病原菌生长;光照对菌丝生长有很大影响,全光照条件菌丝生长最快;对碳源淀粉、葡萄糖及氮源酵母浸出粉利用率最高,培养7 d时菌落直径在7 cm左右。     

Study on the Resistance Induced by Salicylic Acid Against Phytophthora capsici in Pepper （Capsicum annuum）

Pepper Phytophthora blight caused by Phytophthora capsici L. is the most destructive disease for reducing pepper yields in the world. Building up varietal resistance and induced resistance to the disease are of agricultural importance. In this paper, the disease resistance induced by salicylic acid (SA) against P. capsici were studied by using four hot pepper lines with different resistant abilities and one P. capsici strain with middle pathogenicity. Results show that SA could induce significantly the resistance of pepper seedlings to P. capsici, but CaCl2, KH2PO4 and VAM couldn‘t. SA at a relative low concentration from 0, 15 to 0.3 g L^-1 had no antifungal activity in vitro against P. capsici, That means the disease resistant enhancement of the plants treated with SA is due to the induction effect, but not the antifungal effect of SA. About 1 to 5 days internal between SA-treatment and challenge inoculation was sufficient to induce the disease resistance of hot pepper. The resistance could remain more than 20 days after treatment with SA.     

Coronatine Induces an Accumulation of Anthocyanin and Starch in Purple-fleshed Sweetpotato （ Ipomoea batatas Lam.）

[Objective] The objective of this research was to examine the effects of COR on anthocyanin and starch content in storage roots of two PFS genotypes, and to explore the relationships between anthocyanin synthesis and starch accumula- tion. [Method] A field experiment was carried out to determine the changes in yielc components, yield, contents of anthocyanin and starch, activities of phenylalanine ammonia-lyase （PAL） and adenosine 5-diphosphate glucose pyrophosphorylase （AG- Pase） in two genotypes of PFS （Ipomoea batatas L., var. ＇Ayamurasaki＇ and ＇Jishu18＇）. [Result] The application of COR significantly increased starch and antho- cyanin content in storage roots of Jishu18 across developmental stages by inducing the activities of PAL and AGPase, and finally enhanced yield by promoting fresh weight of storage roots. Ayamurasaki was insensitive to treatment with COR al- though its PAL activity temporally increased. The starch and anthocyanin content of Aya, and the anthocyanin content of Jishu18 increased progressively across devel- opmental stages with or without COR application, but the starch content of Jishu18 increased initially, then decreased before increasing again without application of COR. Treatment with COR reduced downward trend of starch accumulation in Jishu18. Thus, the effect of COR on accumulation of anthocyanin and starch in storage roots of PFS differs according to genotypes. [Conclusion] The application of 0.05 μmol/L COR may increase starch and anthocyanin content in PFS genotypes with lower starch and anthocyanin content in storage roots.     

苯丙噻重氮（ASM）对果蔬采后抗病性的诱导及机理

苯丙噻重氮（acibenzolar-S-methyl, ASM）是水杨酸的类似物,也是人工合成的植物抗病性化学诱导剂,能够诱导多种植物的抗病性。采前或采后ASM处理可有效降低梨、桃、葡萄、草莓、甜瓜、橘、芒果、香蕉、枇杷、番茄和马铃薯等多种果蔬的采后病害。ASM的诱抗机理涉及诱导活性氧的积累、活化苯丙烷代谢和促进病程相关蛋白的产生等方面。本文还对扩大ASM的使用范围,提高其使用效果,以及深入阐明ASM的作用机理进行了展望。     

Control of Postharvest Fusarium Rot and Trichothecium Rot in Harvested Muskmelon (cv. Yindi) by Harpin

Preharvest and postharvest application of Harpin was evaluated for its ability to induce resistance in muskmelon fruit and control rots. Preharvest treatments were 30 mg L-1, 60 mg L-1 Harpin or 1 mg L-1 Imazalil either 1 week or 1 day before harvest.The CK was untreated. Fruit were then inoculated with Fusarium semitectum or Trichothecium roseum 48 h after harvest,and stored at 23 ± 1℃, RH (relative humidity) 50-60% for 4 d. All treatments were effective in reducing the lesion area with 60 mg L-1 Harpin the most effectively. No treatments inhibited infection rate. Postharvest treatment was fruit dips of 30 mg L-1, 60 mg L-1 Harpin, 0.1 mg L-1 Imazalil. Fruit were inoculated with F. semitectum or T. roseum 24, 72, 120 or 168 h after treatment, and stored at 23 ± 1 ℃, RH 50-60% for 4 days. All treatments were effective in reducing the lesion area with 60 mg L-1 Harpin the most effectively. No treatments inhibited the infection rate. Postharvest Harpin treatment induced the peroxidase activity increase, peroxidase activity reached maximum after 8 d and the activation lasted at least 10 d.     

Postharvest Chitosan Treatment Induces Resistance in Potato Against Fusarium sulphureum

The effects of chitosan treatment and inoculation on dry rot in tubers and slices of potato were studied. The results showed that chitosan treatment significantly reduced the lesion diameter of potato inoculated with Fusarium sulphureum. The treatment at 0.25% showed the best effect. Chitosan at 0.25% increased the activities of peroxidase and polyphenoloxidase, and the contents of flavonoid compounds and lignin in tissues. Increased activities of 13-1,3-glucanase, and phenylalanine ammonialyase were observed, but there were no significant differences between the treated and the control. These findings suggested that the effects of chitosan could be associated with the induced resistance against Fusarium dry rot in potato.     

Postharvest ASM or Harpin Treatment Induce Resistance of Muskmelons Against Trichothecium roseum

Induced resistance was studied in muskmelons （cv. Yindi） inoculated Trichothecium roseum with postharvest 1,2,3- benzothiadiazole-7-carbothioic acid S-methyl ester （ASM） （100 mg L^-1） or harpin （50 mg L^-1） treatment. Both ASM and harpin significantly reduced lesion diameter in inoculated fruit. Lesion diameter was limited in the treated and untreated halves of the same fruit, indicating that the local and systemic resistance was induced. Inhibiting efficacy of elicitors lasted 7 and 5 days in the treated and untreated halves. The resistance increased by the chemicals was associated with the activation of peroxidase （POD） and chitinase （CHT）. The elicitors induced a significantly and progressively increasing activity of POD and CHT in the treated and untreated halves, and the activation lasted at least 5 days. The activities of POD isoenzymes increased in the treated fruit. However, no new enzyme band was found in the treated and untreated halves.     

弱毒菌株尤Ⅱ对小麦条锈病的诱导抗性 Ⅱ.诱导抗性的病生理变化观察

弱小种尤诱导接种后,PAL活性始终大于同期其他处理;先诱导接种尤再挑战接种条中29号处理的POD活性于72h和120h时产生两个高峰;用条中29号小种挑战接种后PPO活性的变化趋势与单独接种尤的处理相同,均高于单独接种条中29号小种和对照处理;挑战接种条中29处理的SOD活性远比同期其他处理的低。     

过氧化物酶在棉花对枯萎病抗病性中的作用

分析了氟乐灵（２μｇ／ｇ土）诱发处理及枯萎病菌侵染后棉苗叶片和根茎部不同细胞定位过氧化物酶（ＰＯＤ）活性的变化．结果表明：（１）总可溶性ＰＯＤ、胞内ＰＯＤ、胞间ＰＯＤ以及细胞壁结合型ＰＯＤ的活性抗病品种高于感病品种；（２）氟乐灵诱发处理及枯萎病菌侵染可提高棉苗组织中上述五类ＰＯＤ的活性，细胞间隙ＰＯＤ及胞壁结合ＰＯＤ活性上升更为明显；（３）枯萎病菌侵染后经氟乐灵诱发处理并产生诱导抗性的棉苗及抗病品种棉苗中胞壁结合ＰＯＤ活性快速上升，增加幅度大，而感病品种前期无明显增加，后期才有较小幅度的上升．这说明过氧化物酶在棉苗对枯萎病的抗病性及由氟乐灵诱发的诱导抗性中起到重要作用     

VFB诱导烟草叶片生理生化变化与TMV抗性的关系

用VFB对烟草花叶病进行预防和治疗处理,对其抗TMV作用进行初步探讨。结果表明：用VFB的两种处理方式均可使受侵普通烟的叶绿素总含量明显升高,且预防处理要好于治疗处理;可显著降低丙二醛(MDA)的含量;可诱导普通烟中多酚氧化酶(PPO)和过氧化物酶(POD)的活性增强。可见,VFB是一种良好的植物源病毒抑制剂,可诱导植物产生抗病性,增强对TMV侵染的抵抗力。     

水杨酸诱导的月季对甜菜夜蛾的抗性及机理研究

为探明外源水杨酸（SA）诱导月季产生的对甜菜夜蛾的抗性以及产生这种抗性的化学物质基础,采用双选生物测试方法测试了SA处理月季对甜菜夜蛾产卵行为的影响,用GC−MS分析了SA诱导的月季挥发性成分（VOCs）的变化,进一步研究了VOCs中的抗虫活性成分。1.0 mmol/L SA溶液处理月季植株可使甜菜夜蛾在植株上的产卵量显著减少（P<0.05）,处理6、9、12 d后,总产卵量与对照相比分别减少了35.4%、38.9%、47.5%。进一步收集对照植株和处理植株顶空挥发性成分,分别配成溶液,喷施两组相同的未经处理的健康月季枝条,结果表明：在喷施了从处理植株上提取的挥发性成分混合物后,枝条上的产卵量与对照相比显著减少（P<0.05）,处理6、9、12 d后,抑制指数分别为23.9%、25.4%、36.2%。GC−MS结果表明,SA诱导了月季挥发性成分显著变化。正常情况下2−乙基己酸、十四烷醇、棕榈酸甲酯、乙酸十六酯等化合物在健康植株中不会被合成,只有在SA诱导作用下才会被植株合成出来。SA对这4种化合物的诱导作用表现出明显的时间效应,并且它们对甜菜夜蛾产卵行为的抑制作用表现出明显的浓度效应。结果表明,外源SA处理使月季对甜菜夜蛾产生了诱导抗性,月季挥发性成分变化是这种抗性的重要物质基础。     

Study on the Resistance Induced by Salicylic Acid Against Phytophthora capsici in Pepper (Capsicum annuum)

Pepper Phytophthora blight caused by Phytophthora capsici L. is the most destructive disease for reducing pepper yields in the world. Building up varietal resistance and induced resistance to the disease are of agricultural importance. In this paper, the disease resistance induced by salicylic acid (SA) against P. capsici were studied by using four hot pepper lines with different resistant abilities and one P. capsici strain with middle pathogenicity. Results show that SA could induce significantly the resistance of pepper seedlings to P. capsici, but CaC12, KH2PO4 and VAM couldn't. SA at a relative low concentration from 0.15 to 0.3 g L-1 had no antifungal activity in vitro against P. capsici. That means the disease resistant enhancement of the plants treated with SA is due to the induction effect, but not the antifungal effect of SA. About 1 to 5 days internal between SA-treatment and challenge inoculation was sufficient to induce the disease resistance of hot pepper. The resistance could remain more than 20 days after treatment with SA.     

黄瓜嫁接苗愈合过程的解剖观察及过氧化物同工酶分析

通过对黄瓜嫁接愈合过程的解剖观察和伴随嫁接愈合过程及嫁接各部位的过氧化物同工酶分析,研究结果表明:嫁接后第一阶段的隔离层形成时期,嫁接接合部位有1条新的过氧化物酶带形成,嫁接后第二阶段的愈伤组织形成期,有1条新的过氧化物酶带形成,嫁接后第三阶段的愈伤组织的分裂增殖、抱合、连接期,有2条新的过氧化物酶带形成。从各部位过氧化物酶的活性来看,接合部>砧木>CK1和CK2。