基因枪法介导转人工合成Rs-AFP2基因小麦的获得和检测

萝卜（Raphanus sativus）抗菌肽Rs—AFP2在体外强烈抑制小麦赤霉病菌（Fusarium graminenrum）、黄色镰孢菌（Fusarium culmorum）、烟草赤星病（Alternaria longipes）的菌丝生长。为了研究Rs-AFP2在小麦抗病育种上的应用潜力，人工合成了Rs-AFP2基因。通过基因重组技术（包括限制性内切酶酶切和连接），将人工合成的R以FP2基因替代单子叶高效组成型表达栽体pAHC25中的GUS基因，构建了R￡AFP2基因的单子叶高效表达栽体pUAFP2。该栽体除携带受Ubiquitin启动子控制的Rs-AFP2基因表达盒外，还具有1个受Ubiqutin启动子控制的Bar基因表达盒，后者可为后续利用除草剂Bialaphos筛选转化再生植株提供抗性；采用基因枪法轰击小麦品种扬麦12、济麦19、晋麦47和豫麦34幼胚共4042个，经过2～3次Bialaphos筛选，最终获得扬麦12再生植株316株；利用高效表达栽体pUAFP2的Bar和Rs-AFP2基因的特异引物对上述成活的转化植株进行PCR检测，获得Bar和Rs-AFP2基因均为阳性的植株58株，转化率为1．43％。     

Antimicrobial activity of some Indian mosses

The present study was designed to evaluate the antimicrobial activity of ethanolic extracts of 15 Indian mosses. The antibacterial activity of ethanolic extracts was investigated against five G(+) and six G(-) bacterial strains. Antimycotic activity was assayed against 8 fungi. Sphagnum junghuhnianum, Barbula javanica, Barbula arcuata, Brachythecium populeum, Brachythecium rutabulum, Mnium marginatum and Entodon cf rubicundus were found to be most active against all the organisms.     

Composition and antifungal activity of the essential oil of Seseli annuum wild-growing in Serbia

The essential oil from the aerial parts of Seseli annuum, wild-growing in Serbia, was obtained by hydrodistillation and analyzed using GC and GC/MS. A total of 43 components were identified representing 96.5% of S. annuum oil. The most abundant compounds were germacrene D (29.8%), sabinene (10.3%), beta-ocimene Z (9.8%) and limonene (8.6%). The essential oil showed antifungal activity against fifteen fungi with MICs between 12.5 to 50 microl/ml.     

Antagonistic effect of Pseudomonas spp. on pathogenic fungi and enhancement of growth of green gram (Vigna radiata)

species were isolated from the rhizosphere of green gram [Vigna radiata (L.) Wilczek] and some of the rhizobacterial isolates were found to have a wide range of antifungal activity inhibiting growth of the phytopathogenic fungi Aspergillus sp., Curvularia sp., Fusarium oxysporum and Rhizoctonia solani in culture. These isolates also showed slight inhibition of the growth of a Bradyrhizobium strain (Vigna) in a spot test which was mainly a result of nutrient competition as culture supernatants of the Pseudomonas isolates did not inhibit the growth of bradyrhizobia but inhibited the growth of fungi. The rhizobacterial isolates produced siderophores in Fe-deficient succinate medium. However, the inhibition of fungal growth by different Pseudomonas isolates in Luria Bertani and King's medium B which were not limiting in Fe³⁺ ions suggested that, besides siderophores, other antifungal compounds (antibiotics) produced by these rhizobacteria were involved in antagonism. On coinoculation of green gram with Pseudomonas strains MRS13 and MRS16 and Bradyrhizobium sp. (Vigna) strain S24, there was a significant increase in nodule weight, plant dry weight and total plant N as compared to inoculation with Bradyrhizobium strain S24 alone, suggesting that the nodule-promoting effects of Pseudomonas sp. lead to an increase in symbiotic N fixation and plant growth. Received: 27 October 1997     

Integration of Lactobacillus plantarum A7 with thyme and cumin essential oils as a potential biocontrol tool for gray mold rot on strawberry fruit

Chemical fungicides have been intensively used in the control of postharvest decay in fruit in postharvest conditions; nevertheless, continuous use of these fungicides has faced two major obstacles: development of pathogen resistance to many key fungicides, and public knowledge on the health and environmental hazards of these compounds. This study evaluated the efficacy of Lactobacillus plantarum A7, thyme (Thymus vulgaris L.) and cumin (Cuminum cyminum L.) essential oils and the combination of these three elements as postharvest biocontrol agents against Botrytis spp. on strawberry fruit. Thyme oil had a remarkable antifungal effect against Botrytis spp. in vitro, whereas an inhibitory effect of cumin oil was achieved in higher concentrations. With thyme oil (2 h after artificial inoculation of the fruit), among three tested concentrations, only the 200 μL/L concentration showed an inhibitory effect on strawberries against Botrytis spp. (91.97%), while higher concentrations of cumin oil were required to prevent decay significantly. Both combinations of L. plantarum+ cumin oil and L. plantarum+ thyme oil completely inhibited the mycelia growth of the pathogens in vitro. Results showed that the combined treatments of strawberry fruit with L. plantarum+ cumin oil (50 μL/L) and L. plantarum+ thyme oil (100 μL/L) resulted in remarkably improved control of Botrytis infections, in comparison to the stand-alone application of L. plantarum A7 or essential oils. Quality (i.e. pH, acidity and ascorbic acid content) and sensory attributes of the strawberry fruit were better in the case of using cumin compared to thyme oil, when a combination of L. plantarum A7 and essential oils was used. This study has demonstrated that the integration of L. plantarum A7 with thyme and cumin essential oils is a potential biocontrol tool as a biofungicide in postharvest stage.     

苦豆子根抑菌活性物质回流提取工艺

为建立苦豆子根抑菌活性物质的较优提取工艺，以提取物对番茄灰霉病菌的抑菌活性为指标，在单因素试验的基础上，通过正交试验对提取溶剂、液固比等4个工艺条件进行考察。结果表明，其较佳提取工艺条件为以体积分数为75%的乙醇溶液为提取溶剂，液固比V（溶剂）∶m（植物材料）=10 mL∶1 g，80 ℃加热2 h，共提取3次。所得提取物对番茄灰霉病原菌的有效抑制中质量浓度（EC₅₀）为185.4 mg/L，1 000 mg/L剂量下对番茄灰霉病的药效与500 mg/L的w=50%速克灵可湿性粉剂相当。该工艺条件较为简单，对其放大即可满足苦豆子杀菌剂产品的工业化生产要求。     

烟草赤星病生防菌的鉴定及其抑菌机理

由交替链格孢（Alternaria alternata）引起的烟草赤星病是烟草生长中后期重要的叶部病害，直接影响烟叶的产量和品质。为开发烟草赤星病的生防制剂，对生防菌XNB-01进行了多相分类鉴定，并通过盆栽试验、粗提物的抑菌机理等研究，进一步阐明了XNB-01的生防机理。皿内对峙结果表明，XNB-01对交替链格孢的抑菌半径达到 11.0 mm。菌株XNB-01短杆状，与Paenibacillus polymyxa ATTCC 842相似性为98.63%。次生代谢产物检测结果表明，XNB-01可以分泌多种真菌细胞壁降解酶，并具有溶解有机磷、解钾的能力。盆栽试验结果表明，XNB-01在 1×10⁴_{8 CFU/mL的施用浓度下显著增加了烟草幼苗的株高、鲜质量和干质量；在1×10⁹ CFU/mL的施用浓度下显著降低了烟草赤星病的病情指数，防效为60.94%，与菌核净（65.33%）相当。此外，XNB-01 的胞内粗提物可抑制交替链格孢菌丝的生长和孢子萌发，使菌丝膨大，孢子皱缩。经200 μg/mL XNB-01 胞内粗提物处理后，峰值处的胞外电导率、核酸和蛋白质泄漏量分别是对照组的2.97、1.83、8.28倍，丙二醛含量比对照升高1.36倍。综上所述，P.polymyxa XNB-01 具有防治烟草赤星病的生防潜力。}     

木醋液对植物病原真菌呼吸作用的影响

为探究木醋液在植物病害生物防治中的实际应用及对其病原真菌呼吸作用的影响，试验采用菌丝生长速率法测定其对 7 种植物病原真菌的抑菌活性，并研究其对供试敏感菌株——黄色镰刀菌（Fusarium culmorum）的菌体三羧酸循环关键酶和能量代谢的影响。结果表明：木醋液对 7 种供试植物病原真菌均有一定的抑制效果，其中对供试敏感菌株——黄色镰刀菌（Fusarium culmorum）的抑菌作用表现最为显著，其 EC50 值为 4.98 μL/mL，在浓度 5.5 μL/mL 时，木醋液对其孢子萌发和生物量抑制率分别达 90.09% 和 95.22 %；经木醋液处理后，黄色镰刀菌的呼吸速率受到抑制，琥珀酸脱氢酶和苹果酸脱氢酶活性降低，三磷酸腺苷含量降低，二磷酸腺苷和磷酸腺苷含量先升高后降低，能荷水平降低，表明木醋液抑制了黄色镰刀菌的呼吸代谢，阻碍了三羧酸循环的正常运行，干扰了其能量代谢，导致菌体细胞功能紊乱。初步探明，木醋液主要是通过破坏菌体呼吸代谢来实现其抑菌效果。