Biofungicides as alternative to synthetic fungicide control of grey mould (Botrytis cinerea) – prospects and challenges

Botrytis cinerea is one of the most destructive pathogens of ve?getables and fruits both in the field and storage. There have been several research activities focused on developing biocontrol strategies for the pathogen due to its resistance to the commonly used synthetic fungicides. Additionally, concerns have been raised over residual effect of current synthetic fungicides used for its control. Most of these research activities have focused on Trichoderma spp., Ulocladium spp., Bacillus subtilis, plant extracts and their essential oils with some commercial products available on the market for the control of B. cinerea disease. This review summarises some of the current published information on the use of biocontrol agents and plant-based compounds for B. cinerea control. Some limitations and future prospects were also mentioned.     

两种蚜茧蜂及其寄主蚜虫对大豆植株挥发性次生物质的触角电位反应

研究了下列害虫和寄生天敌种类对大豆植株中提取的某些挥发性次生化合物及其不同组合混合相的触角电位反应： 1)豆蚜Aphis craccivora Koch和麦长管蚜Macrosiphum avenae (Fabricius);2)为害大豆植株的大豆蚜Aphis glycines Matsumura和不为害大豆植株的豆蚜二者所共有的寄生天敌豆柄瘤蚜茧蜂Lysiphlebus fabarum Marshall; 3)不为害大豆植株的麦长管蚜的寄生天敌燕麦蚜茧蜂Aphidius picipes Nees。结果表明,与大豆植株相关联的大豆蚜和不相关联的豆蚜所共有的天敌——豆柄瘤蚜茧蜂,对大豆植株的挥发性次生化合物及其混合相反应敏感,而与大豆植株不相关联的豆蚜、麦长管蚜及其寄生天敌——燕麦蚜茧蜂,对大豆植株的挥发性次生化合物及其混合相反应不敏感。再次证明,植物挥发性次生化合物在害虫及其寄生天敌搜寻寄主的过程中起到重要的作用。     

Soybean Kunitz trypsin inhibitor (SKTI) confers resistance to the brown planthopper (Nilaparvata lugens Stål) in transgenic rice

Proteinase inhibitors are widely distributed in animals, plants and microorganisms and their roles in plants are associated with defense against pests. The utilization of proteinase inhibitors for crop protection has been actively investigated with a variety of proteinase inhibitors. Soybean Kunitz trypsin inhibitor (SKTI), one of the major seed storage protein, is synthesized for a short period during seed development. To investigate the role of SKTI in a plant's defense system against insect predation, a recombinant plasmid containing the full-length cDNA of SKTI under control of the CaMV 35S promoter was introduced into rice protoplasts by using the PEG direct gene transfer method and a large number of transgenic rice plants were regenerated. The integration, expression, and inheritance of this gene was demonstrated in R1 and R2 generations by Southern, northern, and western analyses. Accumulation levels (0.05–2.5% of soluble proteins) of SKTI protein were detected in R1 and R2 plants. Bioassay with R1 and R2 transgenic plants revealed that transgenic plants are more resistant to destructive insect pest of rice, brown planthopper (Nilaparvata lugens Stål), than the control plants. Thus, introduction of SKTI into rice plants can be used to control insect pests.     

干旱和复水对大豆(Glycine max)叶片光合及叶绿素荧光的影响

选用河南省大面积种植的大豆品种豫豆29作为实验材料,通过研究逐步干旱和旱后复水条件下大豆叶片光合、叶绿素荧光等指标随土壤水分的动态变化规律,以期为大豆的水分高效利用提供理论依据。研究发现,在土壤相对含水量高于46.5%时,虽然随着土壤相对含水量的下降,豫豆29仍可以保持它的叶片水分状态;豫豆29的叶片净光合速率在土壤水分中等条件下最大,在土壤相对含水量为64.3%时,它比对照组高出11.2%(P<0.01);在实验的第3d,处理组的土壤相对含水量降为46.5%,叶片水势与对照组相比降低了7.2%(P>0.05),净光合速率为对照组的89.6%(P<0.05),但气孔导度却迅速下降为对照组的44.7%(P<0.01),这说明与叶片的光合和水分状况相比,豫豆29的气孔对土壤水分的匮缺更加敏感。复水后,豫豆29叶片的水势、净光合速率、气孔导度和叶绿素荧光等值都可以得到迅速的恢复,并在实验的最后接近对照组的水平,这表明豫豆29的叶片光合在水分胁迫解除后有迅速恢复的能力。     

脲酶抑制剂氢醌对大豆结瘤、固氮和木质部溶质氮形态的影响

首次报导了在白浆土和砂壤土上使用氢醌(HQ)抑制土壤脲酶活性,有效地缓解尿素分解产物及其随后的氧化产物对大豆结瘤和固氮活性的抑制效应,结果表明:1.HQ浓度在40PPM以内对大豆幼苗生长及初生结瘤表现促进作用;进一步提高HQ浓度将使大豆根系生长受阻变态而阻止结瘤。2.HQ(10—50PPM)提高了离体活性大豆根瘤类苗体悬液的耗氧量(79.4—86.1％)和琥珀酸脱氢酶活性(124.7—138.4％)。3.盆栽和田间试验证实,由于HQ缓解了尿素的分解,从而颇大减轻了尿素对大豆结瘤和固氮(乙炔还原活性)的抑制效应;通过大豆木质部中溶质氮形态(酰胺、酰脲和硝酸盐)的分析进一步证实了,大豆植株从根部向地上部运输的氮素形态同土壤氮转化强度和根瘤固氮强度(酰脲相对丰度)之间的紧密联系。4.由于麦秸还田土壤脲酶活性提高,故应提高HQ剂量;与此同时,通过麦秸的“氮因子效应”便能完全解除尿素对大豆结瘤固氮的抑制,并为大豆籽实发育提供了丰富的土壤氮源。     

不同CO2浓度下大豆叶片的光合生理生态特性

CO₂是光合作用的原料和底物,影响着光合作用的进程和光合产物的数量.利用Li-6400-40B同时测量大豆叶片在不同CO₂浓度(300、400、500和600 μmol·mol^-1)下的光合电子传递速率和光合作用对光的响应曲线,并用构建的光合作用对光响应机理模型拟合这些光响应曲线,获得大豆叶片一系列的光合参数、生理生态参数和捕光色素分子的物理参数.结果表明: 电子利用效率、最大电子传递速率和最大净光合速率随CO₂浓度的升高而增加;光补偿点和暗呼吸速率随CO₂浓度的升高而下降;光能利用效率和内禀(瞬时)水分利用效率随CO₂浓度的升高而增加,不同CO₂浓度下的最大光能利用效率和最大内禀(瞬时)水分利用效率之间存在显著差异,但不同CO₂浓度下的最大羧化效率的差异不显著.CO₂浓度的大小对光合作用中原初光反应存在一定程度的影响,即高CO₂浓度有利于减小捕光色素分子处于最低激发态的最小平均寿命,以提高光能传递的速度及增加大豆光合电子流的利用效率.     

Overexpression of a soybean salicylic acid methyltransferase gene confers resistance to soybean cyst nematode

Salicylic acid plays a critical role in activating plant defence responses after pathogen attack. Salicylic acid methyltransferase (SAMT) modulates the level of salicylic acid by converting salicylic acid to methyl salicylate. Here, we report that a SAMT gene from soybean (GmSAMT1) plays a role in soybean defence against soybean cyst nematode (Heterodera glycines Ichinohe, SCN). GmSAMT1 was identified as a candidate SCN defence‐related gene in our previous analysis of soybean defence against SCN using GeneChip microarray experiments. The current study started with the isolation of the full‐length cDNAs of GmSAMT1 from a SCN‐resistant soybean line and from a SCN‐susceptible soybean line. The two cDNAs encode proteins of identical sequences. The GmSAMT1 cDNA was expressed in Escherichia coli. Using in vitro enzyme assays, E. coli‐expressed GmSAMT1 was confirmed to function as salicylic acid methyltransferase. The apparent Km value of GmSAMT1 for salicylic acid was approximately 46 μm . To determine the role of GmSAMT1 in soybean defence against SCN, transgenic hairy roots overexpressing GmSAMT1 were produced and tested for SCN resistance. Overexpression of GmSAMT1 in SCN‐susceptible backgrounds significantly reduced the development of SCN, indicating that overexpression of GmSAMT1 in the transgenic hairy root system could confer resistance to SCN. Overexpression of GmSAMT1 in transgenic hairy roots was also found to affect the expression of selected genes involved in salicylic acid biosynthesis and salicylic acid signal transduction.     

In vitro kinetics and antifungal activity of various extracts of Terminalia chebula seeds against plant pathogenic fungi

The aim of the present study was to examine the efficacy of various seed extracts of Terminalia chebula as an antifungal potential against certain important plant pathogenic fungi. The organic extracts of methanol, ethyl acetate and chloroform at the used concentration of 1500 ppm/disc revealed remarkable antifungal effect as a fungal mycelial growth inhibitor against Fusarium oxysporum, Fusarium solani, Phytophthora capsici and Botrytis cinerea, in the range of 41.6–61.3%, along with MIC values ranging from 62.5 to 500 μg/ml. Also, the extracts had a strong detrimental effect on spore germination of all the tested plant pathogens along with concentration as well as time-dependent kinetic inhibition of B. cinerea. The results obtained from this study suggest that the natural products derived from Terminalia chebula could become an alternative to synthetic fungicides for controlling such important plant pathogenic fungi.     

高纬度地区大豆蛋白含量及氨基酸组分的表型鉴定与聚类分析

对国内外高纬度地区的240份大豆种质资源的蛋白及16个氨基酸组分进行测定,通过遗传多样性、因子和聚类分析,进行了表型鉴定及基因型分类。结果表明,供试大豆种质蛋白及氨基酸组分变异较丰富,遗传多样性程度较高。根据因子分析,将筛选到的3个公因子进行聚类分析,可将供试种质资源分为7类。蛋白含量从高到低的顺序为类群Ⅶ>类群Ⅵ>类群Ⅴ>类群Ⅱ>类群Ⅰ>类群Ⅲ>类群Ⅳ。12个氨基酸组分的变化趋势与蛋白一致。类群Ⅶ和类群Ⅵ为高蛋白遗传群体,可作为高蛋白基因聚合育种的亲本材料。通过前期分析,筛选到24份高蛋氨酸资源,包括有公野04L-141、龙品03-311、Proto、和龙油太、猫眼豆、茶色豆、紫花2号、东农48等,可为高蛋氨酸种质创新提供材料基础。     

大豆种皮色相关基因研究进展

大豆种皮色在从野生大豆到栽培大豆的演变过程中逐渐从黑色变成黄色,是重要的形态标记,因此,大豆种皮色相关基因研究无论对进化理论还是育种实践都具有重要的意义。种皮颜色是通过各种花色苷的沉积而形成的。虽然很多植物色素沉积的分子调控机制比较明晰,但大豆中控制种皮颜色形成的基因尚未被完全了解。文章综述了控制大豆种皮色基因与位点的相关研究进展,主要有I、T、W1、R、O 5个经典遗传位点,其中I位点被定位在第8号染色体(A2连锁群)一个富含查尔酮合成酶(CHS)的区域,CHS基因在大豆中是多基因家族且同源性较高;定位于第6号染色体(C2连锁群)T位点的基因F3’H已被克隆和转基因验证,由于碱基缺失导致所编码的氨基酸缺少了保守域GGEK,从而不能与血红素结合而丧失功能;R位点定位在第9号染色体(K连锁群)A668-1与K387-1两标记之间,可能是R2R3类MYB转录因子,也可能是UDP类黄酮3-O糖基转移酶;O位点定位在第8号染色体(A2连锁群)Satt207与Satt493两标记之间,其分子特性尚不清楚;W1位点可能由F3’5’H基因控制遗传。