Y-S-Y12发酵液和生物质热解液混配对辣椒炭疽病的防治及作用机理

为探究解淀粉芽孢杆菌Y-S-Y12拮抗菌发酵液和生物质热解液混配对辣椒炭疽病的协同防病作用及其作用机理，对不同浓度生物质热解液、拮抗细菌Y-S-Y12菌株的发酵浓缩液及其混配溶液对辣椒炭疽病的抑菌作用进行检测，计算出毒力方程，根据EC50值将两种溶液进行混配，求得最佳配比。通过活体试验检测Y-S-Y12菌株对辣椒炭疽病果实的防治效果，测定叶片超氧化物歧化酶（superoxide dismutase，SOD)、过氧化物酶（peroxidase，POD）和过氧化氢酶（hydrogen peroxidase，CAT）活性，并探究各药剂对辣椒炭疽病病菌菌丝的细胞膜通透性、生理代谢和菌丝形态的影响。结果显示，Y-S-Y12菌株发酵浓缩液和生物质热解液以1∶9混配具有明显的协同增效作用;混配的防效显著高于单剂，防效达到79.62%，进一步说明混配具有增效作用。混剂处理的辣椒炭疽病菌菌丝中的几丁质酶活性、β-1,3-葡聚糖酶活性和蛋白酶活性显著高于对照和单剂处理，处理后菌体的保护屏障被打破，使培养液的电导率、外渗液中蛋白质和核酸含量上升。混剂处理的辣椒叶片中SOD、POD、CAT酶活性显著高于对照和单剂处理，说明辣椒植株抗病性增强。综上，Y-S-Y12菌株发酵液和生物质热解液混配对辣椒炭疽病有协同防病作用，可能是因为Y-S-Y12菌株具有破坏辣椒炭疽病菌菌丝和诱导辣椒植株抗病性作用。研究为辣椒炭疽病无公害防治提供理论依据。     

生防菌株PF-1基于全基因组数据的分类鉴定及拮抗能力分析

基于全基因组数据,确定生防菌株PF-1的分类地位,验证其对植物病原菌的拮抗作用以及挖掘其潜在的生防功能。通过全基因组中16S rRNA基因序列的系统发育分析及基因组分析方法确定生防菌株PF-1的分类地位,通过平板对峙方法研究其对马铃薯枯萎病菌和棉花黄萎病菌的拮抗能力;利用antiSMASH软件分析和预测菌株PF-1的抗生素相关基因并挖掘其生防潜力。基于16S rRNA基因序列的系统发育分析及基因组分析结果,PF-1被鉴定为防御假单胞菌(Pseudomonas protegens),同时发现PF-1基因组中存在15种次生代谢产物基因簇,具有良好的抑制病原菌生长和提高植物抗病性的能力,在农业中具有良好的应用前景。     

Root‐associated microbes in sustainable agriculture: models,metabolites and mechanisms

Since the discovery of penicillin in 1928 and throughout the ‘age of antibiotics’ from the 1940s until the 1980s, the detection of novel antibiotics was restricted by lack of knowledge about the distribution and ecology of antibiotic producers in nature. The discovery that a phenazine compound produced by Pseudomonas bacteria could suppress soilborne plant pathogens, and its recovery from rhizosphere soil in 1990, provided the first incontrovertible evidence that natural metabolites could control plant pathogens in the environment and opened a new era in biological control by root‐associated rhizobacteria. More recently, the advent of genomics, the availability of highly sensitive bioanalytical instrumentation, and the discovery of protective endophytes have accelerated progress toward overcoming many of the impediments that until now have limited the exploitation of beneficial plant‐associated microbes to enhance agricultural sustainability. Here, we present key developments that have established the importance of these microbes in the control of pathogens, discuss concepts resulting from the exploration of classical model systems, and highlight advances emerging from ongoing investigations. © 2019 Society of Chemical Industry     

菲和芘胁迫下AMF和PGPR对高羊茅生理生态的响应

旨在探究菲和芘胁迫下丛枝菌根真菌(AMF)与根围促生细菌(PGPR)对高羊茅生理生态的响应。以菲和芘1∶1混合处理浓度各0、50、100和150mg·kg^-1下对高羊茅接种AMF变形球囊霉(Gv)、PGPR荧光假单胞菌(Ps2-6)、Gv+Ps2-6和不接种对照共16个处理。结果表明,AMF、PGPR或AMF+PGPR处理均显著增加高羊茅生物量和菌根侵染率,增强植物光合作用,提高叶绿素含量,显著提高植物体内生理活性。在土壤中菲和芘100mg·kg^-1水平下,与对照相比,双接种Gv+Ps2-6处理的高羊茅叶片叶绿素a、b和总叶绿素含量分别提高57.7%、41.7%和51.8%;净光合速率(Pn)、蒸腾速率(Tr)、胞间CO2浓度(Ci)和气孔导度(Gs)分别增加70.6%、100.0%、4.5%和78.6%;最大光化学效率(Fv/Fm)和PSⅡ潜在活性(Fv/Fo)分别提高2.2%和8.8%;超氧化物歧化酶(SOD)、过氧化氢酶(CAT)活性、可溶性糖和脯氨酸含量分别是对照的1.6、1.5、2.3和2.7倍,丙二醛含量比对照下降46.0%;高羊茅株高和地上鲜重分别比对照增加63.0%和69.6%;接种PGPR处理能够增加AMF侵染率以及菌根依赖性。供试条件下,双接种Gv+Ps2-6处理增加高羊茅叶绿素含量和抗氧化能力,增强光合作用能力,降低膜脂过氧化水平,促进植物生长的作用最为显著。     

黄瓜品种与其根围主要病原菌的拮抗菌之间关系的研究

对具有不同抗性和品质的黄瓜品种与其根围、根表的主要病原菌（Ｒｈｉｚｏｃｔｏｎｉａｓｏｌａｎｉ和Ｐｙｔｈｉｕｍａｐｈａｎｉｄｅｒｍａｔｕｍ）的拮抗菌之间关系的研究结果表明：黄瓜在不同生长时期,两者的关系不一致。在出苗后２ｄ,７ｄ时,抗病品种根围拮抗菌的数量多于感病品种;在出苗后１４ｄ,在这６个品种中,Ｒ．Ｓｏｌａｎｉ与Ｐ．ａｐｈａｎｉｄｅｒｍａｔｕｍ根围、根表的拮抗菌数均达到最高峰,且品质优良但相对较感病的两个品种浙农１８、上海洋行根围、根表拮抗菌数明显高于其他品种;经Ｄｕｎａｎ＇ｓ多重比较表明,Ｒ．ｓｏｌａｎｉ的根围、根表拮抗菌数与Ｐ．ａｐｈａｎｉｄｅｒｍａｔｕｍ相比,两者差异均达极显著水平,前者明显高于后者。     

水稻白叶枯病菌拮抗细菌B56菌株的拮抗活性研究

B56 菌株经30 ℃振荡培养去菌体,其上清液经2 m ol/L 硫酸铵沉淀获得对水稻白叶枯病菌有拮抗活性的初提液。该初提液具有耐热性,经一定强度热处理后仍保持强的抑菌能力;抑菌效果在pH3～9 之间无明显差异;用胰蛋白酶、蛋白酶K 等处理后拮抗活性无明显变化。利用PhenylSepharose CL-4B疏水色谱柱和DEAE-Sephacel阴离子交换柱分离B56 菌株初提液, 得到一个具有拮抗活性的洗脱峰。该洗脱峰经SDS-PAGE检测发现具有一条分子量约为36 kD 的蛋白带。质粒提取和检测发现B56菌株存在一个稳定的内源质粒。     

Genetic variability of rhizobacteria from wild populations of four Lupinus species based on PCR-RAPDs§

The metabolic capacities of rhizosphere bacteria can depend on intraspecific genetic variability at strain level. We sampled bacteria from the rhizosphere of three populations of four different Lupinus species at two growth stages (flowering: GS1 and fruiting: GS2). Isolates were identified to the genus level by classical biochemical tests. The most abundant genera found were Bacillus, Aureobacterium, Cellulomonas, Pseudomonas, and Arthrobacter. Genetic divergence of rhizobacteria was tested by PCR-RAPDs. The genetic distances were low, with mean values of 37 % for Bacillus, 25 % for Aureobacterium, 46 % for Cellulomonas, 16 % for Pseudomonas, and 23 % for Arthrobacter. Aureobacterium, the most abundant genus, predominated in the rhizosphere of all populations and at both growth stages (GS1 and GS2) of L. angustifolius. The Aureobacterium strains consisted of 11 groups with 90 % similarity indexes. The cluster analysis of these groups shows that strains isolated from different lupin species and sampling times have extraordinary low diversity indexes, or are even identical. This fact, together with the low genetic distance detected in the rhizosphere, reveals a clear specificity in the plant-bacteria interaction. This specificity could be related with several aspects of plant physiology.     

Ameliorative effects of inoculation with the plant growth-promoting rhizobacterium Pseudomonas sp. DW1 on growth of eggplant (Solanum melongena L.) seedlings under salt stress

The objective of this work was to evaluate the effect of inoculation with the plant growth-promoting rhizobacterium Pseudomonas sp. DW1 on eggplant (Solanum melongena L.) growth, mineral uptake and activities of the antioxidant enzymes including superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) of plant leaves under salinity stress. The study was conducted in pot experiments using eggplant (S. melongena L., cv. Yinjia) and a coastal soil. The NaCl concentration of the coastal soil was 0.57 g (kg soil)⁻¹. Four NaCl levels were tested: 0.57, 1.0, 2.0, and 3.0 g NaCl (kg soil)⁻¹, by adding NaCl to soil, respectively. Pseudomonas-inoculated seeds had an increase in the germination percentage over its non-inoculated seeds under salinity. Salinity negatively affected growth of eggplant; however, plants inoculated with Pseudomonas sp. DW1 grew to a significantly greater extent than plants that were not treated with this bacterium. Salinity significantly decreased K⁺ concentration, increased Na⁺ concentration, and did not significantly decrease Ca²⁺ content in shoots of eggplants. Inoculating with Pseudomonas sp. DW1 increased shoot Ca²⁺ of eggplant compared to the non-inoculating eggplant plants under salinity. Inoculating treatments with Pseudomonas sp. DW1 had no effect on shoot Na⁺ concentration in 0.57 and 1 g (kg soil)⁻¹ NaCl, but there were significant decreases in inoculated treatments than in non-inoculated ones at 2 and 3 g (kg soil)⁻¹ NaCl. Salinity decreased SOD activities and increased POD activities, and inoculated Pseudomonas sp. DW1 had an increase effect on SOD activity in the leaves of eggplants. Alteration of mineral uptake and increase in the antioxidant enzyme activities may be two mechanisms for the alleviation of salt stress. Based on the results of the experiment reported herein, the use of the plant growth-promoting rhizobacterium treatment may provide a means of facilitating plant growth under salt stress.     

Perspectives of Using L-Tryptophan for Improving Productivity of Agricultural Crops: A Review

Plant growth regulators are biologically active signaling molecules that regulate a number of plant physiological processes. Auxin (indole-3-acetic acid) is an important plant growth regulator and is synthesized within plant tissues through L-tryptophan (L-TRP)-dependent and -independent pathways. It has been found that plants respond to exogenously applied L-TRP due to insufficient endogenous auxin biosynthesis. The exogenous application of L-TRP is highly significant for normal plant growth and development. L-tryptophan is applied through foliar spray, seed priming, and soil application. Soil-applied L-TRP is either directly taken up by plants or metabolized to auxin by soil microbiota and then absorbed by plant roots. Similarly, foliar spray and seed priming with L-TRP stimulates auxin synthesis within plants and improves the growth and productivity of agricultural crops. Furthermore, L-TRP contains approximately 14% nitrogen (N) in its composition, which is released upon its metabolism within a plant or in the rhizosphere and plays a role in enhancing crop productivity. This review deals with assessing crop responses under the exogenous application of L-TRP in normal and stressed environments, mode of action of L-TRP, advantages of using L-TRP over other auxin precursors, and role of the simultaneous use of L-TRP and auxin-producing microbes in improving the productivity of agricultural crops. To the best of our knowledge, this is the first review reporting the importance of the use of L-TRP in agriculture.     

18个茶树菇菌株的亲缘关系分析及农艺性状评价

为获得不同来源茶树菇的亲缘关系并筛选适合工厂化生产综合农艺性状较优菌株,以18株(4株野生菌株、7株栽培菌株、5株经钴60辐照诱变菌株和2株搭载神州十号的航天飞船诱变菌株)茶树菇菌株为试验材料,采用分子标记ISSR、拮抗和同工酶技术进行菌株分型和亲缘关系分析;通过分析菌盖厚度和直径、菌柄长度和直径、生育期、产量,对18...